1 /*
2 * Copyright (c) 2008, 2022, 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.value.PrimitiveClass;
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.isObjectConstructor())
82 throw new InternalError(member.toString());
83 Class<?> receiverType = PrimitiveClass.isPrimitiveClass(refc) ? PrimitiveClass.asValueType(refc) : refc;
84 mtype = mtype.insertParameterTypes(0, receiverType);
85 }
86 if (!member.isField()) {
87 // refKind reflects the original type of lookup via findSpecial or
88 // findVirtual etc.
89 return switch (refKind) {
90 case REF_invokeSpecial -> {
91 member = member.asSpecial();
92 // if caller is an interface we need to adapt to get the
93 // receiver check inserted
94 if (callerClass == null) {
95 throw new InternalError("callerClass must not be null for REF_invokeSpecial");
96 }
97 LambdaForm lform = preparedLambdaForm(member, callerClass.isInterface());
98 yield new Special(mtype, lform, member, true, callerClass);
99 }
100 case REF_invokeInterface -> {
101 // for interfaces we always need the receiver typecheck,
102 // so we always pass 'true' to ensure we adapt if needed
103 // to include the REF_invokeSpecial case
104 LambdaForm lform = preparedLambdaForm(member, true);
105 yield new Interface(mtype, lform, member, true, refc);
106 }
107 default -> {
108 LambdaForm lform = preparedLambdaForm(member);
109 yield new DirectMethodHandle(mtype, lform, member, true);
110 }
111 };
112 } else {
113 LambdaForm lform = preparedFieldLambdaForm(member);
114 if (member.isStatic()) {
115 long offset = MethodHandleNatives.staticFieldOffset(member);
116 Object base = MethodHandleNatives.staticFieldBase(member);
117 return new StaticAccessor(mtype, lform, member, true, base, offset);
118 } else {
119 long offset = MethodHandleNatives.objectFieldOffset(member);
120 assert(offset == (int)offset);
121 return new Accessor(mtype, lform, member, true, (int)offset);
122 }
123 }
124 }
125 static DirectMethodHandle make(Class<?> refc, MemberName member) {
126 byte refKind = member.getReferenceKind();
127 if (refKind == REF_invokeSpecial)
128 refKind = REF_invokeVirtual;
129 return make(refKind, refc, member, null /* no callerClass context */);
130 }
131 static DirectMethodHandle make(MemberName member) {
132 if (member.isObjectConstructor() && member.getMethodType().returnType() == void.class)
133 return makeAllocator(member);
134 return make(member.getDeclaringClass(), member);
135 }
136 private static DirectMethodHandle makeAllocator(MemberName ctor) {
137 assert(ctor.isObjectConstructor() && !ctor.getDeclaringClass().isValue()) : ctor;
138
139 Class<?> instanceClass = ctor.getDeclaringClass();
140 ctor = ctor.asObjectConstructor();
141 assert(ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
142 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
143 LambdaForm lform = preparedLambdaForm(ctor);
144 MemberName init = ctor.asSpecial();
145 assert(init.getMethodType().returnType() == void.class);
146 return new Constructor(mtype, lform, ctor, true, init, instanceClass);
147 }
148
149 @Override
150 BoundMethodHandle rebind() {
151 return BoundMethodHandle.makeReinvoker(this);
152 }
153
154 @Override
155 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
156 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
157 return new DirectMethodHandle(mt, lf, member, crackable);
158 }
159
160 @Override
161 MethodHandle viewAsType(MethodType newType, boolean strict) {
162 // No actual conversions, just a new view of the same method.
163 // However, we must not expose a DMH that is crackable into a
164 // MethodHandleInfo, so we return a cloned, uncrackable DMH
165 assert(viewAsTypeChecks(newType, strict));
166 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
167 return new DirectMethodHandle(newType, form, member, false);
168 }
169
170 @Override
171 boolean isCrackable() {
172 return crackable;
173 }
174
175 @Override
176 String internalProperties(int indentLevel) {
177 return "\n" + debugPrefix(indentLevel) + "& DMH.MN=" + internalMemberName();
178 }
179
180 //// Implementation methods.
181 @Override
182 @ForceInline
183 MemberName internalMemberName() {
184 return member;
185 }
186
187 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
188
189 /**
190 * Create a LF which can invoke the given method.
191 * Cache and share this structure among all methods with
192 * the same basicType and refKind.
193 */
194 private static LambdaForm preparedLambdaForm(MemberName m, boolean adaptToSpecialIfc) {
195 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
196 MethodType mtype = m.getInvocationType().basicType();
197 assert(!m.isMethodHandleInvoke()) : m;
198 // MemberName.getReferenceKind represents the JVM optimized form of the call
199 // as distinct from the "kind" passed to DMH.make which represents the original
200 // bytecode-equivalent request. Specifically private/final methods that use a direct
201 // call have getReferenceKind adapted to REF_invokeSpecial, even though the actual
202 // invocation mode may be invokevirtual or invokeinterface.
203 int which = switch (m.getReferenceKind()) {
204 case REF_invokeVirtual -> LF_INVVIRTUAL;
205 case REF_invokeStatic -> LF_INVSTATIC;
206 case REF_invokeSpecial -> LF_INVSPECIAL;
207 case REF_invokeInterface -> LF_INVINTERFACE;
208 case REF_newInvokeSpecial -> LF_NEWINVSPECIAL;
209 default -> throw new InternalError(m.toString());
210 };
211 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
212 // precompute the barrier-free version:
213 preparedLambdaForm(mtype, which);
214 which = LF_INVSTATIC_INIT;
215 }
216 if (which == LF_INVSPECIAL && adaptToSpecialIfc) {
217 which = LF_INVSPECIAL_IFC;
218 }
219 LambdaForm lform = preparedLambdaForm(mtype, which);
220 maybeCompile(lform, m);
221 assert(lform.methodType().dropParameterTypes(0, 1)
222 .equals(m.getInvocationType().basicType()))
223 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
224 return lform;
225 }
226
227 private static LambdaForm preparedLambdaForm(MemberName m) {
228 return preparedLambdaForm(m, false);
229 }
230
231 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
232 LambdaForm lform = mtype.form().cachedLambdaForm(which);
233 if (lform != null) return lform;
234 lform = makePreparedLambdaForm(mtype, which);
235 return mtype.form().setCachedLambdaForm(which, lform);
236 }
237
238 static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
239 boolean needsInit = (which == LF_INVSTATIC_INIT);
240 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
241 boolean needsReceiverCheck = (which == LF_INVINTERFACE ||
242 which == LF_INVSPECIAL_IFC);
243
244 String linkerName;
245 LambdaForm.Kind kind;
246 switch (which) {
247 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; kind = DIRECT_INVOKE_VIRTUAL; break;
248 case LF_INVSTATIC: linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC; break;
249 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; kind = DIRECT_INVOKE_STATIC_INIT; break;
250 case LF_INVSPECIAL_IFC:linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL_IFC; break;
251 case LF_INVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_INVOKE_SPECIAL; break;
252 case LF_INVINTERFACE: linkerName = "linkToInterface"; kind = DIRECT_INVOKE_INTERFACE; break;
253 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; kind = DIRECT_NEW_INVOKE_SPECIAL; break;
254 default: throw new InternalError("which="+which);
255 }
256
257 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
258 if (doesAlloc)
259 mtypeWithArg = mtypeWithArg
260 .insertParameterTypes(0, Object.class) // insert newly allocated obj
261 .changeReturnType(void.class); // <init> returns void
262 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
263 try {
264 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, LM_TRUSTED,
265 NoSuchMethodException.class);
266 } catch (ReflectiveOperationException ex) {
267 throw newInternalError(ex);
268 }
269 final int DMH_THIS = 0;
270 final int ARG_BASE = 1;
271 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
272 int nameCursor = ARG_LIMIT;
273 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
274 final int GET_MEMBER = nameCursor++;
275 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
276 final int LINKER_CALL = nameCursor++;
277 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
278 assert(names.length == nameCursor);
279 if (doesAlloc) {
280 // names = { argx,y,z,... new C, init method }
281 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
282 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
283 } else if (needsInit) {
284 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
285 } else {
286 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
287 }
288 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
289 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
290 if (needsReceiverCheck) {
291 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
292 outArgs[0] = names[CHECK_RECEIVER];
293 }
294 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
295 int result = LAST_RESULT;
296 if (doesAlloc) {
297 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
298 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
299 outArgs[0] = names[NEW_OBJ];
300 result = NEW_OBJ;
301 }
302 names[LINKER_CALL] = new Name(linker, outArgs);
303 LambdaForm lform = LambdaForm.create(ARG_LIMIT, names, result, kind);
304
305 // This is a tricky bit of code. Don't send it through the LF interpreter.
306 lform.compileToBytecode();
307 return lform;
308 }
309
310 /* assert */ static Object findDirectMethodHandle(Name name) {
311 if (name.function.equals(getFunction(NF_internalMemberName)) ||
312 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) ||
313 name.function.equals(getFunction(NF_constructorMethod))) {
314 assert(name.arguments.length == 1);
315 return name.arguments[0];
316 }
317 return null;
318 }
319
320 private static void maybeCompile(LambdaForm lform, MemberName m) {
321 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
322 // Help along bootstrapping...
323 lform.compileToBytecode();
324 }
325
326 /** Static wrapper for DirectMethodHandle.internalMemberName. */
327 @ForceInline
328 /*non-public*/
329 static Object internalMemberName(Object mh) {
330 return ((DirectMethodHandle)mh).member;
331 }
332
333 /** Static wrapper for DirectMethodHandle.internalMemberName.
334 * This one also forces initialization.
335 */
336 /*non-public*/
337 static Object internalMemberNameEnsureInit(Object mh) {
338 DirectMethodHandle dmh = (DirectMethodHandle)mh;
339 dmh.ensureInitialized();
340 return dmh.member;
341 }
342
343 /*non-public*/
344 static boolean shouldBeInitialized(MemberName member) {
345 switch (member.getReferenceKind()) {
346 case REF_invokeStatic:
347 case REF_getStatic:
348 case REF_putStatic:
349 case REF_newInvokeSpecial:
350 break;
351 default:
352 // No need to initialize the class on this kind of member.
353 return false;
354 }
355 Class<?> cls = member.getDeclaringClass();
356 if (cls == ValueConversions.class ||
357 cls == MethodHandleImpl.class ||
358 cls == Invokers.class) {
359 // These guys have lots of <clinit> DMH creation but we know
360 // the MHs will not be used until the system is booted.
361 return false;
362 }
363 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
364 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
365 // It is a system class. It is probably in the process of
366 // being initialized, but we will help it along just to be safe.
367 UNSAFE.ensureClassInitialized(cls);
368 return false;
369 }
370 return UNSAFE.shouldBeInitialized(cls);
371 }
372
373 private void ensureInitialized() {
374 if (checkInitialized(member)) {
375 // The coast is clear. Delete the <clinit> barrier.
376 updateForm(new Function<>() {
377 public LambdaForm apply(LambdaForm oldForm) {
378 return (member.isField() ? preparedFieldLambdaForm(member)
379 : preparedLambdaForm(member));
380 }
381 });
382 }
383 }
384 private static boolean checkInitialized(MemberName member) {
385 Class<?> defc = member.getDeclaringClass();
386 UNSAFE.ensureClassInitialized(defc);
387 // Once we get here either defc was fully initialized by another thread, or
388 // defc was already being initialized by the current thread. In the latter case
389 // the barrier must remain. We can detect this simply by checking if initialization
390 // is still needed.
391 return !UNSAFE.shouldBeInitialized(defc);
392 }
393
394 /*non-public*/
395 static void ensureInitialized(Object mh) {
396 ((DirectMethodHandle)mh).ensureInitialized();
397 }
398
399 /** This subclass represents invokespecial instructions. */
400 static final class Special extends DirectMethodHandle {
401 private final Class<?> caller;
402 private Special(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> caller) {
403 super(mtype, form, member, crackable);
404 this.caller = caller;
405 }
406 @Override
407 boolean isInvokeSpecial() {
408 return true;
409 }
410 @Override
411 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
412 return new Special(mt, lf, member, crackable, caller);
413 }
414 @Override
415 MethodHandle viewAsType(MethodType newType, boolean strict) {
416 assert(viewAsTypeChecks(newType, strict));
417 return new Special(newType, form, member, false, caller);
418 }
419 Object checkReceiver(Object recv) {
420 if (!caller.isInstance(recv)) {
421 if (recv != null) {
422 String msg = String.format("Receiver class %s is not a subclass of caller class %s",
423 recv.getClass().getName(), caller.getName());
424 throw new IncompatibleClassChangeError(msg);
425 } else {
426 String msg = String.format("Cannot invoke %s with null receiver", member);
427 throw new NullPointerException(msg);
428 }
429 }
430 return recv;
431 }
432 }
433
434 /** This subclass represents invokeinterface instructions. */
435 static final class Interface extends DirectMethodHandle {
436 private final Class<?> refc;
437 private Interface(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> refc) {
438 super(mtype, form, member, crackable);
439 assert(refc.isInterface()) : refc;
440 this.refc = refc;
441 }
442 @Override
443 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
444 return new Interface(mt, lf, member, crackable, refc);
445 }
446 @Override
447 MethodHandle viewAsType(MethodType newType, boolean strict) {
448 assert(viewAsTypeChecks(newType, strict));
449 return new Interface(newType, form, member, false, refc);
450 }
451 @Override
452 Object checkReceiver(Object recv) {
453 if (!refc.isInstance(recv)) {
454 if (recv != null) {
455 String msg = String.format("Receiver class %s does not implement the requested interface %s",
456 recv.getClass().getName(), refc.getName());
457 throw new IncompatibleClassChangeError(msg);
458 } else {
459 String msg = String.format("Cannot invoke %s with null receiver", member);
460 throw new NullPointerException(msg);
461 }
462 }
463 return recv;
464 }
465 }
466
467 /** Used for interface receiver type checks, by Interface and Special modes. */
468 Object checkReceiver(Object recv) {
469 throw new InternalError("Should only be invoked on a subclass");
470 }
471
472 /** This subclass handles constructor references. */
473 static final class Constructor extends DirectMethodHandle {
474 final MemberName initMethod;
475 final Class<?> instanceClass;
476
477 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
478 boolean crackable, MemberName initMethod, Class<?> instanceClass) {
479 super(mtype, form, constructor, crackable);
480 this.initMethod = initMethod;
481 this.instanceClass = instanceClass;
482 assert(initMethod.isResolved());
483 }
484 @Override
485 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
486 return new Constructor(mt, lf, member, crackable, initMethod, instanceClass);
487 }
488 @Override
489 MethodHandle viewAsType(MethodType newType, boolean strict) {
490 assert(viewAsTypeChecks(newType, strict));
491 return new Constructor(newType, form, member, false, initMethod, instanceClass);
492 }
493 }
494
495 /*non-public*/
496 static Object constructorMethod(Object mh) {
497 Constructor dmh = (Constructor)mh;
498 return dmh.initMethod;
499 }
500
501 /*non-public*/
502 static Object allocateInstance(Object mh) throws InstantiationException {
503 Constructor dmh = (Constructor)mh;
504 return UNSAFE.allocateInstance(dmh.instanceClass);
505 }
506
507 /** This subclass handles non-static field references. */
508 static final class Accessor extends DirectMethodHandle {
509 final Class<?> fieldType;
510 final int fieldOffset;
511 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
512 boolean crackable, int fieldOffset) {
513 super(mtype, form, member, crackable);
514 this.fieldType = member.getFieldType();
515 this.fieldOffset = fieldOffset;
516 }
517
518 @Override Object checkCast(Object obj) {
519 return fieldType.cast(obj);
520 }
521 @Override
522 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
523 return new Accessor(mt, lf, member, crackable, fieldOffset);
524 }
525 @Override
526 MethodHandle viewAsType(MethodType newType, boolean strict) {
527 assert(viewAsTypeChecks(newType, strict));
528 return new Accessor(newType, form, member, false, fieldOffset);
529 }
530 }
531
532 @ForceInline
533 /*non-public*/
534 static long fieldOffset(Object accessorObj) {
535 // Note: We return a long because that is what Unsafe.getObject likes.
536 // We store a plain int because it is more compact.
537 return ((Accessor)accessorObj).fieldOffset;
538 }
539
540 @ForceInline
541 /*non-public*/
542 static Object checkBase(Object obj) {
543 // Note that the object's class has already been verified,
544 // since the parameter type of the Accessor method handle
545 // is either member.getDeclaringClass or a subclass.
546 // This was verified in DirectMethodHandle.make.
547 // Therefore, the only remaining check is for null.
548 // Since this check is *not* guaranteed by Unsafe.getInt
549 // and its siblings, we need to make an explicit one here.
550 return Objects.requireNonNull(obj);
551 }
552
553 /** This subclass handles static field references. */
554 static final class StaticAccessor extends DirectMethodHandle {
555 final Class<?> fieldType;
556 final Object staticBase;
557 final long staticOffset;
558
559 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
560 boolean crackable, Object staticBase, long staticOffset) {
561 super(mtype, form, member, crackable);
562 this.fieldType = member.getFieldType();
563 this.staticBase = staticBase;
564 this.staticOffset = staticOffset;
565 }
566
567 @Override Object checkCast(Object obj) {
568 return fieldType.cast(obj);
569 }
570 @Override
571 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
572 return new StaticAccessor(mt, lf, member, crackable, staticBase, staticOffset);
573 }
574 @Override
575 MethodHandle viewAsType(MethodType newType, boolean strict) {
576 assert(viewAsTypeChecks(newType, strict));
577 return new StaticAccessor(newType, form, member, false, staticBase, staticOffset);
578 }
579 }
580
581 @ForceInline
582 /*non-public*/
583 static Object nullCheck(Object obj) {
584 return Objects.requireNonNull(obj);
585 }
586
587 @ForceInline
588 /*non-public*/
589 static Object staticBase(Object accessorObj) {
590 return ((StaticAccessor)accessorObj).staticBase;
591 }
592
593 @ForceInline
594 /*non-public*/
595 static long staticOffset(Object accessorObj) {
596 return ((StaticAccessor)accessorObj).staticOffset;
597 }
598
599 @ForceInline
600 /*non-public*/
601 static Object checkCast(Object mh, Object obj) {
602 return ((DirectMethodHandle) mh).checkCast(obj);
603 }
604
605 @ForceInline
606 /*non-public*/ static Class<?> fieldType(Object accessorObj) {
607 return ((Accessor) accessorObj).fieldType;
608 }
609
610 @ForceInline
611 /*non-public*/ static Class<?> staticFieldType(Object accessorObj) {
612 return ((StaticAccessor) accessorObj).fieldType;
613 }
614
615 Object checkCast(Object obj) {
616 return member.getMethodType().returnType().cast(obj);
617 }
618
619 // Caching machinery for field accessors:
620 static final byte
621 AF_GETFIELD = 0,
622 AF_PUTFIELD = 1,
623 AF_GETSTATIC = 2,
624 AF_PUTSTATIC = 3,
625 AF_GETSTATIC_INIT = 4,
626 AF_PUTSTATIC_INIT = 5,
627 AF_LIMIT = 6;
628 // Enumerate the different field kinds using Wrapper,
629 // with an extra case added for checked references and value field access
630 static final int
631 FT_LAST_WRAPPER = Wrapper.COUNT-1,
632 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
633 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
634 FT_CHECKED_VALUE = FT_LAST_WRAPPER+2, // flattened and non-flattened
635 FT_LIMIT = FT_LAST_WRAPPER+4;
636 private static int afIndex(byte formOp, boolean isVolatile, boolean isFlatValue, int ftypeKind) {
637 return ((formOp * FT_LIMIT * 2)
638 + (isVolatile ? FT_LIMIT : 0)
639 + (isFlatValue ? 1 : 0)
640 + ftypeKind);
641 }
642 @Stable
643 private static final LambdaForm[] ACCESSOR_FORMS
644 = new LambdaForm[afIndex(AF_LIMIT, false, false, 0)];
645 static int ftypeKind(Class<?> ftype, boolean isValue) {
646 if (ftype.isPrimitive()) {
647 return Wrapper.forPrimitiveType(ftype).ordinal();
648 } else if (ftype.isInterface() || ftype.isAssignableFrom(Object.class)) {
649 // retyping can be done without a cast
650 return FT_UNCHECKED_REF;
651 } else {
652 // null check for value type in addition to check cast
653 return isValue ? FT_CHECKED_VALUE : FT_CHECKED_REF;
654 }
655 }
656
657 /**
658 * Create a LF which can access the given field.
659 * Cache and share this structure among all fields with
660 * the same basicType and refKind.
661 */
662 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
663 Class<?> ftype = m.getFieldType();
664 boolean isVolatile = m.isVolatile();
665 byte formOp = switch (m.getReferenceKind()) {
666 case REF_getField -> AF_GETFIELD;
667 case REF_putField -> AF_PUTFIELD;
668 case REF_getStatic -> AF_GETSTATIC;
669 case REF_putStatic -> AF_PUTSTATIC;
670 default -> throw new InternalError(m.toString());
671 };
672 if (shouldBeInitialized(m)) {
673 // precompute the barrier-free version:
674 preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineableField(), m.isFlattened(), ftype);
675 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
676 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
677 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
678 }
679 LambdaForm lform = preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineableField(), m.isFlattened(), ftype);
680 maybeCompile(lform, m);
681 assert(lform.methodType().dropParameterTypes(0, 1)
682 .equals(m.getInvocationType().basicType()))
683 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
684 return lform;
685 }
686
687 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, Class<?> ftype) {
688 int ftypeKind = ftypeKind(ftype, isValue);
689 int afIndex = afIndex(formOp, isVolatile, isFlatValue, ftypeKind);
690 LambdaForm lform = ACCESSOR_FORMS[afIndex];
691 if (lform != null) return lform;
692 lform = makePreparedFieldLambdaForm(formOp, isVolatile, isValue, isFlatValue, ftypeKind);
693 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
694 return lform;
695 }
696
697 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
698
699 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, boolean isFlatValue, Wrapper wrapper) {
700 if (isGetter) {
701 if (isVolatile) {
702 switch (wrapper) {
703 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
704 case BYTE: return GET_BYTE_VOLATILE;
705 case SHORT: return GET_SHORT_VOLATILE;
706 case CHAR: return GET_CHAR_VOLATILE;
707 case INT: return GET_INT_VOLATILE;
708 case LONG: return GET_LONG_VOLATILE;
709 case FLOAT: return GET_FLOAT_VOLATILE;
710 case DOUBLE: return GET_DOUBLE_VOLATILE;
711 case OBJECT: return isFlatValue ? GET_VALUE_VOLATILE : GET_REFERENCE_VOLATILE;
712 }
713 } else {
714 switch (wrapper) {
715 case BOOLEAN: return GET_BOOLEAN;
716 case BYTE: return GET_BYTE;
717 case SHORT: return GET_SHORT;
718 case CHAR: return GET_CHAR;
719 case INT: return GET_INT;
720 case LONG: return GET_LONG;
721 case FLOAT: return GET_FLOAT;
722 case DOUBLE: return GET_DOUBLE;
723 case OBJECT: return isFlatValue ? GET_VALUE : GET_REFERENCE;
724 }
725 }
726 } else {
727 if (isVolatile) {
728 switch (wrapper) {
729 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
730 case BYTE: return PUT_BYTE_VOLATILE;
731 case SHORT: return PUT_SHORT_VOLATILE;
732 case CHAR: return PUT_CHAR_VOLATILE;
733 case INT: return PUT_INT_VOLATILE;
734 case LONG: return PUT_LONG_VOLATILE;
735 case FLOAT: return PUT_FLOAT_VOLATILE;
736 case DOUBLE: return PUT_DOUBLE_VOLATILE;
737 case OBJECT: return isFlatValue ? PUT_VALUE_VOLATILE : PUT_REFERENCE_VOLATILE;
738 }
739 } else {
740 switch (wrapper) {
741 case BOOLEAN: return PUT_BOOLEAN;
742 case BYTE: return PUT_BYTE;
743 case SHORT: return PUT_SHORT;
744 case CHAR: return PUT_CHAR;
745 case INT: return PUT_INT;
746 case LONG: return PUT_LONG;
747 case FLOAT: return PUT_FLOAT;
748 case DOUBLE: return PUT_DOUBLE;
749 case OBJECT: return isFlatValue ? PUT_VALUE : PUT_REFERENCE;
750 }
751 }
752 }
753 throw new AssertionError("Invalid arguments");
754 }
755
756 /** invoked by GenerateJLIClassesHelper */
757 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftype) {
758 return makePreparedFieldLambdaForm(formOp, isVolatile, false, false, ftype);
759 }
760
761 private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, int ftypeKind) {
762 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
763 boolean isStatic = (formOp >= AF_GETSTATIC);
764 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
765 boolean needsCast = (ftypeKind == FT_CHECKED_REF || ftypeKind == FT_CHECKED_VALUE);
766 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
767 Class<?> ft = fw.primitiveType();
768 assert(needsCast ? true : ftypeKind(ft, isValue) == ftypeKind);
769
770 // getObject, putIntVolatile, etc.
771 Kind kind = getFieldKind(isGetter, isVolatile, isFlatValue, fw);
772
773 MethodType linkerType;
774 boolean hasValueTypeArg = isGetter ? isValue : isFlatValue;
775 if (isGetter) {
776 linkerType = isValue ? MethodType.methodType(ft, Object.class, long.class, Class.class)
777 : MethodType.methodType(ft, Object.class, long.class);
778 } else {
779 linkerType = isFlatValue ? MethodType.methodType(void.class, Object.class, long.class, Class.class, ft)
780 : MethodType.methodType(void.class, Object.class, long.class, ft);
781 }
782 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
783 try {
784 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED,
785 NoSuchMethodException.class);
786 } catch (ReflectiveOperationException ex) {
787 throw newInternalError(ex);
788 }
789
790 // What is the external type of the lambda form?
791 MethodType mtype;
792 if (isGetter)
793 mtype = MethodType.methodType(ft);
794 else
795 mtype = MethodType.methodType(void.class, ft);
796 mtype = mtype.basicType(); // erase short to int, etc.
797 if (!isStatic)
798 mtype = mtype.insertParameterTypes(0, Object.class);
799 final int DMH_THIS = 0;
800 final int ARG_BASE = 1;
801 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
802 // if this is for non-static access, the base pointer is stored at this index:
803 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
804 // if this is for write access, the value to be written is stored at this index:
805 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
806 int nameCursor = ARG_LIMIT;
807 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
808 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
809 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
810 final int U_HOLDER = nameCursor++; // UNSAFE holder
811 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
812 final int VALUE_TYPE = (hasValueTypeArg ? nameCursor++ : -1);
813 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
814 final int LINKER_CALL = nameCursor++;
815 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
816 final int RESULT = nameCursor-1; // either the call or the cast
817 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
818 if (needsInit)
819 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
820 if (needsCast && !isGetter)
821 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
822 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
823 assert (outArgs.length == (isGetter ? 3 : 4) + (hasValueTypeArg ? 1 : 0));
824 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
825 if (isStatic) {
826 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
827 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
828 } else {
829 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
830 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
831 }
832 int x = 3;
833 if (hasValueTypeArg) {
834 outArgs[x++] = names[VALUE_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldType), names[DMH_THIS])
835 : new Name(getFunction(NF_fieldType), names[DMH_THIS]);
836 }
837 if (!isGetter) {
838 outArgs[x] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
839 }
840 for (Object a : outArgs) assert(a != null);
841 names[LINKER_CALL] = new Name(linker, outArgs);
842 if (needsCast && isGetter)
843 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
844 for (Name n : names) assert(n != null);
845
846 LambdaForm form;
847 if (needsCast || needsInit) {
848 // can't use the pre-generated form when casting and/or initializing
849 form = LambdaForm.create(ARG_LIMIT, names, RESULT);
850 } else {
851 form = LambdaForm.create(ARG_LIMIT, names, RESULT, kind);
852 }
853
854 if (LambdaForm.debugNames()) {
855 // add some detail to the lambdaForm debugname,
856 // significant only for debugging
857 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
858 if (isStatic) {
859 nameBuilder.append("Static");
860 } else {
861 nameBuilder.append("Field");
862 }
863 if (needsCast) {
864 nameBuilder.append("Cast");
865 }
866 if (needsInit) {
867 nameBuilder.append("Init");
868 }
869 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
870 }
871 return form;
872 }
873
874 /**
875 * Pre-initialized NamedFunctions for bootstrapping purposes.
876 */
877 static final byte NF_internalMemberName = 0,
878 NF_internalMemberNameEnsureInit = 1,
879 NF_ensureInitialized = 2,
880 NF_fieldOffset = 3,
881 NF_checkBase = 4,
882 NF_staticBase = 5,
883 NF_staticOffset = 6,
884 NF_checkCast = 7,
885 NF_allocateInstance = 8,
886 NF_constructorMethod = 9,
887 NF_UNSAFE = 10,
888 NF_checkReceiver = 11,
889 NF_fieldType = 12,
890 NF_staticFieldType = 13,
891 NF_LIMIT = 14;
892
893 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
894
895 private static NamedFunction getFunction(byte func) {
896 NamedFunction nf = NFS[func];
897 if (nf != null) {
898 return nf;
899 }
900 // Each nf must be statically invocable or we get tied up in our bootstraps.
901 nf = NFS[func] = createFunction(func);
902 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
903 return nf;
904 }
905
906 private static final MethodType CLS_OBJ_TYPE = MethodType.methodType(Class.class, Object.class);
907
908 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
909
910 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
911
912 private static NamedFunction createFunction(byte func) {
913 try {
914 switch (func) {
915 case NF_internalMemberName:
916 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
917 case NF_internalMemberNameEnsureInit:
918 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
919 case NF_ensureInitialized:
920 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
921 case NF_fieldOffset:
922 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
923 case NF_checkBase:
924 return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
925 case NF_staticBase:
926 return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
927 case NF_staticOffset:
928 return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
929 case NF_checkCast:
930 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
931 case NF_allocateInstance:
932 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
933 case NF_constructorMethod:
934 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
935 case NF_UNSAFE:
936 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getStatic);
937 return new NamedFunction(
938 MemberName.getFactory().resolveOrFail(REF_getStatic, member,
939 DirectMethodHandle.class, LM_TRUSTED,
940 NoSuchFieldException.class));
941 case NF_checkReceiver:
942 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
943 return new NamedFunction(
944 MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member,
945 DirectMethodHandle.class, LM_TRUSTED,
946 NoSuchMethodException.class));
947 case NF_fieldType:
948 return getNamedFunction("fieldType", CLS_OBJ_TYPE);
949 case NF_staticFieldType:
950 return getNamedFunction("staticFieldType", CLS_OBJ_TYPE);
951 default:
952 throw newInternalError("Unknown function: " + func);
953 }
954 } catch (ReflectiveOperationException ex) {
955 throw newInternalError(ex);
956 }
957 }
958
959 private static NamedFunction getNamedFunction(String name, MethodType type)
960 throws ReflectiveOperationException
961 {
962 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
963 return new NamedFunction(
964 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member,
965 DirectMethodHandle.class, LM_TRUSTED,
966 NoSuchMethodException.class));
967 }
968
969 static {
970 // The Holder class will contain pre-generated DirectMethodHandles resolved
971 // speculatively using MemberName.getFactory().resolveOrNull. However, that
972 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
973 // initialization of the Holder class we avoid these issues.
974 UNSAFE.ensureClassInitialized(Holder.class);
975 }
976
977 /* Placeholder class for DirectMethodHandles generated ahead of time */
978 final class Holder {}
979 }