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.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);
132 return make(member.getDeclaringClass(), member);
133 }
134 private static DirectMethodHandle makeAllocator(MemberName ctor) {
135 assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
136 Class<?> instanceClass = ctor.getDeclaringClass();
137 ctor = ctor.asConstructor();
138 assert(ctor.isConstructor() && 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 = mtype.appendParameterTypes(MemberName.class);
255 if (doesAlloc)
256 mtypeWithArg = mtypeWithArg
257 .insertParameterTypes(0, Object.class) // insert newly allocated obj
258 .changeReturnType(void.class); // <init> returns void
259 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
260 try {
261 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, LM_TRUSTED,
262 NoSuchMethodException.class);
263 } catch (ReflectiveOperationException ex) {
264 throw newInternalError(ex);
265 }
266 final int DMH_THIS = 0;
267 final int ARG_BASE = 1;
268 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
269 int nameCursor = ARG_LIMIT;
270 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
271 final int GET_MEMBER = nameCursor++;
272 final int CHECK_RECEIVER = (needsReceiverCheck ? nameCursor++ : -1);
273 final int LINKER_CALL = nameCursor++;
274 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
275 assert(names.length == nameCursor);
276 if (doesAlloc) {
277 // names = { argx,y,z,... new C, init method }
278 names[NEW_OBJ] = new Name(getFunction(NF_allocateInstance), names[DMH_THIS]);
279 names[GET_MEMBER] = new Name(getFunction(NF_constructorMethod), names[DMH_THIS]);
280 } else if (needsInit) {
281 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberNameEnsureInit), names[DMH_THIS]);
282 } else {
283 names[GET_MEMBER] = new Name(getFunction(NF_internalMemberName), names[DMH_THIS]);
284 }
285 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
286 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
287 if (needsReceiverCheck) {
288 names[CHECK_RECEIVER] = new Name(getFunction(NF_checkReceiver), names[DMH_THIS], names[ARG_BASE]);
289 outArgs[0] = names[CHECK_RECEIVER];
290 }
291 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
292 int result = LAST_RESULT;
293 if (doesAlloc) {
294 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
295 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
296 outArgs[0] = names[NEW_OBJ];
297 result = NEW_OBJ;
298 }
299 names[LINKER_CALL] = new Name(linker, outArgs);
300 LambdaForm lform = LambdaForm.create(ARG_LIMIT, names, result, kind);
301
302 // This is a tricky bit of code. Don't send it through the LF interpreter.
303 lform.compileToBytecode();
304 return lform;
305 }
306
307 /* assert */ static Object findDirectMethodHandle(Name name) {
308 if (name.function.equals(getFunction(NF_internalMemberName)) ||
309 name.function.equals(getFunction(NF_internalMemberNameEnsureInit)) ||
310 name.function.equals(getFunction(NF_constructorMethod))) {
311 assert(name.arguments.length == 1);
312 return name.arguments[0];
313 }
314 return null;
315 }
316
317 private static void maybeCompile(LambdaForm lform, MemberName m) {
318 if (lform.vmentry == null && VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
319 // Help along bootstrapping...
320 lform.compileToBytecode();
321 }
322
323 /** Static wrapper for DirectMethodHandle.internalMemberName. */
324 @ForceInline
325 /*non-public*/
326 static Object internalMemberName(Object mh) {
327 return ((DirectMethodHandle)mh).member;
328 }
329
330 /** Static wrapper for DirectMethodHandle.internalMemberName.
331 * This one also forces initialization.
332 */
333 /*non-public*/
334 static Object internalMemberNameEnsureInit(Object mh) {
335 DirectMethodHandle dmh = (DirectMethodHandle)mh;
336 dmh.ensureInitialized();
337 return dmh.member;
338 }
339
340 /*non-public*/
341 static boolean shouldBeInitialized(MemberName member) {
342 switch (member.getReferenceKind()) {
343 case REF_invokeStatic:
344 case REF_getStatic:
345 case REF_putStatic:
346 case REF_newInvokeSpecial:
347 break;
348 default:
349 // No need to initialize the class on this kind of member.
350 return false;
351 }
352 Class<?> cls = member.getDeclaringClass();
353 if (cls == ValueConversions.class ||
354 cls == MethodHandleImpl.class ||
355 cls == Invokers.class) {
356 // These guys have lots of <clinit> DMH creation but we know
357 // the MHs will not be used until the system is booted.
358 return false;
359 }
360 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
361 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
362 // It is a system class. It is probably in the process of
363 // being initialized, but we will help it along just to be safe.
364 UNSAFE.ensureClassInitialized(cls);
365 return false;
366 }
367 return UNSAFE.shouldBeInitialized(cls);
368 }
369
370 private void ensureInitialized() {
371 if (checkInitialized(member)) {
372 // The coast is clear. Delete the <clinit> barrier.
373 updateForm(new Function<>() {
374 public LambdaForm apply(LambdaForm oldForm) {
375 return (member.isField() ? preparedFieldLambdaForm(member)
376 : preparedLambdaForm(member));
377 }
378 });
379 }
380 }
381 private static boolean checkInitialized(MemberName member) {
382 Class<?> defc = member.getDeclaringClass();
383 UNSAFE.ensureClassInitialized(defc);
384 // Once we get here either defc was fully initialized by another thread, or
385 // defc was already being initialized by the current thread. In the latter case
386 // the barrier must remain. We can detect this simply by checking if initialization
387 // is still needed.
388 return !UNSAFE.shouldBeInitialized(defc);
389 }
390
391 /*non-public*/
392 static void ensureInitialized(Object mh) {
393 ((DirectMethodHandle)mh).ensureInitialized();
394 }
395
396 /** This subclass represents invokespecial instructions. */
397 static final class Special extends DirectMethodHandle {
398 private final Class<?> caller;
399 private Special(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> caller) {
400 super(mtype, form, member, crackable);
401 this.caller = caller;
402 }
403 @Override
404 boolean isInvokeSpecial() {
405 return true;
406 }
407 @Override
408 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
409 return new Special(mt, lf, member, crackable, caller);
410 }
411 @Override
412 MethodHandle viewAsType(MethodType newType, boolean strict) {
413 assert(viewAsTypeChecks(newType, strict));
414 return new Special(newType, form, member, false, caller);
415 }
416 Object checkReceiver(Object recv) {
417 if (!caller.isInstance(recv)) {
418 if (recv != null) {
419 String msg = String.format("Receiver class %s is not a subclass of caller class %s",
420 recv.getClass().getName(), caller.getName());
421 throw new IncompatibleClassChangeError(msg);
422 } else {
423 String msg = String.format("Cannot invoke %s with null receiver", member);
424 throw new NullPointerException(msg);
425 }
426 }
427 return recv;
428 }
429 }
430
431 /** This subclass represents invokeinterface instructions. */
432 static final class Interface extends DirectMethodHandle {
433 private final Class<?> refc;
434 private Interface(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> refc) {
435 super(mtype, form, member, crackable);
436 assert(refc.isInterface()) : refc;
437 this.refc = refc;
438 }
439 @Override
440 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
441 return new Interface(mt, lf, member, crackable, refc);
442 }
443 @Override
444 MethodHandle viewAsType(MethodType newType, boolean strict) {
445 assert(viewAsTypeChecks(newType, strict));
446 return new Interface(newType, form, member, false, refc);
447 }
448 @Override
449 Object checkReceiver(Object recv) {
450 if (!refc.isInstance(recv)) {
451 if (recv != null) {
452 String msg = String.format("Receiver class %s does not implement the requested interface %s",
453 recv.getClass().getName(), refc.getName());
454 throw new IncompatibleClassChangeError(msg);
455 } else {
456 String msg = String.format("Cannot invoke %s with null receiver", member);
457 throw new NullPointerException(msg);
458 }
459 }
460 return recv;
461 }
462 }
463
464 /** Used for interface receiver type checks, by Interface and Special modes. */
465 Object checkReceiver(Object recv) {
466 throw new InternalError("Should only be invoked on a subclass");
467 }
468
469 /** This subclass handles constructor references. */
470 static final class Constructor extends DirectMethodHandle {
471 final MemberName initMethod;
472 final Class<?> instanceClass;
473
474 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
475 boolean crackable, MemberName initMethod, Class<?> instanceClass) {
476 super(mtype, form, constructor, crackable);
477 this.initMethod = initMethod;
478 this.instanceClass = instanceClass;
479 assert(initMethod.isResolved());
480 }
481 @Override
482 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
483 return new Constructor(mt, lf, member, crackable, initMethod, instanceClass);
484 }
485 @Override
486 MethodHandle viewAsType(MethodType newType, boolean strict) {
487 assert(viewAsTypeChecks(newType, strict));
488 return new Constructor(newType, form, member, false, initMethod, instanceClass);
489 }
490 }
491
492 /*non-public*/
493 static Object constructorMethod(Object mh) {
494 Constructor dmh = (Constructor)mh;
495 return dmh.initMethod;
496 }
497
498 /*non-public*/
499 static Object allocateInstance(Object mh) throws InstantiationException {
500 Constructor dmh = (Constructor)mh;
501 return UNSAFE.allocateInstance(dmh.instanceClass);
502 }
503
504 /** This subclass handles non-static field references. */
505 static final class Accessor extends DirectMethodHandle {
506 final Class<?> fieldType;
507 final int fieldOffset;
508 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
509 boolean crackable, int fieldOffset) {
510 super(mtype, form, member, crackable);
511 this.fieldType = member.getFieldType();
512 this.fieldOffset = fieldOffset;
513 }
514
515 @Override Object checkCast(Object obj) {
516 return fieldType.cast(obj);
517 }
518 @Override
519 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
520 return new Accessor(mt, lf, member, crackable, fieldOffset);
521 }
522 @Override
523 MethodHandle viewAsType(MethodType newType, boolean strict) {
524 assert(viewAsTypeChecks(newType, strict));
525 return new Accessor(newType, form, member, false, fieldOffset);
526 }
527 }
528
529 @ForceInline
530 /*non-public*/
531 static long fieldOffset(Object accessorObj) {
532 // Note: We return a long because that is what Unsafe.getObject likes.
533 // We store a plain int because it is more compact.
534 return ((Accessor)accessorObj).fieldOffset;
535 }
536
537 @ForceInline
538 /*non-public*/
539 static Object checkBase(Object obj) {
540 // Note that the object's class has already been verified,
541 // since the parameter type of the Accessor method handle
542 // is either member.getDeclaringClass or a subclass.
543 // This was verified in DirectMethodHandle.make.
544 // Therefore, the only remaining check is for null.
545 // Since this check is *not* guaranteed by Unsafe.getInt
546 // and its siblings, we need to make an explicit one here.
547 return Objects.requireNonNull(obj);
548 }
549
550 /** This subclass handles static field references. */
551 static final class StaticAccessor extends DirectMethodHandle {
552 private final Class<?> fieldType;
553 private final Object staticBase;
554 private final long staticOffset;
555
556 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
557 boolean crackable, Object staticBase, long staticOffset) {
558 super(mtype, form, member, crackable);
559 this.fieldType = member.getFieldType();
560 this.staticBase = staticBase;
561 this.staticOffset = staticOffset;
562 }
563
564 @Override Object checkCast(Object obj) {
565 return fieldType.cast(obj);
566 }
567 @Override
568 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
569 return new StaticAccessor(mt, lf, member, crackable, staticBase, staticOffset);
570 }
571 @Override
572 MethodHandle viewAsType(MethodType newType, boolean strict) {
573 assert(viewAsTypeChecks(newType, strict));
574 return new StaticAccessor(newType, form, member, false, staticBase, staticOffset);
575 }
576 }
577
578 @ForceInline
579 /*non-public*/
580 static Object nullCheck(Object obj) {
581 return Objects.requireNonNull(obj);
582 }
583
584 @ForceInline
585 /*non-public*/
586 static Object staticBase(Object accessorObj) {
587 return ((StaticAccessor)accessorObj).staticBase;
588 }
589
590 @ForceInline
591 /*non-public*/
592 static long staticOffset(Object accessorObj) {
593 return ((StaticAccessor)accessorObj).staticOffset;
594 }
595
596 @ForceInline
597 /*non-public*/
598 static Object checkCast(Object mh, Object obj) {
599 return ((DirectMethodHandle) mh).checkCast(obj);
600 }
601
602 Object checkCast(Object obj) {
603 return member.getMethodType().returnType().cast(obj);
604 }
605
606 // Caching machinery for field accessors:
607 static final byte
608 AF_GETFIELD = 0,
609 AF_PUTFIELD = 1,
610 AF_GETSTATIC = 2,
611 AF_PUTSTATIC = 3,
612 AF_GETSTATIC_INIT = 4,
613 AF_PUTSTATIC_INIT = 5,
614 AF_LIMIT = 6;
615 // Enumerate the different field kinds using Wrapper,
616 // with an extra case added for checked references.
617 static final int
618 FT_LAST_WRAPPER = Wrapper.COUNT-1,
619 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
620 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
621 FT_LIMIT = FT_LAST_WRAPPER+2;
622 private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) {
623 return ((formOp * FT_LIMIT * 2)
624 + (isVolatile ? FT_LIMIT : 0)
625 + ftypeKind);
626 }
627 @Stable
628 private static final LambdaForm[] ACCESSOR_FORMS
629 = new LambdaForm[afIndex(AF_LIMIT, false, 0)];
630 static int ftypeKind(Class<?> ftype) {
631 if (ftype.isPrimitive()) {
632 return Wrapper.forPrimitiveType(ftype).ordinal();
633 } else if (ftype.isInterface() || ftype.isAssignableFrom(Object.class)) {
634 // retyping can be done without a cast
635 return FT_UNCHECKED_REF;
636 } else {
637 return FT_CHECKED_REF;
638 }
639 }
640
641 /**
642 * Create a LF which can access the given field.
643 * Cache and share this structure among all fields with
644 * the same basicType and refKind.
645 */
646 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
647 Class<?> ftype = m.getFieldType();
648 boolean isVolatile = m.isVolatile();
649 byte formOp = switch (m.getReferenceKind()) {
650 case REF_getField -> AF_GETFIELD;
651 case REF_putField -> AF_PUTFIELD;
652 case REF_getStatic -> AF_GETSTATIC;
653 case REF_putStatic -> AF_PUTSTATIC;
654 default -> throw new InternalError(m.toString());
655 };
656 if (shouldBeInitialized(m)) {
657 // precompute the barrier-free version:
658 preparedFieldLambdaForm(formOp, isVolatile, ftype);
659 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
660 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
661 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
662 }
663 LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype);
664 maybeCompile(lform, m);
665 assert(lform.methodType().dropParameterTypes(0, 1)
666 .equals(m.getInvocationType().basicType()))
667 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
668 return lform;
669 }
670 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) {
671 int ftypeKind = ftypeKind(ftype);
672 int afIndex = afIndex(formOp, isVolatile, ftypeKind);
673 LambdaForm lform = ACCESSOR_FORMS[afIndex];
674 if (lform != null) return lform;
675 lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind);
676 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
677 return lform;
678 }
679
680 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
681
682 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, Wrapper wrapper) {
683 if (isGetter) {
684 if (isVolatile) {
685 switch (wrapper) {
686 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
687 case BYTE: return GET_BYTE_VOLATILE;
688 case SHORT: return GET_SHORT_VOLATILE;
689 case CHAR: return GET_CHAR_VOLATILE;
690 case INT: return GET_INT_VOLATILE;
691 case LONG: return GET_LONG_VOLATILE;
692 case FLOAT: return GET_FLOAT_VOLATILE;
693 case DOUBLE: return GET_DOUBLE_VOLATILE;
694 case OBJECT: return GET_REFERENCE_VOLATILE;
695 }
696 } else {
697 switch (wrapper) {
698 case BOOLEAN: return GET_BOOLEAN;
699 case BYTE: return GET_BYTE;
700 case SHORT: return GET_SHORT;
701 case CHAR: return GET_CHAR;
702 case INT: return GET_INT;
703 case LONG: return GET_LONG;
704 case FLOAT: return GET_FLOAT;
705 case DOUBLE: return GET_DOUBLE;
706 case OBJECT: return GET_REFERENCE;
707 }
708 }
709 } else {
710 if (isVolatile) {
711 switch (wrapper) {
712 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
713 case BYTE: return PUT_BYTE_VOLATILE;
714 case SHORT: return PUT_SHORT_VOLATILE;
715 case CHAR: return PUT_CHAR_VOLATILE;
716 case INT: return PUT_INT_VOLATILE;
717 case LONG: return PUT_LONG_VOLATILE;
718 case FLOAT: return PUT_FLOAT_VOLATILE;
719 case DOUBLE: return PUT_DOUBLE_VOLATILE;
720 case OBJECT: return PUT_REFERENCE_VOLATILE;
721 }
722 } else {
723 switch (wrapper) {
724 case BOOLEAN: return PUT_BOOLEAN;
725 case BYTE: return PUT_BYTE;
726 case SHORT: return PUT_SHORT;
727 case CHAR: return PUT_CHAR;
728 case INT: return PUT_INT;
729 case LONG: return PUT_LONG;
730 case FLOAT: return PUT_FLOAT;
731 case DOUBLE: return PUT_DOUBLE;
732 case OBJECT: return PUT_REFERENCE;
733 }
734 }
735 }
736 throw new AssertionError("Invalid arguments");
737 }
738
739 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) {
740 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
741 boolean isStatic = (formOp >= AF_GETSTATIC);
742 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
743 boolean needsCast = (ftypeKind == FT_CHECKED_REF);
744 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
745 Class<?> ft = fw.primitiveType();
746 assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind);
747
748 // getObject, putIntVolatile, etc.
749 Kind kind = getFieldKind(isGetter, isVolatile, fw);
750
751 MethodType linkerType;
752 if (isGetter)
753 linkerType = MethodType.methodType(ft, Object.class, long.class);
754 else
755 linkerType = MethodType.methodType(void.class, Object.class, long.class, ft);
756 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
757 try {
758 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED,
759 NoSuchMethodException.class);
760 } catch (ReflectiveOperationException ex) {
761 throw newInternalError(ex);
762 }
763
764 // What is the external type of the lambda form?
765 MethodType mtype;
766 if (isGetter)
767 mtype = MethodType.methodType(ft);
768 else
769 mtype = MethodType.methodType(void.class, ft);
770 mtype = mtype.basicType(); // erase short to int, etc.
771 if (!isStatic)
772 mtype = mtype.insertParameterTypes(0, Object.class);
773 final int DMH_THIS = 0;
774 final int ARG_BASE = 1;
775 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
776 // if this is for non-static access, the base pointer is stored at this index:
777 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
778 // if this is for write access, the value to be written is stored at this index:
779 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
780 int nameCursor = ARG_LIMIT;
781 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
782 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
783 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
784 final int U_HOLDER = nameCursor++; // UNSAFE holder
785 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
786 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
787 final int LINKER_CALL = nameCursor++;
788 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
789 final int RESULT = nameCursor-1; // either the call or the cast
790 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
791 if (needsInit)
792 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
793 if (needsCast && !isGetter)
794 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
795 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
796 assert(outArgs.length == (isGetter ? 3 : 4));
797 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
798 if (isStatic) {
799 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
800 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
801 } else {
802 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
803 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
804 }
805 if (!isGetter) {
806 outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
807 }
808 for (Object a : outArgs) assert(a != null);
809 names[LINKER_CALL] = new Name(linker, outArgs);
810 if (needsCast && isGetter)
811 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
812 for (Name n : names) assert(n != null);
813
814 LambdaForm form;
815 if (needsCast || needsInit) {
816 // can't use the pre-generated form when casting and/or initializing
817 form = LambdaForm.create(ARG_LIMIT, names, RESULT);
818 } else {
819 form = LambdaForm.create(ARG_LIMIT, names, RESULT, kind);
820 }
821
822 if (LambdaForm.debugNames()) {
823 // add some detail to the lambdaForm debugname,
824 // significant only for debugging
825 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
826 if (isStatic) {
827 nameBuilder.append("Static");
828 } else {
829 nameBuilder.append("Field");
830 }
831 if (needsCast) {
832 nameBuilder.append("Cast");
833 }
834 if (needsInit) {
835 nameBuilder.append("Init");
836 }
837 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
838 }
839 return form;
840 }
841
842 /**
843 * Pre-initialized NamedFunctions for bootstrapping purposes.
844 */
845 static final byte NF_internalMemberName = 0,
846 NF_internalMemberNameEnsureInit = 1,
847 NF_ensureInitialized = 2,
848 NF_fieldOffset = 3,
849 NF_checkBase = 4,
850 NF_staticBase = 5,
851 NF_staticOffset = 6,
852 NF_checkCast = 7,
853 NF_allocateInstance = 8,
854 NF_constructorMethod = 9,
855 NF_UNSAFE = 10,
856 NF_checkReceiver = 11,
857 NF_LIMIT = 12;
858
859 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
860
861 private static NamedFunction getFunction(byte func) {
862 NamedFunction nf = NFS[func];
863 if (nf != null) {
864 return nf;
865 }
866 // Each nf must be statically invocable or we get tied up in our bootstraps.
867 nf = NFS[func] = createFunction(func);
868 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
869 return nf;
870 }
871
872 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
873
874 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
875
876 private static NamedFunction createFunction(byte func) {
877 try {
878 switch (func) {
879 case NF_internalMemberName:
880 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
881 case NF_internalMemberNameEnsureInit:
882 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
883 case NF_ensureInitialized:
884 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
885 case NF_fieldOffset:
886 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
887 case NF_checkBase:
888 return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
889 case NF_staticBase:
890 return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
891 case NF_staticOffset:
892 return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
893 case NF_checkCast:
894 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
895 case NF_allocateInstance:
896 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
897 case NF_constructorMethod:
898 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
899 case NF_UNSAFE:
900 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getStatic);
901 return new NamedFunction(
902 MemberName.getFactory().resolveOrFail(REF_getStatic, member,
903 DirectMethodHandle.class, LM_TRUSTED,
904 NoSuchFieldException.class));
905 case NF_checkReceiver:
906 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
907 return new NamedFunction(
908 MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member,
909 DirectMethodHandle.class, LM_TRUSTED,
910 NoSuchMethodException.class));
911 default:
912 throw newInternalError("Unknown function: " + func);
913 }
914 } catch (ReflectiveOperationException ex) {
915 throw newInternalError(ex);
916 }
917 }
918
919 private static NamedFunction getNamedFunction(String name, MethodType type)
920 throws ReflectiveOperationException
921 {
922 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
923 return new NamedFunction(
924 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member,
925 DirectMethodHandle.class, LM_TRUSTED,
926 NoSuchMethodException.class));
927 }
928
929 static {
930 // The Holder class will contain pre-generated DirectMethodHandles resolved
931 // speculatively using MemberName.getFactory().resolveOrNull. However, that
932 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
933 // initialization of the Holder class we avoid these issues.
934 UNSAFE.ensureClassInitialized(Holder.class);
935 }
936
937 /* Placeholder class for DirectMethodHandles generated ahead of time */
938 final class Holder {}
939 }