1 /*
2 * Copyright (c) 2008, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.invoke;
27
28 import jdk.internal.misc.Unsafe;
29 import jdk.internal.vm.annotation.ForceInline;
30 import jdk.internal.vm.annotation.Stable;
31 import sun.invoke.util.ValueConversions;
32 import sun.invoke.util.VerifyAccess;
33 import sun.invoke.util.VerifyType;
34 import sun.invoke.util.Wrapper;
35
36 import java.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 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 = refc.isPrimitiveClass() ? refc.asValueType() : 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.getReturnType() == 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() {
177 return "\n& 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 = new LambdaForm(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 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 String msg = String.format("Receiver class %s is not a subclass of caller class %s",
422 recv.getClass().getName(), caller.getName());
423 throw new IncompatibleClassChangeError(msg);
424 }
425 return recv;
426 }
427 }
428
429 /** This subclass represents invokeinterface instructions. */
430 static class Interface extends DirectMethodHandle {
431 private final Class<?> refc;
432 private Interface(MethodType mtype, LambdaForm form, MemberName member, boolean crackable, Class<?> refc) {
433 super(mtype, form, member, crackable);
434 assert(refc.isInterface()) : refc;
435 this.refc = refc;
436 }
437 @Override
438 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
439 return new Interface(mt, lf, member, crackable, refc);
440 }
441 @Override
442 MethodHandle viewAsType(MethodType newType, boolean strict) {
443 assert(viewAsTypeChecks(newType, strict));
444 return new Interface(newType, form, member, false, refc);
445 }
446 @Override
447 Object checkReceiver(Object recv) {
448 if (!refc.isInstance(recv)) {
449 String msg = String.format("Receiver class %s does not implement the requested interface %s",
450 recv.getClass().getName(), refc.getName());
451 throw new IncompatibleClassChangeError(msg);
452 }
453 return recv;
454 }
455 }
456
457 /** Used for interface receiver type checks, by Interface and Special modes. */
458 Object checkReceiver(Object recv) {
459 throw new InternalError("Should only be invoked on a subclass");
460 }
461
462 /** This subclass handles constructor references. */
463 static class Constructor extends DirectMethodHandle {
464 final MemberName initMethod;
465 final Class<?> instanceClass;
466
467 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
468 boolean crackable, MemberName initMethod, Class<?> instanceClass) {
469 super(mtype, form, constructor, crackable);
470 this.initMethod = initMethod;
471 this.instanceClass = instanceClass;
472 assert(initMethod.isResolved());
473 }
474 @Override
475 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
476 return new Constructor(mt, lf, member, crackable, initMethod, instanceClass);
477 }
478 @Override
479 MethodHandle viewAsType(MethodType newType, boolean strict) {
480 assert(viewAsTypeChecks(newType, strict));
481 return new Constructor(newType, form, member, false, initMethod, instanceClass);
482 }
483 }
484
485 /*non-public*/
486 static Object constructorMethod(Object mh) {
487 Constructor dmh = (Constructor)mh;
488 return dmh.initMethod;
489 }
490
491 /*non-public*/
492 static Object allocateInstance(Object mh) throws InstantiationException {
493 Constructor dmh = (Constructor)mh;
494 return UNSAFE.allocateInstance(dmh.instanceClass);
495 }
496
497 /** This subclass handles non-static field references. */
498 static class Accessor extends DirectMethodHandle {
499 final Class<?> fieldType;
500 final int fieldOffset;
501 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
502 boolean crackable, int fieldOffset) {
503 super(mtype, form, member, crackable);
504 this.fieldType = member.getFieldType();
505 this.fieldOffset = fieldOffset;
506 }
507
508 @Override Object checkCast(Object obj) {
509 return fieldType.cast(obj);
510 }
511 @Override
512 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
513 return new Accessor(mt, lf, member, crackable, fieldOffset);
514 }
515 @Override
516 MethodHandle viewAsType(MethodType newType, boolean strict) {
517 assert(viewAsTypeChecks(newType, strict));
518 return new Accessor(newType, form, member, false, fieldOffset);
519 }
520 }
521
522 @ForceInline
523 /*non-public*/
524 static long fieldOffset(Object accessorObj) {
525 // Note: We return a long because that is what Unsafe.getObject likes.
526 // We store a plain int because it is more compact.
527 return ((Accessor)accessorObj).fieldOffset;
528 }
529
530 @ForceInline
531 /*non-public*/
532 static Object checkBase(Object obj) {
533 // Note that the object's class has already been verified,
534 // since the parameter type of the Accessor method handle
535 // is either member.getDeclaringClass or a subclass.
536 // This was verified in DirectMethodHandle.make.
537 // Therefore, the only remaining check is for null.
538 // Since this check is *not* guaranteed by Unsafe.getInt
539 // and its siblings, we need to make an explicit one here.
540 return Objects.requireNonNull(obj);
541 }
542
543 static class StaticAccessor extends DirectMethodHandle {
544 final Class<?> fieldType;
545 final Object staticBase;
546 final long staticOffset;
547
548 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
549 boolean crackable, Object staticBase, long staticOffset) {
550 super(mtype, form, member, crackable);
551 this.fieldType = member.getFieldType();
552 this.staticBase = staticBase;
553 this.staticOffset = staticOffset;
554 }
555
556 @Override Object checkCast(Object obj) {
557 return fieldType.cast(obj);
558 }
559 @Override
560 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
561 return new StaticAccessor(mt, lf, member, crackable, staticBase, staticOffset);
562 }
563 @Override
564 MethodHandle viewAsType(MethodType newType, boolean strict) {
565 assert(viewAsTypeChecks(newType, strict));
566 return new StaticAccessor(newType, form, member, false, staticBase, staticOffset);
567 }
568 }
569
570 @ForceInline
571 /*non-public*/
572 static Object nullCheck(Object obj) {
573 return Objects.requireNonNull(obj);
574 }
575
576 @ForceInline
577 /*non-public*/
578 static Object staticBase(Object accessorObj) {
579 return ((StaticAccessor)accessorObj).staticBase;
580 }
581
582 @ForceInline
583 /*non-public*/
584 static long staticOffset(Object accessorObj) {
585 return ((StaticAccessor)accessorObj).staticOffset;
586 }
587
588 @ForceInline
589 /*non-public*/
590 static Object checkCast(Object mh, Object obj) {
591 return ((DirectMethodHandle) mh).checkCast(obj);
592 }
593
594 @ForceInline
595 /*non-public*/ static Class<?> fieldType(Object accessorObj) {
596 return ((Accessor) accessorObj).fieldType;
597 }
598
599 @ForceInline
600 /*non-public*/ static Class<?> staticFieldType(Object accessorObj) {
601 return ((StaticAccessor) accessorObj).fieldType;
602 }
603
604 Object checkCast(Object obj) {
605 return member.getReturnType().cast(obj);
606 }
607
608 // Caching machinery for field accessors:
609 static final byte
610 AF_GETFIELD = 0,
611 AF_PUTFIELD = 1,
612 AF_GETSTATIC = 2,
613 AF_PUTSTATIC = 3,
614 AF_GETSTATIC_INIT = 4,
615 AF_PUTSTATIC_INIT = 5,
616 AF_LIMIT = 6;
617 // Enumerate the different field kinds using Wrapper,
618 // with an extra case added for checked references and value field access
619 static final int
620 FT_LAST_WRAPPER = Wrapper.COUNT-1,
621 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
622 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
623 FT_CHECKED_VALUE = FT_LAST_WRAPPER+2, // flattened and non-flattened
624 FT_LIMIT = FT_LAST_WRAPPER+4;
625 private static int afIndex(byte formOp, boolean isVolatile, boolean isFlatValue, int ftypeKind) {
626 return ((formOp * FT_LIMIT * 2)
627 + (isVolatile ? FT_LIMIT : 0)
628 + (isFlatValue ? 1 : 0)
629 + ftypeKind);
630 }
631 @Stable
632 private static final LambdaForm[] ACCESSOR_FORMS
633 = new LambdaForm[afIndex(AF_LIMIT, false, false, 0)];
634 static int ftypeKind(Class<?> ftype, boolean isValue) {
635 if (ftype.isPrimitive())
636 return Wrapper.forPrimitiveType(ftype).ordinal();
637 else if (VerifyType.isNullReferenceConversion(Object.class, ftype)) {
638 return FT_UNCHECKED_REF;
639 } else
640 // null check for value type in addition to check cast
641 return isValue ? FT_CHECKED_VALUE : FT_CHECKED_REF;
642 }
643
644 /**
645 * Create a LF which can access the given field.
646 * Cache and share this structure among all fields with
647 * the same basicType and refKind.
648 */
649 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
650 Class<?> ftype = m.getFieldType();
651 boolean isVolatile = m.isVolatile();
652 byte formOp = switch (m.getReferenceKind()) {
653 case REF_getField -> AF_GETFIELD;
654 case REF_putField -> AF_PUTFIELD;
655 case REF_getStatic -> AF_GETSTATIC;
656 case REF_putStatic -> AF_PUTSTATIC;
657 default -> throw new InternalError(m.toString());
658 };
659 if (shouldBeInitialized(m)) {
660 // precompute the barrier-free version:
661 preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineableField(), m.isFlattened(), ftype);
662 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
663 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
664 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
665 }
666 LambdaForm lform = preparedFieldLambdaForm(formOp, m.isVolatile(), m.isInlineableField(), m.isFlattened(), ftype);
667 maybeCompile(lform, m);
668 assert(lform.methodType().dropParameterTypes(0, 1)
669 .equals(m.getInvocationType().basicType()))
670 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
671 return lform;
672 }
673
674 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, Class<?> ftype) {
675 int ftypeKind = ftypeKind(ftype, isValue);
676 int afIndex = afIndex(formOp, isVolatile, isFlatValue, ftypeKind);
677 LambdaForm lform = ACCESSOR_FORMS[afIndex];
678 if (lform != null) return lform;
679 lform = makePreparedFieldLambdaForm(formOp, isVolatile, isValue, isFlatValue, ftypeKind);
680 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
681 return lform;
682 }
683
684 private static final Wrapper[] ALL_WRAPPERS = Wrapper.values();
685
686 private static Kind getFieldKind(boolean isGetter, boolean isVolatile, boolean isFlatValue, Wrapper wrapper) {
687 if (isGetter) {
688 if (isVolatile) {
689 switch (wrapper) {
690 case BOOLEAN: return GET_BOOLEAN_VOLATILE;
691 case BYTE: return GET_BYTE_VOLATILE;
692 case SHORT: return GET_SHORT_VOLATILE;
693 case CHAR: return GET_CHAR_VOLATILE;
694 case INT: return GET_INT_VOLATILE;
695 case LONG: return GET_LONG_VOLATILE;
696 case FLOAT: return GET_FLOAT_VOLATILE;
697 case DOUBLE: return GET_DOUBLE_VOLATILE;
698 case OBJECT: return isFlatValue ? GET_VALUE_VOLATILE : GET_REFERENCE_VOLATILE;
699 }
700 } else {
701 switch (wrapper) {
702 case BOOLEAN: return GET_BOOLEAN;
703 case BYTE: return GET_BYTE;
704 case SHORT: return GET_SHORT;
705 case CHAR: return GET_CHAR;
706 case INT: return GET_INT;
707 case LONG: return GET_LONG;
708 case FLOAT: return GET_FLOAT;
709 case DOUBLE: return GET_DOUBLE;
710 case OBJECT: return isFlatValue ? GET_VALUE : GET_REFERENCE;
711 }
712 }
713 } else {
714 if (isVolatile) {
715 switch (wrapper) {
716 case BOOLEAN: return PUT_BOOLEAN_VOLATILE;
717 case BYTE: return PUT_BYTE_VOLATILE;
718 case SHORT: return PUT_SHORT_VOLATILE;
719 case CHAR: return PUT_CHAR_VOLATILE;
720 case INT: return PUT_INT_VOLATILE;
721 case LONG: return PUT_LONG_VOLATILE;
722 case FLOAT: return PUT_FLOAT_VOLATILE;
723 case DOUBLE: return PUT_DOUBLE_VOLATILE;
724 case OBJECT: return isFlatValue ? PUT_VALUE_VOLATILE : PUT_REFERENCE_VOLATILE;
725 }
726 } else {
727 switch (wrapper) {
728 case BOOLEAN: return PUT_BOOLEAN;
729 case BYTE: return PUT_BYTE;
730 case SHORT: return PUT_SHORT;
731 case CHAR: return PUT_CHAR;
732 case INT: return PUT_INT;
733 case LONG: return PUT_LONG;
734 case FLOAT: return PUT_FLOAT;
735 case DOUBLE: return PUT_DOUBLE;
736 case OBJECT: return isFlatValue ? PUT_VALUE : PUT_REFERENCE;
737 }
738 }
739 }
740 throw new AssertionError("Invalid arguments");
741 }
742
743 /** invoked by GenerateJLIClassesHelper */
744 static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftype) {
745 return makePreparedFieldLambdaForm(formOp, isVolatile, false, false, ftype);
746 }
747
748 private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, boolean isValue, boolean isFlatValue, int ftypeKind) {
749 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
750 boolean isStatic = (formOp >= AF_GETSTATIC);
751 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
752 boolean needsCast = (ftypeKind == FT_CHECKED_REF || ftypeKind == FT_CHECKED_VALUE);
753 Wrapper fw = (needsCast ? Wrapper.OBJECT : ALL_WRAPPERS[ftypeKind]);
754 Class<?> ft = fw.primitiveType();
755 assert(needsCast ? true : ftypeKind(ft, isValue) == ftypeKind);
756
757 // getObject, putIntVolatile, etc.
758 Kind kind = getFieldKind(isGetter, isVolatile, isFlatValue, fw);
759
760 MethodType linkerType;
761 boolean hasValueTypeArg = isGetter ? isValue : isFlatValue;
762 if (isGetter) {
763 linkerType = isValue ? MethodType.methodType(ft, Object.class, long.class, Class.class)
764 : MethodType.methodType(ft, Object.class, long.class);
765 } else {
766 linkerType = isFlatValue ? MethodType.methodType(void.class, Object.class, long.class, Class.class, ft)
767 : MethodType.methodType(void.class, Object.class, long.class, ft);
768 }
769 MemberName linker = new MemberName(Unsafe.class, kind.methodName, linkerType, REF_invokeVirtual);
770 try {
771 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, LM_TRUSTED,
772 NoSuchMethodException.class);
773 } catch (ReflectiveOperationException ex) {
774 throw newInternalError(ex);
775 }
776
777 // What is the external type of the lambda form?
778 MethodType mtype;
779 if (isGetter)
780 mtype = MethodType.methodType(ft);
781 else
782 mtype = MethodType.methodType(void.class, ft);
783 mtype = mtype.basicType(); // erase short to int, etc.
784 if (!isStatic)
785 mtype = mtype.insertParameterTypes(0, Object.class);
786 final int DMH_THIS = 0;
787 final int ARG_BASE = 1;
788 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
789 // if this is for non-static access, the base pointer is stored at this index:
790 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
791 // if this is for write access, the value to be written is stored at this index:
792 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
793 int nameCursor = ARG_LIMIT;
794 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
795 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
796 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
797 final int U_HOLDER = nameCursor++; // UNSAFE holder
798 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
799 final int VALUE_TYPE = (hasValueTypeArg ? nameCursor++ : -1);
800 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
801 final int LINKER_CALL = nameCursor++;
802 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
803 final int RESULT = nameCursor-1; // either the call or the cast
804 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
805 if (needsInit)
806 names[INIT_BAR] = new Name(getFunction(NF_ensureInitialized), names[DMH_THIS]);
807 if (needsCast && !isGetter)
808 names[PRE_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[SET_VALUE]);
809 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
810 assert (outArgs.length == (isGetter ? 3 : 4) + (hasValueTypeArg ? 1 : 0));
811 outArgs[0] = names[U_HOLDER] = new Name(getFunction(NF_UNSAFE));
812 if (isStatic) {
813 outArgs[1] = names[F_HOLDER] = new Name(getFunction(NF_staticBase), names[DMH_THIS]);
814 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_staticOffset), names[DMH_THIS]);
815 } else {
816 outArgs[1] = names[OBJ_CHECK] = new Name(getFunction(NF_checkBase), names[OBJ_BASE]);
817 outArgs[2] = names[F_OFFSET] = new Name(getFunction(NF_fieldOffset), names[DMH_THIS]);
818 }
819 int x = 3;
820 if (hasValueTypeArg) {
821 outArgs[x++] = names[VALUE_TYPE] = isStatic ? new Name(getFunction(NF_staticFieldType), names[DMH_THIS])
822 : new Name(getFunction(NF_fieldType), names[DMH_THIS]);
823 }
824 if (!isGetter) {
825 outArgs[x] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
826 }
827 for (Object a : outArgs) assert(a != null);
828 names[LINKER_CALL] = new Name(linker, outArgs);
829 if (needsCast && isGetter)
830 names[POST_CAST] = new Name(getFunction(NF_checkCast), names[DMH_THIS], names[LINKER_CALL]);
831 for (Name n : names) assert(n != null);
832
833 LambdaForm form;
834 if (needsCast || needsInit) {
835 // can't use the pre-generated form when casting and/or initializing
836 form = new LambdaForm(ARG_LIMIT, names, RESULT);
837 } else {
838 form = new LambdaForm(ARG_LIMIT, names, RESULT, kind);
839 }
840
841 if (LambdaForm.debugNames()) {
842 // add some detail to the lambdaForm debugname,
843 // significant only for debugging
844 StringBuilder nameBuilder = new StringBuilder(kind.methodName);
845 if (isStatic) {
846 nameBuilder.append("Static");
847 } else {
848 nameBuilder.append("Field");
849 }
850 if (needsCast) {
851 nameBuilder.append("Cast");
852 }
853 if (needsInit) {
854 nameBuilder.append("Init");
855 }
856 LambdaForm.associateWithDebugName(form, nameBuilder.toString());
857 }
858 return form;
859 }
860
861 /**
862 * Pre-initialized NamedFunctions for bootstrapping purposes.
863 */
864 static final byte NF_internalMemberName = 0,
865 NF_internalMemberNameEnsureInit = 1,
866 NF_ensureInitialized = 2,
867 NF_fieldOffset = 3,
868 NF_checkBase = 4,
869 NF_staticBase = 5,
870 NF_staticOffset = 6,
871 NF_checkCast = 7,
872 NF_allocateInstance = 8,
873 NF_constructorMethod = 9,
874 NF_UNSAFE = 10,
875 NF_checkReceiver = 11,
876 NF_fieldType = 12,
877 NF_staticFieldType = 13,
878 NF_LIMIT = 14;
879
880 private static final @Stable NamedFunction[] NFS = new NamedFunction[NF_LIMIT];
881
882 private static NamedFunction getFunction(byte func) {
883 NamedFunction nf = NFS[func];
884 if (nf != null) {
885 return nf;
886 }
887 // Each nf must be statically invocable or we get tied up in our bootstraps.
888 nf = NFS[func] = createFunction(func);
889 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nf));
890 return nf;
891 }
892
893 private static final MethodType CLS_OBJ_TYPE = MethodType.methodType(Class.class, Object.class);
894
895 private static final MethodType OBJ_OBJ_TYPE = MethodType.methodType(Object.class, Object.class);
896
897 private static final MethodType LONG_OBJ_TYPE = MethodType.methodType(long.class, Object.class);
898
899 private static NamedFunction createFunction(byte func) {
900 try {
901 switch (func) {
902 case NF_internalMemberName:
903 return getNamedFunction("internalMemberName", OBJ_OBJ_TYPE);
904 case NF_internalMemberNameEnsureInit:
905 return getNamedFunction("internalMemberNameEnsureInit", OBJ_OBJ_TYPE);
906 case NF_ensureInitialized:
907 return getNamedFunction("ensureInitialized", MethodType.methodType(void.class, Object.class));
908 case NF_fieldOffset:
909 return getNamedFunction("fieldOffset", LONG_OBJ_TYPE);
910 case NF_checkBase:
911 return getNamedFunction("checkBase", OBJ_OBJ_TYPE);
912 case NF_staticBase:
913 return getNamedFunction("staticBase", OBJ_OBJ_TYPE);
914 case NF_staticOffset:
915 return getNamedFunction("staticOffset", LONG_OBJ_TYPE);
916 case NF_checkCast:
917 return getNamedFunction("checkCast", MethodType.methodType(Object.class, Object.class, Object.class));
918 case NF_allocateInstance:
919 return getNamedFunction("allocateInstance", OBJ_OBJ_TYPE);
920 case NF_constructorMethod:
921 return getNamedFunction("constructorMethod", OBJ_OBJ_TYPE);
922 case NF_UNSAFE:
923 MemberName member = new MemberName(MethodHandleStatics.class, "UNSAFE", Unsafe.class, REF_getField);
924 return new NamedFunction(
925 MemberName.getFactory().resolveOrFail(REF_getField, member,
926 DirectMethodHandle.class, LM_TRUSTED,
927 NoSuchMethodException.class));
928 case NF_checkReceiver:
929 member = new MemberName(DirectMethodHandle.class, "checkReceiver", OBJ_OBJ_TYPE, REF_invokeVirtual);
930 return new NamedFunction(
931 MemberName.getFactory().resolveOrFail(REF_invokeVirtual, member,
932 DirectMethodHandle.class, LM_TRUSTED,
933 NoSuchMethodException.class));
934 case NF_fieldType:
935 return getNamedFunction("fieldType", CLS_OBJ_TYPE);
936 case NF_staticFieldType:
937 return getNamedFunction("staticFieldType", CLS_OBJ_TYPE);
938 default:
939 throw newInternalError("Unknown function: " + func);
940 }
941 } catch (ReflectiveOperationException ex) {
942 throw newInternalError(ex);
943 }
944 }
945
946 private static NamedFunction getNamedFunction(String name, MethodType type)
947 throws ReflectiveOperationException
948 {
949 MemberName member = new MemberName(DirectMethodHandle.class, name, type, REF_invokeStatic);
950 return new NamedFunction(
951 MemberName.getFactory().resolveOrFail(REF_invokeStatic, member,
952 DirectMethodHandle.class, LM_TRUSTED,
953 NoSuchMethodException.class));
954 }
955
956 static {
957 // The Holder class will contain pre-generated DirectMethodHandles resolved
958 // speculatively using MemberName.getFactory().resolveOrNull. However, that
959 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
960 // initialization of the Holder class we avoid these issues.
961 UNSAFE.ensureClassInitialized(Holder.class);
962 }
963
964 /* Placeholder class for DirectMethodHandles generated ahead of time */
965 final class Holder {}
966 }