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