1 /*
2 * Copyright (c) 2008, 2013, 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.lang.ref.WeakReference;
37 import java.util.Arrays;
38 import java.util.Objects;
39
40 import static java.lang.invoke.LambdaForm.*;
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 class DirectMethodHandle extends MethodHandle {
52 final MemberName member;
53
54 // Constructors and factory methods in this class *must* be package scoped or private.
55 private DirectMethodHandle(MethodType mtype, LambdaForm form, MemberName member) {
56 super(mtype, form);
57 if (!member.isResolved()) throw new InternalError();
58
59 if (member.getDeclaringClass().isInterface() &&
60 member.isMethod() && !member.isAbstract()) {
61 // Check for corner case: invokeinterface of Object method
62 MemberName m = new MemberName(Object.class, member.getName(), member.getMethodType(), member.getReferenceKind());
63 m = MemberName.getFactory().resolveOrNull(m.getReferenceKind(), m, null);
64 if (m != null && m.isPublic()) {
65 assert(member.getReferenceKind() == m.getReferenceKind()); // else this.form is wrong
66 member = m;
67 }
68 }
69
70 this.member = member;
71 }
72
73 // Factory methods:
74 static DirectMethodHandle make(byte refKind, Class<?> receiver, MemberName member) {
75 MethodType mtype = member.getMethodOrFieldType();
76 if (!member.isStatic()) {
77 if (!member.getDeclaringClass().isAssignableFrom(receiver) || member.isConstructor())
78 throw new InternalError(member.toString());
79 mtype = mtype.insertParameterTypes(0, receiver);
80 }
81 if (!member.isField()) {
82 if (refKind == REF_invokeSpecial) {
83 member = member.asSpecial();
84 LambdaForm lform = preparedLambdaForm(member);
85 return new Special(mtype, lform, member);
86 } else {
87 LambdaForm lform = preparedLambdaForm(member);
88 return new DirectMethodHandle(mtype, lform, member);
89 }
90 } else {
91 LambdaForm lform = preparedFieldLambdaForm(member);
92 if (member.isStatic()) {
93 long offset = MethodHandleNatives.staticFieldOffset(member);
94 Object base = MethodHandleNatives.staticFieldBase(member);
95 return new StaticAccessor(mtype, lform, member, base, offset);
96 } else {
97 long offset = MethodHandleNatives.objectFieldOffset(member);
98 assert(offset == (int)offset);
99 return new Accessor(mtype, lform, member, (int)offset);
100 }
101 }
102 }
103 static DirectMethodHandle make(Class<?> receiver, MemberName member) {
104 byte refKind = member.getReferenceKind();
105 if (refKind == REF_invokeSpecial)
106 refKind = REF_invokeVirtual;
107 return make(refKind, receiver, member);
108 }
109 static DirectMethodHandle make(MemberName member) {
110 if (member.isConstructor())
111 return makeAllocator(member);
112 return make(member.getDeclaringClass(), member);
113 }
114 private static DirectMethodHandle makeAllocator(MemberName ctor) {
115 assert(ctor.isConstructor() && ctor.getName().equals("<init>"));
116 Class<?> instanceClass = ctor.getDeclaringClass();
117 ctor = ctor.asConstructor();
118 assert(ctor.isConstructor() && ctor.getReferenceKind() == REF_newInvokeSpecial) : ctor;
119 MethodType mtype = ctor.getMethodType().changeReturnType(instanceClass);
120 LambdaForm lform = preparedLambdaForm(ctor);
121 MemberName init = ctor.asSpecial();
122 assert(init.getMethodType().returnType() == void.class);
123 return new Constructor(mtype, lform, ctor, init, instanceClass);
124 }
125
126 @Override
127 BoundMethodHandle rebind() {
128 return BoundMethodHandle.makeReinvoker(this);
129 }
130
131 @Override
132 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
133 assert(this.getClass() == DirectMethodHandle.class); // must override in subclasses
134 return new DirectMethodHandle(mt, lf, member);
135 }
136
137 @Override
138 String internalProperties() {
139 return "\n& DMH.MN="+internalMemberName();
140 }
141
142 //// Implementation methods.
143 @Override
144 @ForceInline
145 MemberName internalMemberName() {
146 return member;
147 }
148
149 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
150
151 /**
152 * Create a LF which can invoke the given method.
153 * Cache and share this structure among all methods with
154 * the same basicType and refKind.
155 */
156 private static LambdaForm preparedLambdaForm(MemberName m) {
157 assert(m.isInvocable()) : m; // call preparedFieldLambdaForm instead
158 MethodType mtype = m.getInvocationType().basicType();
159 assert(!m.isMethodHandleInvoke()) : m;
160 int which;
161 switch (m.getReferenceKind()) {
162 case REF_invokeVirtual: which = LF_INVVIRTUAL; break;
163 case REF_invokeStatic: which = LF_INVSTATIC; break;
164 case REF_invokeSpecial: which = LF_INVSPECIAL; break;
165 case REF_invokeInterface: which = LF_INVINTERFACE; break;
166 case REF_newInvokeSpecial: which = LF_NEWINVSPECIAL; break;
167 default: throw new InternalError(m.toString());
168 }
169 if (which == LF_INVSTATIC && shouldBeInitialized(m)) {
170 // precompute the barrier-free version:
171 preparedLambdaForm(mtype, which);
172 which = LF_INVSTATIC_INIT;
173 }
174 LambdaForm lform = preparedLambdaForm(mtype, which);
175 maybeCompile(lform, m);
176 assert(lform.methodType().dropParameterTypes(0, 1)
177 .equals(m.getInvocationType().basicType()))
178 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
179 return lform;
180 }
181
182 private static LambdaForm preparedLambdaForm(MethodType mtype, int which) {
183 LambdaForm lform = mtype.form().cachedLambdaForm(which);
184 if (lform != null) return lform;
185 lform = makePreparedLambdaForm(mtype, which);
186 return mtype.form().setCachedLambdaForm(which, lform);
187 }
188
189 private static LambdaForm makePreparedLambdaForm(MethodType mtype, int which) {
190 boolean needsInit = (which == LF_INVSTATIC_INIT);
191 boolean doesAlloc = (which == LF_NEWINVSPECIAL);
192 String linkerName, lambdaName;
193 switch (which) {
194 case LF_INVVIRTUAL: linkerName = "linkToVirtual"; lambdaName = "DMH.invokeVirtual"; break;
195 case LF_INVSTATIC: linkerName = "linkToStatic"; lambdaName = "DMH.invokeStatic"; break;
196 case LF_INVSTATIC_INIT:linkerName = "linkToStatic"; lambdaName = "DMH.invokeStaticInit"; break;
197 case LF_INVSPECIAL: linkerName = "linkToSpecial"; lambdaName = "DMH.invokeSpecial"; break;
198 case LF_INVINTERFACE: linkerName = "linkToInterface"; lambdaName = "DMH.invokeInterface"; break;
199 case LF_NEWINVSPECIAL: linkerName = "linkToSpecial"; lambdaName = "DMH.newInvokeSpecial"; break;
200 default: throw new InternalError("which="+which);
201 }
202
203 MethodType mtypeWithArg = mtype.appendParameterTypes(MemberName.class);
204 if (doesAlloc)
205 mtypeWithArg = mtypeWithArg
206 .insertParameterTypes(0, Object.class) // insert newly allocated obj
207 .changeReturnType(void.class); // <init> returns void
208 MemberName linker = new MemberName(MethodHandle.class, linkerName, mtypeWithArg, REF_invokeStatic);
209 try {
210 linker = IMPL_NAMES.resolveOrFail(REF_invokeStatic, linker, null, NoSuchMethodException.class);
211 } catch (ReflectiveOperationException ex) {
212 throw newInternalError(ex);
213 }
214 final int DMH_THIS = 0;
215 final int ARG_BASE = 1;
216 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
217 int nameCursor = ARG_LIMIT;
218 final int NEW_OBJ = (doesAlloc ? nameCursor++ : -1);
219 final int GET_MEMBER = nameCursor++;
220 final int LINKER_CALL = nameCursor++;
221 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
222 assert(names.length == nameCursor);
223 if (doesAlloc) {
224 // names = { argx,y,z,... new C, init method }
225 names[NEW_OBJ] = new Name(NF_allocateInstance, names[DMH_THIS]);
226 names[GET_MEMBER] = new Name(NF_constructorMethod, names[DMH_THIS]);
227 } else if (needsInit) {
228 names[GET_MEMBER] = new Name(NF_internalMemberNameEnsureInit, names[DMH_THIS]);
229 } else {
230 names[GET_MEMBER] = new Name(NF_internalMemberName, names[DMH_THIS]);
231 }
232 assert(findDirectMethodHandle(names[GET_MEMBER]) == names[DMH_THIS]);
233 Object[] outArgs = Arrays.copyOfRange(names, ARG_BASE, GET_MEMBER+1, Object[].class);
234 assert(outArgs[outArgs.length-1] == names[GET_MEMBER]); // look, shifted args!
235 int result = LAST_RESULT;
236 if (doesAlloc) {
237 assert(outArgs[outArgs.length-2] == names[NEW_OBJ]); // got to move this one
238 System.arraycopy(outArgs, 0, outArgs, 1, outArgs.length-2);
239 outArgs[0] = names[NEW_OBJ];
240 result = NEW_OBJ;
241 }
242 names[LINKER_CALL] = new Name(linker, outArgs);
243 lambdaName += "_" + shortenSignature(basicTypeSignature(mtype));
244 LambdaForm lform = new LambdaForm(lambdaName, ARG_LIMIT, names, result);
245
246 // This is a tricky bit of code. Don't send it through the LF interpreter.
247 lform.compileToBytecode(Holder.class);
248 return lform;
249 }
250
251 /*
252 * NOTE: This method acts as an API hook for use by the
253 * GenerateJLIClassesPlugin to generate a class wrapping DirectMethodHandle
254 * methods for an array of method types.
255 */
256 static byte[] generateDMHClassBytes(String className, MethodType[] methodTypes, int[] types) {
257 LambdaForm[] forms = new LambdaForm[methodTypes.length];
258 for (int i = 0; i < forms.length; i++) {
259 forms[i] = makePreparedLambdaForm(methodTypes[i], types[i]);
260 methodTypes[i] = forms[i].methodType();
261 }
262 return InvokerBytecodeGenerator.generateCodeBytesForMultiple(className, forms, methodTypes);
263 }
264
265 static Object findDirectMethodHandle(Name name) {
266 if (name.function == NF_internalMemberName ||
267 name.function == NF_internalMemberNameEnsureInit ||
268 name.function == NF_constructorMethod) {
269 assert(name.arguments.length == 1);
270 return name.arguments[0];
271 }
272 return null;
273 }
274
275 private static void maybeCompile(LambdaForm lform, MemberName m) {
276 if (VerifyAccess.isSamePackage(m.getDeclaringClass(), MethodHandle.class))
277 // Help along bootstrapping...
278 lform.compileToBytecode();
279 }
280
281 /** Static wrapper for DirectMethodHandle.internalMemberName. */
282 @ForceInline
283 /*non-public*/ static Object internalMemberName(Object mh) {
284 return ((DirectMethodHandle)mh).member;
285 }
286
287 /** Static wrapper for DirectMethodHandle.internalMemberName.
288 * This one also forces initialization.
289 */
290 /*non-public*/ static Object internalMemberNameEnsureInit(Object mh) {
291 DirectMethodHandle dmh = (DirectMethodHandle)mh;
292 dmh.ensureInitialized();
293 return dmh.member;
294 }
295
296 /*non-public*/ static
297 boolean shouldBeInitialized(MemberName member) {
298 switch (member.getReferenceKind()) {
299 case REF_invokeStatic:
300 case REF_getStatic:
301 case REF_putStatic:
302 case REF_newInvokeSpecial:
303 break;
304 default:
305 // No need to initialize the class on this kind of member.
306 return false;
307 }
308 Class<?> cls = member.getDeclaringClass();
309 if (cls == ValueConversions.class ||
310 cls == MethodHandleImpl.class ||
311 cls == Invokers.class) {
312 // These guys have lots of <clinit> DMH creation but we know
313 // the MHs will not be used until the system is booted.
314 return false;
315 }
316 if (VerifyAccess.isSamePackage(MethodHandle.class, cls) ||
317 VerifyAccess.isSamePackage(ValueConversions.class, cls)) {
318 // It is a system class. It is probably in the process of
319 // being initialized, but we will help it along just to be safe.
320 if (UNSAFE.shouldBeInitialized(cls)) {
321 UNSAFE.ensureClassInitialized(cls);
322 }
323 return false;
324 }
325 return UNSAFE.shouldBeInitialized(cls);
326 }
327
328 private static class EnsureInitialized extends ClassValue<WeakReference<Thread>> {
329 @Override
330 protected WeakReference<Thread> computeValue(Class<?> type) {
331 UNSAFE.ensureClassInitialized(type);
332 if (UNSAFE.shouldBeInitialized(type))
333 // If the previous call didn't block, this can happen.
334 // We are executing inside <clinit>.
335 return new WeakReference<>(Thread.currentThread());
336 return null;
337 }
338 static final EnsureInitialized INSTANCE = new EnsureInitialized();
339 }
340
341 private void ensureInitialized() {
342 if (checkInitialized(member)) {
343 // The coast is clear. Delete the <clinit> barrier.
344 if (member.isField())
345 updateForm(preparedFieldLambdaForm(member));
346 else
347 updateForm(preparedLambdaForm(member));
348 }
349 }
350 private static boolean checkInitialized(MemberName member) {
351 Class<?> defc = member.getDeclaringClass();
352 WeakReference<Thread> ref = EnsureInitialized.INSTANCE.get(defc);
353 if (ref == null) {
354 return true; // the final state
355 }
356 Thread clinitThread = ref.get();
357 // Somebody may still be running defc.<clinit>.
358 if (clinitThread == Thread.currentThread()) {
359 // If anybody is running defc.<clinit>, it is this thread.
360 if (UNSAFE.shouldBeInitialized(defc))
361 // Yes, we are running it; keep the barrier for now.
362 return false;
363 } else {
364 // We are in a random thread. Block.
365 UNSAFE.ensureClassInitialized(defc);
366 }
367 assert(!UNSAFE.shouldBeInitialized(defc));
368 // put it into the final state
369 EnsureInitialized.INSTANCE.remove(defc);
370 return true;
371 }
372
373 /*non-public*/ static void ensureInitialized(Object mh) {
374 ((DirectMethodHandle)mh).ensureInitialized();
375 }
376
377 /** This subclass represents invokespecial instructions. */
378 static class Special extends DirectMethodHandle {
379 private Special(MethodType mtype, LambdaForm form, MemberName member) {
380 super(mtype, form, member);
381 }
382 @Override
383 boolean isInvokeSpecial() {
384 return true;
385 }
386 @Override
387 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
388 return new Special(mt, lf, member);
389 }
390 }
391
392 /** This subclass handles constructor references. */
393 static class Constructor extends DirectMethodHandle {
394 final MemberName initMethod;
395 final Class<?> instanceClass;
396
397 private Constructor(MethodType mtype, LambdaForm form, MemberName constructor,
398 MemberName initMethod, Class<?> instanceClass) {
399 super(mtype, form, constructor);
400 this.initMethod = initMethod;
401 this.instanceClass = instanceClass;
402 assert(initMethod.isResolved());
403 }
404 @Override
405 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
406 return new Constructor(mt, lf, member, initMethod, instanceClass);
407 }
408 }
409
410 /*non-public*/ static Object constructorMethod(Object mh) {
411 Constructor dmh = (Constructor)mh;
412 return dmh.initMethod;
413 }
414
415 /*non-public*/ static Object allocateInstance(Object mh) throws InstantiationException {
416 Constructor dmh = (Constructor)mh;
417 return UNSAFE.allocateInstance(dmh.instanceClass);
418 }
419
420 /** This subclass handles non-static field references. */
421 static class Accessor extends DirectMethodHandle {
422 final Class<?> fieldType;
423 final int fieldOffset;
424 private Accessor(MethodType mtype, LambdaForm form, MemberName member,
425 int fieldOffset) {
426 super(mtype, form, member);
427 this.fieldType = member.getFieldType();
428 this.fieldOffset = fieldOffset;
429 }
430
431 @Override Object checkCast(Object obj) {
432 return fieldType.cast(obj);
433 }
434 @Override
435 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
436 return new Accessor(mt, lf, member, fieldOffset);
437 }
438 }
439
440 @ForceInline
441 /*non-public*/ static long fieldOffset(Object accessorObj) {
442 // Note: We return a long because that is what Unsafe.getObject likes.
443 // We store a plain int because it is more compact.
444 return ((Accessor)accessorObj).fieldOffset;
445 }
446
447 @ForceInline
448 /*non-public*/ static Object checkBase(Object obj) {
449 // Note that the object's class has already been verified,
450 // since the parameter type of the Accessor method handle
451 // is either member.getDeclaringClass or a subclass.
452 // This was verified in DirectMethodHandle.make.
453 // Therefore, the only remaining check is for null.
454 // Since this check is *not* guaranteed by Unsafe.getInt
455 // and its siblings, we need to make an explicit one here.
456 return Objects.requireNonNull(obj);
457 }
458
459 /** This subclass handles static field references. */
460 static class StaticAccessor extends DirectMethodHandle {
461 private final Class<?> fieldType;
462 private final Object staticBase;
463 private final long staticOffset;
464
465 private StaticAccessor(MethodType mtype, LambdaForm form, MemberName member,
466 Object staticBase, long staticOffset) {
467 super(mtype, form, member);
468 this.fieldType = member.getFieldType();
469 this.staticBase = staticBase;
470 this.staticOffset = staticOffset;
471 }
472
473 @Override Object checkCast(Object obj) {
474 return fieldType.cast(obj);
475 }
476 @Override
477 MethodHandle copyWith(MethodType mt, LambdaForm lf) {
478 return new StaticAccessor(mt, lf, member, staticBase, staticOffset);
479 }
480 }
481
482 @ForceInline
483 /*non-public*/ static Object nullCheck(Object obj) {
484 return Objects.requireNonNull(obj);
485 }
486
487 @ForceInline
488 /*non-public*/ static Object staticBase(Object accessorObj) {
489 return ((StaticAccessor)accessorObj).staticBase;
490 }
491
492 @ForceInline
493 /*non-public*/ static long staticOffset(Object accessorObj) {
494 return ((StaticAccessor)accessorObj).staticOffset;
495 }
496
497 @ForceInline
498 /*non-public*/ static Object checkCast(Object mh, Object obj) {
499 return ((DirectMethodHandle) mh).checkCast(obj);
500 }
501
502 Object checkCast(Object obj) {
503 return member.getReturnType().cast(obj);
504 }
505
506 // Caching machinery for field accessors:
507 private static final byte
508 AF_GETFIELD = 0,
509 AF_PUTFIELD = 1,
510 AF_GETSTATIC = 2,
511 AF_PUTSTATIC = 3,
512 AF_GETSTATIC_INIT = 4,
513 AF_PUTSTATIC_INIT = 5,
514 AF_LIMIT = 6;
515 // Enumerate the different field kinds using Wrapper,
516 // with an extra case added for checked references.
517 private static final int
518 FT_LAST_WRAPPER = Wrapper.values().length-1,
519 FT_UNCHECKED_REF = Wrapper.OBJECT.ordinal(),
520 FT_CHECKED_REF = FT_LAST_WRAPPER+1,
521 FT_LIMIT = FT_LAST_WRAPPER+2;
522 private static int afIndex(byte formOp, boolean isVolatile, int ftypeKind) {
523 return ((formOp * FT_LIMIT * 2)
524 + (isVolatile ? FT_LIMIT : 0)
525 + ftypeKind);
526 }
527 @Stable
528 private static final LambdaForm[] ACCESSOR_FORMS
529 = new LambdaForm[afIndex(AF_LIMIT, false, 0)];
530 private static int ftypeKind(Class<?> ftype) {
531 if (ftype.isPrimitive())
532 return Wrapper.forPrimitiveType(ftype).ordinal();
533 else if (VerifyType.isNullReferenceConversion(Object.class, ftype))
534 return FT_UNCHECKED_REF;
535 else
536 return FT_CHECKED_REF;
537 }
538
539 /**
540 * Create a LF which can access the given field.
541 * Cache and share this structure among all fields with
542 * the same basicType and refKind.
543 */
544 private static LambdaForm preparedFieldLambdaForm(MemberName m) {
545 Class<?> ftype = m.getFieldType();
546 boolean isVolatile = m.isVolatile();
547 byte formOp;
548 switch (m.getReferenceKind()) {
549 case REF_getField: formOp = AF_GETFIELD; break;
550 case REF_putField: formOp = AF_PUTFIELD; break;
551 case REF_getStatic: formOp = AF_GETSTATIC; break;
552 case REF_putStatic: formOp = AF_PUTSTATIC; break;
553 default: throw new InternalError(m.toString());
554 }
555 if (shouldBeInitialized(m)) {
556 // precompute the barrier-free version:
557 preparedFieldLambdaForm(formOp, isVolatile, ftype);
558 assert((AF_GETSTATIC_INIT - AF_GETSTATIC) ==
559 (AF_PUTSTATIC_INIT - AF_PUTSTATIC));
560 formOp += (AF_GETSTATIC_INIT - AF_GETSTATIC);
561 }
562 LambdaForm lform = preparedFieldLambdaForm(formOp, isVolatile, ftype);
563 maybeCompile(lform, m);
564 assert(lform.methodType().dropParameterTypes(0, 1)
565 .equals(m.getInvocationType().basicType()))
566 : Arrays.asList(m, m.getInvocationType().basicType(), lform, lform.methodType());
567 return lform;
568 }
569 private static LambdaForm preparedFieldLambdaForm(byte formOp, boolean isVolatile, Class<?> ftype) {
570 int ftypeKind = ftypeKind(ftype);
571 int afIndex = afIndex(formOp, isVolatile, ftypeKind);
572 LambdaForm lform = ACCESSOR_FORMS[afIndex];
573 if (lform != null) return lform;
574 lform = makePreparedFieldLambdaForm(formOp, isVolatile, ftypeKind);
575 ACCESSOR_FORMS[afIndex] = lform; // don't bother with a CAS
576 return lform;
577 }
578
579 private static LambdaForm makePreparedFieldLambdaForm(byte formOp, boolean isVolatile, int ftypeKind) {
580 boolean isGetter = (formOp & 1) == (AF_GETFIELD & 1);
581 boolean isStatic = (formOp >= AF_GETSTATIC);
582 boolean needsInit = (formOp >= AF_GETSTATIC_INIT);
583 boolean needsCast = (ftypeKind == FT_CHECKED_REF);
584 Wrapper fw = (needsCast ? Wrapper.OBJECT : Wrapper.values()[ftypeKind]);
585 Class<?> ft = fw.primitiveType();
586 assert(ftypeKind(needsCast ? String.class : ft) == ftypeKind);
587 String tname = fw.primitiveSimpleName();
588 String ctname = Character.toUpperCase(tname.charAt(0)) + tname.substring(1);
589 if (isVolatile) ctname += "Volatile";
590 String getOrPut = (isGetter ? "get" : "put");
591 String linkerName = (getOrPut + ctname); // getObject, putIntVolatile, etc.
592 MethodType linkerType;
593 if (isGetter)
594 linkerType = MethodType.methodType(ft, Object.class, long.class);
595 else
596 linkerType = MethodType.methodType(void.class, Object.class, long.class, ft);
597 MemberName linker = new MemberName(Unsafe.class, linkerName, linkerType, REF_invokeVirtual);
598 try {
599 linker = IMPL_NAMES.resolveOrFail(REF_invokeVirtual, linker, null, NoSuchMethodException.class);
600 } catch (ReflectiveOperationException ex) {
601 throw newInternalError(ex);
602 }
603
604 // What is the external type of the lambda form?
605 MethodType mtype;
606 if (isGetter)
607 mtype = MethodType.methodType(ft);
608 else
609 mtype = MethodType.methodType(void.class, ft);
610 mtype = mtype.basicType(); // erase short to int, etc.
611 if (!isStatic)
612 mtype = mtype.insertParameterTypes(0, Object.class);
613 final int DMH_THIS = 0;
614 final int ARG_BASE = 1;
615 final int ARG_LIMIT = ARG_BASE + mtype.parameterCount();
616 // if this is for non-static access, the base pointer is stored at this index:
617 final int OBJ_BASE = isStatic ? -1 : ARG_BASE;
618 // if this is for write access, the value to be written is stored at this index:
619 final int SET_VALUE = isGetter ? -1 : ARG_LIMIT - 1;
620 int nameCursor = ARG_LIMIT;
621 final int F_HOLDER = (isStatic ? nameCursor++ : -1); // static base if any
622 final int F_OFFSET = nameCursor++; // Either static offset or field offset.
623 final int OBJ_CHECK = (OBJ_BASE >= 0 ? nameCursor++ : -1);
624 final int INIT_BAR = (needsInit ? nameCursor++ : -1);
625 final int PRE_CAST = (needsCast && !isGetter ? nameCursor++ : -1);
626 final int LINKER_CALL = nameCursor++;
627 final int POST_CAST = (needsCast && isGetter ? nameCursor++ : -1);
628 final int RESULT = nameCursor-1; // either the call or the cast
629 Name[] names = arguments(nameCursor - ARG_LIMIT, mtype.invokerType());
630 if (needsInit)
631 names[INIT_BAR] = new Name(NF_ensureInitialized, names[DMH_THIS]);
632 if (needsCast && !isGetter)
633 names[PRE_CAST] = new Name(NF_checkCast, names[DMH_THIS], names[SET_VALUE]);
634 Object[] outArgs = new Object[1 + linkerType.parameterCount()];
635 assert(outArgs.length == (isGetter ? 3 : 4));
636 outArgs[0] = UNSAFE;
637 if (isStatic) {
638 outArgs[1] = names[F_HOLDER] = new Name(NF_staticBase, names[DMH_THIS]);
639 outArgs[2] = names[F_OFFSET] = new Name(NF_staticOffset, names[DMH_THIS]);
640 } else {
641 outArgs[1] = names[OBJ_CHECK] = new Name(NF_checkBase, names[OBJ_BASE]);
642 outArgs[2] = names[F_OFFSET] = new Name(NF_fieldOffset, names[DMH_THIS]);
643 }
644 if (!isGetter) {
645 outArgs[3] = (needsCast ? names[PRE_CAST] : names[SET_VALUE]);
646 }
647 for (Object a : outArgs) assert(a != null);
648 names[LINKER_CALL] = new Name(linker, outArgs);
649 if (needsCast && isGetter)
650 names[POST_CAST] = new Name(NF_checkCast, names[DMH_THIS], names[LINKER_CALL]);
651 for (Name n : names) assert(n != null);
652 String fieldOrStatic = (isStatic ? "Static" : "Field");
653 String lambdaName = (linkerName + fieldOrStatic); // significant only for debugging
654 if (needsCast) lambdaName += "Cast";
655 if (needsInit) lambdaName += "Init";
656 return new LambdaForm(lambdaName, ARG_LIMIT, names, RESULT);
657 }
658
659 /**
660 * Pre-initialized NamedFunctions for bootstrapping purposes.
661 * Factored in an inner class to delay initialization until first usage.
662 */
663 static final NamedFunction
664 NF_internalMemberName,
665 NF_internalMemberNameEnsureInit,
666 NF_ensureInitialized,
667 NF_fieldOffset,
668 NF_checkBase,
669 NF_staticBase,
670 NF_staticOffset,
671 NF_checkCast,
672 NF_allocateInstance,
673 NF_constructorMethod;
674 static {
675 try {
676 NamedFunction nfs[] = {
677 NF_internalMemberName = new NamedFunction(DirectMethodHandle.class
678 .getDeclaredMethod("internalMemberName", Object.class)),
679 NF_internalMemberNameEnsureInit = new NamedFunction(DirectMethodHandle.class
680 .getDeclaredMethod("internalMemberNameEnsureInit", Object.class)),
681 NF_ensureInitialized = new NamedFunction(DirectMethodHandle.class
682 .getDeclaredMethod("ensureInitialized", Object.class)),
683 NF_fieldOffset = new NamedFunction(DirectMethodHandle.class
684 .getDeclaredMethod("fieldOffset", Object.class)),
685 NF_checkBase = new NamedFunction(DirectMethodHandle.class
686 .getDeclaredMethod("checkBase", Object.class)),
687 NF_staticBase = new NamedFunction(DirectMethodHandle.class
688 .getDeclaredMethod("staticBase", Object.class)),
689 NF_staticOffset = new NamedFunction(DirectMethodHandle.class
690 .getDeclaredMethod("staticOffset", Object.class)),
691 NF_checkCast = new NamedFunction(DirectMethodHandle.class
692 .getDeclaredMethod("checkCast", Object.class, Object.class)),
693 NF_allocateInstance = new NamedFunction(DirectMethodHandle.class
694 .getDeclaredMethod("allocateInstance", Object.class)),
695 NF_constructorMethod = new NamedFunction(DirectMethodHandle.class
696 .getDeclaredMethod("constructorMethod", Object.class))
697 };
698 // Each nf must be statically invocable or we get tied up in our bootstraps.
699 assert(InvokerBytecodeGenerator.isStaticallyInvocable(nfs));
700 } catch (ReflectiveOperationException ex) {
701 throw newInternalError(ex);
702 }
703 }
704
705 static {
706 // The DMH class will contain pre-generated DirectMethodHandles resolved
707 // speculatively using MemberName.getFactory().resolveOrNull. However, that
708 // doesn't initialize the class, which subtly breaks inlining etc. By forcing
709 // initialization of the Holder class we avoid these issues.
710 UNSAFE.ensureClassInitialized(Holder.class);
711 }
712
713 /* Placeholder class for DirectMethodHandles generated ahead of time */
714 private final class Holder {}
715 }