1 /*
2 * Copyright (c) 2008, 2024, 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.vm.annotation.Stable;
29
30 import java.util.ArrayList;
31 import java.util.List;
32
33 import static java.lang.invoke.LambdaForm.BasicType;
34 import static java.lang.invoke.LambdaForm.BasicType.*;
35 import static java.lang.invoke.MethodHandles.Lookup.IMPL_LOOKUP;
36 import static java.lang.invoke.MethodHandleNatives.Constants.*;
37 import static java.lang.invoke.MethodHandleStatics.newInternalError;
38 import static java.lang.invoke.MethodHandleStatics.uncaughtException;
39
40 /**
41 * The flavor of method handle which emulates an invoke instruction
42 * on a predetermined argument. The JVM dispatches to the correct method
43 * when the handle is created, not when it is invoked.
44 *
45 * All bound arguments are encapsulated in dedicated species.
46 */
47 /*non-public*/
48 abstract non-sealed class BoundMethodHandle extends MethodHandle {
49
50 /*non-public*/
51 BoundMethodHandle(MethodType type, LambdaForm form) {
52 super(type, form);
53 assert(speciesData() == speciesDataFor(form));
54 }
55
56 //
57 // BMH API and internals
58 //
59
60 /*non-public*/
61 LambdaFormEditor editor() {
62 return form.editor();
63 }
64
65 static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, Object x) {
66 return Species_L.make(type, form, x);
67 }
68
69 @Override // there is a default binder in the super class, for 'L' types only
70 /*non-public*/
71 BoundMethodHandle bindArgumentL(int pos, Object value) {
72 return editor().bindArgumentL(this, pos, value);
73 }
74
75 /*non-public*/
76 BoundMethodHandle bindArgumentI(int pos, int value) {
77 return editor().bindArgumentI(this, pos, value);
78 }
79 /*non-public*/
80 BoundMethodHandle bindArgumentJ(int pos, long value) {
81 return editor().bindArgumentJ(this, pos, value);
82 }
83 /*non-public*/
84 BoundMethodHandle bindArgumentF(int pos, float value) {
85 return editor().bindArgumentF(this, pos, value);
86 }
87 /*non-public*/
88 BoundMethodHandle bindArgumentD(int pos, double value) {
89 return editor().bindArgumentD(this, pos, value);
90 }
91 @Override
92 BoundMethodHandle rebind() {
93 if (!tooComplex()) {
94 return this;
95 }
96 return makeReinvoker(this);
97 }
98
99 private boolean tooComplex() {
100 return (fieldCount() > FIELD_COUNT_THRESHOLD ||
101 form.expressionCount() > FORM_EXPRESSION_THRESHOLD);
102 }
103 private static final int FIELD_COUNT_THRESHOLD = 12; // largest convenient BMH field count
104 private static final int FORM_EXPRESSION_THRESHOLD = 24; // largest convenient BMH expression count
105
106 /**
107 * A reinvoker MH has this form:
108 * {@code lambda (bmh, arg*) { thismh = bmh[0]; invokeBasic(thismh, arg*) }}
109 */
110 static BoundMethodHandle makeReinvoker(MethodHandle target) {
111 LambdaForm form = DelegatingMethodHandle.makeReinvokerForm(
112 target, MethodTypeForm.LF_REBIND,
113 Species_L.BMH_SPECIES, Species_L.BMH_SPECIES.getterFunction(0));
114 return Species_L.make(target.type(), form, target);
115 }
116
117 /**
118 * Return the {@link BoundMethodHandle.SpeciesData} instance representing this BMH species. All subclasses must provide a
119 * static field containing this value, and they must accordingly implement this method.
120 */
121 /*non-public*/
122 abstract BoundMethodHandle.SpeciesData speciesData();
123
124 /*non-public*/
125 static BoundMethodHandle.SpeciesData speciesDataFor(LambdaForm form) {
126 Object c = form.names[0].constraint;
127 if (c instanceof SpeciesData sd) {
128 return sd;
129 }
130 // if there is no BMH constraint, then use the null constraint
131 return SPECIALIZER.topSpecies();
132 }
133
134 /**
135 * Return the number of fields in this BMH. Equivalent to speciesData().fieldCount().
136 */
137 /*non-public*/
138 final int fieldCount() { return speciesData().fieldCount(); }
139
140 @Override
141 Object internalProperties(int indentLevel) {
142 return "\n" + debugPrefix(indentLevel) + "& BMH=" + internalValues(indentLevel);
143 }
144
145 @Override
146 final String internalValues(int indentLevel) {
147 String prefix = debugPrefix(indentLevel);
148 int count = fieldCount();
149 if (count == 1 && indentLevel < 0) {
150 return "[" + arg(0) + "]";
151 }
152 StringBuilder sb = new StringBuilder("[");
153 for (int i = 0; i < count; ++i) {
154 Object theArg = arg(i);
155 sb.append("\n ").append(prefix).append(i);
156 if (indentLevel >= 0 && theArg instanceof MethodHandle mh) {
157 sb.append(": MethodHandle = {").append(mh.debugString(indentLevel+1));
158 sb.append("\n ").append(prefix).append("}");
159 } else {
160 sb.append(": ( ").append(theArg).append(" )");
161 }
162 }
163 return sb.append("\n").append(prefix).append("]").toString();
164 }
165
166 /*non-public*/
167 final Object arg(int i) {
168 try {
169 Class<?> fieldType = speciesData().fieldTypes().get(i);
170 switch (BasicType.basicType(fieldType)) {
171 case L_TYPE: return speciesData().getter(i).invokeBasic(this);
172 case I_TYPE: return (int) speciesData().getter(i).invokeBasic(this);
173 case J_TYPE: return (long) speciesData().getter(i).invokeBasic(this);
174 case F_TYPE: return (float) speciesData().getter(i).invokeBasic(this);
175 case D_TYPE: return (double) speciesData().getter(i).invokeBasic(this);
176 }
177 } catch (Throwable ex) {
178 throw uncaughtException(ex);
179 }
180 throw new InternalError("unexpected type: " + speciesData().key()+"."+i);
181 }
182
183 //
184 // cloning API
185 //
186
187 /*non-public*/
188 abstract BoundMethodHandle copyWith(MethodType mt, LambdaForm lf);
189 /*non-public*/
190 abstract BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg);
191 /*non-public*/
192 abstract BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg);
193 /*non-public*/
194 abstract BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg);
195 /*non-public*/
196 abstract BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg);
197 /*non-public*/
198 abstract BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg);
199
200 //
201 // concrete BMH classes required to close bootstrap loops
202 //
203
204 private // make it private to force users to access the enclosing class first
205 static final class Species_L extends BoundMethodHandle {
206
207 final Object argL0;
208
209 private Species_L(MethodType mt, LambdaForm lf, Object argL0) {
210 super(mt, lf);
211 this.argL0 = argL0;
212 }
213
214 @Override
215 /*non-public*/
216 SpeciesData speciesData() {
217 return BMH_SPECIES;
218 }
219
220 /*non-public*/
221 static @Stable SpeciesData BMH_SPECIES;
222
223 /*non-public*/
224 static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0) {
225 return new Species_L(mt, lf, argL0);
226 }
227 @Override
228 /*non-public*/
229 final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
230 return new Species_L(mt, lf, argL0);
231 }
232 @Override
233 /*non-public*/
234 final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
235 try {
236 return (BoundMethodHandle) BMH_SPECIES.extendWith(L_TYPE).factory().invokeBasic(mt, lf, argL0, narg);
237 } catch (Throwable ex) {
238 throw uncaughtException(ex);
239 }
240 }
241 @Override
242 /*non-public*/
243 final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
244 try {
245 return (BoundMethodHandle) BMH_SPECIES.extendWith(I_TYPE).factory().invokeBasic(mt, lf, argL0, narg);
246 } catch (Throwable ex) {
247 throw uncaughtException(ex);
248 }
249 }
250 @Override
251 /*non-public*/
252 final BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg) {
253 try {
254 return (BoundMethodHandle) BMH_SPECIES.extendWith(J_TYPE).factory().invokeBasic(mt, lf, argL0, narg);
255 } catch (Throwable ex) {
256 throw uncaughtException(ex);
257 }
258 }
259 @Override
260 /*non-public*/
261 final BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg) {
262 try {
263 return (BoundMethodHandle) BMH_SPECIES.extendWith(F_TYPE).factory().invokeBasic(mt, lf, argL0, narg);
264 } catch (Throwable ex) {
265 throw uncaughtException(ex);
266 }
267 }
268 @Override
269 /*non-public*/
270 final BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg) {
271 try {
272 return (BoundMethodHandle) BMH_SPECIES.extendWith(D_TYPE).factory().invokeBasic(mt, lf, argL0, narg);
273 } catch (Throwable ex) {
274 throw uncaughtException(ex);
275 }
276 }
277 }
278
279 //
280 // BMH species meta-data
281 //
282
283 /*non-public*/
284 static final class SpeciesData
285 extends ClassSpecializer<BoundMethodHandle, String, SpeciesData>.SpeciesData {
286 // This array is filled in lazily, as new species come into being over time.
287 @Stable private final SpeciesData[] extensions = new SpeciesData[ARG_TYPE_LIMIT];
288
289 public SpeciesData(Specializer outer, String key) {
290 outer.super(key);
291 }
292
293 @Override
294 protected String deriveClassName() {
295 String typeString = deriveTypeString();
296 if (typeString.isEmpty()) {
297 return SimpleMethodHandle.class.getName();
298 }
299 return BoundMethodHandle.class.getName() + "$Species_" + typeString;
300 }
301
302 @Override
303 protected List<Class<?>> deriveFieldTypes(String key) {
304 ArrayList<Class<?>> types = new ArrayList<>(key.length());
305 for (int i = 0; i < key.length(); i++) {
306 types.add(basicType(key.charAt(i)).basicTypeClass());
307 }
308 return types;
309 }
310
311 @Override
312 protected String deriveTypeString() {
313 // (If/when we have to add nominal types, just inherit the more complex default.)
314 return key();
315 }
316
317 @Override
318 protected MethodHandle deriveTransformHelper(MemberName transform, int whichtm) {
319 if (whichtm == Specializer.TN_COPY_NO_EXTEND) {
320 return factory();
321 } else if (whichtm < ARG_TYPE_LIMIT) {
322 return extendWith(BasicType.basicType((byte) whichtm)).factory();
323 } else {
324 throw newInternalError("bad transform");
325 }
326 }
327
328 @Override
329 protected <X> List<X> deriveTransformHelperArguments(MemberName transform, int whichtm, List<X> args, List<X> fields) {
330 assert(verifyTHAargs(transform, whichtm, args, fields));
331 // The rule is really simple: Keep the first two arguments
332 // the same, then put in the fields, then put any other argument.
333 args.addAll(2, fields);
334 return args;
335 }
336
337 private boolean verifyTHAargs(MemberName transform, int whichtm, List<?> args, List<?> fields) {
338 assert(transform == Specializer.BMH_TRANSFORMS.get(whichtm));
339 MethodType tType = transform.getMethodType();
340 assert(args.size() == tType.parameterCount());
341 assert(fields.size() == this.fieldCount());
342 final int MH_AND_LF = 2;
343 if (whichtm == Specializer.TN_COPY_NO_EXTEND) {
344 assert(tType.parameterCount() == MH_AND_LF);
345 } else if (whichtm < ARG_TYPE_LIMIT) {
346 assert(tType.parameterCount() == MH_AND_LF+1);
347 final BasicType type = basicType((byte) whichtm);
348 assert(tType.parameterType(MH_AND_LF) == type.basicTypeClass());
349 } else {
350 return false;
351 }
352 return true;
353 }
354
355 /*non-public*/
356 SpeciesData extendWith(BasicType basicType) {
357 int typeNum = basicType.ordinal();
358 SpeciesData sd = extensions[typeNum];
359 if (sd != null) return sd;
360 sd = SPECIALIZER.findSpecies(key() + basicType.basicTypeChar());
361 extensions[typeNum] = sd;
362 return sd;
363 }
364 }
365
366 static class AOTHolder {
367 static final Specializer SPECIALIZER = new Specializer();
368 static final SpeciesData SimpleMethodHandle_BMH_SPECIES = SPECIALIZER.findSpecies("");
369 static final SpeciesData Species_L_BMH_SPECIES = SPECIALIZER.findSpecies("L");
370 }
371
372 /*non-public*/
373 static final Specializer SPECIALIZER = AOTHolder.SPECIALIZER;
374 static {
375 SimpleMethodHandle.BMH_SPECIES = AOTHolder.SimpleMethodHandle_BMH_SPECIES;
376 Species_L.BMH_SPECIES = AOTHolder.Species_L_BMH_SPECIES;
377 }
378
379 /*non-public*/
380 static final class Specializer
381 extends ClassSpecializer<BoundMethodHandle, String, SpeciesData> {
382
383 private static final MemberName SPECIES_DATA_ACCESSOR;
384
385 static {
386 try {
387 SPECIES_DATA_ACCESSOR = IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, BoundMethodHandle.class,
388 "speciesData", MethodType.methodType(BoundMethodHandle.SpeciesData.class));
389 } catch (ReflectiveOperationException ex) {
390 throw newInternalError("Bootstrap link error", ex);
391 }
392 }
393
394 private Specializer() {
395 super( // Reified type parameters:
396 BoundMethodHandle.class, String.class, BoundMethodHandle.SpeciesData.class,
397 // Principal constructor type:
398 MethodType.methodType(void.class, MethodType.class, LambdaForm.class),
399 // Required linkage between class and species:
400 SPECIES_DATA_ACCESSOR,
401 "BMH_SPECIES",
402 BMH_TRANSFORMS);
403 }
404
405 @Override
406 protected String topSpeciesKey() {
407 return "";
408 }
409
410 @Override
411 protected BoundMethodHandle.SpeciesData newSpeciesData(String key) {
412 return new BoundMethodHandle.SpeciesData(this, key);
413 }
414
415 static final List<MemberName> BMH_TRANSFORMS;
416 static final int TN_COPY_NO_EXTEND = V_TYPE.ordinal();
417 static {
418 final Class<BoundMethodHandle> BMH = BoundMethodHandle.class;
419 // copyWithExtendLIJFD + copyWith
420 try {
421 BMH_TRANSFORMS = List.of(
422 IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, BMH, "copyWithExtendL", MethodType.methodType(BMH, MethodType.class, LambdaForm.class, Object.class)),
423 IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, BMH, "copyWithExtendI", MethodType.methodType(BMH, MethodType.class, LambdaForm.class, int.class)),
424 IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, BMH, "copyWithExtendJ", MethodType.methodType(BMH, MethodType.class, LambdaForm.class, long.class)),
425 IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, BMH, "copyWithExtendF", MethodType.methodType(BMH, MethodType.class, LambdaForm.class, float.class)),
426 IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, BMH, "copyWithExtendD", MethodType.methodType(BMH, MethodType.class, LambdaForm.class, double.class)),
427 IMPL_LOOKUP.resolveOrFail(REF_invokeVirtual, BMH, "copyWith", MethodType.methodType(BMH, MethodType.class, LambdaForm.class))
428 );
429 } catch (ReflectiveOperationException ex) {
430 throw newInternalError("Failed resolving copyWith methods", ex);
431 }
432
433 // as it happens, there is one transform per BasicType including V_TYPE
434 assert(BMH_TRANSFORMS.size() == TYPE_LIMIT);
435 }
436
437 /**
438 * Generation of concrete BMH classes.
439 *
440 * A concrete BMH species is fit for binding a number of values adhering to a
441 * given type pattern. Reference types are erased.
442 *
443 * BMH species are cached by type pattern.
444 *
445 * A BMH species has a number of fields with the concrete (possibly erased) types of
446 * bound values. Setters are provided as an API in BMH. Getters are exposed as MHs,
447 * which can be included as names in lambda forms.
448 */
449 class Factory extends ClassSpecializer<BoundMethodHandle, String, BoundMethodHandle.SpeciesData>.Factory {
450 @Override
451 protected String chooseFieldName(Class<?> type, int index) {
452 return "arg" + super.chooseFieldName(type, index);
453 }
454 }
455
456 @Override
457 protected Factory makeFactory() {
458 return new Factory();
459 }
460 }
461
462 static SpeciesData speciesData_L() { return Species_L.BMH_SPECIES; }
463 static SpeciesData speciesData_LL() { return SPECIALIZER.findSpecies("LL"); }
464 static SpeciesData speciesData_LLL() { return SPECIALIZER.findSpecies("LLL"); }
465 static SpeciesData speciesData_LLLL() { return SPECIALIZER.findSpecies("LLLL"); }
466 static SpeciesData speciesData_LLLLL() { return SPECIALIZER.findSpecies("LLLLL"); }
467 }