1 /*
2 * Copyright (c) 2008, 2016, 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 import sun.invoke.util.ValueConversions;
30
31 import java.lang.reflect.Method;
32 import java.util.ArrayList;
33 import java.util.List;
34 import java.util.Objects;
35
36 import static java.lang.invoke.LambdaForm.BasicType;
37 import static java.lang.invoke.LambdaForm.BasicType.*;
38 import static java.lang.invoke.MethodHandleStatics.newInternalError;
39 import static java.lang.invoke.MethodHandleStatics.uncaughtException;
40
41 /**
42 * The flavor of method handle which emulates an invoke instruction
43 * on a predetermined argument. The JVM dispatches to the correct method
44 * when the handle is created, not when it is invoked.
45 *
46 * All bound arguments are encapsulated in dedicated species.
47 */
48 /*non-public*/ abstract class BoundMethodHandle extends MethodHandle {
49
50 /*non-public*/ BoundMethodHandle(MethodType type, LambdaForm form) {
51 super(type, form);
52 assert(speciesData() == formSpeciesData(form));
53 }
54
55 //
56 // BMH API and internals
57 //
58
59 static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, BasicType xtype, Object x) {
60 // for some type signatures, there exist pre-defined concrete BMH classes
61 try {
62 switch (xtype) {
63 case L_TYPE:
64 return bindSingle(type, form, x); // Use known fast path.
65 case I_TYPE:
66 return (BoundMethodHandle) SPECIALIZER.topSpecies().extendWith(I_TYPE_NUM).factory().invokeBasic(type, form, ValueConversions.widenSubword(x));
67 case J_TYPE:
68 return (BoundMethodHandle) SPECIALIZER.topSpecies().extendWith(J_TYPE_NUM).factory().invokeBasic(type, form, (long) x);
69 case F_TYPE:
70 return (BoundMethodHandle) SPECIALIZER.topSpecies().extendWith(F_TYPE_NUM).factory().invokeBasic(type, form, (float) x);
71 case D_TYPE:
72 return (BoundMethodHandle) SPECIALIZER.topSpecies().extendWith(D_TYPE_NUM).factory().invokeBasic(type, form, (double) x);
73 default : throw newInternalError("unexpected xtype: " + xtype);
74 }
75 } catch (Throwable t) {
76 throw uncaughtException(t);
77 }
78 }
79
80 /*non-public*/
81 LambdaFormEditor editor() {
82 return form.editor();
83 }
84
85 static BoundMethodHandle bindSingle(MethodType type, LambdaForm form, Object x) {
86 return Species_L.make(type, form, x);
87 }
88
89 @Override // there is a default binder in the super class, for 'L' types only
90 /*non-public*/
91 BoundMethodHandle bindArgumentL(int pos, Object value) {
92 return editor().bindArgumentL(this, pos, value);
93 }
94
95 /*non-public*/
96 BoundMethodHandle bindArgumentI(int pos, int value) {
97 return editor().bindArgumentI(this, pos, value);
98 }
99 /*non-public*/
100 BoundMethodHandle bindArgumentJ(int pos, long value) {
101 return editor().bindArgumentJ(this, pos, value);
102 }
103 /*non-public*/
104 BoundMethodHandle bindArgumentF(int pos, float value) {
105 return editor().bindArgumentF(this, pos, value);
106 }
107 /*non-public*/
108 BoundMethodHandle bindArgumentD(int pos, double value) {
109 return editor().bindArgumentD(this, pos, value);
110 }
111 @Override
112 BoundMethodHandle rebind() {
113 if (!tooComplex()) {
114 return this;
115 }
116 return makeReinvoker(this);
117 }
118
119 private boolean tooComplex() {
120 return (fieldCount() > FIELD_COUNT_THRESHOLD ||
121 form.expressionCount() > FORM_EXPRESSION_THRESHOLD);
122 }
123 private static final int FIELD_COUNT_THRESHOLD = 12; // largest convenient BMH field count
124 private static final int FORM_EXPRESSION_THRESHOLD = 24; // largest convenient BMH expression count
125
126 /**
127 * A reinvoker MH has this form:
128 * {@code lambda (bmh, arg*) { thismh = bmh[0]; invokeBasic(thismh, arg*) }}
129 */
130 static BoundMethodHandle makeReinvoker(MethodHandle target) {
131 LambdaForm form = DelegatingMethodHandle.makeReinvokerForm(
132 target, MethodTypeForm.LF_REBIND,
133 Species_L.BMH_SPECIES, Species_L.BMH_SPECIES.getterFunction(0));
134 return Species_L.make(target.type(), form, target);
135 }
136
137 /**
138 * Return the {@link BMHSpecies} instance representing this BMH species. All subclasses must provide a
139 * static field containing this value, and they must accordingly implement this method.
140 */
141 /*non-public*/ abstract BMHSpecies speciesData();
142
143 /*non-public*/ static BMHSpecies formSpeciesData(LambdaForm form) {
144 Object c = form.names[0].constraint;
145 if (c instanceof BMHSpecies) {
146 return (BMHSpecies) c;
147 }
148 // if there is no BMH constraint, then use the null constraint
149 return SPECIALIZER.topSpecies();
150 }
151
152 /**
153 * Return the number of fields in this BMH. Equivalent to speciesData().fieldCount().
154 */
155 /*non-public*/ final int fieldCount() { return speciesData().fieldCount(); }
156
157 @Override
158 Object internalProperties() {
159 return "\n& BMH="+internalValues();
160 }
161
162 @Override
163 final String internalValues() {
164 int count = fieldCount();
165 if (count == 1) {
166 return "[" + arg(0) + "]";
167 }
168 StringBuilder sb = new StringBuilder("[");
169 for (int i = 0; i < count; ++i) {
170 sb.append("\n ").append(i).append(": ( ").append(arg(i)).append(" )");
171 }
172 return sb.append("\n]").toString();
173 }
174
175 /*non-public*/ final Object arg(int i) {
176 try {
177 switch (BasicType.basicType(speciesData().fieldTypes().get(i))) {
178 case L_TYPE: return speciesData().getter(i).invokeBasic(this);
179 case I_TYPE: return (int) speciesData().getter(i).invokeBasic(this);
180 case J_TYPE: return (long) speciesData().getter(i).invokeBasic(this);
181 case F_TYPE: return (float) speciesData().getter(i).invokeBasic(this);
182 case D_TYPE: return (double) speciesData().getter(i).invokeBasic(this);
183 }
184 } catch (Throwable ex) {
185 throw uncaughtException(ex);
186 }
187 throw new InternalError("unexpected type: " + speciesData().key()+"."+i);
188 }
189
190 //
191 // cloning API
192 //
193
194 /*non-public*/ abstract BoundMethodHandle copyWith(MethodType mt, LambdaForm lf);
195 /*non-public*/ abstract BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg);
196 /*non-public*/ abstract BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg);
197 /*non-public*/ abstract BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg);
198 /*non-public*/ abstract BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg);
199 /*non-public*/ abstract BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg);
200
201 //
202 // concrete BMH classes required to close bootstrap loops
203 //
204
205 private // make it private to force users to access the enclosing class first
206 static final class Species_L extends BoundMethodHandle {
207 final Object argL0;
208 private Species_L(MethodType mt, LambdaForm lf, Object argL0) {
209 super(mt, lf);
210 this.argL0 = argL0;
211 }
212 @Override
213 /*non-public*/ BMHSpecies speciesData() {
214 return BMH_SPECIES;
215 }
216 /*non-public*/ static @Stable
217 BMHSpecies BMH_SPECIES;
218 /*non-public*/ static BoundMethodHandle make(MethodType mt, LambdaForm lf, Object argL0) {
219 return new Species_L(mt, lf, argL0);
220 }
221 @Override
222 /*non-public*/ final BoundMethodHandle copyWith(MethodType mt, LambdaForm lf) {
223 return new Species_L(mt, lf, argL0);
224 }
225 @Override
226 /*non-public*/ final BoundMethodHandle copyWithExtendL(MethodType mt, LambdaForm lf, Object narg) {
227 try {
228 return (BoundMethodHandle) BMH_SPECIES.extendWith(L_TYPE_NUM).factory().invokeBasic(mt, lf, argL0, narg);
229 } catch (Throwable ex) {
230 throw uncaughtException(ex);
231 }
232 }
233 @Override
234 /*non-public*/ final BoundMethodHandle copyWithExtendI(MethodType mt, LambdaForm lf, int narg) {
235 try {
236 return (BoundMethodHandle) BMH_SPECIES.extendWith(I_TYPE_NUM).factory().invokeBasic(mt, lf, argL0, narg);
237 } catch (Throwable ex) {
238 throw uncaughtException(ex);
239 }
240 }
241 @Override
242 /*non-public*/ final BoundMethodHandle copyWithExtendJ(MethodType mt, LambdaForm lf, long narg) {
243 try {
244 return (BoundMethodHandle) BMH_SPECIES.extendWith(J_TYPE_NUM).factory().invokeBasic(mt, lf, argL0, narg);
245 } catch (Throwable ex) {
246 throw uncaughtException(ex);
247 }
248 }
249 @Override
250 /*non-public*/ final BoundMethodHandle copyWithExtendF(MethodType mt, LambdaForm lf, float narg) {
251 try {
252 return (BoundMethodHandle) BMH_SPECIES.extendWith(F_TYPE_NUM).factory().invokeBasic(mt, lf, argL0, narg);
253 } catch (Throwable ex) {
254 throw uncaughtException(ex);
255 }
256 }
257 @Override
258 /*non-public*/ final BoundMethodHandle copyWithExtendD(MethodType mt, LambdaForm lf, double narg) {
259 try {
260 return (BoundMethodHandle) BMH_SPECIES.extendWith(D_TYPE_NUM).factory().invokeBasic(mt, lf, argL0, narg);
261 } catch (Throwable ex) {
262 throw uncaughtException(ex);
263 }
264 }
265 }
266
267 //
268 // BMH species meta-data
269 //
270
271 /*non-public*/
272 static final class BMHSpecies extends ClassSpecializer<BoundMethodHandle, String, BMHSpecies>.SpeciesData<BoundMethodHandle, String> {
273 // This array is filled in lazily, as new species come into being over time.
274 @Stable final private BMHSpecies[] extensions = new BMHSpecies[ARG_TYPE_LIMIT];
275
276 public BMHSpecies(Specializer outer, String key) {
277 outer.super(key);
278 }
279
280 @Override
281 protected List<Class<?>> deriveFieldTypes(String key) {
282 ArrayList<Class<?>> types = new ArrayList<>(key.length());
283 for (int i = 0; i < key.length(); i++) {
284 types.add(basicType(key.charAt(i)).basicTypeClass());
285 }
286 return types;
287 }
288
289 @Override
290 protected String deriveTypeString() {
291 // (If/when we have to add nominal types, just inherit the more complex default.)
292 return key();
293 }
294
295 @Override
296 protected MethodHandle deriveTransformHelper(Method transform, int whichtm) {
297 if (whichtm == Specializer.TN_COPY_NO_EXTEND)
298 return factory();
299 else if (whichtm < ARG_TYPE_LIMIT)
300 return extendWith((byte)whichtm).factory();
301 else
302 throw newInternalError("bad transform");
303 }
304
305 @Override
306 protected <X> List<X> deriveTransformHelperArguments(Method transform, int whichtm, List<X> args, List<X> fields) {
307 assert(verifyTHAargs(transform, whichtm, args, fields));
308 // The rule is really simple: Keep the first two arguments
309 // the same, then put in the fields, then put any other argument.
310 args.addAll(2, fields);
311 return args;
312 }
313 private boolean verifyTHAargs(Method transform, int whichtm, List<?> args, List<?> fields) {
314 assert(transform == Specializer.BMH_TRANSFORMS.get(whichtm));
315 assert(args.size() == transform.getParameterCount());
316 assert(fields.size() == this.fieldCount());
317 final int MH_AND_LF = 2;
318 if (whichtm == Specializer.TN_COPY_NO_EXTEND) {
319 assert(transform.getParameterCount() == MH_AND_LF);
320 } else if (whichtm < ARG_TYPE_LIMIT) {
321 assert(transform.getParameterCount() == MH_AND_LF+1);
322 final BasicType type = basicType((byte) whichtm);
323 assert(transform.getParameterTypes()[MH_AND_LF] == type.basicTypeClass());
324 } else {
325 return false;
326 }
327 return true;
328 }
329 //private boolean verfiyTHA();
330
331 /*non-public*/ BMHSpecies extendWith(byte typeNum) {
332 BMHSpecies sd = extensions[typeNum];
333 if (sd != null) return sd;
334 sd = SPECIALIZER.findSpecies(key() + BasicType.basicType(typeNum).basicTypeChar());
335 extensions[typeNum] = sd;
336 return sd;
337 }
338 }
339
340 /*non-public*/
341 static final Specializer SPECIALIZER = new Specializer();
342
343 /*non-public*/
344 static final class Specializer extends ClassSpecializer<BoundMethodHandle, String, BMHSpecies> {
345 private Specializer() {
346 super( // Reified type parameters:
347 BoundMethodHandle.class, String.class, BMHSpecies.class,
348 // Principal constructor type:
349 MethodType.methodType(void.class, MethodType.class, LambdaForm.class),
350 // Required linkage between class and species:
351 reflectMethod(BoundMethodHandle.class, "speciesData"),
352 "BMH_SPECIES",
353 BMH_TRANSFORMS);
354 }
355
356 @Override
357 protected String topSpeciesKey() {
358 return "";
359 }
360
361 @Override
362 protected String addFieldTypeToKey(String key, Class<?> type) {
363 BasicType bt = basicType(type);
364 if (type != bt.basicTypeClass()) throw newInternalError("must be basic-type");
365 Objects.requireNonNull(key);
366 return key + bt.basicTypeChar();
367 }
368
369 @Override
370 protected List<Class<? extends BoundMethodHandle>> predeclaredSpeciesCode() {
371 List<Class<? extends BoundMethodHandle>> result = new ArrayList<>();
372 // pick up all nested classes (Species_L):
373 result.addAll(super.predeclaredSpeciesCode());
374 // pick up the special nullary version:
375 result.add(SimpleMethodHandle.class);
376 return result;
377 }
378
379 @Override
380 protected BMHSpecies newSpeciesData(String key) {
381 return new BMHSpecies(this, key);
382 }
383
384 static final List<Method> BMH_TRANSFORMS;
385 static final int TN_COPY_NO_EXTEND = V_TYPE_NUM;
386 static {
387 ArrayList<Method> result = new ArrayList<>();
388 final Class<BoundMethodHandle> BMH = BoundMethodHandle.class;
389 Class<?>[] params = { MethodType.class, LambdaForm.class, null };
390 // for each basic type T, note the transform BMH::copyWithExtendT(MT, LF, T)
391 for (BasicType type : BasicType.ARG_TYPES) {
392 final String tname = "copyWithExtend" + type.basicTypeChar();
393 params[params.length-1] = type.basicTypeClass();
394 result.add(ClassSpecializer.reflectMethod(BMH, tname, params));
395 }
396 // at the end add BMH::copyWith(MT, LF)
397 assert(result.size() == TN_COPY_NO_EXTEND);
398 result.add(ClassSpecializer.reflectMethod(BMH, "copyWith", params[0], params[1]));
399 // as it happens, there is one transform per BasicType including V_TYPE
400 assert(result.size() == TYPE_LIMIT);
401 BMH_TRANSFORMS = List.of(result.toArray(new Method[result.size()]));
402 }
403
404 /**
405 * Generation of concrete BMH classes.
406 *
407 * A concrete BMH species is fit for binding a number of values adhering to a
408 * given type pattern. Reference types are erased.
409 *
410 * BMH species are cached by type pattern.
411 *
412 * A BMH species has a number of fields with the concrete (possibly erased) types of
413 * bound values. Setters are provided as an API in BMH. Getters are exposed as MHs,
414 * which can be included as names in lambda forms.
415 */
416 class Factory extends ClassSpecializer<BoundMethodHandle, String, BMHSpecies>.Factory {
417 @Override
418 protected String chooseFieldName(Class<?> type, int index) {
419 return "arg" + super.chooseFieldName(type, index);
420 }
421
422 @Override protected String loadSpeciesKeyFromPredefinedClass(Class<? extends BoundMethodHandle> speciesClass) {
423 if (speciesClass == SimpleMethodHandle.class) return "";
424 assert(speciesClass.getEnclosingClass() == BoundMethodHandle.class);
425 String name = speciesClass.getSimpleName();
426 assert(name.startsWith("Species_"));
427 final String key = name.substring(name.indexOf('_') + 1);
428 return key;
429 }
430 }
431
432 @Override
433 protected Factory makeFactory() {
434 return new Factory();
435 }
436 }
437
438 private static final BMHSpecies[] SPECIES_DATA_CACHE = new BMHSpecies[6];
439 private static BMHSpecies checkCache(int size, String types) {
440 int idx = size - 1;
441 BMHSpecies data = SPECIES_DATA_CACHE[idx];
442 if (data != null) return data;
443 SPECIES_DATA_CACHE[idx] = data = SPECIALIZER.findSpecies(types);
444 return data;
445 }
446 static BMHSpecies speciesData_L() { return checkCache(1, "L"); }
447 static BMHSpecies speciesData_LL() { return checkCache(2, "LL"); }
448 static BMHSpecies speciesData_LLL() { return checkCache(3, "LLL"); }
449 static BMHSpecies speciesData_LLLL() { return checkCache(4, "LLLL"); }
450 static BMHSpecies speciesData_LLLLL() { return checkCache(5, "LLLLL"); }
451 }