1 /*
2 * Copyright (c) 2011, 2023, 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.CDS;
29 import jdk.internal.perf.PerfCounter;
30 import jdk.internal.vm.annotation.DontInline;
31 import jdk.internal.vm.annotation.Hidden;
32 import jdk.internal.vm.annotation.Stable;
33 import sun.invoke.util.Wrapper;
34
35 import java.lang.annotation.ElementType;
36 import java.lang.annotation.Retention;
37 import java.lang.annotation.RetentionPolicy;
38 import java.lang.annotation.Target;
39 import java.lang.reflect.Method;
40 import java.util.Arrays;
41 import java.util.HashMap;
42
43 import static java.lang.invoke.LambdaForm.BasicType.*;
44 import static java.lang.invoke.MethodHandleNatives.Constants.*;
45 import static java.lang.invoke.MethodHandleStatics.*;
46
47 /**
48 * The symbolic, non-executable form of a method handle's invocation semantics.
49 * It consists of a series of names.
50 * The first N (N=arity) names are parameters,
51 * while any remaining names are temporary values.
52 * Each temporary specifies the application of a function to some arguments.
53 * The functions are method handles, while the arguments are mixes of
54 * constant values and local names.
55 * The result of the lambda is defined as one of the names, often the last one.
56 * <p>
57 * Here is an approximate grammar:
58 * <blockquote><pre>{@code
59 * LambdaForm = "(" ArgName* ")=>{" TempName* Result "}"
60 * ArgName = "a" N ":" T
61 * TempName = "t" N ":" T "=" Function "(" Argument* ");"
62 * Function = ConstantValue
63 * Argument = NameRef | ConstantValue
64 * Result = NameRef | "void"
65 * NameRef = "a" N | "t" N
66 * N = (any whole number)
67 * T = "L" | "I" | "J" | "F" | "D" | "V"
68 * }</pre></blockquote>
69 * Names are numbered consecutively from left to right starting at zero.
70 * (The letters are merely a taste of syntax sugar.)
71 * Thus, the first temporary (if any) is always numbered N (where N=arity).
72 * Every occurrence of a name reference in an argument list must refer to
73 * a name previously defined within the same lambda.
74 * A lambda has a void result if and only if its result index is -1.
75 * If a temporary has the type "V", it cannot be the subject of a NameRef,
76 * even though possesses a number.
77 * Note that all reference types are erased to "L", which stands for {@code Object}.
78 * All subword types (boolean, byte, short, char) are erased to "I" which is {@code int}.
79 * The other types stand for the usual primitive types.
80 * <p>
81 * Function invocation closely follows the static rules of the Java verifier.
82 * Arguments and return values must exactly match when their "Name" types are
83 * considered.
84 * Conversions are allowed only if they do not change the erased type.
85 * <ul>
86 * <li>L = Object: casts are used freely to convert into and out of reference types
87 * <li>I = int: subword types are forcibly narrowed when passed as arguments (see {@code explicitCastArguments})
88 * <li>J = long: no implicit conversions
89 * <li>F = float: no implicit conversions
90 * <li>D = double: no implicit conversions
91 * <li>V = void: a function result may be void if and only if its Name is of type "V"
92 * </ul>
93 * Although implicit conversions are not allowed, explicit ones can easily be
94 * encoded by using temporary expressions which call type-transformed identity functions.
95 * <p>
96 * Examples:
97 * <blockquote><pre>{@code
98 * (a0:J)=>{ a0 }
99 * == identity(long)
100 * (a0:I)=>{ t1:V = System.out#println(a0); void }
101 * == System.out#println(int)
102 * (a0:L)=>{ t1:V = System.out#println(a0); a0 }
103 * == identity, with printing side-effect
104 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
105 * t3:L = BoundMethodHandle#target(a0);
106 * t4:L = MethodHandle#invoke(t3, t2, a1); t4 }
107 * == general invoker for unary insertArgument combination
108 * (a0:L, a1:L)=>{ t2:L = FilterMethodHandle#filter(a0);
109 * t3:L = MethodHandle#invoke(t2, a1);
110 * t4:L = FilterMethodHandle#target(a0);
111 * t5:L = MethodHandle#invoke(t4, t3); t5 }
112 * == general invoker for unary filterArgument combination
113 * (a0:L, a1:L)=>{ ...(same as previous example)...
114 * t5:L = MethodHandle#invoke(t4, t3, a1); t5 }
115 * == general invoker for unary/unary foldArgument combination
116 * (a0:L, a1:I)=>{ t2:I = identity(long).asType((int)->long)(a1); t2 }
117 * == invoker for identity method handle which performs i2l
118 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
119 * t3:L = Class#cast(t2,a1); t3 }
120 * == invoker for identity method handle which performs cast
121 * }</pre></blockquote>
122 * <p>
123 * @author John Rose, JSR 292 EG
124 */
125 class LambdaForm {
126 final int arity;
127 final int result;
128 final boolean forceInline;
129 final MethodHandle customized;
130 @Stable final Name[] names;
131 final Kind kind;
132 MemberName vmentry; // low-level behavior, or null if not yet prepared
133 private boolean isCompiled;
134
135 // Either a LambdaForm cache (managed by LambdaFormEditor) or a link to uncustomized version (for customized LF)
136 volatile Object transformCache;
137
138 public static final int VOID_RESULT = -1, LAST_RESULT = -2;
139
140 enum BasicType {
141 L_TYPE('L', Object.class, Wrapper.OBJECT), // all reference types
142 I_TYPE('I', int.class, Wrapper.INT),
143 J_TYPE('J', long.class, Wrapper.LONG),
144 F_TYPE('F', float.class, Wrapper.FLOAT),
145 D_TYPE('D', double.class, Wrapper.DOUBLE), // all primitive types
146 V_TYPE('V', void.class, Wrapper.VOID); // not valid in all contexts
147
148 static final @Stable BasicType[] ALL_TYPES = BasicType.values();
149 static final @Stable BasicType[] ARG_TYPES = Arrays.copyOf(ALL_TYPES, ALL_TYPES.length-1);
150
151 static final int ARG_TYPE_LIMIT = ARG_TYPES.length;
152 static final int TYPE_LIMIT = ALL_TYPES.length;
153
154 final char btChar;
155 final Class<?> btClass;
156 final Wrapper btWrapper;
157
158 private BasicType(char btChar, Class<?> btClass, Wrapper wrapper) {
159 this.btChar = btChar;
160 this.btClass = btClass;
161 this.btWrapper = wrapper;
162 }
163
164 char basicTypeChar() {
165 return btChar;
166 }
167 Class<?> basicTypeClass() {
168 return btClass;
169 }
170 Wrapper basicTypeWrapper() {
171 return btWrapper;
172 }
173 int basicTypeSlots() {
174 return btWrapper.stackSlots();
175 }
176
177 static BasicType basicType(byte type) {
178 return ALL_TYPES[type];
179 }
180 static BasicType basicType(char type) {
181 return switch (type) {
182 case 'L' -> L_TYPE;
183 case 'I' -> I_TYPE;
184 case 'J' -> J_TYPE;
185 case 'F' -> F_TYPE;
186 case 'D' -> D_TYPE;
187 case 'V' -> V_TYPE;
188 // all subword types are represented as ints
189 case 'Z', 'B', 'S', 'C' -> I_TYPE;
190 default -> throw newInternalError("Unknown type char: '" + type + "'");
191 };
192 }
193 static BasicType basicType(Class<?> type) {
194 return basicType(Wrapper.basicTypeChar(type));
195 }
196 static int[] basicTypeOrds(BasicType[] types) {
197 if (types == null) {
198 return null;
199 }
200 int[] a = new int[types.length];
201 for(int i = 0; i < types.length; ++i) {
202 a[i] = types[i].ordinal();
203 }
204 return a;
205 }
206
207 static char basicTypeChar(Class<?> type) {
208 return basicType(type).btChar;
209 }
210
211 static int[] basicTypesOrd(Class<?>[] types) {
212 int[] ords = new int[types.length];
213 for (int i = 0; i < ords.length; i++) {
214 ords[i] = basicType(types[i]).ordinal();
215 }
216 return ords;
217 }
218
219 static boolean isBasicTypeChar(char c) {
220 return "LIJFDV".indexOf(c) >= 0;
221 }
222 static boolean isArgBasicTypeChar(char c) {
223 return "LIJFD".indexOf(c) >= 0;
224 }
225
226 static { assert(checkBasicType()); }
227 private static boolean checkBasicType() {
228 for (int i = 0; i < ARG_TYPE_LIMIT; i++) {
229 assert ARG_TYPES[i].ordinal() == i;
230 assert ARG_TYPES[i] == ALL_TYPES[i];
231 }
232 for (int i = 0; i < TYPE_LIMIT; i++) {
233 assert ALL_TYPES[i].ordinal() == i;
234 }
235 assert ALL_TYPES[TYPE_LIMIT - 1] == V_TYPE;
236 assert !Arrays.asList(ARG_TYPES).contains(V_TYPE);
237 return true;
238 }
239 }
240
241 enum Kind {
242 GENERIC("invoke"),
243 ZERO("zero"),
244 IDENTITY("identity"),
245 BOUND_REINVOKER("BMH.reinvoke", "reinvoke"),
246 REINVOKER("MH.reinvoke", "reinvoke"),
247 DELEGATE("MH.delegate", "delegate"),
248 EXACT_LINKER("MH.invokeExact_MT", "invokeExact_MT"),
249 EXACT_INVOKER("MH.exactInvoker", "exactInvoker"),
250 GENERIC_LINKER("MH.invoke_MT", "invoke_MT"),
251 GENERIC_INVOKER("MH.invoker", "invoker"),
252 LINK_TO_TARGET_METHOD("linkToTargetMethod"),
253 LINK_TO_CALL_SITE("linkToCallSite"),
254 DIRECT_INVOKE_VIRTUAL("DMH.invokeVirtual", "invokeVirtual"),
255 DIRECT_INVOKE_SPECIAL("DMH.invokeSpecial", "invokeSpecial"),
256 DIRECT_INVOKE_SPECIAL_IFC("DMH.invokeSpecialIFC", "invokeSpecialIFC"),
257 DIRECT_INVOKE_STATIC("DMH.invokeStatic", "invokeStatic"),
258 DIRECT_NEW_INVOKE_SPECIAL("DMH.newInvokeSpecial", "newInvokeSpecial"),
259 DIRECT_INVOKE_INTERFACE("DMH.invokeInterface", "invokeInterface"),
260 DIRECT_INVOKE_STATIC_INIT("DMH.invokeStaticInit", "invokeStaticInit"),
261 GET_REFERENCE("getReference"),
262 PUT_REFERENCE("putReference"),
263 GET_REFERENCE_VOLATILE("getReferenceVolatile"),
264 PUT_REFERENCE_VOLATILE("putReferenceVolatile"),
265 GET_INT("getInt"),
266 PUT_INT("putInt"),
267 GET_INT_VOLATILE("getIntVolatile"),
268 PUT_INT_VOLATILE("putIntVolatile"),
269 GET_BOOLEAN("getBoolean"),
270 PUT_BOOLEAN("putBoolean"),
271 GET_BOOLEAN_VOLATILE("getBooleanVolatile"),
272 PUT_BOOLEAN_VOLATILE("putBooleanVolatile"),
273 GET_BYTE("getByte"),
274 PUT_BYTE("putByte"),
275 GET_BYTE_VOLATILE("getByteVolatile"),
276 PUT_BYTE_VOLATILE("putByteVolatile"),
277 GET_CHAR("getChar"),
278 PUT_CHAR("putChar"),
279 GET_CHAR_VOLATILE("getCharVolatile"),
280 PUT_CHAR_VOLATILE("putCharVolatile"),
281 GET_SHORT("getShort"),
282 PUT_SHORT("putShort"),
283 GET_SHORT_VOLATILE("getShortVolatile"),
284 PUT_SHORT_VOLATILE("putShortVolatile"),
285 GET_LONG("getLong"),
286 PUT_LONG("putLong"),
287 GET_LONG_VOLATILE("getLongVolatile"),
288 PUT_LONG_VOLATILE("putLongVolatile"),
289 GET_FLOAT("getFloat"),
290 PUT_FLOAT("putFloat"),
291 GET_FLOAT_VOLATILE("getFloatVolatile"),
292 PUT_FLOAT_VOLATILE("putFloatVolatile"),
293 GET_DOUBLE("getDouble"),
294 PUT_DOUBLE("putDouble"),
295 GET_DOUBLE_VOLATILE("getDoubleVolatile"),
296 PUT_DOUBLE_VOLATILE("putDoubleVolatile"),
297 TRY_FINALLY("tryFinally"),
298 TABLE_SWITCH("tableSwitch"),
299 COLLECT("collect"),
300 COLLECTOR("collector"),
301 CONVERT("convert"),
302 SPREAD("spread"),
303 LOOP("loop"),
304 FIELD("field"),
305 GUARD("guard"),
306 GUARD_WITH_CATCH("guardWithCatch"),
307 VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
308 VARHANDLE_INVOKER("VH.invoker", "invoker"),
309 VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
310
311 final String defaultLambdaName;
312 final String methodName;
313
314 private Kind(String defaultLambdaName) {
315 this(defaultLambdaName, defaultLambdaName);
316 }
317
318 private Kind(String defaultLambdaName, String methodName) {
319 this.defaultLambdaName = defaultLambdaName;
320 this.methodName = methodName;
321 }
322 }
323
324 // private version that doesn't do checks or defensive copies
325 private LambdaForm(int arity, int result, boolean forceInline, MethodHandle customized, Name[] names, Kind kind) {
326 this.arity = arity;
327 this.result = result;
328 this.forceInline = forceInline;
329 this.customized = customized;
330 this.names = names;
331 this.kind = kind;
332 this.vmentry = null;
333 this.isCompiled = false;
334 }
335
336 // root factory pre/post processing and calls simple constructor
337 private static LambdaForm create(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
338 names = names.clone();
339 assert(namesOK(arity, names));
340 result = fixResult(result, names);
341
342 boolean canInterpret = normalizeNames(arity, names);
343 LambdaForm form = new LambdaForm(arity, result, forceInline, customized, names, kind);
344 assert(form.nameRefsAreLegal());
345 if (!canInterpret) {
346 form.compileToBytecode();
347 }
348 return form;
349 }
350
351 // derived factories with defaults
352 private static final int DEFAULT_RESULT = LAST_RESULT;
353 private static final boolean DEFAULT_FORCE_INLINE = true;
354 private static final MethodHandle DEFAULT_CUSTOMIZED = null;
355 private static final Kind DEFAULT_KIND = Kind.GENERIC;
356
357 static LambdaForm create(int arity, Name[] names, int result) {
358 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
359 }
360 static LambdaForm create(int arity, Name[] names, int result, Kind kind) {
361 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
362 }
363 static LambdaForm create(int arity, Name[] names) {
364 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
365 }
366 static LambdaForm create(int arity, Name[] names, Kind kind) {
367 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
368 }
369 static LambdaForm create(int arity, Name[] names, boolean forceInline, Kind kind) {
370 return create(arity, names, DEFAULT_RESULT, forceInline, DEFAULT_CUSTOMIZED, kind);
371 }
372
373 private static LambdaForm createBlankForType(MethodType mt) {
374 // Make a blank lambda form, which returns a constant zero or null.
375 // It is used as a template for managing the invocation of similar forms that are non-empty.
376 // Called only from getPreparedForm.
377 int arity = mt.parameterCount();
378 int result = (mt.returnType() == void.class || mt.returnType() == Void.class) ? VOID_RESULT : arity;
379 Name[] names = buildEmptyNames(arity, mt, result == VOID_RESULT);
380 boolean canInterpret = normalizeNames(arity, names);
381 LambdaForm form = new LambdaForm(arity, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, names, Kind.ZERO);
382 assert(form.nameRefsAreLegal() && form.isEmpty() && isValidSignature(form.basicTypeSignature()));
383 if (!canInterpret) {
384 form.compileToBytecode();
385 }
386 return form;
387 }
388
389 private static Name[] buildEmptyNames(int arity, MethodType mt, boolean isVoid) {
390 Name[] names = arguments(isVoid ? 0 : 1, mt);
391 if (!isVoid) {
392 Name zero = new Name(constantZero(basicType(mt.returnType())));
393 names[arity] = zero.newIndex(arity);
394 }
395 assert(namesOK(arity, names));
396 return names;
397 }
398
399 private static int fixResult(int result, Name[] names) {
400 if (result == LAST_RESULT)
401 result = names.length - 1; // might still be void
402 if (result >= 0 && names[result].type == V_TYPE)
403 result = VOID_RESULT;
404 return result;
405 }
406
407 static boolean debugNames() {
408 return DEBUG_NAME_COUNTERS != null;
409 }
410
411 static void associateWithDebugName(LambdaForm form, String name) {
412 assert (debugNames());
413 synchronized (DEBUG_NAMES) {
414 DEBUG_NAMES.put(form, name);
415 }
416 }
417
418 String lambdaName() {
419 if (DEBUG_NAMES != null) {
420 synchronized (DEBUG_NAMES) {
421 String name = DEBUG_NAMES.get(this);
422 if (name == null) {
423 name = generateDebugName();
424 }
425 return name;
426 }
427 }
428 return kind.defaultLambdaName;
429 }
430
431 private String generateDebugName() {
432 assert (debugNames());
433 String debugNameStem = kind.defaultLambdaName;
434 Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
435 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
436 StringBuilder buf = new StringBuilder(debugNameStem);
437 int leadingZero = buf.length();
438 buf.append((int) ctr);
439 for (int i = buf.length() - leadingZero; i < 3; i++) {
440 buf.insert(leadingZero, '0');
441 }
442 buf.append('_');
443 buf.append(basicTypeSignature());
444 String name = buf.toString();
445 associateWithDebugName(this, name);
446 return name;
447 }
448
449 private static boolean namesOK(int arity, Name[] names) {
450 for (int i = 0; i < names.length; i++) {
451 Name n = names[i];
452 assert(n != null) : "n is null";
453 if (i < arity)
454 assert( n.isParam()) : n + " is not param at " + i;
455 else
456 assert(!n.isParam()) : n + " is param at " + i;
457 }
458 return true;
459 }
460
461 /** Customize LambdaForm for a particular MethodHandle */
462 LambdaForm customize(MethodHandle mh) {
463 if (customized == mh) {
464 return this;
465 }
466 LambdaForm customForm = LambdaForm.create(arity, names, result, forceInline, mh, kind);
467 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
468 // If shared LambdaForm has been compiled, compile customized version as well.
469 customForm.compileToBytecode();
470 }
471 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
472 return customForm;
473 }
474
475 /** Get uncustomized flavor of the LambdaForm */
476 LambdaForm uncustomize() {
477 if (customized == null) {
478 return this;
479 }
480 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
481 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
482 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
483 // If customized LambdaForm has been compiled, compile uncustomized version as well.
484 uncustomizedForm.compileToBytecode();
485 }
486 return uncustomizedForm;
487 }
488
489 /** Renumber and/or replace params so that they are interned and canonically numbered.
490 * @return true if we can interpret
491 */
492 private static boolean normalizeNames(int arity, Name[] names) {
493 Name[] oldNames = null;
494 int maxOutArity = 0;
495 int changesStart = 0;
496 for (int i = 0; i < names.length; i++) {
497 Name n = names[i];
498 if (!n.initIndex(i)) {
499 if (oldNames == null) {
500 oldNames = names.clone();
501 changesStart = i;
502 }
503 names[i] = n.cloneWithIndex(i);
504 }
505 if (n.arguments != null && maxOutArity < n.arguments.length)
506 maxOutArity = n.arguments.length;
507 }
508 if (oldNames != null) {
509 int startFixing = arity;
510 if (startFixing <= changesStart)
511 startFixing = changesStart+1;
512 for (int i = startFixing; i < names.length; i++) {
513 Name fixed = names[i].replaceNames(oldNames, names, changesStart, i);
514 names[i] = fixed.newIndex(i);
515 }
516 }
517 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
518 boolean needIntern = false;
519 for (int i = 0; i < maxInterned; i++) {
520 Name n = names[i], n2 = internArgument(n);
521 if (n != n2) {
522 names[i] = n2;
523 needIntern = true;
524 }
525 }
526 if (needIntern) {
527 for (int i = arity; i < names.length; i++) {
528 names[i].internArguments();
529 }
530 }
531
532 // return true if we can interpret
533 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
534 // Cannot use LF interpreter on very high arity expressions.
535 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
536 return false;
537 }
538 return true;
539 }
540
541 /**
542 * Check that all embedded Name references are localizable to this lambda,
543 * and are properly ordered after their corresponding definitions.
544 * <p>
545 * Note that a Name can be local to multiple lambdas, as long as
546 * it possesses the same index in each use site.
547 * This allows Name references to be freely reused to construct
548 * fresh lambdas, without confusion.
549 */
550 boolean nameRefsAreLegal() {
551 assert(arity >= 0 && arity <= names.length);
552 assert(result >= -1 && result < names.length);
553 // Do all names possess an index consistent with their local definition order?
554 for (int i = 0; i < arity; i++) {
555 Name n = names[i];
556 assert(n.index() == i) : Arrays.asList(n.index(), i);
557 assert(n.isParam());
558 }
559 // Also, do all local name references
560 for (int i = arity; i < names.length; i++) {
561 Name n = names[i];
562 assert(n.index() == i);
563 for (Object arg : n.arguments) {
564 if (arg instanceof Name n2) {
565 int i2 = n2.index;
566 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
567 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
568 assert(i2 < i); // ref must come after def!
569 }
570 }
571 }
572 return true;
573 }
574
575 // /** Invoke this form on the given arguments. */
576 // final Object invoke(Object... args) throws Throwable {
577 // // NYI: fit this into the fast path?
578 // return interpretWithArguments(args);
579 // }
580
581 /** Report the return type. */
582 BasicType returnType() {
583 if (result < 0) return V_TYPE;
584 Name n = names[result];
585 return n.type;
586 }
587
588 /** Report the N-th argument type. */
589 BasicType parameterType(int n) {
590 return parameter(n).type;
591 }
592
593 /** Report the N-th argument name. */
594 Name parameter(int n) {
595 Name param = names[n];
596 assert(n < arity && param.isParam());
597 return param;
598 }
599
600 /** Report the N-th argument type constraint. */
601 Object parameterConstraint(int n) {
602 return parameter(n).constraint;
603 }
604
605 /** Report the arity. */
606 int arity() {
607 return arity;
608 }
609
610 /** Report the number of expressions (non-parameter names). */
611 int expressionCount() {
612 return names.length - arity;
613 }
614
615 /** Return the method type corresponding to my basic type signature. */
616 MethodType methodType() {
617 Class<?>[] ptypes = new Class<?>[arity];
618 for (int i = 0; i < arity; ++i) {
619 ptypes[i] = parameterType(i).btClass;
620 }
621 return MethodType.methodType(returnType().btClass, ptypes, true);
622 }
623
624 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
625 final String basicTypeSignature() {
626 StringBuilder buf = new StringBuilder(arity() + 3);
627 for (int i = 0, a = arity(); i < a; i++)
628 buf.append(parameterType(i).basicTypeChar());
629 return buf.append('_').append(returnType().basicTypeChar()).toString();
630 }
631 static int signatureArity(String sig) {
632 assert(isValidSignature(sig));
633 return sig.indexOf('_');
634 }
635 static boolean isValidSignature(String sig) {
636 int arity = sig.indexOf('_');
637 if (arity < 0) return false; // must be of the form *_*
638 int siglen = sig.length();
639 if (siglen != arity + 2) return false; // *_X
640 for (int i = 0; i < siglen; i++) {
641 if (i == arity) continue; // skip '_'
642 char c = sig.charAt(i);
643 if (c == 'V')
644 return (i == siglen - 1 && arity == siglen - 2);
645 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
646 }
647 return true; // [LIJFD]*_[LIJFDV]
648 }
649
650 /**
651 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
652 */
653 boolean isSelectAlternative(int pos) {
654 // selectAlternative idiom:
655 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
656 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
657 if (pos+1 >= names.length) return false;
658 Name name0 = names[pos];
659 Name name1 = names[pos+1];
660 return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
661 name1.isInvokeBasic() &&
662 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
663 lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
664 }
665
666 private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
667 if (pos+2 >= names.length) return false;
668 Name name0 = names[pos];
669 Name name1 = names[pos+1];
670 Name name2 = names[pos+2];
671 return name1.refersTo(MethodHandleImpl.class, idiomName) &&
672 name0.isInvokeBasic() &&
673 name2.isInvokeBasic() &&
674 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
675 lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
676 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
677 lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
678 }
679
680 /**
681 * Check if i-th name is a start of GuardWithCatch idiom.
682 */
683 boolean isGuardWithCatch(int pos) {
684 // GuardWithCatch idiom:
685 // t_{n}:L=MethodHandle.invokeBasic(...)
686 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
687 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
688 return isMatchingIdiom(pos, "guardWithCatch", 3);
689 }
690
691 /**
692 * Check if i-th name is a start of the tryFinally idiom.
693 */
694 boolean isTryFinally(int pos) {
695 // tryFinally idiom:
696 // t_{n}:L=MethodHandle.invokeBasic(...)
697 // t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
698 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
699 return isMatchingIdiom(pos, "tryFinally", 2);
700 }
701
702 /**
703 * Check if i-th name is a start of the tableSwitch idiom.
704 */
705 boolean isTableSwitch(int pos) {
706 // tableSwitch idiom:
707 // t_{n}:L=MethodHandle.invokeBasic(...) // args
708 // t_{n+1}:L=MethodHandleImpl.tableSwitch(*, *, *, t_{n})
709 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
710 if (pos + 2 >= names.length) return false;
711
712 final int POS_COLLECT_ARGS = pos;
713 final int POS_TABLE_SWITCH = pos + 1;
714 final int POS_UNBOX_RESULT = pos + 2;
715
716 Name collectArgs = names[POS_COLLECT_ARGS];
717 Name tableSwitch = names[POS_TABLE_SWITCH];
718 Name unboxResult = names[POS_UNBOX_RESULT];
719 return tableSwitch.refersTo(MethodHandleImpl.class, "tableSwitch") &&
720 collectArgs.isInvokeBasic() &&
721 unboxResult.isInvokeBasic() &&
722 tableSwitch.lastUseIndex(collectArgs) == 3 && // t_{n+1}:L=MethodHandleImpl.<invoker>(*, *, *, t_{n});
723 lastUseIndex(collectArgs) == POS_TABLE_SWITCH && // t_{n} is local: used only in t_{n+1}
724 unboxResult.lastUseIndex(tableSwitch) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
725 lastUseIndex(tableSwitch) == POS_UNBOX_RESULT; // t_{n+1} is local: used only in t_{n+2}
726 }
727
728 /**
729 * Check if i-th name is a start of the loop idiom.
730 */
731 boolean isLoop(int pos) {
732 // loop idiom:
733 // t_{n}:L=MethodHandle.invokeBasic(...)
734 // t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
735 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
736 return isMatchingIdiom(pos, "loop", 2);
737 }
738
739 /*
740 * Code generation issues:
741 *
742 * Compiled LFs should be reusable in general.
743 * The biggest issue is how to decide when to pull a name into
744 * the bytecode, versus loading a reified form from the MH data.
745 *
746 * For example, an asType wrapper may require execution of a cast
747 * after a call to a MH. The target type of the cast can be placed
748 * as a constant in the LF itself. This will force the cast type
749 * to be compiled into the bytecodes and native code for the MH.
750 * Or, the target type of the cast can be erased in the LF, and
751 * loaded from the MH data. (Later on, if the MH as a whole is
752 * inlined, the data will flow into the inlined instance of the LF,
753 * as a constant, and the end result will be an optimal cast.)
754 *
755 * This erasure of cast types can be done with any use of
756 * reference types. It can also be done with whole method
757 * handles. Erasing a method handle might leave behind
758 * LF code that executes correctly for any MH of a given
759 * type, and load the required MH from the enclosing MH's data.
760 * Or, the erasure might even erase the expected MT.
761 *
762 * Also, for direct MHs, the MemberName of the target
763 * could be erased, and loaded from the containing direct MH.
764 * As a simple case, a LF for all int-valued non-static
765 * field getters would perform a cast on its input argument
766 * (to non-constant base type derived from the MemberName)
767 * and load an integer value from the input object
768 * (at a non-constant offset also derived from the MemberName).
769 * Such MN-erased LFs would be inlinable back to optimized
770 * code, whenever a constant enclosing DMH is available
771 * to supply a constant MN from its data.
772 *
773 * The main problem here is to keep LFs reasonably generic,
774 * while ensuring that hot spots will inline good instances.
775 * "Reasonably generic" means that we don't end up with
776 * repeated versions of bytecode or machine code that do
777 * not differ in their optimized form. Repeated versions
778 * of machine would have the undesirable overheads of
779 * (a) redundant compilation work and (b) extra I$ pressure.
780 * To control repeated versions, we need to be ready to
781 * erase details from LFs and move them into MH data,
782 * whenever those details are not relevant to significant
783 * optimization. "Significant" means optimization of
784 * code that is actually hot.
785 *
786 * Achieving this may require dynamic splitting of MHs, by replacing
787 * a generic LF with a more specialized one, on the same MH,
788 * if (a) the MH is frequently executed and (b) the MH cannot
789 * be inlined into a containing caller, such as an invokedynamic.
790 *
791 * Compiled LFs that are no longer used should be GC-able.
792 * If they contain non-BCP references, they should be properly
793 * interlinked with the class loader(s) that their embedded types
794 * depend on. This probably means that reusable compiled LFs
795 * will be tabulated (indexed) on relevant class loaders,
796 * or else that the tables that cache them will have weak links.
797 */
798
799 /**
800 * Make this LF directly executable, as part of a MethodHandle.
801 * Invariant: Every MH which is invoked must prepare its LF
802 * before invocation.
803 * (In principle, the JVM could do this very lazily,
804 * as a sort of pre-invocation linkage step.)
805 */
806 public void prepare() {
807 if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
808 compileToBytecode();
809 }
810 if (this.vmentry != null) {
811 // already prepared (e.g., a primitive DMH invoker form)
812 return;
813 }
814 MethodType mtype = methodType();
815 LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
816 if (prep == null) {
817 assert (isValidSignature(basicTypeSignature()));
818 prep = LambdaForm.createBlankForType(mtype);
819 prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
820 prep = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
821 }
822 this.vmentry = prep.vmentry;
823 // TO DO: Maybe add invokeGeneric, invokeWithArguments
824 }
825
826 private static @Stable PerfCounter LF_FAILED;
827
828 private static PerfCounter failedCompilationCounter() {
829 if (LF_FAILED == null) {
830 LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
831 }
832 return LF_FAILED;
833 }
834
835 /** Generate optimizable bytecode for this form. */
836 void compileToBytecode() {
837 if (forceInterpretation()) {
838 return; // this should not be compiled
839 }
840 if (vmentry != null && isCompiled) {
841 return; // already compiled somehow
842 }
843
844 // Obtain the invoker MethodType outside of the following try block.
845 // This ensures that an IllegalArgumentException is directly thrown if the
846 // type would have 256 or more parameters
847 MethodType invokerType = methodType();
848 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
849 try {
850 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
851 if (TRACE_INTERPRETER)
852 traceInterpreter("compileToBytecode", this);
853 isCompiled = true;
854 } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
855 // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
856 invocationCounter = -1;
857 failedCompilationCounter().increment();
858 if (LOG_LF_COMPILATION_FAILURE) {
859 System.out.println("LambdaForm compilation failed: " + this);
860 bge.printStackTrace(System.out);
861 }
862 } catch (Error e) {
863 // Pass through any error
864 throw e;
865 } catch (Exception e) {
866 // Wrap any exception
867 throw newInternalError(this.toString(), e);
868 }
869 }
870
871 // The next few routines are called only from assert expressions
872 // They verify that the built-in invokers process the correct raw data types.
873 private static boolean argumentTypesMatch(String sig, Object[] av) {
874 int arity = signatureArity(sig);
875 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
876 assert(av[0] instanceof MethodHandle) : "av[0] not instance of MethodHandle: " + av[0];
877 MethodHandle mh = (MethodHandle) av[0];
878 MethodType mt = mh.type();
879 assert(mt.parameterCount() == arity-1);
880 for (int i = 0; i < av.length; i++) {
881 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
882 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
883 }
884 return true;
885 }
886 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
887 // The following line is needed because (...)void method handles can use non-void invokers
888 if (type == void.class) tc = V_TYPE; // can drop any kind of value
889 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
890 switch (tc) {
891 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
892 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
893 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
894 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
895 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
896 case V_TYPE: break; // allow anything here; will be dropped
897 default: assert(false);
898 }
899 return true;
900 }
901 private static boolean checkInt(Class<?> type, Object x) {
902 assert(x instanceof Integer);
903 if (type == int.class) return true;
904 Wrapper w = Wrapper.forBasicType(type);
905 assert(w.isSubwordOrInt());
906 Object x1 = Wrapper.INT.wrap(w.wrap(x));
907 return x.equals(x1);
908 }
909 private static boolean checkRef(Class<?> type, Object x) {
910 assert(!type.isPrimitive());
911 if (x == null) return true;
912 if (type.isInterface()) return true;
913 return type.isInstance(x);
914 }
915
916 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
917 private static final int COMPILE_THRESHOLD;
918 static {
919 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
920 }
921 private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
922
923 private boolean forceInterpretation() {
924 return invocationCounter == -1;
925 }
926
927 /** Interpretively invoke this form on the given arguments. */
928 @Hidden
929 @DontInline
930 Object interpretWithArguments(Object... argumentValues) throws Throwable {
931 if (TRACE_INTERPRETER)
932 return interpretWithArgumentsTracing(argumentValues);
933 checkInvocationCounter();
934 assert(arityCheck(argumentValues));
935 Object[] values = Arrays.copyOf(argumentValues, names.length);
936 for (int i = argumentValues.length; i < values.length; i++) {
937 values[i] = interpretName(names[i], values);
938 }
939 Object rv = (result < 0) ? null : values[result];
940 assert(resultCheck(argumentValues, rv));
941 return rv;
942 }
943
944 /** Evaluate a single Name within this form, applying its function to its arguments. */
945 @Hidden
946 @DontInline
947 Object interpretName(Name name, Object[] values) throws Throwable {
948 if (TRACE_INTERPRETER)
949 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
950 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
951 for (int i = 0; i < arguments.length; i++) {
952 Object a = arguments[i];
953 if (a instanceof Name n) {
954 int i2 = n.index();
955 assert(names[i2] == a);
956 a = values[i2];
957 arguments[i] = a;
958 }
959 }
960 return name.function.invokeWithArguments(arguments);
961 }
962
963 private void checkInvocationCounter() {
964 if (COMPILE_THRESHOLD != 0 &&
965 !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
966 invocationCounter++; // benign race
967 if (invocationCounter >= COMPILE_THRESHOLD) {
968 // Replace vmentry with a bytecode version of this LF.
969 compileToBytecode();
970 }
971 }
972 }
973 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
974 traceInterpreter("[ interpretWithArguments", this, argumentValues);
975 if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
976 int ctr = invocationCounter++; // benign race
977 traceInterpreter("| invocationCounter", ctr);
978 if (invocationCounter >= COMPILE_THRESHOLD) {
979 compileToBytecode();
980 }
981 }
982 Object rval;
983 try {
984 assert(arityCheck(argumentValues));
985 Object[] values = Arrays.copyOf(argumentValues, names.length);
986 for (int i = argumentValues.length; i < values.length; i++) {
987 values[i] = interpretName(names[i], values);
988 }
989 rval = (result < 0) ? null : values[result];
990 } catch (Throwable ex) {
991 traceInterpreter("] throw =>", ex);
992 throw ex;
993 }
994 traceInterpreter("] return =>", rval);
995 return rval;
996 }
997
998 static void traceInterpreter(String event, Object obj, Object... args) {
999 if (TRACE_INTERPRETER) {
1000 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
1001 }
1002 }
1003 static void traceInterpreter(String event, Object obj) {
1004 traceInterpreter(event, obj, (Object[])null);
1005 }
1006 private boolean arityCheck(Object[] argumentValues) {
1007 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
1008 // also check that the leading (receiver) argument is somehow bound to this LF:
1009 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
1010 MethodHandle mh = (MethodHandle) argumentValues[0];
1011 assert(mh.internalForm() == this);
1012 // note: argument #0 could also be an interface wrapper, in the future
1013 argumentTypesMatch(basicTypeSignature(), argumentValues);
1014 return true;
1015 }
1016 private boolean resultCheck(Object[] argumentValues, Object result) {
1017 MethodHandle mh = (MethodHandle) argumentValues[0];
1018 MethodType mt = mh.type();
1019 assert(valueMatches(returnType(), mt.returnType(), result));
1020 return true;
1021 }
1022
1023 private boolean isEmpty() {
1024 if (result < 0)
1025 return (names.length == arity);
1026 else if (result == arity && names.length == arity + 1)
1027 return names[arity].isConstantZero();
1028 else
1029 return false;
1030 }
1031
1032 public String toString() {
1033 return debugString(-1);
1034 }
1035
1036 String debugString(int indentLevel) {
1037 String prefix = MethodHandle.debugPrefix(indentLevel);
1038 String lambdaName = lambdaName();
1039 StringBuilder buf = new StringBuilder(lambdaName);
1040 buf.append("=Lambda(");
1041 for (int i = 0; i < names.length; i++) {
1042 if (i == arity) buf.append(")=>{");
1043 Name n = names[i];
1044 if (i >= arity) buf.append("\n ").append(prefix);
1045 buf.append(n.paramString());
1046 if (i < arity) {
1047 if (i+1 < arity) buf.append(",");
1048 continue;
1049 }
1050 buf.append("=").append(n.exprString());
1051 buf.append(";");
1052 }
1053 if (arity == names.length) buf.append(")=>{");
1054 buf.append(result < 0 ? "void" : names[result]).append("}");
1055 if (TRACE_INTERPRETER) {
1056 // Extra verbosity:
1057 buf.append(":").append(basicTypeSignature());
1058 buf.append("/").append(vmentry);
1059 }
1060 return buf.toString();
1061 }
1062
1063 @Override
1064 public boolean equals(Object obj) {
1065 return obj instanceof LambdaForm lf && equals(lf);
1066 }
1067 public boolean equals(LambdaForm that) {
1068 if (this.result != that.result) return false;
1069 return Arrays.equals(this.names, that.names);
1070 }
1071 public int hashCode() {
1072 return result + 31 * Arrays.hashCode(names);
1073 }
1074 LambdaFormEditor editor() {
1075 return LambdaFormEditor.lambdaFormEditor(this);
1076 }
1077
1078 boolean contains(Name name) {
1079 int pos = name.index();
1080 if (pos >= 0) {
1081 return pos < names.length && name.equals(names[pos]);
1082 }
1083 for (int i = arity; i < names.length; i++) {
1084 if (name.equals(names[i]))
1085 return true;
1086 }
1087 return false;
1088 }
1089
1090 static class NamedFunction {
1091 final MemberName member;
1092 private @Stable MethodHandle resolvedHandle;
1093 private @Stable MethodType type;
1094
1095 NamedFunction(MethodHandle resolvedHandle) {
1096 this(resolvedHandle.internalMemberName(), resolvedHandle);
1097 }
1098 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1099 this.member = member;
1100 this.resolvedHandle = resolvedHandle;
1101 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1102 //assert(!isInvokeBasic(member));
1103 }
1104 NamedFunction(MethodType basicInvokerType) {
1105 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1106 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1107 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1108 this.member = resolvedHandle.internalMemberName();
1109 } else {
1110 // necessary to pass BigArityTest
1111 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1112 }
1113 assert(isInvokeBasic(member));
1114 }
1115
1116 private static boolean isInvokeBasic(MemberName member) {
1117 return member != null &&
1118 member.getDeclaringClass() == MethodHandle.class &&
1119 "invokeBasic".equals(member.getName());
1120 }
1121
1122 // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1123 // Any LambdaForm containing such a member is not interpretable.
1124 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1125 // And even without the resolvedHandle, the name can still be compiled and optimized.
1126 NamedFunction(Method method) {
1127 this(new MemberName(method));
1128 }
1129 NamedFunction(MemberName member) {
1130 this(member, null);
1131 }
1132
1133 MethodHandle resolvedHandle() {
1134 if (resolvedHandle == null) resolve();
1135 return resolvedHandle;
1136 }
1137
1138 synchronized void resolve() {
1139 if (resolvedHandle == null) {
1140 resolvedHandle = DirectMethodHandle.make(member);
1141 }
1142 }
1143
1144 @Override
1145 public boolean equals(Object other) {
1146 if (this == other) return true;
1147 if (other == null) return false;
1148 return (other instanceof NamedFunction that)
1149 && this.member != null
1150 && this.member.equals(that.member);
1151 }
1152
1153 @Override
1154 public int hashCode() {
1155 if (member != null)
1156 return member.hashCode();
1157 return super.hashCode();
1158 }
1159
1160 static final MethodType INVOKER_METHOD_TYPE;
1161 private static @Stable MethodType[] archivedObjects;
1162
1163 static {
1164 CDS.initializeFromArchive(NamedFunction.class);
1165 if (archivedObjects != null) {
1166 INVOKER_METHOD_TYPE = archivedObjects[0];
1167 } else {
1168 INVOKER_METHOD_TYPE =
1169 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1170 }
1171 }
1172
1173 static void dumpSharedArchive() {
1174 archivedObjects = new MethodType[1];
1175 archivedObjects[0] = INVOKER_METHOD_TYPE;
1176 }
1177
1178 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1179 typeForm = typeForm.basicType().form(); // normalize to basic type
1180 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1181 if (mh != null) return mh;
1182 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1183 mh = DirectMethodHandle.make(invoker);
1184 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1185 if (mh2 != null) return mh2; // benign race
1186 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1187 throw newInternalError(mh.debugString());
1188 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1189 }
1190
1191 @Hidden
1192 Object invokeWithArguments(Object... arguments) throws Throwable {
1193 // If we have a cached invoker, call it right away.
1194 // NOTE: The invoker always returns a reference value.
1195 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1196 return invoker().invokeBasic(resolvedHandle(), arguments);
1197 }
1198
1199 @Hidden
1200 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1201 Object rval;
1202 try {
1203 traceInterpreter("[ call", this, arguments);
1204 // resolvedHandle might be uninitialized, ok for tracing
1205 if (resolvedHandle == null) {
1206 traceInterpreter("| resolve", this);
1207 resolvedHandle();
1208 }
1209 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1210 } catch (Throwable ex) {
1211 traceInterpreter("] throw =>", ex);
1212 throw ex;
1213 }
1214 traceInterpreter("] return =>", rval);
1215 return rval;
1216 }
1217
1218 private MethodHandle invoker() {
1219 return computeInvoker(methodType().form());
1220 }
1221
1222 MethodType methodType() {
1223 MethodType type = this.type;
1224 if (type == null) {
1225 this.type = type = calculateMethodType(member, resolvedHandle);
1226 }
1227 return type;
1228 }
1229
1230 private static MethodType calculateMethodType(MemberName member, MethodHandle resolvedHandle) {
1231 if (resolvedHandle != null) {
1232 return resolvedHandle.type();
1233 } else {
1234 // only for certain internal LFs during bootstrapping
1235 return member.getInvocationType();
1236 }
1237 }
1238
1239 MemberName member() {
1240 assert(assertMemberIsConsistent());
1241 return member;
1242 }
1243
1244 // Called only from assert.
1245 private boolean assertMemberIsConsistent() {
1246 if (resolvedHandle instanceof DirectMethodHandle) {
1247 MemberName m = resolvedHandle.internalMemberName();
1248 assert(m.equals(member));
1249 }
1250 return true;
1251 }
1252
1253 Class<?> memberDeclaringClassOrNull() {
1254 return (member == null) ? null : member.getDeclaringClass();
1255 }
1256
1257 BasicType returnType() {
1258 return basicType(methodType().returnType());
1259 }
1260
1261 BasicType parameterType(int n) {
1262 return basicType(methodType().parameterType(n));
1263 }
1264
1265 int arity() {
1266 return methodType().parameterCount();
1267 }
1268
1269 public String toString() {
1270 if (member == null) return String.valueOf(resolvedHandle);
1271 return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1272 }
1273
1274 public boolean isIdentity() {
1275 return this.equals(identity(returnType()));
1276 }
1277
1278 public boolean isConstantZero() {
1279 return this.equals(constantZero(returnType()));
1280 }
1281
1282 public MethodHandleImpl.Intrinsic intrinsicName() {
1283 return resolvedHandle != null
1284 ? resolvedHandle.intrinsicName()
1285 : MethodHandleImpl.Intrinsic.NONE;
1286 }
1287
1288 public Object intrinsicData() {
1289 return resolvedHandle != null
1290 ? resolvedHandle.intrinsicData()
1291 : null;
1292 }
1293 }
1294
1295 public static String basicTypeSignature(MethodType type) {
1296 int params = type.parameterCount();
1297 char[] sig = new char[params + 2];
1298 int sigp = 0;
1299 while (sigp < params) {
1300 sig[sigp] = basicTypeChar(type.parameterType(sigp++));
1301 }
1302 sig[sigp++] = '_';
1303 sig[sigp++] = basicTypeChar(type.returnType());
1304 assert(sigp == sig.length);
1305 return String.valueOf(sig);
1306 }
1307
1308 /** Hack to make signatures more readable when they show up in method names.
1309 * Signature should start with a sequence of uppercase ASCII letters.
1310 * Runs of three or more are replaced by a single letter plus a decimal repeat count.
1311 * A tail of anything other than uppercase ASCII is passed through unchanged.
1312 * @param signature sequence of uppercase ASCII letters with possible repetitions
1313 * @return same sequence, with repetitions counted by decimal numerals
1314 */
1315 public static String shortenSignature(String signature) {
1316 final int NO_CHAR = -1, MIN_RUN = 3;
1317 int c0, c1 = NO_CHAR, c1reps = 0;
1318 StringBuilder buf = null;
1319 int len = signature.length();
1320 if (len < MIN_RUN) return signature;
1321 for (int i = 0; i <= len; i++) {
1322 if (c1 != NO_CHAR && !('A' <= c1 && c1 <= 'Z')) {
1323 // wrong kind of char; bail out here
1324 if (buf != null) {
1325 buf.append(signature, i - c1reps, len);
1326 }
1327 break;
1328 }
1329 // shift in the next char:
1330 c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1331 if (c1 == c0) { ++c1reps; continue; }
1332 // shift in the next count:
1333 int c0reps = c1reps; c1reps = 1;
1334 // end of a character run
1335 if (c0reps < MIN_RUN) {
1336 if (buf != null) {
1337 while (--c0reps >= 0)
1338 buf.append((char)c0);
1339 }
1340 continue;
1341 }
1342 // found three or more in a row
1343 if (buf == null)
1344 buf = new StringBuilder().append(signature, 0, i - c0reps);
1345 buf.append((char)c0).append(c0reps);
1346 }
1347 return (buf == null) ? signature : buf.toString();
1348 }
1349
1350 static final class Name {
1351 final BasicType type;
1352 @Stable short index;
1353 final NamedFunction function;
1354 final Object constraint; // additional type information, if not null
1355 @Stable final Object[] arguments;
1356
1357 private static final Object[] EMPTY_ARGS = new Object[0];
1358
1359 private Name(int index, BasicType type, NamedFunction function, Object[] arguments) {
1360 this.index = (short)index;
1361 this.type = type;
1362 this.function = function;
1363 this.arguments = arguments;
1364 this.constraint = null;
1365 assert(this.index == index && typesMatch(function, this.arguments));
1366 }
1367 private Name(Name that, Object constraint) {
1368 this.index = that.index;
1369 this.type = that.type;
1370 this.function = that.function;
1371 this.arguments = that.arguments;
1372 this.constraint = constraint;
1373 assert(constraint == null || isParam()); // only params have constraints
1374 assert(constraint == null || constraint instanceof ClassSpecializer.SpeciesData || constraint instanceof Class);
1375 }
1376 Name(MethodHandle function, Object... arguments) {
1377 this(new NamedFunction(function), arguments);
1378 }
1379 Name(MethodType functionType, Object... arguments) {
1380 this(new NamedFunction(functionType), arguments);
1381 assert(arguments[0] instanceof Name name && name.type == L_TYPE);
1382 }
1383 Name(MemberName function, Object... arguments) {
1384 this(new NamedFunction(function), arguments);
1385 }
1386 Name(NamedFunction function) {
1387 this(-1, function.returnType(), function, EMPTY_ARGS);
1388 }
1389 Name(NamedFunction function, Object arg) {
1390 this(-1, function.returnType(), function, new Object[] { arg });
1391 }
1392 Name(NamedFunction function, Object arg0, Object arg1) {
1393 this(-1, function.returnType(), function, new Object[] { arg0, arg1 });
1394 }
1395 Name(NamedFunction function, Object... arguments) {
1396 this(-1, function.returnType(), function, Arrays.copyOf(arguments, arguments.length, Object[].class));
1397 }
1398 /** Create a raw parameter of the given type, with an expected index. */
1399 Name(int index, BasicType type) {
1400 this(index, type, null, null);
1401 }
1402 /** Create a raw parameter of the given type. */
1403 Name(BasicType type) { this(-1, type); }
1404
1405 BasicType type() { return type; }
1406 int index() { return index; }
1407 boolean initIndex(int i) {
1408 if (index != i) {
1409 if (index != -1) return false;
1410 index = (short)i;
1411 }
1412 return true;
1413 }
1414 char typeChar() {
1415 return type.btChar;
1416 }
1417
1418 Name newIndex(int i) {
1419 if (initIndex(i)) return this;
1420 return cloneWithIndex(i);
1421 }
1422 Name cloneWithIndex(int i) {
1423 Object[] newArguments = (arguments == null) ? null : arguments.clone();
1424 return new Name(i, type, function, newArguments).withConstraint(constraint);
1425 }
1426 Name withConstraint(Object constraint) {
1427 if (constraint == this.constraint) return this;
1428 return new Name(this, constraint);
1429 }
1430 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1431 if (oldName == newName) return this;
1432 @SuppressWarnings("LocalVariableHidesMemberVariable")
1433 Object[] arguments = this.arguments;
1434 if (arguments == null) return this;
1435 boolean replaced = false;
1436 for (int j = 0; j < arguments.length; j++) {
1437 if (arguments[j] == oldName) {
1438 if (!replaced) {
1439 replaced = true;
1440 arguments = arguments.clone();
1441 }
1442 arguments[j] = newName;
1443 }
1444 }
1445 if (!replaced) return this;
1446 return new Name(function, arguments);
1447 }
1448 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1449 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1450 */
1451 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1452 if (start >= end) return this;
1453 @SuppressWarnings("LocalVariableHidesMemberVariable")
1454 Object[] arguments = this.arguments;
1455 boolean replaced = false;
1456 eachArg:
1457 for (int j = 0; j < arguments.length; j++) {
1458 if (arguments[j] instanceof Name n) {
1459 int check = n.index;
1460 // harmless check to see if the thing is already in newNames:
1461 if (check >= 0 && check < newNames.length && n == newNames[check])
1462 continue eachArg;
1463 // n might not have the correct index: n != oldNames[n.index].
1464 for (int i = start; i < end; i++) {
1465 if (n == oldNames[i]) {
1466 if (n == newNames[i])
1467 continue eachArg;
1468 if (!replaced) {
1469 replaced = true;
1470 arguments = arguments.clone();
1471 }
1472 arguments[j] = newNames[i];
1473 continue eachArg;
1474 }
1475 }
1476 }
1477 }
1478 if (!replaced) return this;
1479 return new Name(function, arguments);
1480 }
1481 void internArguments() {
1482 @SuppressWarnings("LocalVariableHidesMemberVariable")
1483 Object[] arguments = this.arguments;
1484 for (int j = 0; j < arguments.length; j++) {
1485 if (arguments[j] instanceof Name n) {
1486 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1487 arguments[j] = internArgument(n);
1488 }
1489 }
1490 }
1491 boolean isParam() {
1492 return function == null;
1493 }
1494 boolean isConstantZero() {
1495 return !isParam() && arguments.length == 0 && function.isConstantZero();
1496 }
1497
1498 boolean refersTo(Class<?> declaringClass, String methodName) {
1499 return function != null &&
1500 function.member() != null && function.member().refersTo(declaringClass, methodName);
1501 }
1502
1503 /**
1504 * Check if MemberName is a call to MethodHandle.invokeBasic.
1505 */
1506 boolean isInvokeBasic() {
1507 if (function == null)
1508 return false;
1509 if (arguments.length < 1)
1510 return false; // must have MH argument
1511 MemberName member = function.member();
1512 return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1513 !member.isPublic() && !member.isStatic();
1514 }
1515
1516 /**
1517 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1518 */
1519 boolean isLinkerMethodInvoke() {
1520 if (function == null)
1521 return false;
1522 if (arguments.length < 1)
1523 return false; // must have MH argument
1524 MemberName member = function.member();
1525 return member != null &&
1526 member.getDeclaringClass() == MethodHandle.class &&
1527 !member.isPublic() && member.isStatic() &&
1528 member.getName().startsWith("linkTo");
1529 }
1530
1531 public String toString() {
1532 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1533 }
1534 public String debugString() {
1535 String s = paramString();
1536 return (function == null) ? s : s + "=" + exprString();
1537 }
1538 public String paramString() {
1539 String s = toString();
1540 Object c = constraint;
1541 if (c == null)
1542 return s;
1543 if (c instanceof Class<?> cl) c = cl.getSimpleName();
1544 return s + "/" + c;
1545 }
1546 public String exprString() {
1547 if (function == null) return toString();
1548 StringBuilder buf = new StringBuilder(function.toString());
1549 buf.append("(");
1550 String cma = "";
1551 for (Object a : arguments) {
1552 buf.append(cma); cma = ",";
1553 if (a instanceof Name || a instanceof Integer)
1554 buf.append(a);
1555 else
1556 buf.append("(").append(a).append(")");
1557 }
1558 buf.append(")");
1559 return buf.toString();
1560 }
1561
1562 private boolean typesMatch(NamedFunction function, Object ... arguments) {
1563 if (arguments == null) {
1564 assert(function == null);
1565 return true;
1566 }
1567 assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1568 for (int i = 0; i < arguments.length; i++) {
1569 assert (typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1570 }
1571 return true;
1572 }
1573
1574 private static boolean typesMatch(BasicType parameterType, Object object) {
1575 if (object instanceof Name name) {
1576 return name.type == parameterType;
1577 }
1578 switch (parameterType) {
1579 case I_TYPE: return object instanceof Integer;
1580 case J_TYPE: return object instanceof Long;
1581 case F_TYPE: return object instanceof Float;
1582 case D_TYPE: return object instanceof Double;
1583 }
1584 assert(parameterType == L_TYPE);
1585 return true;
1586 }
1587
1588 /** Return the index of the last occurrence of n in the argument array.
1589 * Return -1 if the name is not used.
1590 */
1591 int lastUseIndex(Name n) {
1592 if (arguments == null) return -1;
1593 for (int i = arguments.length; --i >= 0; ) {
1594 if (arguments[i] == n) return i;
1595 }
1596 return -1;
1597 }
1598
1599 /** Return the number of occurrences of n in the argument array.
1600 * Return 0 if the name is not used.
1601 */
1602 int useCount(Name n) {
1603 int count = 0;
1604 if (arguments != null) {
1605 for (Object argument : arguments) {
1606 if (argument == n) {
1607 count++;
1608 }
1609 }
1610 }
1611 return count;
1612 }
1613
1614 public boolean equals(Name that) {
1615 if (this == that) return true;
1616 if (isParam())
1617 // each parameter is a unique atom
1618 return false; // this != that
1619 return
1620 //this.index == that.index &&
1621 this.type == that.type &&
1622 this.function.equals(that.function) &&
1623 Arrays.equals(this.arguments, that.arguments);
1624 }
1625 @Override
1626 public boolean equals(Object x) {
1627 return x instanceof Name n && equals(n);
1628 }
1629 @Override
1630 public int hashCode() {
1631 if (isParam())
1632 return index | (type.ordinal() << 8);
1633 return function.hashCode() ^ Arrays.hashCode(arguments);
1634 }
1635 }
1636
1637 /** Return the index of the last name which contains n as an argument.
1638 * Return -1 if the name is not used. Return names.length if it is the return value.
1639 */
1640 int lastUseIndex(Name n) {
1641 int ni = n.index, nmax = names.length;
1642 assert(names[ni] == n);
1643 if (result == ni) return nmax; // live all the way beyond the end
1644 for (int i = nmax; --i > ni; ) {
1645 if (names[i].lastUseIndex(n) >= 0)
1646 return i;
1647 }
1648 return -1;
1649 }
1650
1651 /** Return the number of times n is used as an argument or return value. */
1652 int useCount(Name n) {
1653 int count = (result == n.index) ? 1 : 0;
1654 int i = Math.max(n.index + 1, arity);
1655 while (i < names.length) {
1656 count += names[i++].useCount(n);
1657 }
1658 return count;
1659 }
1660
1661 static Name argument(int which, BasicType type) {
1662 if (which >= INTERNED_ARGUMENT_LIMIT)
1663 return new Name(which, type);
1664 return INTERNED_ARGUMENTS[type.ordinal()][which];
1665 }
1666 static Name internArgument(Name n) {
1667 assert(n.isParam()) : "not param: " + n;
1668 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1669 if (n.constraint != null) return n;
1670 return argument(n.index, n.type);
1671 }
1672 static Name[] arguments(int extra, MethodType types) {
1673 int length = types.parameterCount();
1674 Name[] names = new Name[length + extra];
1675 for (int i = 0; i < length; i++)
1676 names[i] = argument(i, basicType(types.parameterType(i)));
1677 return names;
1678 }
1679 static final int INTERNED_ARGUMENT_LIMIT = 10;
1680 private static final Name[][] INTERNED_ARGUMENTS
1681 = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1682 static {
1683 for (BasicType type : BasicType.ARG_TYPES) {
1684 int ord = type.ordinal();
1685 for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1686 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1687 }
1688 }
1689 }
1690
1691 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1692
1693 static LambdaForm identityForm(BasicType type) {
1694 int ord = type.ordinal();
1695 LambdaForm form = LF_identity[ord];
1696 if (form != null) {
1697 return form;
1698 }
1699 createFormsFor(type);
1700 return LF_identity[ord];
1701 }
1702
1703 static LambdaForm zeroForm(BasicType type) {
1704 int ord = type.ordinal();
1705 LambdaForm form = LF_zero[ord];
1706 if (form != null) {
1707 return form;
1708 }
1709 createFormsFor(type);
1710 return LF_zero[ord];
1711 }
1712
1713 static NamedFunction identity(BasicType type) {
1714 int ord = type.ordinal();
1715 NamedFunction function = NF_identity[ord];
1716 if (function != null) {
1717 return function;
1718 }
1719 createFormsFor(type);
1720 return NF_identity[ord];
1721 }
1722
1723 static NamedFunction constantZero(BasicType type) {
1724 int ord = type.ordinal();
1725 NamedFunction function = NF_zero[ord];
1726 if (function != null) {
1727 return function;
1728 }
1729 createFormsFor(type);
1730 return NF_zero[ord];
1731 }
1732
1733 private static final @Stable LambdaForm[] LF_identity = new LambdaForm[TYPE_LIMIT];
1734 private static final @Stable LambdaForm[] LF_zero = new LambdaForm[TYPE_LIMIT];
1735 private static final @Stable NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1736 private static final @Stable NamedFunction[] NF_zero = new NamedFunction[TYPE_LIMIT];
1737
1738 private static final Object createFormsLock = new Object();
1739 private static void createFormsFor(BasicType type) {
1740 // Avoid racy initialization during bootstrap
1741 UNSAFE.ensureClassInitialized(BoundMethodHandle.class);
1742 synchronized (createFormsLock) {
1743 final int ord = type.ordinal();
1744 LambdaForm idForm = LF_identity[ord];
1745 if (idForm != null) {
1746 return;
1747 }
1748 char btChar = type.basicTypeChar();
1749 boolean isVoid = (type == V_TYPE);
1750 Class<?> btClass = type.btClass;
1751 MethodType zeType = MethodType.methodType(btClass);
1752 MethodType idType = (isVoid) ? zeType : MethodType.methodType(btClass, btClass);
1753
1754 // Look up symbolic names. It might not be necessary to have these,
1755 // but if we need to emit direct references to bytecodes, it helps.
1756 // Zero is built from a call to an identity function with a constant zero input.
1757 MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1758 MemberName zeMem = null;
1759 try {
1760 idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, LM_TRUSTED, NoSuchMethodException.class);
1761 if (!isVoid) {
1762 zeMem = new MemberName(LambdaForm.class, "zero_"+btChar, zeType, REF_invokeStatic);
1763 zeMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, zeMem, null, LM_TRUSTED, NoSuchMethodException.class);
1764 }
1765 } catch (IllegalAccessException|NoSuchMethodException ex) {
1766 throw newInternalError(ex);
1767 }
1768
1769 NamedFunction idFun;
1770 LambdaForm zeForm;
1771 NamedFunction zeFun;
1772
1773 // Create the LFs and NamedFunctions. Precompiling LFs to byte code is needed to break circular
1774 // bootstrap dependency on this method in case we're interpreting LFs
1775 if (isVoid) {
1776 Name[] idNames = new Name[] { argument(0, L_TYPE) };
1777 idForm = LambdaForm.create(1, idNames, VOID_RESULT, Kind.IDENTITY);
1778 idForm.compileToBytecode();
1779 idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm));
1780
1781 zeForm = idForm;
1782 zeFun = idFun;
1783 } else {
1784 Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1785 idForm = LambdaForm.create(2, idNames, 1, Kind.IDENTITY);
1786 idForm.compileToBytecode();
1787 idFun = new NamedFunction(idMem, MethodHandleImpl.makeIntrinsic(SimpleMethodHandle.make(idMem.getInvocationType(), idForm),
1788 MethodHandleImpl.Intrinsic.IDENTITY));
1789
1790 Object zeValue = Wrapper.forBasicType(btChar).zero();
1791 Name[] zeNames = new Name[] { argument(0, L_TYPE), new Name(idFun, zeValue) };
1792 zeForm = LambdaForm.create(1, zeNames, 1, Kind.ZERO);
1793 zeForm.compileToBytecode();
1794 zeFun = new NamedFunction(zeMem, MethodHandleImpl.makeIntrinsic(SimpleMethodHandle.make(zeMem.getInvocationType(), zeForm),
1795 MethodHandleImpl.Intrinsic.ZERO));
1796 }
1797
1798 LF_zero[ord] = zeForm;
1799 NF_zero[ord] = zeFun;
1800 LF_identity[ord] = idForm;
1801 NF_identity[ord] = idFun;
1802
1803 assert(idFun.isIdentity());
1804 assert(zeFun.isConstantZero());
1805 assert(new Name(zeFun).isConstantZero());
1806 }
1807 }
1808
1809 // Avoid appealing to ValueConversions at bootstrap time:
1810 private static int identity_I(int x) { return x; }
1811 private static long identity_J(long x) { return x; }
1812 private static float identity_F(float x) { return x; }
1813 private static double identity_D(double x) { return x; }
1814 private static Object identity_L(Object x) { return x; }
1815 private static void identity_V() { return; }
1816 private static int zero_I() { return 0; }
1817 private static long zero_J() { return 0; }
1818 private static float zero_F() { return 0; }
1819 private static double zero_D() { return 0; }
1820 private static Object zero_L() { return null; }
1821
1822 /**
1823 * Internal marker for byte-compiled LambdaForms.
1824 */
1825 /*non-public*/
1826 @Target(ElementType.METHOD)
1827 @Retention(RetentionPolicy.RUNTIME)
1828 @interface Compiled {
1829 }
1830
1831 private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1832 private static final HashMap<LambdaForm,String> DEBUG_NAMES;
1833 static {
1834 if (debugEnabled()) {
1835 DEBUG_NAME_COUNTERS = new HashMap<>();
1836 DEBUG_NAMES = new HashMap<>();
1837 } else {
1838 DEBUG_NAME_COUNTERS = null;
1839 DEBUG_NAMES = null;
1840 }
1841 }
1842
1843 static {
1844 // The Holder class will contain pre-generated forms resolved
1845 // using MemberName.getFactory(). However, that doesn't initialize the
1846 // class, which subtly breaks inlining etc. By forcing
1847 // initialization of the Holder class we avoid these issues.
1848 UNSAFE.ensureClassInitialized(Holder.class);
1849 }
1850
1851 /* Placeholder class for zero and identity forms generated ahead of time */
1852 final class Holder {}
1853
1854 // The following hack is necessary in order to suppress TRACE_INTERPRETER
1855 // during execution of the static initializes of this class.
1856 // Turning on TRACE_INTERPRETER too early will cause
1857 // stack overflows and other misbehavior during attempts to trace events
1858 // that occur during LambdaForm.<clinit>.
1859 // Therefore, do not move this line higher in this file, and do not remove.
1860 private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1861 }