1 /*
2 * Copyright (c) 2011, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.invoke;
27
28 import jdk.internal.perf.PerfCounter;
29 import jdk.internal.vm.annotation.DontInline;
30 import jdk.internal.vm.annotation.Hidden;
31 import jdk.internal.vm.annotation.Stable;
32 import sun.invoke.util.Wrapper;
33
34 import java.lang.annotation.ElementType;
35 import java.lang.annotation.Retention;
36 import java.lang.annotation.RetentionPolicy;
37 import java.lang.annotation.Target;
38 import java.lang.reflect.Method;
39 import java.util.Arrays;
40 import java.util.HashMap;
41
42 import static java.lang.invoke.LambdaForm.BasicType.*;
43 import static java.lang.invoke.MethodHandleNatives.Constants.*;
44 import static java.lang.invoke.MethodHandleStatics.*;
45
46 /**
47 * The symbolic, non-executable form of a method handle's invocation semantics.
48 * It consists of a series of names.
49 * The first N (N=arity) names are parameters,
50 * while any remaining names are temporary values.
51 * Each temporary specifies the application of a function to some arguments.
52 * The functions are method handles, while the arguments are mixes of
53 * constant values and local names.
54 * The result of the lambda is defined as one of the names, often the last one.
55 * <p>
56 * Here is an approximate grammar:
57 * <blockquote><pre>{@code
58 * LambdaForm = "(" ArgName* ")=>{" TempName* Result "}"
59 * ArgName = "a" N ":" T
60 * TempName = "t" N ":" T "=" Function "(" Argument* ");"
61 * Function = ConstantValue
62 * Argument = NameRef | ConstantValue
63 * Result = NameRef | "void"
64 * NameRef = "a" N | "t" N
65 * N = (any whole number)
66 * T = "L" | "I" | "J" | "F" | "D" | "V"
67 * }</pre></blockquote>
68 * Names are numbered consecutively from left to right starting at zero.
69 * (The letters are merely a taste of syntax sugar.)
70 * Thus, the first temporary (if any) is always numbered N (where N=arity).
71 * Every occurrence of a name reference in an argument list must refer to
72 * a name previously defined within the same lambda.
73 * A lambda has a void result if and only if its result index is -1.
74 * If a temporary has the type "V", it cannot be the subject of a NameRef,
75 * even though possesses a number.
76 * Note that all reference types are erased to "L", which stands for {@code Object}.
77 * All subword types (boolean, byte, short, char) are erased to "I" which is {@code int}.
78 * The other types stand for the usual primitive types.
79 * <p>
80 * Function invocation closely follows the static rules of the Java verifier.
81 * Arguments and return values must exactly match when their "Name" types are
82 * considered.
83 * Conversions are allowed only if they do not change the erased type.
84 * <ul>
85 * <li>L = Object: casts are used freely to convert into and out of reference types
86 * <li>I = int: subword types are forcibly narrowed when passed as arguments (see {@code explicitCastArguments})
87 * <li>J = long: no implicit conversions
88 * <li>F = float: no implicit conversions
89 * <li>D = double: no implicit conversions
90 * <li>V = void: a function result may be void if and only if its Name is of type "V"
91 * </ul>
92 * Although implicit conversions are not allowed, explicit ones can easily be
93 * encoded by using temporary expressions which call type-transformed identity functions.
94 * <p>
95 * Examples:
96 * <blockquote><pre>{@code
97 * (a0:J)=>{ a0 }
98 * == identity(long)
99 * (a0:I)=>{ t1:V = System.out#println(a0); void }
100 * == System.out#println(int)
101 * (a0:L)=>{ t1:V = System.out#println(a0); a0 }
102 * == identity, with printing side-effect
103 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
104 * t3:L = BoundMethodHandle#target(a0);
105 * t4:L = MethodHandle#invoke(t3, t2, a1); t4 }
106 * == general invoker for unary insertArgument combination
107 * (a0:L, a1:L)=>{ t2:L = FilterMethodHandle#filter(a0);
108 * t3:L = MethodHandle#invoke(t2, a1);
109 * t4:L = FilterMethodHandle#target(a0);
110 * t5:L = MethodHandle#invoke(t4, t3); t5 }
111 * == general invoker for unary filterArgument combination
112 * (a0:L, a1:L)=>{ ...(same as previous example)...
113 * t5:L = MethodHandle#invoke(t4, t3, a1); t5 }
114 * == general invoker for unary/unary foldArgument combination
115 * (a0:L, a1:I)=>{ t2:I = identity(long).asType((int)->long)(a1); t2 }
116 * == invoker for identity method handle which performs i2l
117 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
118 * t3:L = Class#cast(t2,a1); t3 }
119 * == invoker for identity method handle which performs cast
120 * }</pre></blockquote>
121 * <p>
122 * @author John Rose, JSR 292 EG
123 */
124 class LambdaForm {
125 final int arity;
126 final int result;
127 final boolean forceInline;
128 final MethodHandle customized;
129 @Stable final Name[] names;
130 final Kind kind;
131 MemberName vmentry; // low-level behavior, or null if not yet prepared
132 private boolean isCompiled;
133
134 // Either a LambdaForm cache (managed by LambdaFormEditor) or a link to uncustomized version (for customized LF)
135 volatile Object transformCache;
136
137 public static final int VOID_RESULT = -1, LAST_RESULT = -2;
138
139 enum BasicType {
140 L_TYPE('L', Object.class, Wrapper.OBJECT), // all reference types
141 I_TYPE('I', int.class, Wrapper.INT),
142 J_TYPE('J', long.class, Wrapper.LONG),
143 F_TYPE('F', float.class, Wrapper.FLOAT),
144 D_TYPE('D', double.class, Wrapper.DOUBLE), // all primitive types
145 V_TYPE('V', void.class, Wrapper.VOID); // not valid in all contexts
146
147 static final @Stable BasicType[] ALL_TYPES = BasicType.values();
148 static final @Stable BasicType[] ARG_TYPES = Arrays.copyOf(ALL_TYPES, ALL_TYPES.length-1);
149
150 static final int ARG_TYPE_LIMIT = ARG_TYPES.length;
151 static final int TYPE_LIMIT = ALL_TYPES.length;
152
153 // Derived int constants, which (unlike the enums) can be constant folded.
154 // We can remove them when JDK-8161245 is fixed.
155 static final byte
156 L_TYPE_NUM = (byte) L_TYPE.ordinal(),
157 I_TYPE_NUM = (byte) I_TYPE.ordinal(),
158 J_TYPE_NUM = (byte) J_TYPE.ordinal(),
159 F_TYPE_NUM = (byte) F_TYPE.ordinal(),
160 D_TYPE_NUM = (byte) D_TYPE.ordinal(),
161 V_TYPE_NUM = (byte) V_TYPE.ordinal();
162
163 final char btChar;
164 final Class<?> btClass;
165 final Wrapper btWrapper;
166
167 private BasicType(char btChar, Class<?> btClass, Wrapper wrapper) {
168 this.btChar = btChar;
169 this.btClass = btClass;
170 this.btWrapper = wrapper;
171 }
172
173 char basicTypeChar() {
174 return btChar;
175 }
176 Class<?> basicTypeClass() {
177 return btClass;
178 }
179 Wrapper basicTypeWrapper() {
180 return btWrapper;
181 }
182 int basicTypeSlots() {
183 return btWrapper.stackSlots();
184 }
185
186 static BasicType basicType(byte type) {
187 return ALL_TYPES[type];
188 }
189 static BasicType basicType(char type) {
190 return switch (type) {
191 case 'L' -> L_TYPE;
192 case 'I' -> I_TYPE;
193 case 'J' -> J_TYPE;
194 case 'F' -> F_TYPE;
195 case 'D' -> D_TYPE;
196 case 'V' -> V_TYPE;
197 // all subword types are represented as ints
198 case 'Z', 'B', 'S', 'C' -> I_TYPE;
199 default -> throw newInternalError("Unknown type char: '" + type + "'");
200 };
201 }
202 static BasicType basicType(Wrapper type) {
203 char c = type.basicTypeChar();
204 return basicType(c);
205 }
206 static BasicType basicType(Class<?> type) {
207 if (!type.isPrimitive()) return L_TYPE;
208 return basicType(Wrapper.forPrimitiveType(type));
209 }
210 static int[] basicTypeOrds(BasicType[] types) {
211 if (types == null) {
212 return null;
213 }
214 int[] a = new int[types.length];
215 for(int i = 0; i < types.length; ++i) {
216 a[i] = types[i].ordinal();
217 }
218 return a;
219 }
220
221 static char basicTypeChar(Class<?> type) {
222 return basicType(type).btChar;
223 }
224
225 static byte[] basicTypesOrd(Class<?>[] types) {
226 byte[] ords = new byte[types.length];
227 for (int i = 0; i < ords.length; i++) {
228 ords[i] = (byte)basicType(types[i]).ordinal();
229 }
230 return ords;
231 }
232
233 static boolean isBasicTypeChar(char c) {
234 return "LIJFDV".indexOf(c) >= 0;
235 }
236 static boolean isArgBasicTypeChar(char c) {
237 return "LIJFD".indexOf(c) >= 0;
238 }
239
240 static { assert(checkBasicType()); }
241 private static boolean checkBasicType() {
242 for (int i = 0; i < ARG_TYPE_LIMIT; i++) {
243 assert ARG_TYPES[i].ordinal() == i;
244 assert ARG_TYPES[i] == ALL_TYPES[i];
245 }
246 for (int i = 0; i < TYPE_LIMIT; i++) {
247 assert ALL_TYPES[i].ordinal() == i;
248 }
249 assert ALL_TYPES[TYPE_LIMIT - 1] == V_TYPE;
250 assert !Arrays.asList(ARG_TYPES).contains(V_TYPE);
251 return true;
252 }
253 }
254
255 enum Kind {
256 GENERIC("invoke"),
257 ZERO("zero"),
258 IDENTITY("identity"),
259 BOUND_REINVOKER("BMH.reinvoke", "reinvoke"),
260 REINVOKER("MH.reinvoke", "reinvoke"),
261 DELEGATE("MH.delegate", "delegate"),
262 EXACT_LINKER("MH.invokeExact_MT", "invokeExact_MT"),
263 EXACT_INVOKER("MH.exactInvoker", "exactInvoker"),
264 GENERIC_LINKER("MH.invoke_MT", "invoke_MT"),
265 GENERIC_INVOKER("MH.invoker", "invoker"),
266 LINK_TO_TARGET_METHOD("linkToTargetMethod"),
267 LINK_TO_CALL_SITE("linkToCallSite"),
268 DIRECT_INVOKE_VIRTUAL("DMH.invokeVirtual", "invokeVirtual"),
269 DIRECT_INVOKE_SPECIAL("DMH.invokeSpecial", "invokeSpecial"),
270 DIRECT_INVOKE_SPECIAL_IFC("DMH.invokeSpecialIFC", "invokeSpecialIFC"),
271 DIRECT_INVOKE_STATIC("DMH.invokeStatic", "invokeStatic"),
272 DIRECT_NEW_INVOKE_SPECIAL("DMH.newInvokeSpecial", "newInvokeSpecial"),
273 DIRECT_INVOKE_INTERFACE("DMH.invokeInterface", "invokeInterface"),
274 DIRECT_INVOKE_STATIC_INIT("DMH.invokeStaticInit", "invokeStaticInit"),
275 GET_REFERENCE("getReference"),
276 PUT_REFERENCE("putReference"),
277 GET_REFERENCE_VOLATILE("getReferenceVolatile"),
278 PUT_REFERENCE_VOLATILE("putReferenceVolatile"),
279 GET_VALUE("getValue"),
280 PUT_VALUE("putValue"),
281 GET_VALUE_VOLATILE("getValueVolatile"),
282 PUT_VALUE_VOLATILE("putValueVolatile"),
283 GET_INT("getInt"),
284 PUT_INT("putInt"),
285 GET_INT_VOLATILE("getIntVolatile"),
286 PUT_INT_VOLATILE("putIntVolatile"),
287 GET_BOOLEAN("getBoolean"),
288 PUT_BOOLEAN("putBoolean"),
289 GET_BOOLEAN_VOLATILE("getBooleanVolatile"),
290 PUT_BOOLEAN_VOLATILE("putBooleanVolatile"),
291 GET_BYTE("getByte"),
292 PUT_BYTE("putByte"),
293 GET_BYTE_VOLATILE("getByteVolatile"),
294 PUT_BYTE_VOLATILE("putByteVolatile"),
295 GET_CHAR("getChar"),
296 PUT_CHAR("putChar"),
297 GET_CHAR_VOLATILE("getCharVolatile"),
298 PUT_CHAR_VOLATILE("putCharVolatile"),
299 GET_SHORT("getShort"),
300 PUT_SHORT("putShort"),
301 GET_SHORT_VOLATILE("getShortVolatile"),
302 PUT_SHORT_VOLATILE("putShortVolatile"),
303 GET_LONG("getLong"),
304 PUT_LONG("putLong"),
305 GET_LONG_VOLATILE("getLongVolatile"),
306 PUT_LONG_VOLATILE("putLongVolatile"),
307 GET_FLOAT("getFloat"),
308 PUT_FLOAT("putFloat"),
309 GET_FLOAT_VOLATILE("getFloatVolatile"),
310 PUT_FLOAT_VOLATILE("putFloatVolatile"),
311 GET_DOUBLE("getDouble"),
312 PUT_DOUBLE("putDouble"),
313 GET_DOUBLE_VOLATILE("getDoubleVolatile"),
314 PUT_DOUBLE_VOLATILE("putDoubleVolatile"),
315 TRY_FINALLY("tryFinally"),
316 TABLE_SWITCH("tableSwitch"),
317 COLLECT("collect"),
318 COLLECTOR("collector"),
319 CONVERT("convert"),
320 SPREAD("spread"),
321 LOOP("loop"),
322 FIELD("field"),
323 GUARD("guard"),
324 GUARD_WITH_CATCH("guardWithCatch"),
325 VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
326 VARHANDLE_INVOKER("VH.invoker", "invoker"),
327 VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
328
329 final String defaultLambdaName;
330 final String methodName;
331
332 private Kind(String defaultLambdaName) {
333 this(defaultLambdaName, defaultLambdaName);
334 }
335
336 private Kind(String defaultLambdaName, String methodName) {
337 this.defaultLambdaName = defaultLambdaName;
338 this.methodName = methodName;
339 }
340 }
341
342 LambdaForm(int arity, Name[] names, int result) {
343 this(arity, names, result, /*forceInline=*/true, /*customized=*/null, Kind.GENERIC);
344 }
345 LambdaForm(int arity, Name[] names, int result, Kind kind) {
346 this(arity, names, result, /*forceInline=*/true, /*customized=*/null, kind);
347 }
348 LambdaForm(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized) {
349 this(arity, names, result, forceInline, customized, Kind.GENERIC);
350 }
351 LambdaForm(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
352 assert(namesOK(arity, names));
353 this.arity = arity;
354 this.result = fixResult(result, names);
355 this.names = names.clone();
356 this.forceInline = forceInline;
357 this.customized = customized;
358 this.kind = kind;
359 int maxOutArity = normalize();
360 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
361 // Cannot use LF interpreter on very high arity expressions.
362 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
363 compileToBytecode();
364 }
365 }
366 LambdaForm(int arity, Name[] names) {
367 this(arity, names, LAST_RESULT, /*forceInline=*/true, /*customized=*/null, Kind.GENERIC);
368 }
369 LambdaForm(int arity, Name[] names, Kind kind) {
370 this(arity, names, LAST_RESULT, /*forceInline=*/true, /*customized=*/null, kind);
371 }
372 LambdaForm(int arity, Name[] names, boolean forceInline, Kind kind) {
373 this(arity, names, LAST_RESULT, forceInline, /*customized=*/null, kind);
374 }
375
376 private static Name[] buildNames(Name[] formals, Name[] temps, Name result) {
377 int arity = formals.length;
378 int length = arity + temps.length + (result == null ? 0 : 1);
379 Name[] names = Arrays.copyOf(formals, length);
380 System.arraycopy(temps, 0, names, arity, temps.length);
381 if (result != null)
382 names[length - 1] = result;
383 return names;
384 }
385
386 private LambdaForm(MethodType mt) {
387 // Make a blank lambda form, which returns a constant zero or null.
388 // It is used as a template for managing the invocation of similar forms that are non-empty.
389 // Called only from getPreparedForm.
390 this.arity = mt.parameterCount();
391 this.result = (mt.returnType() == void.class || mt.returnType() == Void.class) ? -1 : arity;
392 this.names = buildEmptyNames(arity, mt, result == -1);
393 this.forceInline = true;
394 this.customized = null;
395 this.kind = Kind.ZERO;
396 assert(nameRefsAreLegal());
397 assert(isEmpty());
398 String sig = null;
399 assert(isValidSignature(sig = basicTypeSignature()));
400 assert(sig.equals(basicTypeSignature())) : sig + " != " + basicTypeSignature();
401 }
402
403 private static Name[] buildEmptyNames(int arity, MethodType mt, boolean isVoid) {
404 Name[] names = arguments(isVoid ? 0 : 1, mt);
405 if (!isVoid) {
406 Name zero = new Name(constantZero(basicType(mt.returnType())));
407 names[arity] = zero.newIndex(arity);
408 }
409 return names;
410 }
411
412 private static int fixResult(int result, Name[] names) {
413 if (result == LAST_RESULT)
414 result = names.length - 1; // might still be void
415 if (result >= 0 && names[result].type == V_TYPE)
416 result = VOID_RESULT;
417 return result;
418 }
419
420 static boolean debugNames() {
421 return DEBUG_NAME_COUNTERS != null;
422 }
423
424 static void associateWithDebugName(LambdaForm form, String name) {
425 assert (debugNames());
426 synchronized (DEBUG_NAMES) {
427 DEBUG_NAMES.put(form, name);
428 }
429 }
430
431 String lambdaName() {
432 if (DEBUG_NAMES != null) {
433 synchronized (DEBUG_NAMES) {
434 String name = DEBUG_NAMES.get(this);
435 if (name == null) {
436 name = generateDebugName();
437 }
438 return name;
439 }
440 }
441 return kind.defaultLambdaName;
442 }
443
444 private String generateDebugName() {
445 assert (debugNames());
446 String debugNameStem = kind.defaultLambdaName;
447 Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
448 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
449 StringBuilder buf = new StringBuilder(debugNameStem);
450 int leadingZero = buf.length();
451 buf.append((int) ctr);
452 for (int i = buf.length() - leadingZero; i < 3; i++) {
453 buf.insert(leadingZero, '0');
454 }
455 buf.append('_');
456 buf.append(basicTypeSignature());
457 String name = buf.toString();
458 associateWithDebugName(this, name);
459 return name;
460 }
461
462 private static boolean namesOK(int arity, Name[] names) {
463 for (int i = 0; i < names.length; i++) {
464 Name n = names[i];
465 assert(n != null) : "n is null";
466 if (i < arity)
467 assert( n.isParam()) : n + " is not param at " + i;
468 else
469 assert(!n.isParam()) : n + " is param at " + i;
470 }
471 return true;
472 }
473
474 /** Customize LambdaForm for a particular MethodHandle */
475 LambdaForm customize(MethodHandle mh) {
476 if (customized == mh) {
477 return this;
478 }
479 LambdaForm customForm = new LambdaForm(arity, names, result, forceInline, mh, kind);
480 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
481 // If shared LambdaForm has been compiled, compile customized version as well.
482 customForm.compileToBytecode();
483 }
484 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
485 return customForm;
486 }
487
488 /** Get uncustomized flavor of the LambdaForm */
489 LambdaForm uncustomize() {
490 if (customized == null) {
491 return this;
492 }
493 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
494 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
495 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
496 // If customized LambdaForm has been compiled, compile uncustomized version as well.
497 uncustomizedForm.compileToBytecode();
498 }
499 return uncustomizedForm;
500 }
501
502 /** Renumber and/or replace params so that they are interned and canonically numbered.
503 * @return maximum argument list length among the names (since we have to pass over them anyway)
504 */
505 private int normalize() {
506 Name[] oldNames = null;
507 int maxOutArity = 0;
508 int changesStart = 0;
509 for (int i = 0; i < names.length; i++) {
510 Name n = names[i];
511 if (!n.initIndex(i)) {
512 if (oldNames == null) {
513 oldNames = names.clone();
514 changesStart = i;
515 }
516 names[i] = n.cloneWithIndex(i);
517 }
518 if (n.arguments != null && maxOutArity < n.arguments.length)
519 maxOutArity = n.arguments.length;
520 }
521 if (oldNames != null) {
522 int startFixing = arity;
523 if (startFixing <= changesStart)
524 startFixing = changesStart+1;
525 for (int i = startFixing; i < names.length; i++) {
526 Name fixed = names[i].replaceNames(oldNames, names, changesStart, i);
527 names[i] = fixed.newIndex(i);
528 }
529 }
530 assert(nameRefsAreLegal());
531 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
532 boolean needIntern = false;
533 for (int i = 0; i < maxInterned; i++) {
534 Name n = names[i], n2 = internArgument(n);
535 if (n != n2) {
536 names[i] = n2;
537 needIntern = true;
538 }
539 }
540 if (needIntern) {
541 for (int i = arity; i < names.length; i++) {
542 names[i].internArguments();
543 }
544 }
545 assert(nameRefsAreLegal());
546 return maxOutArity;
547 }
548
549 /**
550 * Check that all embedded Name references are localizable to this lambda,
551 * and are properly ordered after their corresponding definitions.
552 * <p>
553 * Note that a Name can be local to multiple lambdas, as long as
554 * it possesses the same index in each use site.
555 * This allows Name references to be freely reused to construct
556 * fresh lambdas, without confusion.
557 */
558 boolean nameRefsAreLegal() {
559 assert(arity >= 0 && arity <= names.length);
560 assert(result >= -1 && result < names.length);
561 // Do all names possess an index consistent with their local definition order?
562 for (int i = 0; i < arity; i++) {
563 Name n = names[i];
564 assert(n.index() == i) : Arrays.asList(n.index(), i);
565 assert(n.isParam());
566 }
567 // Also, do all local name references
568 for (int i = arity; i < names.length; i++) {
569 Name n = names[i];
570 assert(n.index() == i);
571 for (Object arg : n.arguments) {
572 if (arg instanceof Name n2) {
573 int i2 = n2.index;
574 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
575 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
576 assert(i2 < i); // ref must come after def!
577 }
578 }
579 }
580 return true;
581 }
582
583 /** Invoke this form on the given arguments. */
584 // final Object invoke(Object... args) throws Throwable {
585 // // NYI: fit this into the fast path?
586 // return interpretWithArguments(args);
587 // }
588
589 /** Report the return type. */
590 BasicType returnType() {
591 if (result < 0) return V_TYPE;
592 Name n = names[result];
593 return n.type;
594 }
595
596 /** Report the N-th argument type. */
597 BasicType parameterType(int n) {
598 return parameter(n).type;
599 }
600
601 /** Report the N-th argument name. */
602 Name parameter(int n) {
603 Name param = names[n];
604 assert(n < arity && param.isParam());
605 return param;
606 }
607
608 /** Report the N-th argument type constraint. */
609 Object parameterConstraint(int n) {
610 return parameter(n).constraint;
611 }
612
613 /** Report the arity. */
614 int arity() {
615 return arity;
616 }
617
618 /** Report the number of expressions (non-parameter names). */
619 int expressionCount() {
620 return names.length - arity;
621 }
622
623 /** Return the method type corresponding to my basic type signature. */
624 MethodType methodType() {
625 Class<?>[] ptypes = new Class<?>[arity];
626 for (int i = 0; i < arity; ++i) {
627 ptypes[i] = parameterType(i).btClass;
628 }
629 return MethodType.makeImpl(returnType().btClass, ptypes, true);
630 }
631
632 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
633 final String basicTypeSignature() {
634 StringBuilder buf = new StringBuilder(arity() + 3);
635 for (int i = 0, a = arity(); i < a; i++)
636 buf.append(parameterType(i).basicTypeChar());
637 return buf.append('_').append(returnType().basicTypeChar()).toString();
638 }
639 static int signatureArity(String sig) {
640 assert(isValidSignature(sig));
641 return sig.indexOf('_');
642 }
643 static boolean isValidSignature(String sig) {
644 int arity = sig.indexOf('_');
645 if (arity < 0) return false; // must be of the form *_*
646 int siglen = sig.length();
647 if (siglen != arity + 2) return false; // *_X
648 for (int i = 0; i < siglen; i++) {
649 if (i == arity) continue; // skip '_'
650 char c = sig.charAt(i);
651 if (c == 'V')
652 return (i == siglen - 1 && arity == siglen - 2);
653 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
654 }
655 return true; // [LIJFD]*_[LIJFDV]
656 }
657
658 /**
659 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
660 */
661 boolean isSelectAlternative(int pos) {
662 // selectAlternative idiom:
663 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
664 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
665 if (pos+1 >= names.length) return false;
666 Name name0 = names[pos];
667 Name name1 = names[pos+1];
668 return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
669 name1.isInvokeBasic() &&
670 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
671 lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
672 }
673
674 private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
675 if (pos+2 >= names.length) return false;
676 Name name0 = names[pos];
677 Name name1 = names[pos+1];
678 Name name2 = names[pos+2];
679 return name1.refersTo(MethodHandleImpl.class, idiomName) &&
680 name0.isInvokeBasic() &&
681 name2.isInvokeBasic() &&
682 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
683 lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
684 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
685 lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
686 }
687
688 /**
689 * Check if i-th name is a start of GuardWithCatch idiom.
690 */
691 boolean isGuardWithCatch(int pos) {
692 // GuardWithCatch idiom:
693 // t_{n}:L=MethodHandle.invokeBasic(...)
694 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
695 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
696 return isMatchingIdiom(pos, "guardWithCatch", 3);
697 }
698
699 /**
700 * Check if i-th name is a start of the tryFinally idiom.
701 */
702 boolean isTryFinally(int pos) {
703 // tryFinally idiom:
704 // t_{n}:L=MethodHandle.invokeBasic(...)
705 // t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
706 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
707 return isMatchingIdiom(pos, "tryFinally", 2);
708 }
709
710 /**
711 * Check if i-th name is a start of the tableSwitch idiom.
712 */
713 boolean isTableSwitch(int pos) {
714 // tableSwitch idiom:
715 // t_{n}:L=MethodHandle.invokeBasic(...) // args
716 // t_{n+1}:L=MethodHandleImpl.tableSwitch(*, *, *, t_{n})
717 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
718 if (pos + 2 >= names.length) return false;
719
720 final int POS_COLLECT_ARGS = pos;
721 final int POS_TABLE_SWITCH = pos + 1;
722 final int POS_UNBOX_RESULT = pos + 2;
723
724 Name collectArgs = names[POS_COLLECT_ARGS];
725 Name tableSwitch = names[POS_TABLE_SWITCH];
726 Name unboxResult = names[POS_UNBOX_RESULT];
727 return tableSwitch.refersTo(MethodHandleImpl.class, "tableSwitch") &&
728 collectArgs.isInvokeBasic() &&
729 unboxResult.isInvokeBasic() &&
730 tableSwitch.lastUseIndex(collectArgs) == 3 && // t_{n+1}:L=MethodHandleImpl.<invoker>(*, *, *, t_{n});
731 lastUseIndex(collectArgs) == POS_TABLE_SWITCH && // t_{n} is local: used only in t_{n+1}
732 unboxResult.lastUseIndex(tableSwitch) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
733 lastUseIndex(tableSwitch) == POS_UNBOX_RESULT; // t_{n+1} is local: used only in t_{n+2}
734 }
735
736 /**
737 * Check if i-th name is a start of the loop idiom.
738 */
739 boolean isLoop(int pos) {
740 // loop idiom:
741 // t_{n}:L=MethodHandle.invokeBasic(...)
742 // t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
743 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
744 return isMatchingIdiom(pos, "loop", 2);
745 }
746
747 /*
748 * Code generation issues:
749 *
750 * Compiled LFs should be reusable in general.
751 * The biggest issue is how to decide when to pull a name into
752 * the bytecode, versus loading a reified form from the MH data.
753 *
754 * For example, an asType wrapper may require execution of a cast
755 * after a call to a MH. The target type of the cast can be placed
756 * as a constant in the LF itself. This will force the cast type
757 * to be compiled into the bytecodes and native code for the MH.
758 * Or, the target type of the cast can be erased in the LF, and
759 * loaded from the MH data. (Later on, if the MH as a whole is
760 * inlined, the data will flow into the inlined instance of the LF,
761 * as a constant, and the end result will be an optimal cast.)
762 *
763 * This erasure of cast types can be done with any use of
764 * reference types. It can also be done with whole method
765 * handles. Erasing a method handle might leave behind
766 * LF code that executes correctly for any MH of a given
767 * type, and load the required MH from the enclosing MH's data.
768 * Or, the erasure might even erase the expected MT.
769 *
770 * Also, for direct MHs, the MemberName of the target
771 * could be erased, and loaded from the containing direct MH.
772 * As a simple case, a LF for all int-valued non-static
773 * field getters would perform a cast on its input argument
774 * (to non-constant base type derived from the MemberName)
775 * and load an integer value from the input object
776 * (at a non-constant offset also derived from the MemberName).
777 * Such MN-erased LFs would be inlinable back to optimized
778 * code, whenever a constant enclosing DMH is available
779 * to supply a constant MN from its data.
780 *
781 * The main problem here is to keep LFs reasonably generic,
782 * while ensuring that hot spots will inline good instances.
783 * "Reasonably generic" means that we don't end up with
784 * repeated versions of bytecode or machine code that do
785 * not differ in their optimized form. Repeated versions
786 * of machine would have the undesirable overheads of
787 * (a) redundant compilation work and (b) extra I$ pressure.
788 * To control repeated versions, we need to be ready to
789 * erase details from LFs and move them into MH data,
790 * whenever those details are not relevant to significant
791 * optimization. "Significant" means optimization of
792 * code that is actually hot.
793 *
794 * Achieving this may require dynamic splitting of MHs, by replacing
795 * a generic LF with a more specialized one, on the same MH,
796 * if (a) the MH is frequently executed and (b) the MH cannot
797 * be inlined into a containing caller, such as an invokedynamic.
798 *
799 * Compiled LFs that are no longer used should be GC-able.
800 * If they contain non-BCP references, they should be properly
801 * interlinked with the class loader(s) that their embedded types
802 * depend on. This probably means that reusable compiled LFs
803 * will be tabulated (indexed) on relevant class loaders,
804 * or else that the tables that cache them will have weak links.
805 */
806
807 /**
808 * Make this LF directly executable, as part of a MethodHandle.
809 * Invariant: Every MH which is invoked must prepare its LF
810 * before invocation.
811 * (In principle, the JVM could do this very lazily,
812 * as a sort of pre-invocation linkage step.)
813 */
814 public void prepare() {
815 if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
816 compileToBytecode();
817 }
818 if (this.vmentry != null) {
819 // already prepared (e.g., a primitive DMH invoker form)
820 return;
821 }
822 MethodType mtype = methodType();
823 LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
824 if (prep == null) {
825 assert (isValidSignature(basicTypeSignature()));
826 prep = new LambdaForm(mtype);
827 prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
828 prep = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
829 }
830 this.vmentry = prep.vmentry;
831 // TO DO: Maybe add invokeGeneric, invokeWithArguments
832 }
833
834 private static @Stable PerfCounter LF_FAILED;
835
836 private static PerfCounter failedCompilationCounter() {
837 if (LF_FAILED == null) {
838 LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
839 }
840 return LF_FAILED;
841 }
842
843 /** Generate optimizable bytecode for this form. */
844 void compileToBytecode() {
845 if (forceInterpretation()) {
846 return; // this should not be compiled
847 }
848 if (vmentry != null && isCompiled) {
849 return; // already compiled somehow
850 }
851
852 // Obtain the invoker MethodType outside of the following try block.
853 // This ensures that an IllegalArgumentException is directly thrown if the
854 // type would have 256 or more parameters
855 MethodType invokerType = methodType();
856 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
857 try {
858 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
859 if (TRACE_INTERPRETER)
860 traceInterpreter("compileToBytecode", this);
861 isCompiled = true;
862 } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
863 // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
864 invocationCounter = -1;
865 failedCompilationCounter().increment();
866 if (LOG_LF_COMPILATION_FAILURE) {
867 System.out.println("LambdaForm compilation failed: " + this);
868 bge.printStackTrace(System.out);
869 }
870 } catch (Error e) {
871 // Pass through any error
872 throw e;
873 } catch (Exception e) {
874 // Wrap any exception
875 throw newInternalError(this.toString(), e);
876 }
877 }
878
879 // The next few routines are called only from assert expressions
880 // They verify that the built-in invokers process the correct raw data types.
881 private static boolean argumentTypesMatch(String sig, Object[] av) {
882 int arity = signatureArity(sig);
883 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
884 assert(av[0] instanceof MethodHandle) : "av[0] not instance of MethodHandle: " + av[0];
885 MethodHandle mh = (MethodHandle) av[0];
886 MethodType mt = mh.type();
887 assert(mt.parameterCount() == arity-1);
888 for (int i = 0; i < av.length; i++) {
889 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
890 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
891 }
892 return true;
893 }
894 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
895 // The following line is needed because (...)void method handles can use non-void invokers
896 if (type == void.class) tc = V_TYPE; // can drop any kind of value
897 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
898 switch (tc) {
899 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
900 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
901 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
902 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
903 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
904 case V_TYPE: break; // allow anything here; will be dropped
905 default: assert(false);
906 }
907 return true;
908 }
909 private static boolean checkInt(Class<?> type, Object x) {
910 assert(x instanceof Integer);
911 if (type == int.class) return true;
912 Wrapper w = Wrapper.forBasicType(type);
913 assert(w.isSubwordOrInt());
914 Object x1 = Wrapper.INT.wrap(w.wrap(x));
915 return x.equals(x1);
916 }
917 private static boolean checkRef(Class<?> type, Object x) {
918 assert(!type.isPrimitive());
919 if (x == null) return true;
920 if (type.isInterface()) return true;
921 return type.isInstance(x);
922 }
923
924 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
925 private static final int COMPILE_THRESHOLD;
926 static {
927 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
928 }
929 private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
930
931 private boolean forceInterpretation() {
932 return invocationCounter == -1;
933 }
934
935 @Hidden
936 @DontInline
937 /** Interpretively invoke this form on the given arguments. */
938 Object interpretWithArguments(Object... argumentValues) throws Throwable {
939 if (TRACE_INTERPRETER)
940 return interpretWithArgumentsTracing(argumentValues);
941 checkInvocationCounter();
942 assert(arityCheck(argumentValues));
943 Object[] values = Arrays.copyOf(argumentValues, names.length);
944 for (int i = argumentValues.length; i < values.length; i++) {
945 values[i] = interpretName(names[i], values);
946 }
947 Object rv = (result < 0) ? null : values[result];
948 assert(resultCheck(argumentValues, rv));
949 return rv;
950 }
951
952 @Hidden
953 @DontInline
954 /** Evaluate a single Name within this form, applying its function to its arguments. */
955 Object interpretName(Name name, Object[] values) throws Throwable {
956 if (TRACE_INTERPRETER)
957 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
958 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
959 for (int i = 0; i < arguments.length; i++) {
960 Object a = arguments[i];
961 if (a instanceof Name) {
962 int i2 = ((Name)a).index();
963 assert(names[i2] == a);
964 a = values[i2];
965 arguments[i] = a;
966 }
967 }
968 return name.function.invokeWithArguments(arguments);
969 }
970
971 private void checkInvocationCounter() {
972 if (COMPILE_THRESHOLD != 0 &&
973 !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
974 invocationCounter++; // benign race
975 if (invocationCounter >= COMPILE_THRESHOLD) {
976 // Replace vmentry with a bytecode version of this LF.
977 compileToBytecode();
978 }
979 }
980 }
981 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
982 traceInterpreter("[ interpretWithArguments", this, argumentValues);
983 if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
984 int ctr = invocationCounter++; // benign race
985 traceInterpreter("| invocationCounter", ctr);
986 if (invocationCounter >= COMPILE_THRESHOLD) {
987 compileToBytecode();
988 }
989 }
990 Object rval;
991 try {
992 assert(arityCheck(argumentValues));
993 Object[] values = Arrays.copyOf(argumentValues, names.length);
994 for (int i = argumentValues.length; i < values.length; i++) {
995 values[i] = interpretName(names[i], values);
996 }
997 rval = (result < 0) ? null : values[result];
998 } catch (Throwable ex) {
999 traceInterpreter("] throw =>", ex);
1000 throw ex;
1001 }
1002 traceInterpreter("] return =>", rval);
1003 return rval;
1004 }
1005
1006 static void traceInterpreter(String event, Object obj, Object... args) {
1007 if (TRACE_INTERPRETER) {
1008 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
1009 }
1010 }
1011 static void traceInterpreter(String event, Object obj) {
1012 traceInterpreter(event, obj, (Object[])null);
1013 }
1014 private boolean arityCheck(Object[] argumentValues) {
1015 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
1016 // also check that the leading (receiver) argument is somehow bound to this LF:
1017 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
1018 MethodHandle mh = (MethodHandle) argumentValues[0];
1019 assert(mh.internalForm() == this);
1020 // note: argument #0 could also be an interface wrapper, in the future
1021 argumentTypesMatch(basicTypeSignature(), argumentValues);
1022 return true;
1023 }
1024 private boolean resultCheck(Object[] argumentValues, Object result) {
1025 MethodHandle mh = (MethodHandle) argumentValues[0];
1026 MethodType mt = mh.type();
1027 assert(valueMatches(returnType(), mt.returnType(), result));
1028 return true;
1029 }
1030
1031 private boolean isEmpty() {
1032 if (result < 0)
1033 return (names.length == arity);
1034 else if (result == arity && names.length == arity + 1)
1035 return names[arity].isConstantZero();
1036 else
1037 return false;
1038 }
1039
1040 public String toString() {
1041 String lambdaName = lambdaName();
1042 StringBuilder buf = new StringBuilder(lambdaName + "=Lambda(");
1043 for (int i = 0; i < names.length; i++) {
1044 if (i == arity) buf.append(")=>{");
1045 Name n = names[i];
1046 if (i >= arity) buf.append("\n ");
1047 buf.append(n.paramString());
1048 if (i < arity) {
1049 if (i+1 < arity) buf.append(",");
1050 continue;
1051 }
1052 buf.append("=").append(n.exprString());
1053 buf.append(";");
1054 }
1055 if (arity == names.length) buf.append(")=>{");
1056 buf.append(result < 0 ? "void" : names[result]).append("}");
1057 if (TRACE_INTERPRETER) {
1058 // Extra verbosity:
1059 buf.append(":").append(basicTypeSignature());
1060 buf.append("/").append(vmentry);
1061 }
1062 return buf.toString();
1063 }
1064
1065 @Override
1066 public boolean equals(Object obj) {
1067 return obj instanceof LambdaForm && equals((LambdaForm)obj);
1068 }
1069 public boolean equals(LambdaForm that) {
1070 if (this.result != that.result) return false;
1071 return Arrays.equals(this.names, that.names);
1072 }
1073 public int hashCode() {
1074 return result + 31 * Arrays.hashCode(names);
1075 }
1076 LambdaFormEditor editor() {
1077 return LambdaFormEditor.lambdaFormEditor(this);
1078 }
1079
1080 boolean contains(Name name) {
1081 int pos = name.index();
1082 if (pos >= 0) {
1083 return pos < names.length && name.equals(names[pos]);
1084 }
1085 for (int i = arity; i < names.length; i++) {
1086 if (name.equals(names[i]))
1087 return true;
1088 }
1089 return false;
1090 }
1091
1092 static class NamedFunction {
1093 final MemberName member;
1094 private @Stable MethodHandle resolvedHandle;
1095 @Stable MethodHandle invoker;
1096
1097 NamedFunction(MethodHandle resolvedHandle) {
1098 this(resolvedHandle.internalMemberName(), resolvedHandle);
1099 }
1100 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1101 this.member = member;
1102 this.resolvedHandle = resolvedHandle;
1103 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1104 //assert(!isInvokeBasic(member));
1105 }
1106 NamedFunction(MethodType basicInvokerType) {
1107 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1108 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1109 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1110 this.member = resolvedHandle.internalMemberName();
1111 } else {
1112 // necessary to pass BigArityTest
1113 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1114 }
1115 assert(isInvokeBasic(member));
1116 }
1117
1118 private static boolean isInvokeBasic(MemberName member) {
1119 return member != null &&
1120 member.getDeclaringClass() == MethodHandle.class &&
1121 "invokeBasic".equals(member.getName());
1122 }
1123
1124 // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1125 // Any LambdaForm containing such a member is not interpretable.
1126 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1127 // And even without the resolvedHandle, the name can still be compiled and optimized.
1128 NamedFunction(Method method) {
1129 this(new MemberName(method));
1130 }
1131 NamedFunction(MemberName member) {
1132 this(member, null);
1133 }
1134
1135 MethodHandle resolvedHandle() {
1136 if (resolvedHandle == null) resolve();
1137 return resolvedHandle;
1138 }
1139
1140 synchronized void resolve() {
1141 if (resolvedHandle == null) {
1142 resolvedHandle = DirectMethodHandle.make(member);
1143 }
1144 }
1145
1146 @Override
1147 public boolean equals(Object other) {
1148 if (this == other) return true;
1149 if (other == null) return false;
1150 return (other instanceof NamedFunction that)
1151 && this.member != null
1152 && this.member.equals(that.member);
1153 }
1154
1155 @Override
1156 public int hashCode() {
1157 if (member != null)
1158 return member.hashCode();
1159 return super.hashCode();
1160 }
1161
1162 static final MethodType INVOKER_METHOD_TYPE =
1163 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1164
1165 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1166 typeForm = typeForm.basicType().form(); // normalize to basic type
1167 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1168 if (mh != null) return mh;
1169 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1170 mh = DirectMethodHandle.make(invoker);
1171 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1172 if (mh2 != null) return mh2; // benign race
1173 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1174 throw newInternalError(mh.debugString());
1175 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1176 }
1177
1178 @Hidden
1179 Object invokeWithArguments(Object... arguments) throws Throwable {
1180 // If we have a cached invoker, call it right away.
1181 // NOTE: The invoker always returns a reference value.
1182 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1183 return invoker().invokeBasic(resolvedHandle(), arguments);
1184 }
1185
1186 @Hidden
1187 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1188 Object rval;
1189 try {
1190 traceInterpreter("[ call", this, arguments);
1191 if (invoker == null) {
1192 traceInterpreter("| getInvoker", this);
1193 invoker();
1194 }
1195 // resolvedHandle might be uninitialized, ok for tracing
1196 if (resolvedHandle == null) {
1197 traceInterpreter("| resolve", this);
1198 resolvedHandle();
1199 }
1200 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1201 } catch (Throwable ex) {
1202 traceInterpreter("] throw =>", ex);
1203 throw ex;
1204 }
1205 traceInterpreter("] return =>", rval);
1206 return rval;
1207 }
1208
1209 private MethodHandle invoker() {
1210 if (invoker != null) return invoker;
1211 // Get an invoker and cache it.
1212 return invoker = computeInvoker(methodType().form());
1213 }
1214
1215 MethodType methodType() {
1216 if (resolvedHandle != null)
1217 return resolvedHandle.type();
1218 else
1219 // only for certain internal LFs during bootstrapping
1220 return member.getInvocationType();
1221 }
1222
1223 MemberName member() {
1224 assert(assertMemberIsConsistent());
1225 return member;
1226 }
1227
1228 // Called only from assert.
1229 private boolean assertMemberIsConsistent() {
1230 if (resolvedHandle instanceof DirectMethodHandle) {
1231 MemberName m = resolvedHandle.internalMemberName();
1232 assert(m.equals(member));
1233 }
1234 return true;
1235 }
1236
1237 Class<?> memberDeclaringClassOrNull() {
1238 return (member == null) ? null : member.getDeclaringClass();
1239 }
1240
1241 BasicType returnType() {
1242 return basicType(methodType().returnType());
1243 }
1244
1245 BasicType parameterType(int n) {
1246 return basicType(methodType().parameterType(n));
1247 }
1248
1249 int arity() {
1250 return methodType().parameterCount();
1251 }
1252
1253 public String toString() {
1254 if (member == null) return String.valueOf(resolvedHandle);
1255 return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1256 }
1257
1258 public boolean isIdentity() {
1259 return this.equals(identity(returnType()));
1260 }
1261
1262 public boolean isConstantZero() {
1263 return this.equals(constantZero(returnType()));
1264 }
1265
1266 public MethodHandleImpl.Intrinsic intrinsicName() {
1267 return resolvedHandle != null
1268 ? resolvedHandle.intrinsicName()
1269 : MethodHandleImpl.Intrinsic.NONE;
1270 }
1271
1272 public Object intrinsicData() {
1273 return resolvedHandle != null
1274 ? resolvedHandle.intrinsicData()
1275 : null;
1276 }
1277 }
1278
1279 public static String basicTypeSignature(MethodType type) {
1280 int params = type.parameterCount();
1281 char[] sig = new char[params + 2];
1282 int sigp = 0;
1283 while (sigp < params) {
1284 sig[sigp] = basicTypeChar(type.parameterType(sigp++));
1285 }
1286 sig[sigp++] = '_';
1287 sig[sigp++] = basicTypeChar(type.returnType());
1288 assert(sigp == sig.length);
1289 return String.valueOf(sig);
1290 }
1291
1292 /** Hack to make signatures more readable when they show up in method names.
1293 * Signature should start with a sequence of uppercase ASCII letters.
1294 * Runs of three or more are replaced by a single letter plus a decimal repeat count.
1295 * A tail of anything other than uppercase ASCII is passed through unchanged.
1296 * @param signature sequence of uppercase ASCII letters with possible repetitions
1297 * @return same sequence, with repetitions counted by decimal numerals
1298 */
1299 public static String shortenSignature(String signature) {
1300 final int NO_CHAR = -1, MIN_RUN = 3;
1301 int c0, c1 = NO_CHAR, c1reps = 0;
1302 StringBuilder buf = null;
1303 int len = signature.length();
1304 if (len < MIN_RUN) return signature;
1305 for (int i = 0; i <= len; i++) {
1306 if (c1 != NO_CHAR && !('A' <= c1 && c1 <= 'Z')) {
1307 // wrong kind of char; bail out here
1308 if (buf != null) {
1309 buf.append(signature, i - c1reps, len);
1310 }
1311 break;
1312 }
1313 // shift in the next char:
1314 c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1315 if (c1 == c0) { ++c1reps; continue; }
1316 // shift in the next count:
1317 int c0reps = c1reps; c1reps = 1;
1318 // end of a character run
1319 if (c0reps < MIN_RUN) {
1320 if (buf != null) {
1321 while (--c0reps >= 0)
1322 buf.append((char)c0);
1323 }
1324 continue;
1325 }
1326 // found three or more in a row
1327 if (buf == null)
1328 buf = new StringBuilder().append(signature, 0, i - c0reps);
1329 buf.append((char)c0).append(c0reps);
1330 }
1331 return (buf == null) ? signature : buf.toString();
1332 }
1333
1334 static final class Name {
1335 final BasicType type;
1336 @Stable short index;
1337 final NamedFunction function;
1338 final Object constraint; // additional type information, if not null
1339 @Stable final Object[] arguments;
1340
1341 private Name(int index, BasicType type, NamedFunction function, Object[] arguments) {
1342 this.index = (short)index;
1343 this.type = type;
1344 this.function = function;
1345 this.arguments = arguments;
1346 this.constraint = null;
1347 assert(this.index == index);
1348 }
1349 private Name(Name that, Object constraint) {
1350 this.index = that.index;
1351 this.type = that.type;
1352 this.function = that.function;
1353 this.arguments = that.arguments;
1354 this.constraint = constraint;
1355 assert(constraint == null || isParam()); // only params have constraints
1356 assert(constraint == null || constraint instanceof ClassSpecializer.SpeciesData || constraint instanceof Class);
1357 }
1358 Name(MethodHandle function, Object... arguments) {
1359 this(new NamedFunction(function), arguments);
1360 }
1361 Name(MethodType functionType, Object... arguments) {
1362 this(new NamedFunction(functionType), arguments);
1363 assert(arguments[0] instanceof Name && ((Name)arguments[0]).type == L_TYPE);
1364 }
1365 Name(MemberName function, Object... arguments) {
1366 this(new NamedFunction(function), arguments);
1367 }
1368 Name(NamedFunction function, Object... arguments) {
1369 this(-1, function.returnType(), function, arguments = Arrays.copyOf(arguments, arguments.length, Object[].class));
1370 assert(typesMatch(function, arguments));
1371 }
1372 /** Create a raw parameter of the given type, with an expected index. */
1373 Name(int index, BasicType type) {
1374 this(index, type, null, null);
1375 }
1376 /** Create a raw parameter of the given type. */
1377 Name(BasicType type) { this(-1, type); }
1378
1379 BasicType type() { return type; }
1380 int index() { return index; }
1381 boolean initIndex(int i) {
1382 if (index != i) {
1383 if (index != -1) return false;
1384 index = (short)i;
1385 }
1386 return true;
1387 }
1388 char typeChar() {
1389 return type.btChar;
1390 }
1391
1392 Name newIndex(int i) {
1393 if (initIndex(i)) return this;
1394 return cloneWithIndex(i);
1395 }
1396 Name cloneWithIndex(int i) {
1397 Object[] newArguments = (arguments == null) ? null : arguments.clone();
1398 return new Name(i, type, function, newArguments).withConstraint(constraint);
1399 }
1400 Name withConstraint(Object constraint) {
1401 if (constraint == this.constraint) return this;
1402 return new Name(this, constraint);
1403 }
1404 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1405 if (oldName == newName) return this;
1406 @SuppressWarnings("LocalVariableHidesMemberVariable")
1407 Object[] arguments = this.arguments;
1408 if (arguments == null) return this;
1409 boolean replaced = false;
1410 for (int j = 0; j < arguments.length; j++) {
1411 if (arguments[j] == oldName) {
1412 if (!replaced) {
1413 replaced = true;
1414 arguments = arguments.clone();
1415 }
1416 arguments[j] = newName;
1417 }
1418 }
1419 if (!replaced) return this;
1420 return new Name(function, arguments);
1421 }
1422 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1423 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1424 */
1425 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1426 if (start >= end) return this;
1427 @SuppressWarnings("LocalVariableHidesMemberVariable")
1428 Object[] arguments = this.arguments;
1429 boolean replaced = false;
1430 eachArg:
1431 for (int j = 0; j < arguments.length; j++) {
1432 if (arguments[j] instanceof Name n) {
1433 int check = n.index;
1434 // harmless check to see if the thing is already in newNames:
1435 if (check >= 0 && check < newNames.length && n == newNames[check])
1436 continue eachArg;
1437 // n might not have the correct index: n != oldNames[n.index].
1438 for (int i = start; i < end; i++) {
1439 if (n == oldNames[i]) {
1440 if (n == newNames[i])
1441 continue eachArg;
1442 if (!replaced) {
1443 replaced = true;
1444 arguments = arguments.clone();
1445 }
1446 arguments[j] = newNames[i];
1447 continue eachArg;
1448 }
1449 }
1450 }
1451 }
1452 if (!replaced) return this;
1453 return new Name(function, arguments);
1454 }
1455 void internArguments() {
1456 @SuppressWarnings("LocalVariableHidesMemberVariable")
1457 Object[] arguments = this.arguments;
1458 for (int j = 0; j < arguments.length; j++) {
1459 if (arguments[j] instanceof Name n) {
1460 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1461 arguments[j] = internArgument(n);
1462 }
1463 }
1464 }
1465 boolean isParam() {
1466 return function == null;
1467 }
1468 boolean isConstantZero() {
1469 return !isParam() && arguments.length == 0 && function.isConstantZero();
1470 }
1471
1472 boolean refersTo(Class<?> declaringClass, String methodName) {
1473 return function != null &&
1474 function.member() != null && function.member().refersTo(declaringClass, methodName);
1475 }
1476
1477 /**
1478 * Check if MemberName is a call to MethodHandle.invokeBasic.
1479 */
1480 boolean isInvokeBasic() {
1481 if (function == null)
1482 return false;
1483 if (arguments.length < 1)
1484 return false; // must have MH argument
1485 MemberName member = function.member();
1486 return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1487 !member.isPublic() && !member.isStatic();
1488 }
1489
1490 /**
1491 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1492 */
1493 boolean isLinkerMethodInvoke() {
1494 if (function == null)
1495 return false;
1496 if (arguments.length < 1)
1497 return false; // must have MH argument
1498 MemberName member = function.member();
1499 return member != null &&
1500 member.getDeclaringClass() == MethodHandle.class &&
1501 !member.isPublic() && member.isStatic() &&
1502 member.getName().startsWith("linkTo");
1503 }
1504
1505 public String toString() {
1506 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1507 }
1508 public String debugString() {
1509 String s = paramString();
1510 return (function == null) ? s : s + "=" + exprString();
1511 }
1512 public String paramString() {
1513 String s = toString();
1514 Object c = constraint;
1515 if (c == null)
1516 return s;
1517 if (c instanceof Class) c = ((Class<?>)c).getSimpleName();
1518 return s + "/" + c;
1519 }
1520 public String exprString() {
1521 if (function == null) return toString();
1522 StringBuilder buf = new StringBuilder(function.toString());
1523 buf.append("(");
1524 String cma = "";
1525 for (Object a : arguments) {
1526 buf.append(cma); cma = ",";
1527 if (a instanceof Name || a instanceof Integer)
1528 buf.append(a);
1529 else
1530 buf.append("(").append(a).append(")");
1531 }
1532 buf.append(")");
1533 return buf.toString();
1534 }
1535
1536 private boolean typesMatch(NamedFunction function, Object ... arguments) {
1537 assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1538 for (int i = 0; i < arguments.length; i++) {
1539 assert (typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1540 }
1541 return true;
1542 }
1543
1544 private static boolean typesMatch(BasicType parameterType, Object object) {
1545 if (object instanceof Name) {
1546 return ((Name)object).type == parameterType;
1547 }
1548 switch (parameterType) {
1549 case I_TYPE: return object instanceof Integer;
1550 case J_TYPE: return object instanceof Long;
1551 case F_TYPE: return object instanceof Float;
1552 case D_TYPE: return object instanceof Double;
1553 }
1554 assert(parameterType == L_TYPE);
1555 return true;
1556 }
1557
1558 /** Return the index of the last occurrence of n in the argument array.
1559 * Return -1 if the name is not used.
1560 */
1561 int lastUseIndex(Name n) {
1562 if (arguments == null) return -1;
1563 for (int i = arguments.length; --i >= 0; ) {
1564 if (arguments[i] == n) return i;
1565 }
1566 return -1;
1567 }
1568
1569 /** Return the number of occurrences of n in the argument array.
1570 * Return 0 if the name is not used.
1571 */
1572 int useCount(Name n) {
1573 int count = 0;
1574 if (arguments != null) {
1575 for (Object argument : arguments) {
1576 if (argument == n) {
1577 count++;
1578 }
1579 }
1580 }
1581 return count;
1582 }
1583
1584 public boolean equals(Name that) {
1585 if (this == that) return true;
1586 if (isParam())
1587 // each parameter is a unique atom
1588 return false; // this != that
1589 return
1590 //this.index == that.index &&
1591 this.type == that.type &&
1592 this.function.equals(that.function) &&
1593 Arrays.equals(this.arguments, that.arguments);
1594 }
1595 @Override
1596 public boolean equals(Object x) {
1597 return x instanceof Name && equals((Name)x);
1598 }
1599 @Override
1600 public int hashCode() {
1601 if (isParam())
1602 return index | (type.ordinal() << 8);
1603 return function.hashCode() ^ Arrays.hashCode(arguments);
1604 }
1605 }
1606
1607 /** Return the index of the last name which contains n as an argument.
1608 * Return -1 if the name is not used. Return names.length if it is the return value.
1609 */
1610 int lastUseIndex(Name n) {
1611 int ni = n.index, nmax = names.length;
1612 assert(names[ni] == n);
1613 if (result == ni) return nmax; // live all the way beyond the end
1614 for (int i = nmax; --i > ni; ) {
1615 if (names[i].lastUseIndex(n) >= 0)
1616 return i;
1617 }
1618 return -1;
1619 }
1620
1621 /** Return the number of times n is used as an argument or return value. */
1622 int useCount(Name n) {
1623 int count = (result == n.index) ? 1 : 0;
1624 int i = Math.max(n.index + 1, arity);
1625 while (i < names.length) {
1626 count += names[i++].useCount(n);
1627 }
1628 return count;
1629 }
1630
1631 static Name argument(int which, BasicType type) {
1632 if (which >= INTERNED_ARGUMENT_LIMIT)
1633 return new Name(which, type);
1634 return INTERNED_ARGUMENTS[type.ordinal()][which];
1635 }
1636 static Name internArgument(Name n) {
1637 assert(n.isParam()) : "not param: " + n;
1638 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1639 if (n.constraint != null) return n;
1640 return argument(n.index, n.type);
1641 }
1642 static Name[] arguments(int extra, MethodType types) {
1643 int length = types.parameterCount();
1644 Name[] names = new Name[length + extra];
1645 for (int i = 0; i < length; i++)
1646 names[i] = argument(i, basicType(types.parameterType(i)));
1647 return names;
1648 }
1649 static final int INTERNED_ARGUMENT_LIMIT = 10;
1650 private static final Name[][] INTERNED_ARGUMENTS
1651 = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1652 static {
1653 for (BasicType type : BasicType.ARG_TYPES) {
1654 int ord = type.ordinal();
1655 for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1656 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1657 }
1658 }
1659 }
1660
1661 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1662
1663 static LambdaForm identityForm(BasicType type) {
1664 int ord = type.ordinal();
1665 LambdaForm form = LF_identity[ord];
1666 if (form != null) {
1667 return form;
1668 }
1669 createFormsFor(type);
1670 return LF_identity[ord];
1671 }
1672
1673 static LambdaForm zeroForm(BasicType type) {
1674 int ord = type.ordinal();
1675 LambdaForm form = LF_zero[ord];
1676 if (form != null) {
1677 return form;
1678 }
1679 createFormsFor(type);
1680 return LF_zero[ord];
1681 }
1682
1683 static NamedFunction identity(BasicType type) {
1684 int ord = type.ordinal();
1685 NamedFunction function = NF_identity[ord];
1686 if (function != null) {
1687 return function;
1688 }
1689 createFormsFor(type);
1690 return NF_identity[ord];
1691 }
1692
1693 static NamedFunction constantZero(BasicType type) {
1694 int ord = type.ordinal();
1695 NamedFunction function = NF_zero[ord];
1696 if (function != null) {
1697 return function;
1698 }
1699 createFormsFor(type);
1700 return NF_zero[ord];
1701 }
1702
1703 private static final @Stable LambdaForm[] LF_identity = new LambdaForm[TYPE_LIMIT];
1704 private static final @Stable LambdaForm[] LF_zero = new LambdaForm[TYPE_LIMIT];
1705 private static final @Stable NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1706 private static final @Stable NamedFunction[] NF_zero = new NamedFunction[TYPE_LIMIT];
1707
1708 private static final Object createFormsLock = new Object();
1709 private static void createFormsFor(BasicType type) {
1710 // Avoid racy initialization during bootstrap
1711 UNSAFE.ensureClassInitialized(BoundMethodHandle.class);
1712 synchronized (createFormsLock) {
1713 final int ord = type.ordinal();
1714 LambdaForm idForm = LF_identity[ord];
1715 if (idForm != null) {
1716 return;
1717 }
1718 char btChar = type.basicTypeChar();
1719 boolean isVoid = (type == V_TYPE);
1720 Class<?> btClass = type.btClass;
1721 MethodType zeType = MethodType.methodType(btClass);
1722 MethodType idType = (isVoid) ? zeType : MethodType.methodType(btClass, btClass);
1723
1724 // Look up symbolic names. It might not be necessary to have these,
1725 // but if we need to emit direct references to bytecodes, it helps.
1726 // Zero is built from a call to an identity function with a constant zero input.
1727 MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1728 MemberName zeMem = null;
1729 try {
1730 idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, LM_TRUSTED, NoSuchMethodException.class);
1731 if (!isVoid) {
1732 zeMem = new MemberName(LambdaForm.class, "zero_"+btChar, zeType, REF_invokeStatic);
1733 zeMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, zeMem, null, LM_TRUSTED, NoSuchMethodException.class);
1734 }
1735 } catch (IllegalAccessException|NoSuchMethodException ex) {
1736 throw newInternalError(ex);
1737 }
1738
1739 NamedFunction idFun;
1740 LambdaForm zeForm;
1741 NamedFunction zeFun;
1742
1743 // Create the LFs and NamedFunctions. Precompiling LFs to byte code is needed to break circular
1744 // bootstrap dependency on this method in case we're interpreting LFs
1745 if (isVoid) {
1746 Name[] idNames = new Name[] { argument(0, L_TYPE) };
1747 idForm = new LambdaForm(1, idNames, VOID_RESULT, Kind.IDENTITY);
1748 idForm.compileToBytecode();
1749 idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm));
1750
1751 zeForm = idForm;
1752 zeFun = idFun;
1753 } else {
1754 Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1755 idForm = new LambdaForm(2, idNames, 1, Kind.IDENTITY);
1756 idForm.compileToBytecode();
1757 idFun = new NamedFunction(idMem, MethodHandleImpl.makeIntrinsic(SimpleMethodHandle.make(idMem.getInvocationType(), idForm),
1758 MethodHandleImpl.Intrinsic.IDENTITY));
1759
1760 Object zeValue = Wrapper.forBasicType(btChar).zero();
1761 Name[] zeNames = new Name[] { argument(0, L_TYPE), new Name(idFun, zeValue) };
1762 zeForm = new LambdaForm(1, zeNames, 1, Kind.ZERO);
1763 zeForm.compileToBytecode();
1764 zeFun = new NamedFunction(zeMem, MethodHandleImpl.makeIntrinsic(SimpleMethodHandle.make(zeMem.getInvocationType(), zeForm),
1765 MethodHandleImpl.Intrinsic.ZERO));
1766 }
1767
1768 LF_zero[ord] = zeForm;
1769 NF_zero[ord] = zeFun;
1770 LF_identity[ord] = idForm;
1771 NF_identity[ord] = idFun;
1772
1773 assert(idFun.isIdentity());
1774 assert(zeFun.isConstantZero());
1775 assert(new Name(zeFun).isConstantZero());
1776 }
1777 }
1778
1779 // Avoid appealing to ValueConversions at bootstrap time:
1780 private static int identity_I(int x) { return x; }
1781 private static long identity_J(long x) { return x; }
1782 private static float identity_F(float x) { return x; }
1783 private static double identity_D(double x) { return x; }
1784 private static Object identity_L(Object x) { return x; }
1785 private static void identity_V() { return; }
1786 private static int zero_I() { return 0; }
1787 private static long zero_J() { return 0; }
1788 private static float zero_F() { return 0; }
1789 private static double zero_D() { return 0; }
1790 private static Object zero_L() { return null; }
1791
1792 /**
1793 * Internal marker for byte-compiled LambdaForms.
1794 */
1795 /*non-public*/
1796 @Target(ElementType.METHOD)
1797 @Retention(RetentionPolicy.RUNTIME)
1798 @interface Compiled {
1799 }
1800
1801 private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1802 private static final HashMap<LambdaForm,String> DEBUG_NAMES;
1803 static {
1804 if (debugEnabled()) {
1805 DEBUG_NAME_COUNTERS = new HashMap<>();
1806 DEBUG_NAMES = new HashMap<>();
1807 } else {
1808 DEBUG_NAME_COUNTERS = null;
1809 DEBUG_NAMES = null;
1810 }
1811 }
1812
1813 static {
1814 // The Holder class will contain pre-generated forms resolved
1815 // using MemberName.getFactory(). However, that doesn't initialize the
1816 // class, which subtly breaks inlining etc. By forcing
1817 // initialization of the Holder class we avoid these issues.
1818 UNSAFE.ensureClassInitialized(Holder.class);
1819 }
1820
1821 /* Placeholder class for zero and identity forms generated ahead of time */
1822 final class Holder {}
1823
1824 // The following hack is necessary in order to suppress TRACE_INTERPRETER
1825 // during execution of the static initializes of this class.
1826 // Turning on TRACE_INTERPRETER too early will cause
1827 // stack overflows and other misbehavior during attempts to trace events
1828 // that occur during LambdaForm.<clinit>.
1829 // Therefore, do not move this line higher in this file, and do not remove.
1830 private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1831 }