1 /*
2 * Copyright (c) 2011, 2024, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package java.lang.invoke;
27
28 import java.lang.classfile.TypeKind;
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, TypeKind.REFERENCE), // all reference types
142 I_TYPE('I', int.class, Wrapper.INT, TypeKind.INT),
143 J_TYPE('J', long.class, Wrapper.LONG, TypeKind.LONG),
144 F_TYPE('F', float.class, Wrapper.FLOAT, TypeKind.FLOAT),
145 D_TYPE('D', double.class, Wrapper.DOUBLE, TypeKind.DOUBLE), // all primitive types
146 V_TYPE('V', void.class, Wrapper.VOID, TypeKind.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 final TypeKind btKind;
158
159 private BasicType(char btChar, Class<?> btClass, Wrapper wrapper, TypeKind typeKind) {
160 this.btChar = btChar;
161 this.btClass = btClass;
162 this.btWrapper = wrapper;
163 this.btKind = typeKind;
164 }
165
166 char basicTypeChar() {
167 return btChar;
168 }
169 Class<?> basicTypeClass() {
170 return btClass;
171 }
172 Wrapper basicTypeWrapper() {
173 return btWrapper;
174 }
175 TypeKind basicTypeKind() {
176 return btKind;
177 }
178 int basicTypeSlots() {
179 return btWrapper.stackSlots();
180 }
181
182 static BasicType basicType(byte type) {
183 return ALL_TYPES[type];
184 }
185 static BasicType basicType(char type) {
186 return switch (type) {
187 case 'L' -> L_TYPE;
188 case 'I' -> I_TYPE;
189 case 'J' -> J_TYPE;
190 case 'F' -> F_TYPE;
191 case 'D' -> D_TYPE;
192 case 'V' -> V_TYPE;
193 // all subword types are represented as ints
194 case 'Z', 'B', 'S', 'C' -> I_TYPE;
195 default -> throw newInternalError("Unknown type char: '" + type + "'");
196 };
197 }
198 static BasicType basicType(Class<?> type) {
199 return basicType(Wrapper.basicTypeChar(type));
200 }
201 static int[] basicTypeOrds(BasicType[] types) {
202 if (types == null) {
203 return null;
204 }
205 int[] a = new int[types.length];
206 for(int i = 0; i < types.length; ++i) {
207 a[i] = types[i].ordinal();
208 }
209 return a;
210 }
211
212 static char basicTypeChar(Class<?> type) {
213 return basicType(type).btChar;
214 }
215
216 static int[] basicTypesOrd(Class<?>[] types) {
217 int[] ords = new int[types.length];
218 for (int i = 0; i < ords.length; i++) {
219 ords[i] = basicType(types[i]).ordinal();
220 }
221 return ords;
222 }
223
224 static boolean isBasicTypeChar(char c) {
225 return "LIJFDV".indexOf(c) >= 0;
226 }
227 static boolean isArgBasicTypeChar(char c) {
228 return "LIJFD".indexOf(c) >= 0;
229 }
230
231 static { assert(checkBasicType()); }
232 private static boolean checkBasicType() {
233 for (int i = 0; i < ARG_TYPE_LIMIT; i++) {
234 assert ARG_TYPES[i].ordinal() == i;
235 assert ARG_TYPES[i] == ALL_TYPES[i];
236 }
237 for (int i = 0; i < TYPE_LIMIT; i++) {
238 assert ALL_TYPES[i].ordinal() == i;
239 }
240 assert ALL_TYPES[TYPE_LIMIT - 1] == V_TYPE;
241 assert !Arrays.asList(ARG_TYPES).contains(V_TYPE);
242 return true;
243 }
244 }
245
246 enum Kind {
247 GENERIC("invoke"),
248 ZERO("zero"),
249 IDENTITY("identity"),
250 BOUND_REINVOKER("BMH.reinvoke", "reinvoke"),
251 REINVOKER("MH.reinvoke", "reinvoke"),
252 DELEGATE("MH.delegate", "delegate"),
253 EXACT_LINKER("MH.invokeExact_MT", "invokeExact_MT"),
254 EXACT_INVOKER("MH.exactInvoker", "exactInvoker"),
255 GENERIC_LINKER("MH.invoke_MT", "invoke_MT"),
256 GENERIC_INVOKER("MH.invoker", "invoker"),
257 LINK_TO_TARGET_METHOD("linkToTargetMethod"),
258 LINK_TO_CALL_SITE("linkToCallSite"),
259 DIRECT_INVOKE_VIRTUAL("DMH.invokeVirtual", "invokeVirtual"),
260 DIRECT_INVOKE_SPECIAL("DMH.invokeSpecial", "invokeSpecial"),
261 DIRECT_INVOKE_SPECIAL_IFC("DMH.invokeSpecialIFC", "invokeSpecialIFC"),
262 DIRECT_INVOKE_STATIC("DMH.invokeStatic", "invokeStatic"),
263 DIRECT_NEW_INVOKE_SPECIAL("DMH.newInvokeSpecial", "newInvokeSpecial"),
264 DIRECT_INVOKE_INTERFACE("DMH.invokeInterface", "invokeInterface"),
265 DIRECT_INVOKE_STATIC_INIT("DMH.invokeStaticInit", "invokeStaticInit"),
266 GET_REFERENCE("getReference"),
267 PUT_REFERENCE("putReference"),
268 GET_REFERENCE_VOLATILE("getReferenceVolatile"),
269 PUT_REFERENCE_VOLATILE("putReferenceVolatile"),
270 GET_VALUE("getValue"),
271 PUT_VALUE("putValue"),
272 GET_VALUE_VOLATILE("getValueVolatile"),
273 PUT_VALUE_VOLATILE("putValueVolatile"),
274 GET_INT("getInt"),
275 PUT_INT("putInt"),
276 GET_INT_VOLATILE("getIntVolatile"),
277 PUT_INT_VOLATILE("putIntVolatile"),
278 GET_BOOLEAN("getBoolean"),
279 PUT_BOOLEAN("putBoolean"),
280 GET_BOOLEAN_VOLATILE("getBooleanVolatile"),
281 PUT_BOOLEAN_VOLATILE("putBooleanVolatile"),
282 GET_BYTE("getByte"),
283 PUT_BYTE("putByte"),
284 GET_BYTE_VOLATILE("getByteVolatile"),
285 PUT_BYTE_VOLATILE("putByteVolatile"),
286 GET_CHAR("getChar"),
287 PUT_CHAR("putChar"),
288 GET_CHAR_VOLATILE("getCharVolatile"),
289 PUT_CHAR_VOLATILE("putCharVolatile"),
290 GET_SHORT("getShort"),
291 PUT_SHORT("putShort"),
292 GET_SHORT_VOLATILE("getShortVolatile"),
293 PUT_SHORT_VOLATILE("putShortVolatile"),
294 GET_LONG("getLong"),
295 PUT_LONG("putLong"),
296 GET_LONG_VOLATILE("getLongVolatile"),
297 PUT_LONG_VOLATILE("putLongVolatile"),
298 GET_FLOAT("getFloat"),
299 PUT_FLOAT("putFloat"),
300 GET_FLOAT_VOLATILE("getFloatVolatile"),
301 PUT_FLOAT_VOLATILE("putFloatVolatile"),
302 GET_DOUBLE("getDouble"),
303 PUT_DOUBLE("putDouble"),
304 GET_DOUBLE_VOLATILE("getDoubleVolatile"),
305 PUT_DOUBLE_VOLATILE("putDoubleVolatile"),
306 TRY_FINALLY("tryFinally"),
307 TABLE_SWITCH("tableSwitch"),
308 COLLECTOR("collector"),
309 LOOP("loop"),
310 GUARD("guard"),
311 GUARD_WITH_CATCH("guardWithCatch"),
312 VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
313 VARHANDLE_INVOKER("VH.invoker", "invoker"),
314 VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
315
316 final String defaultLambdaName;
317 final String methodName;
318
319 private Kind(String defaultLambdaName) {
320 this(defaultLambdaName, defaultLambdaName);
321 }
322
323 private Kind(String defaultLambdaName, String methodName) {
324 this.defaultLambdaName = defaultLambdaName;
325 this.methodName = methodName;
326 }
327 }
328
329 // private version that doesn't do checks or defensive copies
330 private LambdaForm(int arity, int result, boolean forceInline, MethodHandle customized, Name[] names, Kind kind) {
331 this.arity = arity;
332 this.result = result;
333 this.forceInline = forceInline;
334 this.customized = customized;
335 this.names = names;
336 this.kind = kind;
337 this.vmentry = null;
338 this.isCompiled = false;
339 }
340
341 // root factory pre/post processing and calls simple constructor
342 private static LambdaForm create(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
343 names = names.clone();
344 assert(namesOK(arity, names));
345 result = fixResult(result, names);
346
347 boolean canInterpret = normalizeNames(arity, names);
348 LambdaForm form = new LambdaForm(arity, result, forceInline, customized, names, kind);
349 assert(form.nameRefsAreLegal());
350 if (!canInterpret) {
351 form.compileToBytecode();
352 }
353 return form;
354 }
355
356 // derived factories with defaults
357 private static final int DEFAULT_RESULT = LAST_RESULT;
358 private static final boolean DEFAULT_FORCE_INLINE = true;
359 private static final MethodHandle DEFAULT_CUSTOMIZED = null;
360 private static final Kind DEFAULT_KIND = Kind.GENERIC;
361
362 static LambdaForm create(int arity, Name[] names, int result) {
363 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
364 }
365 static LambdaForm create(int arity, Name[] names, int result, Kind kind) {
366 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
367 }
368 static LambdaForm create(int arity, Name[] names) {
369 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
370 }
371 static LambdaForm create(int arity, Name[] names, Kind kind) {
372 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
373 }
374 static LambdaForm create(int arity, Name[] names, boolean forceInline, Kind kind) {
375 return create(arity, names, DEFAULT_RESULT, forceInline, DEFAULT_CUSTOMIZED, kind);
376 }
377
378 private static LambdaForm createBlankForType(MethodType mt) {
379 // Make a blank lambda form, which returns a constant zero or null.
380 // It is used as a template for managing the invocation of similar forms that are non-empty.
381 // Called only from getPreparedForm.
382 int arity = mt.parameterCount();
383 int result = (mt.returnType() == void.class || mt.returnType() == Void.class) ? VOID_RESULT : arity;
384 Name[] names = buildEmptyNames(arity, mt, result == VOID_RESULT);
385 boolean canInterpret = normalizeNames(arity, names);
386 LambdaForm form = new LambdaForm(arity, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, names, Kind.ZERO);
387 assert(form.nameRefsAreLegal() && form.isEmpty() && isValidSignature(form.basicTypeSignature()));
388 if (!canInterpret) {
389 form.compileToBytecode();
390 }
391 return form;
392 }
393
394 private static Name[] buildEmptyNames(int arity, MethodType mt, boolean isVoid) {
395 Name[] names = arguments(isVoid ? 0 : 1, mt);
396 if (!isVoid) {
397 Name zero = new Name(constantZero(basicType(mt.returnType())));
398 names[arity] = zero.withIndex(arity);
399 }
400 assert(namesOK(arity, names));
401 return names;
402 }
403
404 private static int fixResult(int result, Name[] names) {
405 if (result == LAST_RESULT)
406 result = names.length - 1; // might still be void
407 if (result >= 0 && names[result].type == V_TYPE)
408 result = VOID_RESULT;
409 return result;
410 }
411
412 static boolean debugNames() {
413 return DEBUG_NAME_COUNTERS != null;
414 }
415
416 static void associateWithDebugName(LambdaForm form, String name) {
417 assert (debugNames());
418 synchronized (DEBUG_NAMES) {
419 DEBUG_NAMES.put(form, name);
420 }
421 }
422
423 String lambdaName() {
424 if (DEBUG_NAMES != null) {
425 synchronized (DEBUG_NAMES) {
426 String name = DEBUG_NAMES.get(this);
427 if (name == null) {
428 name = generateDebugName();
429 }
430 return name;
431 }
432 }
433 return kind.defaultLambdaName;
434 }
435
436 private String generateDebugName() {
437 assert (debugNames());
438 String debugNameStem = kind.defaultLambdaName;
439 Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
440 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
441 StringBuilder buf = new StringBuilder(debugNameStem);
442 int leadingZero = buf.length();
443 buf.append((int) ctr);
444 for (int i = buf.length() - leadingZero; i < 3; i++) {
445 buf.insert(leadingZero, '0');
446 }
447 buf.append('_');
448 buf.append(basicTypeSignature());
449 String name = buf.toString();
450 associateWithDebugName(this, name);
451 return name;
452 }
453
454 private static boolean namesOK(int arity, Name[] names) {
455 for (int i = 0; i < names.length; i++) {
456 Name n = names[i];
457 assert(n != null) : "n is null";
458 if (i < arity)
459 assert( n.isParam()) : n + " is not param at " + i;
460 else
461 assert(!n.isParam()) : n + " is param at " + i;
462 }
463 return true;
464 }
465
466 /** Customize LambdaForm for a particular MethodHandle */
467 LambdaForm customize(MethodHandle mh) {
468 if (customized == mh) {
469 return this;
470 }
471 LambdaForm customForm = LambdaForm.create(arity, names, result, forceInline, mh, kind);
472 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
473 // If shared LambdaForm has been compiled, compile customized version as well.
474 customForm.compileToBytecode();
475 }
476 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
477 return customForm;
478 }
479
480 /** Get uncustomized flavor of the LambdaForm */
481 LambdaForm uncustomize() {
482 if (customized == null) {
483 return this;
484 }
485 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
486 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
487 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
488 // If customized LambdaForm has been compiled, compile uncustomized version as well.
489 uncustomizedForm.compileToBytecode();
490 }
491 return uncustomizedForm;
492 }
493
494 /** Renumber and/or replace params so that they are interned and canonically numbered.
495 * @return true if we can interpret
496 */
497 private static boolean normalizeNames(int arity, Name[] names) {
498 Name[] oldNames = names.clone();
499 int maxOutArity = 0;
500 for (int i = 0; i < names.length; i++) {
501 Name n = names[i];
502 names[i] = n.withIndex(i);
503 if (n.arguments != null && maxOutArity < n.arguments.length)
504 maxOutArity = n.arguments.length;
505 }
506 if (oldNames != null) {
507 for (int i = Math.max(1, arity); i < names.length; i++) {
508 Name fixed = names[i].replaceNames(oldNames, names, 0, i);
509 names[i] = fixed.withIndex(i);
510 }
511 }
512 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
513 boolean needIntern = false;
514 for (int i = 0; i < maxInterned; i++) {
515 Name n = names[i], n2 = internArgument(n);
516 if (n != n2) {
517 names[i] = n2;
518 needIntern = true;
519 }
520 }
521 if (needIntern) {
522 for (int i = arity; i < names.length; i++) {
523 names[i].internArguments();
524 }
525 }
526
527 // return true if we can interpret
528 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
529 // Cannot use LF interpreter on very high arity expressions.
530 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
531 return false;
532 }
533 return true;
534 }
535
536 /**
537 * Check that all embedded Name references are localizable to this lambda,
538 * and are properly ordered after their corresponding definitions.
539 * <p>
540 * Note that a Name can be local to multiple lambdas, as long as
541 * it possesses the same index in each use site.
542 * This allows Name references to be freely reused to construct
543 * fresh lambdas, without confusion.
544 */
545 boolean nameRefsAreLegal() {
546 assert(arity >= 0 && arity <= names.length);
547 assert(result >= -1 && result < names.length);
548 // Do all names possess an index consistent with their local definition order?
549 for (int i = 0; i < arity; i++) {
550 Name n = names[i];
551 assert(n.index() == i) : Arrays.asList(n.index(), i);
552 assert(n.isParam());
553 }
554 // Also, do all local name references
555 for (int i = arity; i < names.length; i++) {
556 Name n = names[i];
557 assert(n.index() == i);
558 for (Object arg : n.arguments) {
559 if (arg instanceof Name n2) {
560 int i2 = n2.index;
561 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
562 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
563 assert(i2 < i); // ref must come after def!
564 }
565 }
566 }
567 return true;
568 }
569
570 // /** Invoke this form on the given arguments. */
571 // final Object invoke(Object... args) throws Throwable {
572 // // NYI: fit this into the fast path?
573 // return interpretWithArguments(args);
574 // }
575
576 /** Report the return type. */
577 BasicType returnType() {
578 if (result < 0) return V_TYPE;
579 Name n = names[result];
580 return n.type;
581 }
582
583 /** Report the N-th argument type. */
584 BasicType parameterType(int n) {
585 return parameter(n).type;
586 }
587
588 /** Report the N-th argument name. */
589 Name parameter(int n) {
590 Name param = names[n];
591 assert(n < arity && param.isParam());
592 return param;
593 }
594
595 /** Report the N-th argument type constraint. */
596 Object parameterConstraint(int n) {
597 return parameter(n).constraint;
598 }
599
600 /** Report the arity. */
601 int arity() {
602 return arity;
603 }
604
605 /** Report the number of expressions (non-parameter names). */
606 int expressionCount() {
607 return names.length - arity;
608 }
609
610 /** Return the method type corresponding to my basic type signature. */
611 MethodType methodType() {
612 Class<?>[] ptypes = new Class<?>[arity];
613 for (int i = 0; i < arity; ++i) {
614 ptypes[i] = parameterType(i).btClass;
615 }
616 return MethodType.methodType(returnType().btClass, ptypes, true);
617 }
618
619 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
620 final String basicTypeSignature() {
621 StringBuilder buf = new StringBuilder(arity() + 3);
622 for (int i = 0, a = arity(); i < a; i++)
623 buf.append(parameterType(i).basicTypeChar());
624 return buf.append('_').append(returnType().basicTypeChar()).toString();
625 }
626 static int signatureArity(String sig) {
627 assert(isValidSignature(sig));
628 return sig.indexOf('_');
629 }
630 static boolean isValidSignature(String sig) {
631 int arity = sig.indexOf('_');
632 if (arity < 0) return false; // must be of the form *_*
633 int siglen = sig.length();
634 if (siglen != arity + 2) return false; // *_X
635 for (int i = 0; i < siglen; i++) {
636 if (i == arity) continue; // skip '_'
637 char c = sig.charAt(i);
638 if (c == 'V')
639 return (i == siglen - 1 && arity == siglen - 2);
640 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
641 }
642 return true; // [LIJFD]*_[LIJFDV]
643 }
644
645 /**
646 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
647 */
648 boolean isSelectAlternative(int pos) {
649 // selectAlternative idiom:
650 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
651 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
652 if (pos+1 >= names.length) return false;
653 Name name0 = names[pos];
654 Name name1 = names[pos+1];
655 return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
656 name1.isInvokeBasic() &&
657 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
658 lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
659 }
660
661 private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
662 if (pos+2 >= names.length) return false;
663 Name name0 = names[pos];
664 Name name1 = names[pos+1];
665 Name name2 = names[pos+2];
666 return name1.refersTo(MethodHandleImpl.class, idiomName) &&
667 name0.isInvokeBasic() &&
668 name2.isInvokeBasic() &&
669 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
670 lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
671 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
672 lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
673 }
674
675 /**
676 * Check if i-th name is a start of GuardWithCatch idiom.
677 */
678 boolean isGuardWithCatch(int pos) {
679 // GuardWithCatch idiom:
680 // t_{n}:L=MethodHandle.invokeBasic(...)
681 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
682 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
683 return isMatchingIdiom(pos, "guardWithCatch", 3);
684 }
685
686 /**
687 * Check if i-th name is a start of the tryFinally idiom.
688 */
689 boolean isTryFinally(int pos) {
690 // tryFinally idiom:
691 // t_{n}:L=MethodHandle.invokeBasic(...)
692 // t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
693 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
694 return isMatchingIdiom(pos, "tryFinally", 2);
695 }
696
697 /**
698 * Check if i-th name is a start of the tableSwitch idiom.
699 */
700 boolean isTableSwitch(int pos) {
701 // tableSwitch idiom:
702 // t_{n}:L=MethodHandle.invokeBasic(...) // args
703 // t_{n+1}:L=MethodHandleImpl.tableSwitch(*, *, *, t_{n})
704 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
705 if (pos + 2 >= names.length) return false;
706
707 final int POS_COLLECT_ARGS = pos;
708 final int POS_TABLE_SWITCH = pos + 1;
709 final int POS_UNBOX_RESULT = pos + 2;
710
711 Name collectArgs = names[POS_COLLECT_ARGS];
712 Name tableSwitch = names[POS_TABLE_SWITCH];
713 Name unboxResult = names[POS_UNBOX_RESULT];
714 return tableSwitch.refersTo(MethodHandleImpl.class, "tableSwitch") &&
715 collectArgs.isInvokeBasic() &&
716 unboxResult.isInvokeBasic() &&
717 tableSwitch.lastUseIndex(collectArgs) == 3 && // t_{n+1}:L=MethodHandleImpl.<invoker>(*, *, *, t_{n});
718 lastUseIndex(collectArgs) == POS_TABLE_SWITCH && // t_{n} is local: used only in t_{n+1}
719 unboxResult.lastUseIndex(tableSwitch) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
720 lastUseIndex(tableSwitch) == POS_UNBOX_RESULT; // t_{n+1} is local: used only in t_{n+2}
721 }
722
723 /**
724 * Check if i-th name is a start of the loop idiom.
725 */
726 boolean isLoop(int pos) {
727 // loop idiom:
728 // t_{n}:L=MethodHandle.invokeBasic(...)
729 // t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
730 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
731 return isMatchingIdiom(pos, "loop", 2);
732 }
733
734 /*
735 * Code generation issues:
736 *
737 * Compiled LFs should be reusable in general.
738 * The biggest issue is how to decide when to pull a name into
739 * the bytecode, versus loading a reified form from the MH data.
740 *
741 * For example, an asType wrapper may require execution of a cast
742 * after a call to a MH. The target type of the cast can be placed
743 * as a constant in the LF itself. This will force the cast type
744 * to be compiled into the bytecodes and native code for the MH.
745 * Or, the target type of the cast can be erased in the LF, and
746 * loaded from the MH data. (Later on, if the MH as a whole is
747 * inlined, the data will flow into the inlined instance of the LF,
748 * as a constant, and the end result will be an optimal cast.)
749 *
750 * This erasure of cast types can be done with any use of
751 * reference types. It can also be done with whole method
752 * handles. Erasing a method handle might leave behind
753 * LF code that executes correctly for any MH of a given
754 * type, and load the required MH from the enclosing MH's data.
755 * Or, the erasure might even erase the expected MT.
756 *
757 * Also, for direct MHs, the MemberName of the target
758 * could be erased, and loaded from the containing direct MH.
759 * As a simple case, a LF for all int-valued non-static
760 * field getters would perform a cast on its input argument
761 * (to non-constant base type derived from the MemberName)
762 * and load an integer value from the input object
763 * (at a non-constant offset also derived from the MemberName).
764 * Such MN-erased LFs would be inlinable back to optimized
765 * code, whenever a constant enclosing DMH is available
766 * to supply a constant MN from its data.
767 *
768 * The main problem here is to keep LFs reasonably generic,
769 * while ensuring that hot spots will inline good instances.
770 * "Reasonably generic" means that we don't end up with
771 * repeated versions of bytecode or machine code that do
772 * not differ in their optimized form. Repeated versions
773 * of machine would have the undesirable overheads of
774 * (a) redundant compilation work and (b) extra I$ pressure.
775 * To control repeated versions, we need to be ready to
776 * erase details from LFs and move them into MH data,
777 * whenever those details are not relevant to significant
778 * optimization. "Significant" means optimization of
779 * code that is actually hot.
780 *
781 * Achieving this may require dynamic splitting of MHs, by replacing
782 * a generic LF with a more specialized one, on the same MH,
783 * if (a) the MH is frequently executed and (b) the MH cannot
784 * be inlined into a containing caller, such as an invokedynamic.
785 *
786 * Compiled LFs that are no longer used should be GC-able.
787 * If they contain non-BCP references, they should be properly
788 * interlinked with the class loader(s) that their embedded types
789 * depend on. This probably means that reusable compiled LFs
790 * will be tabulated (indexed) on relevant class loaders,
791 * or else that the tables that cache them will have weak links.
792 */
793
794 /**
795 * Make this LF directly executable, as part of a MethodHandle.
796 * Invariant: Every MH which is invoked must prepare its LF
797 * before invocation.
798 * (In principle, the JVM could do this very lazily,
799 * as a sort of pre-invocation linkage step.)
800 */
801 public void prepare() {
802 if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
803 compileToBytecode();
804 }
805 if (this.vmentry != null) {
806 // already prepared (e.g., a primitive DMH invoker form)
807 return;
808 }
809 MethodType mtype = methodType();
810 LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
811 if (prep == null) {
812 assert (isValidSignature(basicTypeSignature()));
813 prep = LambdaForm.createBlankForType(mtype);
814 prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
815 prep = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
816 }
817 this.vmentry = prep.vmentry;
818 // TO DO: Maybe add invokeGeneric, invokeWithArguments
819 }
820
821 private static @Stable PerfCounter LF_FAILED;
822
823 private static PerfCounter failedCompilationCounter() {
824 if (LF_FAILED == null) {
825 LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
826 }
827 return LF_FAILED;
828 }
829
830 /** Generate optimizable bytecode for this form. */
831 void compileToBytecode() {
832 if (forceInterpretation()) {
833 return; // this should not be compiled
834 }
835 if (vmentry != null && isCompiled) {
836 return; // already compiled somehow
837 }
838
839 // Obtain the invoker MethodType outside of the following try block.
840 // This ensures that an IllegalArgumentException is directly thrown if the
841 // type would have 256 or more parameters
842 MethodType invokerType = methodType();
843 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
844 try {
845 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
846 if (TRACE_INTERPRETER)
847 traceInterpreter("compileToBytecode", this);
848 isCompiled = true;
849 } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
850 // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
851 invocationCounter = -1;
852 failedCompilationCounter().increment();
853 if (LOG_LF_COMPILATION_FAILURE) {
854 System.out.println("LambdaForm compilation failed: " + this);
855 bge.printStackTrace(System.out);
856 }
857 } catch (Error e) {
858 // Pass through any error
859 throw e;
860 } catch (Exception e) {
861 // Wrap any exception
862 throw newInternalError(this.toString(), e);
863 }
864 }
865
866 // The next few routines are called only from assert expressions
867 // They verify that the built-in invokers process the correct raw data types.
868 private static boolean argumentTypesMatch(String sig, Object[] av) {
869 int arity = signatureArity(sig);
870 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
871 assert(av[0] instanceof MethodHandle) : "av[0] not instance of MethodHandle: " + av[0];
872 MethodHandle mh = (MethodHandle) av[0];
873 MethodType mt = mh.type();
874 assert(mt.parameterCount() == arity-1);
875 for (int i = 0; i < av.length; i++) {
876 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
877 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
878 }
879 return true;
880 }
881 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
882 // The following line is needed because (...)void method handles can use non-void invokers
883 if (type == void.class) tc = V_TYPE; // can drop any kind of value
884 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
885 switch (tc) {
886 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
887 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
888 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
889 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
890 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
891 case V_TYPE: break; // allow anything here; will be dropped
892 default: assert(false);
893 }
894 return true;
895 }
896 private static boolean checkInt(Class<?> type, Object x) {
897 assert(x instanceof Integer);
898 if (type == int.class) return true;
899 Wrapper w = Wrapper.forBasicType(type);
900 assert(w.isSubwordOrInt());
901 Object x1 = Wrapper.INT.wrap(w.wrap(x));
902 return x.equals(x1);
903 }
904 private static boolean checkRef(Class<?> type, Object x) {
905 assert(!type.isPrimitive());
906 if (x == null) return true;
907 if (type.isInterface()) return true;
908 return type.isInstance(x);
909 }
910
911 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
912 private static final int COMPILE_THRESHOLD;
913 static {
914 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
915 }
916 private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
917
918 private boolean forceInterpretation() {
919 return invocationCounter == -1;
920 }
921
922 /** Interpretively invoke this form on the given arguments. */
923 @Hidden
924 @DontInline
925 Object interpretWithArguments(Object... argumentValues) throws Throwable {
926 if (TRACE_INTERPRETER)
927 return interpretWithArgumentsTracing(argumentValues);
928 checkInvocationCounter();
929 assert(arityCheck(argumentValues));
930 Object[] values = Arrays.copyOf(argumentValues, names.length);
931 for (int i = argumentValues.length; i < values.length; i++) {
932 values[i] = interpretName(names[i], values);
933 }
934 Object rv = (result < 0) ? null : values[result];
935 assert(resultCheck(argumentValues, rv));
936 return rv;
937 }
938
939 /** Evaluate a single Name within this form, applying its function to its arguments. */
940 @Hidden
941 @DontInline
942 Object interpretName(Name name, Object[] values) throws Throwable {
943 if (TRACE_INTERPRETER)
944 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
945 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
946 for (int i = 0; i < arguments.length; i++) {
947 Object a = arguments[i];
948 if (a instanceof Name n) {
949 int i2 = n.index();
950 assert(names[i2] == a);
951 a = values[i2];
952 arguments[i] = a;
953 }
954 }
955 return name.function.invokeWithArguments(arguments);
956 }
957
958 private void checkInvocationCounter() {
959 if (COMPILE_THRESHOLD != 0 &&
960 !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
961 invocationCounter++; // benign race
962 if (invocationCounter >= COMPILE_THRESHOLD) {
963 // Replace vmentry with a bytecode version of this LF.
964 compileToBytecode();
965 }
966 }
967 }
968 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
969 traceInterpreter("[ interpretWithArguments", this, argumentValues);
970 if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
971 int ctr = invocationCounter++; // benign race
972 traceInterpreter("| invocationCounter", ctr);
973 if (invocationCounter >= COMPILE_THRESHOLD) {
974 compileToBytecode();
975 }
976 }
977 Object rval;
978 try {
979 assert(arityCheck(argumentValues));
980 Object[] values = Arrays.copyOf(argumentValues, names.length);
981 for (int i = argumentValues.length; i < values.length; i++) {
982 values[i] = interpretName(names[i], values);
983 }
984 rval = (result < 0) ? null : values[result];
985 } catch (Throwable ex) {
986 traceInterpreter("] throw =>", ex);
987 throw ex;
988 }
989 traceInterpreter("] return =>", rval);
990 return rval;
991 }
992
993 static void traceInterpreter(String event, Object obj, Object... args) {
994 if (TRACE_INTERPRETER) {
995 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
996 }
997 }
998 static void traceInterpreter(String event, Object obj) {
999 traceInterpreter(event, obj, (Object[])null);
1000 }
1001 private boolean arityCheck(Object[] argumentValues) {
1002 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
1003 // also check that the leading (receiver) argument is somehow bound to this LF:
1004 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
1005 MethodHandle mh = (MethodHandle) argumentValues[0];
1006 assert(mh.internalForm() == this);
1007 // note: argument #0 could also be an interface wrapper, in the future
1008 argumentTypesMatch(basicTypeSignature(), argumentValues);
1009 return true;
1010 }
1011 private boolean resultCheck(Object[] argumentValues, Object result) {
1012 MethodHandle mh = (MethodHandle) argumentValues[0];
1013 MethodType mt = mh.type();
1014 assert(valueMatches(returnType(), mt.returnType(), result));
1015 return true;
1016 }
1017
1018 private boolean isEmpty() {
1019 if (result < 0)
1020 return (names.length == arity);
1021 else if (result == arity && names.length == arity + 1)
1022 return names[arity].isConstantZero();
1023 else
1024 return false;
1025 }
1026
1027 public String toString() {
1028 return debugString(-1);
1029 }
1030
1031 String debugString(int indentLevel) {
1032 String prefix = MethodHandle.debugPrefix(indentLevel);
1033 String lambdaName = lambdaName();
1034 StringBuilder buf = new StringBuilder(lambdaName);
1035 buf.append("=Lambda(");
1036 for (int i = 0; i < names.length; i++) {
1037 if (i == arity) buf.append(")=>{");
1038 Name n = names[i];
1039 if (i >= arity) buf.append("\n ").append(prefix);
1040 buf.append(n.paramString());
1041 if (i < arity) {
1042 if (i+1 < arity) buf.append(",");
1043 continue;
1044 }
1045 buf.append("=").append(n.exprString());
1046 buf.append(";");
1047 }
1048 if (arity == names.length) buf.append(")=>{");
1049 buf.append(result < 0 ? "void" : names[result]).append("}");
1050 if (TRACE_INTERPRETER) {
1051 // Extra verbosity:
1052 buf.append(":").append(basicTypeSignature());
1053 buf.append("/").append(vmentry);
1054 }
1055 return buf.toString();
1056 }
1057
1058 @Override
1059 public boolean equals(Object obj) {
1060 return obj instanceof LambdaForm lf && equals(lf);
1061 }
1062 public boolean equals(LambdaForm that) {
1063 if (this.result != that.result) return false;
1064 return Arrays.equals(this.names, that.names);
1065 }
1066 public int hashCode() {
1067 return result + 31 * Arrays.hashCode(names);
1068 }
1069 LambdaFormEditor editor() {
1070 return LambdaFormEditor.lambdaFormEditor(this);
1071 }
1072
1073 boolean contains(Name name) {
1074 int pos = name.index();
1075 if (pos >= 0) {
1076 return pos < names.length && name.equals(names[pos]);
1077 }
1078 for (int i = arity; i < names.length; i++) {
1079 if (name.equals(names[i]))
1080 return true;
1081 }
1082 return false;
1083 }
1084
1085 static class NamedFunction {
1086 final MemberName member;
1087 private @Stable MethodHandle resolvedHandle;
1088 private @Stable MethodType type;
1089
1090 NamedFunction(MethodHandle resolvedHandle) {
1091 this(resolvedHandle.internalMemberName(), resolvedHandle);
1092 }
1093 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1094 this.member = member;
1095 this.resolvedHandle = resolvedHandle;
1096 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1097 //assert(!isInvokeBasic(member));
1098 }
1099 NamedFunction(MethodType basicInvokerType) {
1100 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1101 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1102 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1103 this.member = resolvedHandle.internalMemberName();
1104 } else {
1105 // necessary to pass BigArityTest
1106 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1107 }
1108 assert(isInvokeBasic(member));
1109 }
1110
1111 private static boolean isInvokeBasic(MemberName member) {
1112 return member != null &&
1113 member.getDeclaringClass() == MethodHandle.class &&
1114 "invokeBasic".equals(member.getName());
1115 }
1116
1117 // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1118 // Any LambdaForm containing such a member is not interpretable.
1119 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1120 // And even without the resolvedHandle, the name can still be compiled and optimized.
1121 NamedFunction(Method method) {
1122 this(new MemberName(method));
1123 }
1124 NamedFunction(MemberName member) {
1125 this(member, null);
1126 }
1127
1128 MethodHandle resolvedHandle() {
1129 if (resolvedHandle == null) resolve();
1130 return resolvedHandle;
1131 }
1132
1133 synchronized void resolve() {
1134 if (resolvedHandle == null) {
1135 resolvedHandle = DirectMethodHandle.make(member);
1136 }
1137 }
1138
1139 @Override
1140 public boolean equals(Object other) {
1141 if (this == other) return true;
1142 if (other == null) return false;
1143 return (other instanceof NamedFunction that)
1144 && this.member != null
1145 && this.member.equals(that.member);
1146 }
1147
1148 @Override
1149 public int hashCode() {
1150 if (member != null)
1151 return member.hashCode();
1152 return super.hashCode();
1153 }
1154
1155 static final MethodType INVOKER_METHOD_TYPE =
1156 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1157
1158 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1159 typeForm = typeForm.basicType().form(); // normalize to basic type
1160 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1161 if (mh != null) return mh;
1162 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1163 mh = DirectMethodHandle.make(invoker);
1164 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1165 if (mh2 != null) return mh2; // benign race
1166 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1167 throw newInternalError(mh.debugString());
1168 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1169 }
1170
1171 @Hidden
1172 Object invokeWithArguments(Object... arguments) throws Throwable {
1173 // If we have a cached invoker, call it right away.
1174 // NOTE: The invoker always returns a reference value.
1175 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1176 return invoker().invokeBasic(resolvedHandle(), arguments);
1177 }
1178
1179 @Hidden
1180 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1181 Object rval;
1182 try {
1183 traceInterpreter("[ call", this, arguments);
1184 // resolvedHandle might be uninitialized, ok for tracing
1185 if (resolvedHandle == null) {
1186 traceInterpreter("| resolve", this);
1187 resolvedHandle();
1188 }
1189 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1190 } catch (Throwable ex) {
1191 traceInterpreter("] throw =>", ex);
1192 throw ex;
1193 }
1194 traceInterpreter("] return =>", rval);
1195 return rval;
1196 }
1197
1198 private MethodHandle invoker() {
1199 return computeInvoker(methodType().form());
1200 }
1201
1202 MethodType methodType() {
1203 MethodType type = this.type;
1204 if (type == null) {
1205 this.type = type = calculateMethodType(member, resolvedHandle);
1206 }
1207 return type;
1208 }
1209
1210 private static MethodType calculateMethodType(MemberName member, MethodHandle resolvedHandle) {
1211 if (resolvedHandle != null) {
1212 return resolvedHandle.type();
1213 } else {
1214 // only for certain internal LFs during bootstrapping
1215 return member.getInvocationType();
1216 }
1217 }
1218
1219 MemberName member() {
1220 assert(assertMemberIsConsistent());
1221 return member;
1222 }
1223
1224 // Called only from assert.
1225 private boolean assertMemberIsConsistent() {
1226 if (resolvedHandle instanceof DirectMethodHandle) {
1227 MemberName m = resolvedHandle.internalMemberName();
1228 assert(m.equals(member));
1229 }
1230 return true;
1231 }
1232
1233 Class<?> memberDeclaringClassOrNull() {
1234 return (member == null) ? null : member.getDeclaringClass();
1235 }
1236
1237 BasicType returnType() {
1238 return basicType(methodType().returnType());
1239 }
1240
1241 BasicType parameterType(int n) {
1242 return basicType(methodType().parameterType(n));
1243 }
1244
1245 int arity() {
1246 return methodType().parameterCount();
1247 }
1248
1249 public String toString() {
1250 if (member == null) return String.valueOf(resolvedHandle);
1251 return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1252 }
1253
1254 public boolean isIdentity() {
1255 return this.equals(identity(returnType()));
1256 }
1257
1258 public boolean isConstantZero() {
1259 return this.equals(constantZero(returnType()));
1260 }
1261
1262 public MethodHandleImpl.Intrinsic intrinsicName() {
1263 return resolvedHandle != null
1264 ? resolvedHandle.intrinsicName()
1265 : MethodHandleImpl.Intrinsic.NONE;
1266 }
1267
1268 public Object intrinsicData() {
1269 return resolvedHandle != null
1270 ? resolvedHandle.intrinsicData()
1271 : null;
1272 }
1273 }
1274
1275 public static String basicTypeSignature(MethodType type) {
1276 int params = type.parameterCount();
1277 char[] sig = new char[params + 2];
1278 int sigp = 0;
1279 while (sigp < params) {
1280 sig[sigp] = basicTypeChar(type.parameterType(sigp++));
1281 }
1282 sig[sigp++] = '_';
1283 sig[sigp++] = basicTypeChar(type.returnType());
1284 assert(sigp == sig.length);
1285 return String.valueOf(sig);
1286 }
1287
1288 /** Hack to make signatures more readable when they show up in method names.
1289 * Signature should start with a sequence of uppercase ASCII letters.
1290 * Runs of three or more are replaced by a single letter plus a decimal repeat count.
1291 * A tail of anything other than uppercase ASCII is passed through unchanged.
1292 * @param signature sequence of uppercase ASCII letters with possible repetitions
1293 * @return same sequence, with repetitions counted by decimal numerals
1294 */
1295 public static String shortenSignature(String signature) {
1296 final int NO_CHAR = -1, MIN_RUN = 3;
1297 int c0, c1 = NO_CHAR, c1reps = 0;
1298 StringBuilder buf = null;
1299 int len = signature.length();
1300 if (len < MIN_RUN) return signature;
1301 for (int i = 0; i <= len; i++) {
1302 if (c1 != NO_CHAR && !('A' <= c1 && c1 <= 'Z')) {
1303 // wrong kind of char; bail out here
1304 if (buf != null) {
1305 buf.append(signature, i - c1reps, len);
1306 }
1307 break;
1308 }
1309 // shift in the next char:
1310 c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1311 if (c1 == c0) { ++c1reps; continue; }
1312 // shift in the next count:
1313 int c0reps = c1reps; c1reps = 1;
1314 // end of a character run
1315 if (c0reps < MIN_RUN) {
1316 if (buf != null) {
1317 while (--c0reps >= 0)
1318 buf.append((char)c0);
1319 }
1320 continue;
1321 }
1322 // found three or more in a row
1323 if (buf == null)
1324 buf = new StringBuilder().append(signature, 0, i - c0reps);
1325 buf.append((char)c0).append(c0reps);
1326 }
1327 return (buf == null) ? signature : buf.toString();
1328 }
1329
1330 static final class Name {
1331 final BasicType type;
1332 final short index;
1333 final NamedFunction function;
1334 final Object constraint; // additional type information, if not null
1335 @Stable final Object[] arguments;
1336
1337 private static final Object[] EMPTY_ARGS = new Object[0];
1338
1339 private Name(int index, BasicType type, NamedFunction function, Object[] arguments, Object constraint) {
1340 this.index = (short)index;
1341 this.type = type;
1342 this.function = function;
1343 this.arguments = arguments;
1344 this.constraint = constraint;
1345 assert(this.index == index && typesMatch(function, arguments));
1346 assert(constraint == null || isParam()); // only params have constraints
1347 assert(constraint == null || constraint instanceof ClassSpecializer.SpeciesData || constraint instanceof Class);
1348 }
1349
1350 Name(MethodHandle function, Object... arguments) {
1351 this(new NamedFunction(function), arguments);
1352 }
1353 Name(MethodType functionType, Object... arguments) {
1354 this(new NamedFunction(functionType), arguments);
1355 assert(arguments[0] instanceof Name name && name.type == L_TYPE);
1356 }
1357 Name(MemberName function, Object... arguments) {
1358 this(new NamedFunction(function), arguments);
1359 }
1360 Name(NamedFunction function) {
1361 this(-1, function.returnType(), function, EMPTY_ARGS, null);
1362 }
1363 Name(NamedFunction function, Object arg) {
1364 this(-1, function.returnType(), function, new Object[] { arg }, null);
1365 }
1366 Name(NamedFunction function, Object arg0, Object arg1) {
1367 this(-1, function.returnType(), function, new Object[] { arg0, arg1 }, null);
1368 }
1369 Name(NamedFunction function, Object... arguments) {
1370 this(-1, function.returnType(), function, Arrays.copyOf(arguments, arguments.length, Object[].class), null);
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, 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
1382 char typeChar() {
1383 return type.btChar;
1384 }
1385
1386 Name withIndex(int i) {
1387 if (i == this.index) return this;
1388 return new Name(i, type, function, arguments, constraint);
1389 }
1390
1391 Name withConstraint(Object constraint) {
1392 if (constraint == this.constraint) return this;
1393 return new Name(index, type, function, arguments, constraint);
1394 }
1395
1396 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1397 if (oldName == newName) return this;
1398 @SuppressWarnings("LocalVariableHidesMemberVariable")
1399 Object[] arguments = this.arguments;
1400 if (arguments == null) return this;
1401 boolean replaced = false;
1402 for (int j = 0; j < arguments.length; j++) {
1403 if (arguments[j] == oldName) {
1404 if (!replaced) {
1405 replaced = true;
1406 arguments = arguments.clone();
1407 }
1408 arguments[j] = newName;
1409 }
1410 }
1411 if (!replaced) return this;
1412 return new Name(function, arguments);
1413 }
1414 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1415 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1416 */
1417 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1418 if (start >= end) return this;
1419 @SuppressWarnings("LocalVariableHidesMemberVariable")
1420 Object[] arguments = this.arguments;
1421 boolean replaced = false;
1422 eachArg:
1423 for (int j = 0; j < arguments.length; j++) {
1424 if (arguments[j] instanceof Name n) {
1425 int check = n.index;
1426 // harmless check to see if the thing is already in newNames:
1427 if (check >= 0 && check < newNames.length && n == newNames[check])
1428 continue eachArg;
1429 // n might not have the correct index: n != oldNames[n.index].
1430 for (int i = start; i < end; i++) {
1431 if (n == oldNames[i]) {
1432 if (n == newNames[i])
1433 continue eachArg;
1434 if (!replaced) {
1435 replaced = true;
1436 arguments = arguments.clone();
1437 }
1438 arguments[j] = newNames[i];
1439 continue eachArg;
1440 }
1441 }
1442 }
1443 }
1444 if (!replaced) return this;
1445 return new Name(function, arguments);
1446 }
1447 void internArguments() {
1448 @SuppressWarnings("LocalVariableHidesMemberVariable")
1449 Object[] arguments = this.arguments;
1450 for (int j = 0; j < arguments.length; j++) {
1451 if (arguments[j] instanceof Name n) {
1452 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1453 arguments[j] = internArgument(n);
1454 }
1455 }
1456 }
1457 boolean isParam() {
1458 return function == null;
1459 }
1460 boolean isConstantZero() {
1461 return !isParam() && arguments.length == 0 && function.isConstantZero();
1462 }
1463
1464 boolean refersTo(Class<?> declaringClass, String methodName) {
1465 return function != null &&
1466 function.member() != null && function.member().refersTo(declaringClass, methodName);
1467 }
1468
1469 /**
1470 * Check if MemberName is a call to MethodHandle.invokeBasic.
1471 */
1472 boolean isInvokeBasic() {
1473 if (function == null)
1474 return false;
1475 if (arguments.length < 1)
1476 return false; // must have MH argument
1477 MemberName member = function.member();
1478 return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1479 !member.isPublic() && !member.isStatic();
1480 }
1481
1482 /**
1483 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1484 */
1485 boolean isLinkerMethodInvoke() {
1486 if (function == null)
1487 return false;
1488 if (arguments.length < 1)
1489 return false; // must have MH argument
1490 MemberName member = function.member();
1491 return member != null &&
1492 member.getDeclaringClass() == MethodHandle.class &&
1493 !member.isPublic() && member.isStatic() &&
1494 member.getName().startsWith("linkTo");
1495 }
1496
1497 public String toString() {
1498 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1499 }
1500 public String debugString() {
1501 String s = paramString();
1502 return (function == null) ? s : s + "=" + exprString();
1503 }
1504 public String paramString() {
1505 String s = toString();
1506 Object c = constraint;
1507 if (c == null)
1508 return s;
1509 if (c instanceof Class<?> cl) c = cl.getSimpleName();
1510 return s + "/" + c;
1511 }
1512 public String exprString() {
1513 if (function == null) return toString();
1514 StringBuilder buf = new StringBuilder(function.toString());
1515 buf.append("(");
1516 String cma = "";
1517 for (Object a : arguments) {
1518 buf.append(cma); cma = ",";
1519 if (a instanceof Name || a instanceof Integer)
1520 buf.append(a);
1521 else
1522 buf.append("(").append(a).append(")");
1523 }
1524 buf.append(")");
1525 return buf.toString();
1526 }
1527
1528 private boolean typesMatch(NamedFunction function, Object ... arguments) {
1529 if (arguments == null) {
1530 assert(function == null);
1531 return true;
1532 }
1533 assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1534 for (int i = 0; i < arguments.length; i++) {
1535 assert (typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1536 }
1537 return true;
1538 }
1539
1540 private static boolean typesMatch(BasicType parameterType, Object object) {
1541 if (object instanceof Name name) {
1542 return name.type == parameterType;
1543 }
1544 switch (parameterType) {
1545 case I_TYPE: return object instanceof Integer;
1546 case J_TYPE: return object instanceof Long;
1547 case F_TYPE: return object instanceof Float;
1548 case D_TYPE: return object instanceof Double;
1549 }
1550 assert(parameterType == L_TYPE);
1551 return true;
1552 }
1553
1554 /** Return the index of the last occurrence of n in the argument array.
1555 * Return -1 if the name is not used.
1556 */
1557 int lastUseIndex(Name n) {
1558 Object[] arguments = this.arguments;
1559 if (arguments == null) return -1;
1560 for (int i = arguments.length; --i >= 0; ) {
1561 if (arguments[i] == n) return i;
1562 }
1563 return -1;
1564 }
1565
1566 public boolean equals(Name that) {
1567 if (this == that) return true;
1568 if (isParam())
1569 // each parameter is a unique atom
1570 return false; // this != that
1571 return
1572 //this.index == that.index &&
1573 this.type == that.type &&
1574 this.function.equals(that.function) &&
1575 Arrays.equals(this.arguments, that.arguments);
1576 }
1577 @Override
1578 public boolean equals(Object x) {
1579 return x instanceof Name n && equals(n);
1580 }
1581 @Override
1582 public int hashCode() {
1583 if (isParam())
1584 return index | (type.ordinal() << 8);
1585 return function.hashCode() ^ Arrays.hashCode(arguments);
1586 }
1587 }
1588
1589 /** Return the index of the last name which contains n as an argument.
1590 * Return -1 if the name is not used. Return names.length if it is the return value.
1591 */
1592 int lastUseIndex(Name n) {
1593 int ni = n.index, nmax = names.length;
1594 assert(names[ni] == n);
1595 if (result == ni) return nmax; // live all the way beyond the end
1596 for (int i = nmax; --i > ni; ) {
1597 if (names[i].lastUseIndex(n) >= 0)
1598 return i;
1599 }
1600 return -1;
1601 }
1602
1603 /** Return the number of times n is used as an argument or return value. */
1604 int useCount(Name n) {
1605 int count = (result == n.index) ? 1 : 0;
1606 int i = Math.max(n.index + 1, arity);
1607 Name[] names = this.names;
1608 while (i < names.length) {
1609 Object[] arguments = names[i++].arguments;
1610 if (arguments != null) {
1611 for (Object argument : arguments) {
1612 if (argument == n) {
1613 count++;
1614 }
1615 }
1616 }
1617 }
1618 return count;
1619 }
1620
1621 static Name argument(int which, BasicType type) {
1622 if (which >= INTERNED_ARGUMENT_LIMIT)
1623 return new Name(which, type);
1624 return INTERNED_ARGUMENTS[type.ordinal()][which];
1625 }
1626 static Name internArgument(Name n) {
1627 assert(n.isParam()) : "not param: " + n;
1628 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1629 if (n.constraint != null) return n;
1630 return argument(n.index, n.type);
1631 }
1632 static Name[] arguments(int extra, MethodType types) {
1633 int length = types.parameterCount();
1634 Name[] names = new Name[length + extra];
1635 for (int i = 0; i < length; i++)
1636 names[i] = argument(i, basicType(types.parameterType(i)));
1637 return names;
1638 }
1639
1640 static Name[] invokeArguments(int extra, MethodType types) {
1641 int length = types.parameterCount();
1642 Name[] names = new Name[length + extra + 1];
1643 names[0] = argument(0, L_TYPE);
1644 for (int i = 0; i < length; i++)
1645 names[i + 1] = argument(i + 1, basicType(types.parameterType(i)));
1646 return names;
1647 }
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 = LambdaForm.create(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 = LambdaForm.create(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 = LambdaForm.create(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 }