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 COLLECT("collect"),
309 COLLECTOR("collector"),
310 CONVERT("convert"),
311 SPREAD("spread"),
312 LOOP("loop"),
313 FIELD("field"),
314 GUARD("guard"),
315 GUARD_WITH_CATCH("guardWithCatch"),
316 VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
317 VARHANDLE_INVOKER("VH.invoker", "invoker"),
318 VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
319
320 final String defaultLambdaName;
321 final String methodName;
322
323 private Kind(String defaultLambdaName) {
324 this(defaultLambdaName, defaultLambdaName);
325 }
326
327 private Kind(String defaultLambdaName, String methodName) {
328 this.defaultLambdaName = defaultLambdaName;
329 this.methodName = methodName;
330 }
331 }
332
333 // private version that doesn't do checks or defensive copies
334 private LambdaForm(int arity, int result, boolean forceInline, MethodHandle customized, Name[] names, Kind kind) {
335 this.arity = arity;
336 this.result = result;
337 this.forceInline = forceInline;
338 this.customized = customized;
339 this.names = names;
340 this.kind = kind;
341 this.vmentry = null;
342 this.isCompiled = false;
343 }
344
345 // root factory pre/post processing and calls simple constructor
346 private static LambdaForm create(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
347 names = names.clone();
348 assert(namesOK(arity, names));
349 result = fixResult(result, names);
350
351 boolean canInterpret = normalizeNames(arity, names);
352 LambdaForm form = new LambdaForm(arity, result, forceInline, customized, names, kind);
353 assert(form.nameRefsAreLegal());
354 if (!canInterpret) {
355 form.compileToBytecode();
356 }
357 return form;
358 }
359
360 // derived factories with defaults
361 private static final int DEFAULT_RESULT = LAST_RESULT;
362 private static final boolean DEFAULT_FORCE_INLINE = true;
363 private static final MethodHandle DEFAULT_CUSTOMIZED = null;
364 private static final Kind DEFAULT_KIND = Kind.GENERIC;
365
366 static LambdaForm create(int arity, Name[] names, int result) {
367 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
368 }
369 static LambdaForm create(int arity, Name[] names, int result, Kind kind) {
370 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
371 }
372 static LambdaForm create(int arity, Name[] names) {
373 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
374 }
375 static LambdaForm create(int arity, Name[] names, Kind kind) {
376 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
377 }
378 static LambdaForm create(int arity, Name[] names, boolean forceInline, Kind kind) {
379 return create(arity, names, DEFAULT_RESULT, forceInline, DEFAULT_CUSTOMIZED, kind);
380 }
381
382 private static LambdaForm createBlankForType(MethodType mt) {
383 // Make a blank lambda form, which returns a constant zero or null.
384 // It is used as a template for managing the invocation of similar forms that are non-empty.
385 // Called only from getPreparedForm.
386 int arity = mt.parameterCount();
387 int result = (mt.returnType() == void.class || mt.returnType() == Void.class) ? VOID_RESULT : arity;
388 Name[] names = buildEmptyNames(arity, mt, result == VOID_RESULT);
389 boolean canInterpret = normalizeNames(arity, names);
390 LambdaForm form = new LambdaForm(arity, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, names, Kind.ZERO);
391 assert(form.nameRefsAreLegal() && form.isEmpty() && isValidSignature(form.basicTypeSignature()));
392 if (!canInterpret) {
393 form.compileToBytecode();
394 }
395 return form;
396 }
397
398 private static Name[] buildEmptyNames(int arity, MethodType mt, boolean isVoid) {
399 Name[] names = arguments(isVoid ? 0 : 1, mt);
400 if (!isVoid) {
401 Name zero = new Name(constantZero(basicType(mt.returnType())));
402 names[arity] = zero.withIndex(arity);
403 }
404 assert(namesOK(arity, names));
405 return names;
406 }
407
408 private static int fixResult(int result, Name[] names) {
409 if (result == LAST_RESULT)
410 result = names.length - 1; // might still be void
411 if (result >= 0 && names[result].type == V_TYPE)
412 result = VOID_RESULT;
413 return result;
414 }
415
416 static boolean debugNames() {
417 return DEBUG_NAME_COUNTERS != null;
418 }
419
420 static void associateWithDebugName(LambdaForm form, String name) {
421 assert (debugNames());
422 synchronized (DEBUG_NAMES) {
423 DEBUG_NAMES.put(form, name);
424 }
425 }
426
427 String lambdaName() {
428 if (DEBUG_NAMES != null) {
429 synchronized (DEBUG_NAMES) {
430 String name = DEBUG_NAMES.get(this);
431 if (name == null) {
432 name = generateDebugName();
433 }
434 return name;
435 }
436 }
437 return kind.defaultLambdaName;
438 }
439
440 private String generateDebugName() {
441 assert (debugNames());
442 String debugNameStem = kind.defaultLambdaName;
443 Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
444 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
445 StringBuilder buf = new StringBuilder(debugNameStem);
446 int leadingZero = buf.length();
447 buf.append((int) ctr);
448 for (int i = buf.length() - leadingZero; i < 3; i++) {
449 buf.insert(leadingZero, '0');
450 }
451 buf.append('_');
452 buf.append(basicTypeSignature());
453 String name = buf.toString();
454 associateWithDebugName(this, name);
455 return name;
456 }
457
458 private static boolean namesOK(int arity, Name[] names) {
459 for (int i = 0; i < names.length; i++) {
460 Name n = names[i];
461 assert(n != null) : "n is null";
462 if (i < arity)
463 assert( n.isParam()) : n + " is not param at " + i;
464 else
465 assert(!n.isParam()) : n + " is param at " + i;
466 }
467 return true;
468 }
469
470 /** Customize LambdaForm for a particular MethodHandle */
471 LambdaForm customize(MethodHandle mh) {
472 if (customized == mh) {
473 return this;
474 }
475 LambdaForm customForm = LambdaForm.create(arity, names, result, forceInline, mh, kind);
476 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
477 // If shared LambdaForm has been compiled, compile customized version as well.
478 customForm.compileToBytecode();
479 }
480 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
481 return customForm;
482 }
483
484 /** Get uncustomized flavor of the LambdaForm */
485 LambdaForm uncustomize() {
486 if (customized == null) {
487 return this;
488 }
489 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
490 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
491 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
492 // If customized LambdaForm has been compiled, compile uncustomized version as well.
493 uncustomizedForm.compileToBytecode();
494 }
495 return uncustomizedForm;
496 }
497
498 /** Renumber and/or replace params so that they are interned and canonically numbered.
499 * @return true if we can interpret
500 */
501 private static boolean normalizeNames(int arity, Name[] names) {
502 Name[] oldNames = names.clone();
503 int maxOutArity = 0;
504 for (int i = 0; i < names.length; i++) {
505 Name n = names[i];
506 names[i] = n.withIndex(i);
507 if (n.arguments != null && maxOutArity < n.arguments.length)
508 maxOutArity = n.arguments.length;
509 }
510 if (oldNames != null) {
511 for (int i = Math.max(1, arity); i < names.length; i++) {
512 Name fixed = names[i].replaceNames(oldNames, names, 0, i);
513 names[i] = fixed.withIndex(i);
514 }
515 }
516 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
517 boolean needIntern = false;
518 for (int i = 0; i < maxInterned; i++) {
519 Name n = names[i], n2 = internArgument(n);
520 if (n != n2) {
521 names[i] = n2;
522 needIntern = true;
523 }
524 }
525 if (needIntern) {
526 for (int i = arity; i < names.length; i++) {
527 names[i].internArguments();
528 }
529 }
530
531 // return true if we can interpret
532 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
533 // Cannot use LF interpreter on very high arity expressions.
534 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
535 return false;
536 }
537 return true;
538 }
539
540 /**
541 * Check that all embedded Name references are localizable to this lambda,
542 * and are properly ordered after their corresponding definitions.
543 * <p>
544 * Note that a Name can be local to multiple lambdas, as long as
545 * it possesses the same index in each use site.
546 * This allows Name references to be freely reused to construct
547 * fresh lambdas, without confusion.
548 */
549 boolean nameRefsAreLegal() {
550 assert(arity >= 0 && arity <= names.length);
551 assert(result >= -1 && result < names.length);
552 // Do all names possess an index consistent with their local definition order?
553 for (int i = 0; i < arity; i++) {
554 Name n = names[i];
555 assert(n.index() == i) : Arrays.asList(n.index(), i);
556 assert(n.isParam());
557 }
558 // Also, do all local name references
559 for (int i = arity; i < names.length; i++) {
560 Name n = names[i];
561 assert(n.index() == i);
562 for (Object arg : n.arguments) {
563 if (arg instanceof Name n2) {
564 int i2 = n2.index;
565 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
566 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
567 assert(i2 < i); // ref must come after def!
568 }
569 }
570 }
571 return true;
572 }
573
574 // /** Invoke this form on the given arguments. */
575 // final Object invoke(Object... args) throws Throwable {
576 // // NYI: fit this into the fast path?
577 // return interpretWithArguments(args);
578 // }
579
580 /** Report the return type. */
581 BasicType returnType() {
582 if (result < 0) return V_TYPE;
583 Name n = names[result];
584 return n.type;
585 }
586
587 /** Report the N-th argument type. */
588 BasicType parameterType(int n) {
589 return parameter(n).type;
590 }
591
592 /** Report the N-th argument name. */
593 Name parameter(int n) {
594 Name param = names[n];
595 assert(n < arity && param.isParam());
596 return param;
597 }
598
599 /** Report the N-th argument type constraint. */
600 Object parameterConstraint(int n) {
601 return parameter(n).constraint;
602 }
603
604 /** Report the arity. */
605 int arity() {
606 return arity;
607 }
608
609 /** Report the number of expressions (non-parameter names). */
610 int expressionCount() {
611 return names.length - arity;
612 }
613
614 /** Return the method type corresponding to my basic type signature. */
615 MethodType methodType() {
616 Class<?>[] ptypes = new Class<?>[arity];
617 for (int i = 0; i < arity; ++i) {
618 ptypes[i] = parameterType(i).btClass;
619 }
620 return MethodType.methodType(returnType().btClass, ptypes, true);
621 }
622
623 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
624 final String basicTypeSignature() {
625 StringBuilder buf = new StringBuilder(arity() + 3);
626 for (int i = 0, a = arity(); i < a; i++)
627 buf.append(parameterType(i).basicTypeChar());
628 return buf.append('_').append(returnType().basicTypeChar()).toString();
629 }
630 static int signatureArity(String sig) {
631 assert(isValidSignature(sig));
632 return sig.indexOf('_');
633 }
634 static boolean isValidSignature(String sig) {
635 int arity = sig.indexOf('_');
636 if (arity < 0) return false; // must be of the form *_*
637 int siglen = sig.length();
638 if (siglen != arity + 2) return false; // *_X
639 for (int i = 0; i < siglen; i++) {
640 if (i == arity) continue; // skip '_'
641 char c = sig.charAt(i);
642 if (c == 'V')
643 return (i == siglen - 1 && arity == siglen - 2);
644 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
645 }
646 return true; // [LIJFD]*_[LIJFDV]
647 }
648
649 /**
650 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
651 */
652 boolean isSelectAlternative(int pos) {
653 // selectAlternative idiom:
654 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
655 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
656 if (pos+1 >= names.length) return false;
657 Name name0 = names[pos];
658 Name name1 = names[pos+1];
659 return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
660 name1.isInvokeBasic() &&
661 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
662 lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
663 }
664
665 private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
666 if (pos+2 >= names.length) return false;
667 Name name0 = names[pos];
668 Name name1 = names[pos+1];
669 Name name2 = names[pos+2];
670 return name1.refersTo(MethodHandleImpl.class, idiomName) &&
671 name0.isInvokeBasic() &&
672 name2.isInvokeBasic() &&
673 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
674 lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
675 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
676 lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
677 }
678
679 /**
680 * Check if i-th name is a start of GuardWithCatch idiom.
681 */
682 boolean isGuardWithCatch(int pos) {
683 // GuardWithCatch idiom:
684 // t_{n}:L=MethodHandle.invokeBasic(...)
685 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
686 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
687 return isMatchingIdiom(pos, "guardWithCatch", 3);
688 }
689
690 /**
691 * Check if i-th name is a start of the tryFinally idiom.
692 */
693 boolean isTryFinally(int pos) {
694 // tryFinally idiom:
695 // t_{n}:L=MethodHandle.invokeBasic(...)
696 // t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
697 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
698 return isMatchingIdiom(pos, "tryFinally", 2);
699 }
700
701 /**
702 * Check if i-th name is a start of the tableSwitch idiom.
703 */
704 boolean isTableSwitch(int pos) {
705 // tableSwitch idiom:
706 // t_{n}:L=MethodHandle.invokeBasic(...) // args
707 // t_{n+1}:L=MethodHandleImpl.tableSwitch(*, *, *, t_{n})
708 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
709 if (pos + 2 >= names.length) return false;
710
711 final int POS_COLLECT_ARGS = pos;
712 final int POS_TABLE_SWITCH = pos + 1;
713 final int POS_UNBOX_RESULT = pos + 2;
714
715 Name collectArgs = names[POS_COLLECT_ARGS];
716 Name tableSwitch = names[POS_TABLE_SWITCH];
717 Name unboxResult = names[POS_UNBOX_RESULT];
718 return tableSwitch.refersTo(MethodHandleImpl.class, "tableSwitch") &&
719 collectArgs.isInvokeBasic() &&
720 unboxResult.isInvokeBasic() &&
721 tableSwitch.lastUseIndex(collectArgs) == 3 && // t_{n+1}:L=MethodHandleImpl.<invoker>(*, *, *, t_{n});
722 lastUseIndex(collectArgs) == POS_TABLE_SWITCH && // t_{n} is local: used only in t_{n+1}
723 unboxResult.lastUseIndex(tableSwitch) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
724 lastUseIndex(tableSwitch) == POS_UNBOX_RESULT; // t_{n+1} is local: used only in t_{n+2}
725 }
726
727 /**
728 * Check if i-th name is a start of the loop idiom.
729 */
730 boolean isLoop(int pos) {
731 // loop idiom:
732 // t_{n}:L=MethodHandle.invokeBasic(...)
733 // t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
734 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
735 return isMatchingIdiom(pos, "loop", 2);
736 }
737
738 /*
739 * Code generation issues:
740 *
741 * Compiled LFs should be reusable in general.
742 * The biggest issue is how to decide when to pull a name into
743 * the bytecode, versus loading a reified form from the MH data.
744 *
745 * For example, an asType wrapper may require execution of a cast
746 * after a call to a MH. The target type of the cast can be placed
747 * as a constant in the LF itself. This will force the cast type
748 * to be compiled into the bytecodes and native code for the MH.
749 * Or, the target type of the cast can be erased in the LF, and
750 * loaded from the MH data. (Later on, if the MH as a whole is
751 * inlined, the data will flow into the inlined instance of the LF,
752 * as a constant, and the end result will be an optimal cast.)
753 *
754 * This erasure of cast types can be done with any use of
755 * reference types. It can also be done with whole method
756 * handles. Erasing a method handle might leave behind
757 * LF code that executes correctly for any MH of a given
758 * type, and load the required MH from the enclosing MH's data.
759 * Or, the erasure might even erase the expected MT.
760 *
761 * Also, for direct MHs, the MemberName of the target
762 * could be erased, and loaded from the containing direct MH.
763 * As a simple case, a LF for all int-valued non-static
764 * field getters would perform a cast on its input argument
765 * (to non-constant base type derived from the MemberName)
766 * and load an integer value from the input object
767 * (at a non-constant offset also derived from the MemberName).
768 * Such MN-erased LFs would be inlinable back to optimized
769 * code, whenever a constant enclosing DMH is available
770 * to supply a constant MN from its data.
771 *
772 * The main problem here is to keep LFs reasonably generic,
773 * while ensuring that hot spots will inline good instances.
774 * "Reasonably generic" means that we don't end up with
775 * repeated versions of bytecode or machine code that do
776 * not differ in their optimized form. Repeated versions
777 * of machine would have the undesirable overheads of
778 * (a) redundant compilation work and (b) extra I$ pressure.
779 * To control repeated versions, we need to be ready to
780 * erase details from LFs and move them into MH data,
781 * whenever those details are not relevant to significant
782 * optimization. "Significant" means optimization of
783 * code that is actually hot.
784 *
785 * Achieving this may require dynamic splitting of MHs, by replacing
786 * a generic LF with a more specialized one, on the same MH,
787 * if (a) the MH is frequently executed and (b) the MH cannot
788 * be inlined into a containing caller, such as an invokedynamic.
789 *
790 * Compiled LFs that are no longer used should be GC-able.
791 * If they contain non-BCP references, they should be properly
792 * interlinked with the class loader(s) that their embedded types
793 * depend on. This probably means that reusable compiled LFs
794 * will be tabulated (indexed) on relevant class loaders,
795 * or else that the tables that cache them will have weak links.
796 */
797
798 /**
799 * Make this LF directly executable, as part of a MethodHandle.
800 * Invariant: Every MH which is invoked must prepare its LF
801 * before invocation.
802 * (In principle, the JVM could do this very lazily,
803 * as a sort of pre-invocation linkage step.)
804 */
805 public void prepare() {
806 if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
807 compileToBytecode();
808 }
809 if (this.vmentry != null) {
810 // already prepared (e.g., a primitive DMH invoker form)
811 return;
812 }
813 MethodType mtype = methodType();
814 LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
815 if (prep == null) {
816 assert (isValidSignature(basicTypeSignature()));
817 prep = LambdaForm.createBlankForType(mtype);
818 prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
819 prep = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
820 }
821 this.vmentry = prep.vmentry;
822 // TO DO: Maybe add invokeGeneric, invokeWithArguments
823 }
824
825 private static @Stable PerfCounter LF_FAILED;
826
827 private static PerfCounter failedCompilationCounter() {
828 if (LF_FAILED == null) {
829 LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
830 }
831 return LF_FAILED;
832 }
833
834 /** Generate optimizable bytecode for this form. */
835 void compileToBytecode() {
836 if (forceInterpretation()) {
837 return; // this should not be compiled
838 }
839 if (vmentry != null && isCompiled) {
840 return; // already compiled somehow
841 }
842
843 // Obtain the invoker MethodType outside of the following try block.
844 // This ensures that an IllegalArgumentException is directly thrown if the
845 // type would have 256 or more parameters
846 MethodType invokerType = methodType();
847 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
848 try {
849 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
850 if (TRACE_INTERPRETER)
851 traceInterpreter("compileToBytecode", this);
852 isCompiled = true;
853 } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
854 // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
855 invocationCounter = -1;
856 failedCompilationCounter().increment();
857 if (LOG_LF_COMPILATION_FAILURE) {
858 System.out.println("LambdaForm compilation failed: " + this);
859 bge.printStackTrace(System.out);
860 }
861 } catch (Error e) {
862 // Pass through any error
863 throw e;
864 } catch (Exception e) {
865 // Wrap any exception
866 throw newInternalError(this.toString(), e);
867 }
868 }
869
870 // The next few routines are called only from assert expressions
871 // They verify that the built-in invokers process the correct raw data types.
872 private static boolean argumentTypesMatch(String sig, Object[] av) {
873 int arity = signatureArity(sig);
874 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
875 assert(av[0] instanceof MethodHandle) : "av[0] not instance of MethodHandle: " + av[0];
876 MethodHandle mh = (MethodHandle) av[0];
877 MethodType mt = mh.type();
878 assert(mt.parameterCount() == arity-1);
879 for (int i = 0; i < av.length; i++) {
880 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
881 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
882 }
883 return true;
884 }
885 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
886 // The following line is needed because (...)void method handles can use non-void invokers
887 if (type == void.class) tc = V_TYPE; // can drop any kind of value
888 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
889 switch (tc) {
890 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
891 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
892 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
893 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
894 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
895 case V_TYPE: break; // allow anything here; will be dropped
896 default: assert(false);
897 }
898 return true;
899 }
900 private static boolean checkInt(Class<?> type, Object x) {
901 assert(x instanceof Integer);
902 if (type == int.class) return true;
903 Wrapper w = Wrapper.forBasicType(type);
904 assert(w.isSubwordOrInt());
905 Object x1 = Wrapper.INT.wrap(w.wrap(x));
906 return x.equals(x1);
907 }
908 private static boolean checkRef(Class<?> type, Object x) {
909 assert(!type.isPrimitive());
910 if (x == null) return true;
911 if (type.isInterface()) return true;
912 return type.isInstance(x);
913 }
914
915 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
916 private static final int COMPILE_THRESHOLD;
917 static {
918 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
919 }
920 private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
921
922 private boolean forceInterpretation() {
923 return invocationCounter == -1;
924 }
925
926 /** Interpretively invoke this form on the given arguments. */
927 @Hidden
928 @DontInline
929 Object interpretWithArguments(Object... argumentValues) throws Throwable {
930 if (TRACE_INTERPRETER)
931 return interpretWithArgumentsTracing(argumentValues);
932 checkInvocationCounter();
933 assert(arityCheck(argumentValues));
934 Object[] values = Arrays.copyOf(argumentValues, names.length);
935 for (int i = argumentValues.length; i < values.length; i++) {
936 values[i] = interpretName(names[i], values);
937 }
938 Object rv = (result < 0) ? null : values[result];
939 assert(resultCheck(argumentValues, rv));
940 return rv;
941 }
942
943 /** Evaluate a single Name within this form, applying its function to its arguments. */
944 @Hidden
945 @DontInline
946 Object interpretName(Name name, Object[] values) throws Throwable {
947 if (TRACE_INTERPRETER)
948 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
949 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
950 for (int i = 0; i < arguments.length; i++) {
951 Object a = arguments[i];
952 if (a instanceof Name n) {
953 int i2 = n.index();
954 assert(names[i2] == a);
955 a = values[i2];
956 arguments[i] = a;
957 }
958 }
959 return name.function.invokeWithArguments(arguments);
960 }
961
962 private void checkInvocationCounter() {
963 if (COMPILE_THRESHOLD != 0 &&
964 !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
965 invocationCounter++; // benign race
966 if (invocationCounter >= COMPILE_THRESHOLD) {
967 // Replace vmentry with a bytecode version of this LF.
968 compileToBytecode();
969 }
970 }
971 }
972 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
973 traceInterpreter("[ interpretWithArguments", this, argumentValues);
974 if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
975 int ctr = invocationCounter++; // benign race
976 traceInterpreter("| invocationCounter", ctr);
977 if (invocationCounter >= COMPILE_THRESHOLD) {
978 compileToBytecode();
979 }
980 }
981 Object rval;
982 try {
983 assert(arityCheck(argumentValues));
984 Object[] values = Arrays.copyOf(argumentValues, names.length);
985 for (int i = argumentValues.length; i < values.length; i++) {
986 values[i] = interpretName(names[i], values);
987 }
988 rval = (result < 0) ? null : values[result];
989 } catch (Throwable ex) {
990 traceInterpreter("] throw =>", ex);
991 throw ex;
992 }
993 traceInterpreter("] return =>", rval);
994 return rval;
995 }
996
997 static void traceInterpreter(String event, Object obj, Object... args) {
998 if (TRACE_INTERPRETER) {
999 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
1000 }
1001 }
1002 static void traceInterpreter(String event, Object obj) {
1003 traceInterpreter(event, obj, (Object[])null);
1004 }
1005 private boolean arityCheck(Object[] argumentValues) {
1006 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
1007 // also check that the leading (receiver) argument is somehow bound to this LF:
1008 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
1009 MethodHandle mh = (MethodHandle) argumentValues[0];
1010 assert(mh.internalForm() == this);
1011 // note: argument #0 could also be an interface wrapper, in the future
1012 argumentTypesMatch(basicTypeSignature(), argumentValues);
1013 return true;
1014 }
1015 private boolean resultCheck(Object[] argumentValues, Object result) {
1016 MethodHandle mh = (MethodHandle) argumentValues[0];
1017 MethodType mt = mh.type();
1018 assert(valueMatches(returnType(), mt.returnType(), result));
1019 return true;
1020 }
1021
1022 private boolean isEmpty() {
1023 if (result < 0)
1024 return (names.length == arity);
1025 else if (result == arity && names.length == arity + 1)
1026 return names[arity].isConstantZero();
1027 else
1028 return false;
1029 }
1030
1031 public String toString() {
1032 return debugString(-1);
1033 }
1034
1035 String debugString(int indentLevel) {
1036 String prefix = MethodHandle.debugPrefix(indentLevel);
1037 String lambdaName = lambdaName();
1038 StringBuilder buf = new StringBuilder(lambdaName);
1039 buf.append("=Lambda(");
1040 for (int i = 0; i < names.length; i++) {
1041 if (i == arity) buf.append(")=>{");
1042 Name n = names[i];
1043 if (i >= arity) buf.append("\n ").append(prefix);
1044 buf.append(n.paramString());
1045 if (i < arity) {
1046 if (i+1 < arity) buf.append(",");
1047 continue;
1048 }
1049 buf.append("=").append(n.exprString());
1050 buf.append(";");
1051 }
1052 if (arity == names.length) buf.append(")=>{");
1053 buf.append(result < 0 ? "void" : names[result]).append("}");
1054 if (TRACE_INTERPRETER) {
1055 // Extra verbosity:
1056 buf.append(":").append(basicTypeSignature());
1057 buf.append("/").append(vmentry);
1058 }
1059 return buf.toString();
1060 }
1061
1062 @Override
1063 public boolean equals(Object obj) {
1064 return obj instanceof LambdaForm lf && equals(lf);
1065 }
1066 public boolean equals(LambdaForm that) {
1067 if (this.result != that.result) return false;
1068 return Arrays.equals(this.names, that.names);
1069 }
1070 public int hashCode() {
1071 return result + 31 * Arrays.hashCode(names);
1072 }
1073 LambdaFormEditor editor() {
1074 return LambdaFormEditor.lambdaFormEditor(this);
1075 }
1076
1077 boolean contains(Name name) {
1078 int pos = name.index();
1079 if (pos >= 0) {
1080 return pos < names.length && name.equals(names[pos]);
1081 }
1082 for (int i = arity; i < names.length; i++) {
1083 if (name.equals(names[i]))
1084 return true;
1085 }
1086 return false;
1087 }
1088
1089 static class NamedFunction {
1090 final MemberName member;
1091 private @Stable MethodHandle resolvedHandle;
1092 private @Stable MethodType type;
1093
1094 NamedFunction(MethodHandle resolvedHandle) {
1095 this(resolvedHandle.internalMemberName(), resolvedHandle);
1096 }
1097 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1098 this.member = member;
1099 this.resolvedHandle = resolvedHandle;
1100 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1101 //assert(!isInvokeBasic(member));
1102 }
1103 NamedFunction(MethodType basicInvokerType) {
1104 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1105 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1106 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1107 this.member = resolvedHandle.internalMemberName();
1108 } else {
1109 // necessary to pass BigArityTest
1110 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1111 }
1112 assert(isInvokeBasic(member));
1113 }
1114
1115 private static boolean isInvokeBasic(MemberName member) {
1116 return member != null &&
1117 member.getDeclaringClass() == MethodHandle.class &&
1118 "invokeBasic".equals(member.getName());
1119 }
1120
1121 // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1122 // Any LambdaForm containing such a member is not interpretable.
1123 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1124 // And even without the resolvedHandle, the name can still be compiled and optimized.
1125 NamedFunction(Method method) {
1126 this(new MemberName(method));
1127 }
1128 NamedFunction(MemberName member) {
1129 this(member, null);
1130 }
1131
1132 MethodHandle resolvedHandle() {
1133 if (resolvedHandle == null) resolve();
1134 return resolvedHandle;
1135 }
1136
1137 synchronized void resolve() {
1138 if (resolvedHandle == null) {
1139 resolvedHandle = DirectMethodHandle.make(member);
1140 }
1141 }
1142
1143 @Override
1144 public boolean equals(Object other) {
1145 if (this == other) return true;
1146 if (other == null) return false;
1147 return (other instanceof NamedFunction that)
1148 && this.member != null
1149 && this.member.equals(that.member);
1150 }
1151
1152 @Override
1153 public int hashCode() {
1154 if (member != null)
1155 return member.hashCode();
1156 return super.hashCode();
1157 }
1158
1159 static final MethodType INVOKER_METHOD_TYPE =
1160 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1161
1162 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1163 typeForm = typeForm.basicType().form(); // normalize to basic type
1164 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1165 if (mh != null) return mh;
1166 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1167 mh = DirectMethodHandle.make(invoker);
1168 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1169 if (mh2 != null) return mh2; // benign race
1170 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1171 throw newInternalError(mh.debugString());
1172 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1173 }
1174
1175 @Hidden
1176 Object invokeWithArguments(Object... arguments) throws Throwable {
1177 // If we have a cached invoker, call it right away.
1178 // NOTE: The invoker always returns a reference value.
1179 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1180 return invoker().invokeBasic(resolvedHandle(), arguments);
1181 }
1182
1183 @Hidden
1184 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1185 Object rval;
1186 try {
1187 traceInterpreter("[ call", this, arguments);
1188 // resolvedHandle might be uninitialized, ok for tracing
1189 if (resolvedHandle == null) {
1190 traceInterpreter("| resolve", this);
1191 resolvedHandle();
1192 }
1193 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1194 } catch (Throwable ex) {
1195 traceInterpreter("] throw =>", ex);
1196 throw ex;
1197 }
1198 traceInterpreter("] return =>", rval);
1199 return rval;
1200 }
1201
1202 private MethodHandle invoker() {
1203 return computeInvoker(methodType().form());
1204 }
1205
1206 MethodType methodType() {
1207 MethodType type = this.type;
1208 if (type == null) {
1209 this.type = type = calculateMethodType(member, resolvedHandle);
1210 }
1211 return type;
1212 }
1213
1214 private static MethodType calculateMethodType(MemberName member, MethodHandle resolvedHandle) {
1215 if (resolvedHandle != null) {
1216 return resolvedHandle.type();
1217 } else {
1218 // only for certain internal LFs during bootstrapping
1219 return member.getInvocationType();
1220 }
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 final short index;
1337 final NamedFunction function;
1338 final Object constraint; // additional type information, if not null
1339 @Stable final Object[] arguments;
1340
1341 private static final Object[] EMPTY_ARGS = new Object[0];
1342
1343 private Name(int index, BasicType type, NamedFunction function, Object[] arguments, Object constraint) {
1344 this.index = (short)index;
1345 this.type = type;
1346 this.function = function;
1347 this.arguments = arguments;
1348 this.constraint = constraint;
1349 assert(this.index == index && typesMatch(function, arguments));
1350 assert(constraint == null || isParam()); // only params have constraints
1351 assert(constraint == null || constraint instanceof ClassSpecializer.SpeciesData || constraint instanceof Class);
1352 }
1353
1354 Name(MethodHandle function, Object... arguments) {
1355 this(new NamedFunction(function), arguments);
1356 }
1357 Name(MethodType functionType, Object... arguments) {
1358 this(new NamedFunction(functionType), arguments);
1359 assert(arguments[0] instanceof Name name && name.type == L_TYPE);
1360 }
1361 Name(MemberName function, Object... arguments) {
1362 this(new NamedFunction(function), arguments);
1363 }
1364 Name(NamedFunction function) {
1365 this(-1, function.returnType(), function, EMPTY_ARGS, null);
1366 }
1367 Name(NamedFunction function, Object arg) {
1368 this(-1, function.returnType(), function, new Object[] { arg }, null);
1369 }
1370 Name(NamedFunction function, Object arg0, Object arg1) {
1371 this(-1, function.returnType(), function, new Object[] { arg0, arg1 }, null);
1372 }
1373 Name(NamedFunction function, Object... arguments) {
1374 this(-1, function.returnType(), function, Arrays.copyOf(arguments, arguments.length, Object[].class), null);
1375 }
1376 /** Create a raw parameter of the given type, with an expected index. */
1377 Name(int index, BasicType type) {
1378 this(index, type, null, null, null);
1379 }
1380 /** Create a raw parameter of the given type. */
1381 Name(BasicType type) { this(-1, type); }
1382
1383 BasicType type() { return type; }
1384 int index() { return index; }
1385
1386 char typeChar() {
1387 return type.btChar;
1388 }
1389
1390 Name withIndex(int i) {
1391 if (i == this.index) return this;
1392 return new Name(i, type, function, arguments, constraint);
1393 }
1394
1395 Name withConstraint(Object constraint) {
1396 if (constraint == this.constraint) return this;
1397 return new Name(index, type, function, arguments, constraint);
1398 }
1399
1400 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1401 if (oldName == newName) return this;
1402 @SuppressWarnings("LocalVariableHidesMemberVariable")
1403 Object[] arguments = this.arguments;
1404 if (arguments == null) return this;
1405 boolean replaced = false;
1406 for (int j = 0; j < arguments.length; j++) {
1407 if (arguments[j] == oldName) {
1408 if (!replaced) {
1409 replaced = true;
1410 arguments = arguments.clone();
1411 }
1412 arguments[j] = newName;
1413 }
1414 }
1415 if (!replaced) return this;
1416 return new Name(function, arguments);
1417 }
1418 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1419 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1420 */
1421 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1422 if (start >= end) return this;
1423 @SuppressWarnings("LocalVariableHidesMemberVariable")
1424 Object[] arguments = this.arguments;
1425 boolean replaced = false;
1426 eachArg:
1427 for (int j = 0; j < arguments.length; j++) {
1428 if (arguments[j] instanceof Name n) {
1429 int check = n.index;
1430 // harmless check to see if the thing is already in newNames:
1431 if (check >= 0 && check < newNames.length && n == newNames[check])
1432 continue eachArg;
1433 // n might not have the correct index: n != oldNames[n.index].
1434 for (int i = start; i < end; i++) {
1435 if (n == oldNames[i]) {
1436 if (n == newNames[i])
1437 continue eachArg;
1438 if (!replaced) {
1439 replaced = true;
1440 arguments = arguments.clone();
1441 }
1442 arguments[j] = newNames[i];
1443 continue eachArg;
1444 }
1445 }
1446 }
1447 }
1448 if (!replaced) return this;
1449 return new Name(function, arguments);
1450 }
1451 void internArguments() {
1452 @SuppressWarnings("LocalVariableHidesMemberVariable")
1453 Object[] arguments = this.arguments;
1454 for (int j = 0; j < arguments.length; j++) {
1455 if (arguments[j] instanceof Name n) {
1456 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1457 arguments[j] = internArgument(n);
1458 }
1459 }
1460 }
1461 boolean isParam() {
1462 return function == null;
1463 }
1464 boolean isConstantZero() {
1465 return !isParam() && arguments.length == 0 && function.isConstantZero();
1466 }
1467
1468 boolean refersTo(Class<?> declaringClass, String methodName) {
1469 return function != null &&
1470 function.member() != null && function.member().refersTo(declaringClass, methodName);
1471 }
1472
1473 /**
1474 * Check if MemberName is a call to MethodHandle.invokeBasic.
1475 */
1476 boolean isInvokeBasic() {
1477 if (function == null)
1478 return false;
1479 if (arguments.length < 1)
1480 return false; // must have MH argument
1481 MemberName member = function.member();
1482 return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1483 !member.isPublic() && !member.isStatic();
1484 }
1485
1486 /**
1487 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1488 */
1489 boolean isLinkerMethodInvoke() {
1490 if (function == null)
1491 return false;
1492 if (arguments.length < 1)
1493 return false; // must have MH argument
1494 MemberName member = function.member();
1495 return member != null &&
1496 member.getDeclaringClass() == MethodHandle.class &&
1497 !member.isPublic() && member.isStatic() &&
1498 member.getName().startsWith("linkTo");
1499 }
1500
1501 public String toString() {
1502 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1503 }
1504 public String debugString() {
1505 String s = paramString();
1506 return (function == null) ? s : s + "=" + exprString();
1507 }
1508 public String paramString() {
1509 String s = toString();
1510 Object c = constraint;
1511 if (c == null)
1512 return s;
1513 if (c instanceof Class<?> cl) c = cl.getSimpleName();
1514 return s + "/" + c;
1515 }
1516 public String exprString() {
1517 if (function == null) return toString();
1518 StringBuilder buf = new StringBuilder(function.toString());
1519 buf.append("(");
1520 String cma = "";
1521 for (Object a : arguments) {
1522 buf.append(cma); cma = ",";
1523 if (a instanceof Name || a instanceof Integer)
1524 buf.append(a);
1525 else
1526 buf.append("(").append(a).append(")");
1527 }
1528 buf.append(")");
1529 return buf.toString();
1530 }
1531
1532 private boolean typesMatch(NamedFunction function, Object ... arguments) {
1533 if (arguments == null) {
1534 assert(function == null);
1535 return true;
1536 }
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 name) {
1546 return name.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 Object[] arguments = this.arguments;
1563 if (arguments == null) return -1;
1564 for (int i = arguments.length; --i >= 0; ) {
1565 if (arguments[i] == n) return i;
1566 }
1567 return -1;
1568 }
1569
1570 public boolean equals(Name that) {
1571 if (this == that) return true;
1572 if (isParam())
1573 // each parameter is a unique atom
1574 return false; // this != that
1575 return
1576 //this.index == that.index &&
1577 this.type == that.type &&
1578 this.function.equals(that.function) &&
1579 Arrays.equals(this.arguments, that.arguments);
1580 }
1581 @Override
1582 public boolean equals(Object x) {
1583 return x instanceof Name n && equals(n);
1584 }
1585 @Override
1586 public int hashCode() {
1587 if (isParam())
1588 return index | (type.ordinal() << 8);
1589 return function.hashCode() ^ Arrays.hashCode(arguments);
1590 }
1591 }
1592
1593 /** Return the index of the last name which contains n as an argument.
1594 * Return -1 if the name is not used. Return names.length if it is the return value.
1595 */
1596 int lastUseIndex(Name n) {
1597 int ni = n.index, nmax = names.length;
1598 assert(names[ni] == n);
1599 if (result == ni) return nmax; // live all the way beyond the end
1600 for (int i = nmax; --i > ni; ) {
1601 if (names[i].lastUseIndex(n) >= 0)
1602 return i;
1603 }
1604 return -1;
1605 }
1606
1607 /** Return the number of times n is used as an argument or return value. */
1608 int useCount(Name n) {
1609 int count = (result == n.index) ? 1 : 0;
1610 int i = Math.max(n.index + 1, arity);
1611 Name[] names = this.names;
1612 while (i < names.length) {
1613 Object[] arguments = names[i++].arguments;
1614 if (arguments != null) {
1615 for (Object argument : arguments) {
1616 if (argument == n) {
1617 count++;
1618 }
1619 }
1620 }
1621 }
1622 return count;
1623 }
1624
1625 static Name argument(int which, BasicType type) {
1626 if (which >= INTERNED_ARGUMENT_LIMIT)
1627 return new Name(which, type);
1628 return INTERNED_ARGUMENTS[type.ordinal()][which];
1629 }
1630 static Name internArgument(Name n) {
1631 assert(n.isParam()) : "not param: " + n;
1632 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1633 if (n.constraint != null) return n;
1634 return argument(n.index, n.type);
1635 }
1636 static Name[] arguments(int extra, MethodType types) {
1637 int length = types.parameterCount();
1638 Name[] names = new Name[length + extra];
1639 for (int i = 0; i < length; i++)
1640 names[i] = argument(i, basicType(types.parameterType(i)));
1641 return names;
1642 }
1643
1644 static Name[] invokeArguments(int extra, MethodType types) {
1645 int length = types.parameterCount();
1646 Name[] names = new Name[length + extra + 1];
1647 names[0] = argument(0, L_TYPE);
1648 for (int i = 0; i < length; i++)
1649 names[i + 1] = argument(i + 1, basicType(types.parameterType(i)));
1650 return names;
1651 }
1652
1653 static final int INTERNED_ARGUMENT_LIMIT = 10;
1654 private static final Name[][] INTERNED_ARGUMENTS
1655 = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1656 static {
1657 for (BasicType type : BasicType.ARG_TYPES) {
1658 int ord = type.ordinal();
1659 for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1660 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1661 }
1662 }
1663 }
1664
1665 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1666
1667 static LambdaForm identityForm(BasicType type) {
1668 int ord = type.ordinal();
1669 LambdaForm form = LF_identity[ord];
1670 if (form != null) {
1671 return form;
1672 }
1673 createFormsFor(type);
1674 return LF_identity[ord];
1675 }
1676
1677 static LambdaForm zeroForm(BasicType type) {
1678 int ord = type.ordinal();
1679 LambdaForm form = LF_zero[ord];
1680 if (form != null) {
1681 return form;
1682 }
1683 createFormsFor(type);
1684 return LF_zero[ord];
1685 }
1686
1687 static NamedFunction identity(BasicType type) {
1688 int ord = type.ordinal();
1689 NamedFunction function = NF_identity[ord];
1690 if (function != null) {
1691 return function;
1692 }
1693 createFormsFor(type);
1694 return NF_identity[ord];
1695 }
1696
1697 static NamedFunction constantZero(BasicType type) {
1698 int ord = type.ordinal();
1699 NamedFunction function = NF_zero[ord];
1700 if (function != null) {
1701 return function;
1702 }
1703 createFormsFor(type);
1704 return NF_zero[ord];
1705 }
1706
1707 private static final @Stable LambdaForm[] LF_identity = new LambdaForm[TYPE_LIMIT];
1708 private static final @Stable LambdaForm[] LF_zero = new LambdaForm[TYPE_LIMIT];
1709 private static final @Stable NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1710 private static final @Stable NamedFunction[] NF_zero = new NamedFunction[TYPE_LIMIT];
1711
1712 private static final Object createFormsLock = new Object();
1713 private static void createFormsFor(BasicType type) {
1714 // Avoid racy initialization during bootstrap
1715 UNSAFE.ensureClassInitialized(BoundMethodHandle.class);
1716 synchronized (createFormsLock) {
1717 final int ord = type.ordinal();
1718 LambdaForm idForm = LF_identity[ord];
1719 if (idForm != null) {
1720 return;
1721 }
1722 char btChar = type.basicTypeChar();
1723 boolean isVoid = (type == V_TYPE);
1724 Class<?> btClass = type.btClass;
1725 MethodType zeType = MethodType.methodType(btClass);
1726 MethodType idType = (isVoid) ? zeType : MethodType.methodType(btClass, btClass);
1727
1728 // Look up symbolic names. It might not be necessary to have these,
1729 // but if we need to emit direct references to bytecodes, it helps.
1730 // Zero is built from a call to an identity function with a constant zero input.
1731 MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1732 MemberName zeMem = null;
1733 try {
1734 idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, LM_TRUSTED, NoSuchMethodException.class);
1735 if (!isVoid) {
1736 zeMem = new MemberName(LambdaForm.class, "zero_"+btChar, zeType, REF_invokeStatic);
1737 zeMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, zeMem, null, LM_TRUSTED, NoSuchMethodException.class);
1738 }
1739 } catch (IllegalAccessException|NoSuchMethodException ex) {
1740 throw newInternalError(ex);
1741 }
1742
1743 NamedFunction idFun;
1744 LambdaForm zeForm;
1745 NamedFunction zeFun;
1746
1747 // Create the LFs and NamedFunctions. Precompiling LFs to byte code is needed to break circular
1748 // bootstrap dependency on this method in case we're interpreting LFs
1749 if (isVoid) {
1750 Name[] idNames = new Name[] { argument(0, L_TYPE) };
1751 idForm = LambdaForm.create(1, idNames, VOID_RESULT, Kind.IDENTITY);
1752 idForm.compileToBytecode();
1753 idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm));
1754
1755 zeForm = idForm;
1756 zeFun = idFun;
1757 } else {
1758 Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1759 idForm = LambdaForm.create(2, idNames, 1, Kind.IDENTITY);
1760 idForm.compileToBytecode();
1761 idFun = new NamedFunction(idMem, MethodHandleImpl.makeIntrinsic(SimpleMethodHandle.make(idMem.getInvocationType(), idForm),
1762 MethodHandleImpl.Intrinsic.IDENTITY));
1763
1764 Object zeValue = Wrapper.forBasicType(btChar).zero();
1765 Name[] zeNames = new Name[] { argument(0, L_TYPE), new Name(idFun, zeValue) };
1766 zeForm = LambdaForm.create(1, zeNames, 1, Kind.ZERO);
1767 zeForm.compileToBytecode();
1768 zeFun = new NamedFunction(zeMem, MethodHandleImpl.makeIntrinsic(SimpleMethodHandle.make(zeMem.getInvocationType(), zeForm),
1769 MethodHandleImpl.Intrinsic.ZERO));
1770 }
1771
1772 LF_zero[ord] = zeForm;
1773 NF_zero[ord] = zeFun;
1774 LF_identity[ord] = idForm;
1775 NF_identity[ord] = idFun;
1776
1777 assert(idFun.isIdentity());
1778 assert(zeFun.isConstantZero());
1779 assert(new Name(zeFun).isConstantZero());
1780 }
1781 }
1782
1783 // Avoid appealing to ValueConversions at bootstrap time:
1784 private static int identity_I(int x) { return x; }
1785 private static long identity_J(long x) { return x; }
1786 private static float identity_F(float x) { return x; }
1787 private static double identity_D(double x) { return x; }
1788 private static Object identity_L(Object x) { return x; }
1789 private static void identity_V() { return; }
1790 private static int zero_I() { return 0; }
1791 private static long zero_J() { return 0; }
1792 private static float zero_F() { return 0; }
1793 private static double zero_D() { return 0; }
1794 private static Object zero_L() { return null; }
1795
1796 /**
1797 * Internal marker for byte-compiled LambdaForms.
1798 */
1799 /*non-public*/
1800 @Target(ElementType.METHOD)
1801 @Retention(RetentionPolicy.RUNTIME)
1802 @interface Compiled {
1803 }
1804
1805 private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1806 private static final HashMap<LambdaForm,String> DEBUG_NAMES;
1807 static {
1808 if (debugEnabled()) {
1809 DEBUG_NAME_COUNTERS = new HashMap<>();
1810 DEBUG_NAMES = new HashMap<>();
1811 } else {
1812 DEBUG_NAME_COUNTERS = null;
1813 DEBUG_NAMES = null;
1814 }
1815 }
1816
1817 static {
1818 // The Holder class will contain pre-generated forms resolved
1819 // using MemberName.getFactory(). However, that doesn't initialize the
1820 // class, which subtly breaks inlining etc. By forcing
1821 // initialization of the Holder class we avoid these issues.
1822 UNSAFE.ensureClassInitialized(Holder.class);
1823 }
1824
1825 /* Placeholder class for zero and identity forms generated ahead of time */
1826 final class Holder {}
1827
1828 // The following hack is necessary in order to suppress TRACE_INTERPRETER
1829 // during execution of the static initializes of this class.
1830 // Turning on TRACE_INTERPRETER too early will cause
1831 // stack overflows and other misbehavior during attempts to trace events
1832 // that occur during LambdaForm.<clinit>.
1833 // Therefore, do not move this line higher in this file, and do not remove.
1834 private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1835 }