1 /*
2 * Copyright (c) 2011, 2025, 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 IDENTITY("identity"),
249 CONSTANT("constant"),
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_INT("getInt"),
271 PUT_INT("putInt"),
272 GET_INT_VOLATILE("getIntVolatile"),
273 PUT_INT_VOLATILE("putIntVolatile"),
274 GET_BOOLEAN("getBoolean"),
275 PUT_BOOLEAN("putBoolean"),
276 GET_BOOLEAN_VOLATILE("getBooleanVolatile"),
277 PUT_BOOLEAN_VOLATILE("putBooleanVolatile"),
278 GET_BYTE("getByte"),
279 PUT_BYTE("putByte"),
280 GET_BYTE_VOLATILE("getByteVolatile"),
281 PUT_BYTE_VOLATILE("putByteVolatile"),
282 GET_CHAR("getChar"),
283 PUT_CHAR("putChar"),
284 GET_CHAR_VOLATILE("getCharVolatile"),
285 PUT_CHAR_VOLATILE("putCharVolatile"),
286 GET_SHORT("getShort"),
287 PUT_SHORT("putShort"),
288 GET_SHORT_VOLATILE("getShortVolatile"),
289 PUT_SHORT_VOLATILE("putShortVolatile"),
290 GET_LONG("getLong"),
291 PUT_LONG("putLong"),
292 GET_LONG_VOLATILE("getLongVolatile"),
293 PUT_LONG_VOLATILE("putLongVolatile"),
294 GET_FLOAT("getFloat"),
295 PUT_FLOAT("putFloat"),
296 GET_FLOAT_VOLATILE("getFloatVolatile"),
297 PUT_FLOAT_VOLATILE("putFloatVolatile"),
298 GET_DOUBLE("getDouble"),
299 PUT_DOUBLE("putDouble"),
300 GET_DOUBLE_VOLATILE("getDoubleVolatile"),
301 PUT_DOUBLE_VOLATILE("putDoubleVolatile"),
302 TRY_FINALLY("tryFinally"),
303 TABLE_SWITCH("tableSwitch"),
304 COLLECTOR("collector"),
305 LOOP("loop"),
306 GUARD("guard"),
307 GUARD_WITH_CATCH("guardWithCatch"),
308 VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
309 VARHANDLE_INVOKER("VH.invoker", "invoker"),
310 VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
311
312 final String defaultLambdaName;
313 final String methodName;
314
315 private Kind(String defaultLambdaName) {
316 this(defaultLambdaName, defaultLambdaName);
317 }
318
319 private Kind(String defaultLambdaName, String methodName) {
320 this.defaultLambdaName = defaultLambdaName;
321 this.methodName = methodName;
322 }
323 }
324
325 // private version that doesn't do checks or defensive copies
326 private LambdaForm(int arity, int result, boolean forceInline, MethodHandle customized, Name[] names, Kind kind) {
327 this.arity = arity;
328 this.result = result;
329 this.forceInline = forceInline;
330 this.customized = customized;
331 this.names = names;
332 this.kind = kind;
333 this.vmentry = null;
334 this.isCompiled = false;
335 }
336
337 // root factory pre/post processing and calls simple constructor
338 private static LambdaForm create(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
339 names = names.clone();
340 assert(namesOK(arity, names));
341 result = fixResult(result, names);
342
343 boolean canInterpret = normalizeNames(arity, names);
344 LambdaForm form = new LambdaForm(arity, result, forceInline, customized, names, kind);
345 assert(form.nameRefsAreLegal());
346 if (!canInterpret) {
347 form.compileToBytecode();
348 }
349 return form;
350 }
351
352 // derived factories with defaults
353 private static final int DEFAULT_RESULT = LAST_RESULT;
354 private static final boolean DEFAULT_FORCE_INLINE = true;
355 private static final MethodHandle DEFAULT_CUSTOMIZED = null;
356 private static final Kind DEFAULT_KIND = Kind.GENERIC;
357
358 static LambdaForm create(int arity, Name[] names, int result) {
359 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
360 }
361 static LambdaForm create(int arity, Name[] names, int result, Kind kind) {
362 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
363 }
364 static LambdaForm create(int arity, Name[] names) {
365 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
366 }
367 static LambdaForm create(int arity, Name[] names, Kind kind) {
368 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
369 }
370 static LambdaForm create(int arity, Name[] names, boolean forceInline, Kind kind) {
371 return create(arity, names, DEFAULT_RESULT, forceInline, DEFAULT_CUSTOMIZED, kind);
372 }
373
374 private static int fixResult(int result, Name[] names) {
375 if (result == LAST_RESULT)
376 result = names.length - 1; // might still be void
377 if (result >= 0 && names[result].type == V_TYPE)
378 result = VOID_RESULT;
379 return result;
380 }
381
382 static boolean debugNames() {
383 return DEBUG_NAME_COUNTERS != null;
384 }
385
386 static void associateWithDebugName(LambdaForm form, String name) {
387 assert (debugNames());
388 synchronized (DEBUG_NAMES) {
389 DEBUG_NAMES.put(form, name);
390 }
391 }
392
393 String lambdaName() {
394 if (DEBUG_NAMES != null) {
395 synchronized (DEBUG_NAMES) {
396 String name = DEBUG_NAMES.get(this);
397 if (name == null) {
398 name = generateDebugName();
399 }
400 return name;
401 }
402 }
403 return kind.defaultLambdaName;
404 }
405
406 private String generateDebugName() {
407 assert (debugNames());
408 String debugNameStem = kind.defaultLambdaName;
409 Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
410 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
411 StringBuilder buf = new StringBuilder(debugNameStem);
412 int leadingZero = buf.length();
413 buf.append((int) ctr);
414 for (int i = buf.length() - leadingZero; i < 3; i++) {
415 buf.insert(leadingZero, '0');
416 }
417 buf.append('_');
418 buf.append(basicTypeSignature());
419 String name = buf.toString();
420 associateWithDebugName(this, name);
421 return name;
422 }
423
424 private static boolean namesOK(int arity, Name[] names) {
425 for (int i = 0; i < names.length; i++) {
426 Name n = names[i];
427 assert(n != null) : "n is null";
428 if (i < arity)
429 assert( n.isParam()) : n + " is not param at " + i;
430 else
431 assert(!n.isParam()) : n + " is param at " + i;
432 }
433 return true;
434 }
435
436 /** Customize LambdaForm for a particular MethodHandle */
437 LambdaForm customize(MethodHandle mh) {
438 if (customized == mh) {
439 return this;
440 }
441 LambdaForm customForm = LambdaForm.create(arity, names, result, forceInline, mh, kind);
442 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
443 // If shared LambdaForm has been compiled, compile customized version as well.
444 customForm.compileToBytecode();
445 }
446 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
447 return customForm;
448 }
449
450 /** Get uncustomized flavor of the LambdaForm */
451 LambdaForm uncustomize() {
452 if (customized == null) {
453 return this;
454 }
455 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
456 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
457 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
458 // If customized LambdaForm has been compiled, compile uncustomized version as well.
459 uncustomizedForm.compileToBytecode();
460 }
461 return uncustomizedForm;
462 }
463
464 /** Renumber and/or replace params so that they are interned and canonically numbered.
465 * @return true if we can interpret
466 */
467 private static boolean normalizeNames(int arity, Name[] names) {
468 Name[] oldNames = names.clone();
469 int maxOutArity = 0;
470 for (int i = 0; i < names.length; i++) {
471 Name n = names[i];
472 names[i] = n.withIndex(i);
473 if (n.arguments != null && maxOutArity < n.arguments.length)
474 maxOutArity = n.arguments.length;
475 }
476 if (oldNames != null) {
477 for (int i = Math.max(1, arity); i < names.length; i++) {
478 Name fixed = names[i].replaceNames(oldNames, names, 0, i);
479 names[i] = fixed.withIndex(i);
480 }
481 }
482 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
483 boolean needIntern = false;
484 for (int i = 0; i < maxInterned; i++) {
485 Name n = names[i], n2 = internArgument(n);
486 if (n != n2) {
487 names[i] = n2;
488 needIntern = true;
489 }
490 }
491 if (needIntern) {
492 for (int i = arity; i < names.length; i++) {
493 names[i].internArguments();
494 }
495 }
496
497 // return true if we can interpret
498 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
499 // Cannot use LF interpreter on very high arity expressions.
500 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
501 return false;
502 }
503 return true;
504 }
505
506 /**
507 * Check that all embedded Name references are localizable to this lambda,
508 * and are properly ordered after their corresponding definitions.
509 * <p>
510 * Note that a Name can be local to multiple lambdas, as long as
511 * it possesses the same index in each use site.
512 * This allows Name references to be freely reused to construct
513 * fresh lambdas, without confusion.
514 */
515 boolean nameRefsAreLegal() {
516 assert(arity >= 0 && arity <= names.length);
517 assert(result >= -1 && result < names.length);
518 // Do all names possess an index consistent with their local definition order?
519 for (int i = 0; i < arity; i++) {
520 Name n = names[i];
521 assert(n.index() == i) : Arrays.asList(n.index(), i);
522 assert(n.isParam());
523 }
524 // Also, do all local name references
525 for (int i = arity; i < names.length; i++) {
526 Name n = names[i];
527 assert(n.index() == i);
528 for (Object arg : n.arguments) {
529 if (arg instanceof Name n2) {
530 int i2 = n2.index;
531 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
532 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
533 assert(i2 < i); // ref must come after def!
534 }
535 }
536 }
537 return true;
538 }
539
540 // /** Invoke this form on the given arguments. */
541 // final Object invoke(Object... args) throws Throwable {
542 // // NYI: fit this into the fast path?
543 // return interpretWithArguments(args);
544 // }
545
546 /** Report the return type. */
547 BasicType returnType() {
548 if (result < 0) return V_TYPE;
549 Name n = names[result];
550 return n.type;
551 }
552
553 /** Report the N-th argument type. */
554 BasicType parameterType(int n) {
555 return parameter(n).type;
556 }
557
558 /** Report the N-th argument name. */
559 Name parameter(int n) {
560 Name param = names[n];
561 assert(n < arity && param.isParam());
562 return param;
563 }
564
565 /** Report the N-th argument type constraint. */
566 Object parameterConstraint(int n) {
567 return parameter(n).constraint;
568 }
569
570 /** Report the arity. */
571 int arity() {
572 return arity;
573 }
574
575 /** Report the number of expressions (non-parameter names). */
576 int expressionCount() {
577 return names.length - arity;
578 }
579
580 /** Return the method type corresponding to my basic type signature. */
581 MethodType methodType() {
582 Class<?>[] ptypes = new Class<?>[arity];
583 for (int i = 0; i < arity; ++i) {
584 ptypes[i] = parameterType(i).btClass;
585 }
586 return MethodType.methodType(returnType().btClass, ptypes, true);
587 }
588
589 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
590 final String basicTypeSignature() {
591 StringBuilder buf = new StringBuilder(arity() + 3);
592 for (int i = 0, a = arity(); i < a; i++)
593 buf.append(parameterType(i).basicTypeChar());
594 return buf.append('_').append(returnType().basicTypeChar()).toString();
595 }
596 static int signatureArity(String sig) {
597 assert(isValidSignature(sig));
598 return sig.indexOf('_');
599 }
600 static boolean isValidSignature(String sig) {
601 int arity = sig.indexOf('_');
602 if (arity < 0) return false; // must be of the form *_*
603 int siglen = sig.length();
604 if (siglen != arity + 2) return false; // *_X
605 for (int i = 0; i < siglen; i++) {
606 if (i == arity) continue; // skip '_'
607 char c = sig.charAt(i);
608 if (c == 'V')
609 return (i == siglen - 1 && arity == siglen - 2);
610 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
611 }
612 return true; // [LIJFD]*_[LIJFDV]
613 }
614
615 /**
616 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
617 */
618 boolean isSelectAlternative(int pos) {
619 // selectAlternative idiom:
620 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
621 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
622 if (pos+1 >= names.length) return false;
623 Name name0 = names[pos];
624 Name name1 = names[pos+1];
625 return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
626 name1.isInvokeBasic() &&
627 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
628 lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
629 }
630
631 private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
632 if (pos+2 >= names.length) return false;
633 Name name0 = names[pos];
634 Name name1 = names[pos+1];
635 Name name2 = names[pos+2];
636 return name1.refersTo(MethodHandleImpl.class, idiomName) &&
637 name0.isInvokeBasic() &&
638 name2.isInvokeBasic() &&
639 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
640 lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
641 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
642 lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
643 }
644
645 /**
646 * Check if i-th name is a start of GuardWithCatch idiom.
647 */
648 boolean isGuardWithCatch(int pos) {
649 // GuardWithCatch idiom:
650 // t_{n}:L=MethodHandle.invokeBasic(...)
651 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
652 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
653 return isMatchingIdiom(pos, "guardWithCatch", 3);
654 }
655
656 /**
657 * Check if i-th name is a start of the tryFinally idiom.
658 */
659 boolean isTryFinally(int pos) {
660 // tryFinally idiom:
661 // t_{n}:L=MethodHandle.invokeBasic(...)
662 // t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
663 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
664 return isMatchingIdiom(pos, "tryFinally", 2);
665 }
666
667 /**
668 * Check if i-th name is a start of the tableSwitch idiom.
669 */
670 boolean isTableSwitch(int pos) {
671 // tableSwitch idiom:
672 // t_{n}:L=MethodHandle.invokeBasic(...) // args
673 // t_{n+1}:L=MethodHandleImpl.tableSwitch(*, *, *, t_{n})
674 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
675 if (pos + 2 >= names.length) return false;
676
677 final int POS_COLLECT_ARGS = pos;
678 final int POS_TABLE_SWITCH = pos + 1;
679 final int POS_UNBOX_RESULT = pos + 2;
680
681 Name collectArgs = names[POS_COLLECT_ARGS];
682 Name tableSwitch = names[POS_TABLE_SWITCH];
683 Name unboxResult = names[POS_UNBOX_RESULT];
684 return tableSwitch.refersTo(MethodHandleImpl.class, "tableSwitch") &&
685 collectArgs.isInvokeBasic() &&
686 unboxResult.isInvokeBasic() &&
687 tableSwitch.lastUseIndex(collectArgs) == 3 && // t_{n+1}:L=MethodHandleImpl.<invoker>(*, *, *, t_{n});
688 lastUseIndex(collectArgs) == POS_TABLE_SWITCH && // t_{n} is local: used only in t_{n+1}
689 unboxResult.lastUseIndex(tableSwitch) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
690 lastUseIndex(tableSwitch) == POS_UNBOX_RESULT; // t_{n+1} is local: used only in t_{n+2}
691 }
692
693 /**
694 * Check if i-th name is a start of the loop idiom.
695 */
696 boolean isLoop(int pos) {
697 // loop idiom:
698 // t_{n}:L=MethodHandle.invokeBasic(...)
699 // t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
700 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
701 return isMatchingIdiom(pos, "loop", 2);
702 }
703
704 /*
705 * Code generation issues:
706 *
707 * Compiled LFs should be reusable in general.
708 * The biggest issue is how to decide when to pull a name into
709 * the bytecode, versus loading a reified form from the MH data.
710 *
711 * For example, an asType wrapper may require execution of a cast
712 * after a call to a MH. The target type of the cast can be placed
713 * as a constant in the LF itself. This will force the cast type
714 * to be compiled into the bytecodes and native code for the MH.
715 * Or, the target type of the cast can be erased in the LF, and
716 * loaded from the MH data. (Later on, if the MH as a whole is
717 * inlined, the data will flow into the inlined instance of the LF,
718 * as a constant, and the end result will be an optimal cast.)
719 *
720 * This erasure of cast types can be done with any use of
721 * reference types. It can also be done with whole method
722 * handles. Erasing a method handle might leave behind
723 * LF code that executes correctly for any MH of a given
724 * type, and load the required MH from the enclosing MH's data.
725 * Or, the erasure might even erase the expected MT.
726 *
727 * Also, for direct MHs, the MemberName of the target
728 * could be erased, and loaded from the containing direct MH.
729 * As a simple case, a LF for all int-valued non-static
730 * field getters would perform a cast on its input argument
731 * (to non-constant base type derived from the MemberName)
732 * and load an integer value from the input object
733 * (at a non-constant offset also derived from the MemberName).
734 * Such MN-erased LFs would be inlinable back to optimized
735 * code, whenever a constant enclosing DMH is available
736 * to supply a constant MN from its data.
737 *
738 * The main problem here is to keep LFs reasonably generic,
739 * while ensuring that hot spots will inline good instances.
740 * "Reasonably generic" means that we don't end up with
741 * repeated versions of bytecode or machine code that do
742 * not differ in their optimized form. Repeated versions
743 * of machine would have the undesirable overheads of
744 * (a) redundant compilation work and (b) extra I$ pressure.
745 * To control repeated versions, we need to be ready to
746 * erase details from LFs and move them into MH data,
747 * whenever those details are not relevant to significant
748 * optimization. "Significant" means optimization of
749 * code that is actually hot.
750 *
751 * Achieving this may require dynamic splitting of MHs, by replacing
752 * a generic LF with a more specialized one, on the same MH,
753 * if (a) the MH is frequently executed and (b) the MH cannot
754 * be inlined into a containing caller, such as an invokedynamic.
755 *
756 * Compiled LFs that are no longer used should be GC-able.
757 * If they contain non-BCP references, they should be properly
758 * interlinked with the class loader(s) that their embedded types
759 * depend on. This probably means that reusable compiled LFs
760 * will be tabulated (indexed) on relevant class loaders,
761 * or else that the tables that cache them will have weak links.
762 */
763
764 /**
765 * Make this LF directly executable, as part of a MethodHandle.
766 * Invariant: Every MH which is invoked must prepare its LF
767 * before invocation.
768 * (In principle, the JVM could do this very lazily,
769 * as a sort of pre-invocation linkage step.)
770 */
771 public void prepare() {
772 if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
773 compileToBytecode();
774 }
775 if (this.vmentry != null) {
776 // already prepared (e.g., a primitive DMH invoker form)
777 return;
778 }
779 MethodType mtype = methodType();
780 MethodTypeForm form = mtype.form();
781
782 MemberName entry = form.cachedInterpretEntry();
783 if (entry == null) {
784 assert (isValidSignature(basicTypeSignature()));
785 entry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
786 entry = form.setCachedInterpretEntry(entry);
787 }
788 this.vmentry = entry;
789 // TO DO: Maybe add invokeGeneric, invokeWithArguments
790 }
791
792 private static @Stable PerfCounter LF_FAILED;
793
794 private static PerfCounter failedCompilationCounter() {
795 if (LF_FAILED == null) {
796 LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
797 }
798 return LF_FAILED;
799 }
800
801 /** Generate optimizable bytecode for this form. */
802 void compileToBytecode() {
803 if (forceInterpretation()) {
804 return; // this should not be compiled
805 }
806 if (vmentry != null && isCompiled) {
807 return; // already compiled somehow
808 }
809
810 // Obtain the invoker MethodType outside of the following try block.
811 // This ensures that an IllegalArgumentException is directly thrown if the
812 // type would have 256 or more parameters
813 MethodType invokerType = methodType();
814 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
815 try {
816 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
817 if (TRACE_INTERPRETER)
818 traceInterpreter("compileToBytecode", this);
819 isCompiled = true;
820 } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
821 // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
822 invocationCounter = -1;
823 failedCompilationCounter().increment();
824 if (LOG_LF_COMPILATION_FAILURE) {
825 System.out.println("LambdaForm compilation failed: " + this);
826 bge.printStackTrace(System.out);
827 }
828 } catch (Error e) {
829 // Pass through any error
830 throw e;
831 } catch (Exception e) {
832 // Wrap any exception
833 throw newInternalError(this.toString(), e);
834 }
835 }
836
837 // The next few routines are called only from assert expressions
838 // They verify that the built-in invokers process the correct raw data types.
839 private static boolean argumentTypesMatch(String sig, Object[] av) {
840 int arity = signatureArity(sig);
841 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
842 assert(av[0] instanceof MethodHandle) : "av[0] not instance of MethodHandle: " + av[0];
843 MethodHandle mh = (MethodHandle) av[0];
844 MethodType mt = mh.type();
845 assert(mt.parameterCount() == arity-1);
846 for (int i = 0; i < av.length; i++) {
847 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
848 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
849 }
850 return true;
851 }
852 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
853 // The following line is needed because (...)void method handles can use non-void invokers
854 if (type == void.class) tc = V_TYPE; // can drop any kind of value
855 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
856 switch (tc) {
857 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
858 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
859 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
860 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
861 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
862 case V_TYPE: break; // allow anything here; will be dropped
863 default: assert(false);
864 }
865 return true;
866 }
867 private static boolean checkInt(Class<?> type, Object x) {
868 assert(x instanceof Integer);
869 if (type == int.class) return true;
870 Wrapper w = Wrapper.forBasicType(type);
871 assert(w.isSubwordOrInt());
872 Object x1 = Wrapper.INT.wrap(w.wrap(x));
873 return x.equals(x1);
874 }
875 private static boolean checkRef(Class<?> type, Object x) {
876 assert(!type.isPrimitive());
877 if (x == null) return true;
878 if (type.isInterface()) return true;
879 return type.isInstance(x);
880 }
881
882 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
883 private static final int COMPILE_THRESHOLD;
884 static {
885 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
886 }
887 private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
888
889 private boolean forceInterpretation() {
890 return invocationCounter == -1;
891 }
892
893 /** Interpretively invoke this form on the given arguments. */
894 @Hidden
895 @DontInline
896 Object interpretWithArguments(Object... argumentValues) throws Throwable {
897 if (TRACE_INTERPRETER)
898 return interpretWithArgumentsTracing(argumentValues);
899 checkInvocationCounter();
900 assert(arityCheck(argumentValues));
901 Object[] values = Arrays.copyOf(argumentValues, names.length);
902 for (int i = argumentValues.length; i < values.length; i++) {
903 values[i] = interpretName(names[i], values);
904 }
905 Object rv = (result < 0) ? null : values[result];
906 assert(resultCheck(argumentValues, rv));
907 return rv;
908 }
909
910 /** Evaluate a single Name within this form, applying its function to its arguments. */
911 @Hidden
912 @DontInline
913 Object interpretName(Name name, Object[] values) throws Throwable {
914 if (TRACE_INTERPRETER)
915 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
916 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
917 for (int i = 0; i < arguments.length; i++) {
918 Object a = arguments[i];
919 if (a instanceof Name n) {
920 int i2 = n.index();
921 assert(names[i2] == a);
922 a = values[i2];
923 arguments[i] = a;
924 }
925 }
926 return name.function.invokeWithArguments(arguments);
927 }
928
929 private void checkInvocationCounter() {
930 if (COMPILE_THRESHOLD != 0 &&
931 !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
932 invocationCounter++; // benign race
933 if (invocationCounter >= COMPILE_THRESHOLD) {
934 // Replace vmentry with a bytecode version of this LF.
935 compileToBytecode();
936 }
937 }
938 }
939 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
940 traceInterpreter("[ interpretWithArguments", this, argumentValues);
941 if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
942 int ctr = invocationCounter++; // benign race
943 traceInterpreter("| invocationCounter", ctr);
944 if (invocationCounter >= COMPILE_THRESHOLD) {
945 compileToBytecode();
946 }
947 }
948 Object rval;
949 try {
950 assert(arityCheck(argumentValues));
951 Object[] values = Arrays.copyOf(argumentValues, names.length);
952 for (int i = argumentValues.length; i < values.length; i++) {
953 values[i] = interpretName(names[i], values);
954 }
955 rval = (result < 0) ? null : values[result];
956 } catch (Throwable ex) {
957 traceInterpreter("] throw =>", ex);
958 throw ex;
959 }
960 traceInterpreter("] return =>", rval);
961 return rval;
962 }
963
964 static void traceInterpreter(String event, Object obj, Object... args) {
965 if (TRACE_INTERPRETER) {
966 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
967 }
968 }
969 static void traceInterpreter(String event, Object obj) {
970 traceInterpreter(event, obj, (Object[])null);
971 }
972 private boolean arityCheck(Object[] argumentValues) {
973 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
974 // also check that the leading (receiver) argument is somehow bound to this LF:
975 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
976 MethodHandle mh = (MethodHandle) argumentValues[0];
977 assert(mh.internalForm() == this);
978 // note: argument #0 could also be an interface wrapper, in the future
979 argumentTypesMatch(basicTypeSignature(), argumentValues);
980 return true;
981 }
982 private boolean resultCheck(Object[] argumentValues, Object result) {
983 MethodHandle mh = (MethodHandle) argumentValues[0];
984 MethodType mt = mh.type();
985 assert(valueMatches(returnType(), mt.returnType(), result));
986 return true;
987 }
988
989 public String toString() {
990 return debugString(-1);
991 }
992
993 String debugString(int indentLevel) {
994 String prefix = MethodHandle.debugPrefix(indentLevel);
995 String lambdaName = lambdaName();
996 StringBuilder buf = new StringBuilder(lambdaName);
997 buf.append("=Lambda(");
998 for (int i = 0; i < names.length; i++) {
999 if (i == arity) buf.append(")=>{");
1000 Name n = names[i];
1001 if (i >= arity) buf.append("\n ").append(prefix);
1002 buf.append(n.paramString());
1003 if (i < arity) {
1004 if (i+1 < arity) buf.append(",");
1005 continue;
1006 }
1007 buf.append("=").append(n.exprString());
1008 buf.append(";");
1009 }
1010 if (arity == names.length) buf.append(")=>{");
1011 buf.append(result < 0 ? "void" : names[result]).append("}");
1012 if (TRACE_INTERPRETER) {
1013 // Extra verbosity:
1014 buf.append(":").append(basicTypeSignature());
1015 buf.append("/").append(vmentry);
1016 }
1017 return buf.toString();
1018 }
1019
1020 @Override
1021 public boolean equals(Object obj) {
1022 return obj instanceof LambdaForm lf && equals(lf);
1023 }
1024 public boolean equals(LambdaForm that) {
1025 if (this.result != that.result) return false;
1026 return Arrays.equals(this.names, that.names);
1027 }
1028 public int hashCode() {
1029 return result + 31 * Arrays.hashCode(names);
1030 }
1031 LambdaFormEditor editor() {
1032 return LambdaFormEditor.lambdaFormEditor(this);
1033 }
1034
1035 boolean contains(Name name) {
1036 int pos = name.index();
1037 if (pos >= 0) {
1038 return pos < names.length && name.equals(names[pos]);
1039 }
1040 for (int i = arity; i < names.length; i++) {
1041 if (name.equals(names[i]))
1042 return true;
1043 }
1044 return false;
1045 }
1046
1047 static class NamedFunction {
1048 final MemberName member;
1049 private @Stable MethodHandle resolvedHandle;
1050 private @Stable MethodType type;
1051
1052 NamedFunction(MethodHandle resolvedHandle) {
1053 this(resolvedHandle.internalMemberName(), resolvedHandle);
1054 }
1055 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1056 this.member = member;
1057 this.resolvedHandle = resolvedHandle;
1058 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1059 //assert(!isInvokeBasic(member));
1060 }
1061 NamedFunction(MethodType basicInvokerType) {
1062 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1063 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1064 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1065 this.member = resolvedHandle.internalMemberName();
1066 } else {
1067 // necessary to pass BigArityTest
1068 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1069 }
1070 assert(isInvokeBasic(member));
1071 }
1072
1073 private static boolean isInvokeBasic(MemberName member) {
1074 return member != null &&
1075 member.getDeclaringClass() == MethodHandle.class &&
1076 "invokeBasic".equals(member.getName());
1077 }
1078
1079 // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1080 // Any LambdaForm containing such a member is not interpretable.
1081 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1082 // And even without the resolvedHandle, the name can still be compiled and optimized.
1083 NamedFunction(Method method) {
1084 this(new MemberName(method));
1085 }
1086 NamedFunction(MemberName member) {
1087 this(member, null);
1088 }
1089
1090 MethodHandle resolvedHandle() {
1091 if (resolvedHandle == null) resolve();
1092 return resolvedHandle;
1093 }
1094
1095 synchronized void resolve() {
1096 if (resolvedHandle == null) {
1097 resolvedHandle = DirectMethodHandle.make(member);
1098 }
1099 }
1100
1101 @Override
1102 public boolean equals(Object other) {
1103 if (this == other) return true;
1104 if (other == null) return false;
1105 return (other instanceof NamedFunction that)
1106 && this.member != null
1107 && this.member.equals(that.member);
1108 }
1109
1110 @Override
1111 public int hashCode() {
1112 if (member != null)
1113 return member.hashCode();
1114 return super.hashCode();
1115 }
1116
1117 static final MethodType INVOKER_METHOD_TYPE =
1118 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1119
1120 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1121 typeForm = typeForm.basicType().form(); // normalize to basic type
1122 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1123 if (mh != null) return mh;
1124 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1125 mh = DirectMethodHandle.make(invoker);
1126 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1127 if (mh2 != null) return mh2; // benign race
1128 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1129 throw newInternalError(mh.debugString());
1130 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1131 }
1132
1133 @Hidden
1134 Object invokeWithArguments(Object... arguments) throws Throwable {
1135 // If we have a cached invoker, call it right away.
1136 // NOTE: The invoker always returns a reference value.
1137 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1138 return invoker().invokeBasic(resolvedHandle(), arguments);
1139 }
1140
1141 @Hidden
1142 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1143 Object rval;
1144 try {
1145 traceInterpreter("[ call", this, arguments);
1146 // resolvedHandle might be uninitialized, ok for tracing
1147 if (resolvedHandle == null) {
1148 traceInterpreter("| resolve", this);
1149 resolvedHandle();
1150 }
1151 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1152 } catch (Throwable ex) {
1153 traceInterpreter("] throw =>", ex);
1154 throw ex;
1155 }
1156 traceInterpreter("] return =>", rval);
1157 return rval;
1158 }
1159
1160 private MethodHandle invoker() {
1161 return computeInvoker(methodType().form());
1162 }
1163
1164 MethodType methodType() {
1165 MethodType type = this.type;
1166 if (type == null) {
1167 this.type = type = calculateMethodType(member, resolvedHandle);
1168 }
1169 return type;
1170 }
1171
1172 private static MethodType calculateMethodType(MemberName member, MethodHandle resolvedHandle) {
1173 if (resolvedHandle != null) {
1174 return resolvedHandle.type();
1175 } else {
1176 // only for certain internal LFs during bootstrapping
1177 return member.getInvocationType();
1178 }
1179 }
1180
1181 MemberName member() {
1182 assert(assertMemberIsConsistent());
1183 return member;
1184 }
1185
1186 // Called only from assert.
1187 private boolean assertMemberIsConsistent() {
1188 if (resolvedHandle instanceof DirectMethodHandle) {
1189 MemberName m = resolvedHandle.internalMemberName();
1190 assert(m.equals(member));
1191 }
1192 return true;
1193 }
1194
1195 Class<?> memberDeclaringClassOrNull() {
1196 return (member == null) ? null : member.getDeclaringClass();
1197 }
1198
1199 BasicType returnType() {
1200 return basicType(methodType().returnType());
1201 }
1202
1203 BasicType parameterType(int n) {
1204 return basicType(methodType().parameterType(n));
1205 }
1206
1207 int arity() {
1208 return methodType().parameterCount();
1209 }
1210
1211 public String toString() {
1212 if (member == null) return String.valueOf(resolvedHandle);
1213 return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1214 }
1215
1216 public boolean isIdentity() {
1217 return this.equals(identity(returnType()));
1218 }
1219
1220 public MethodHandleImpl.Intrinsic intrinsicName() {
1221 return resolvedHandle != null
1222 ? resolvedHandle.intrinsicName()
1223 : MethodHandleImpl.Intrinsic.NONE;
1224 }
1225
1226 public Object intrinsicData() {
1227 return resolvedHandle != null
1228 ? resolvedHandle.intrinsicData()
1229 : null;
1230 }
1231 }
1232
1233 public static String basicTypeSignature(MethodType type) {
1234 int params = type.parameterCount();
1235 char[] sig = new char[params + 2];
1236 int sigp = 0;
1237 while (sigp < params) {
1238 sig[sigp] = basicTypeChar(type.parameterType(sigp++));
1239 }
1240 sig[sigp++] = '_';
1241 sig[sigp++] = basicTypeChar(type.returnType());
1242 assert(sigp == sig.length);
1243 return String.valueOf(sig);
1244 }
1245
1246 /** Hack to make signatures more readable when they show up in method names.
1247 * Signature should start with a sequence of uppercase ASCII letters.
1248 * Runs of three or more are replaced by a single letter plus a decimal repeat count.
1249 * A tail of anything other than uppercase ASCII is passed through unchanged.
1250 * @param signature sequence of uppercase ASCII letters with possible repetitions
1251 * @return same sequence, with repetitions counted by decimal numerals
1252 */
1253 public static String shortenSignature(String signature) {
1254 final int NO_CHAR = -1, MIN_RUN = 3;
1255 int c0, c1 = NO_CHAR, c1reps = 0;
1256 StringBuilder buf = null;
1257 int len = signature.length();
1258 if (len < MIN_RUN) return signature;
1259 for (int i = 0; i <= len; i++) {
1260 if (c1 != NO_CHAR && !('A' <= c1 && c1 <= 'Z')) {
1261 // wrong kind of char; bail out here
1262 if (buf != null) {
1263 buf.append(signature, i - c1reps, len);
1264 }
1265 break;
1266 }
1267 // shift in the next char:
1268 c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1269 if (c1 == c0) { ++c1reps; continue; }
1270 // shift in the next count:
1271 int c0reps = c1reps; c1reps = 1;
1272 // end of a character run
1273 if (c0reps < MIN_RUN) {
1274 if (buf != null) {
1275 while (--c0reps >= 0)
1276 buf.append((char)c0);
1277 }
1278 continue;
1279 }
1280 // found three or more in a row
1281 if (buf == null)
1282 buf = new StringBuilder().append(signature, 0, i - c0reps);
1283 buf.append((char)c0).append(c0reps);
1284 }
1285 return (buf == null) ? signature : buf.toString();
1286 }
1287
1288 static final class Name {
1289 final BasicType type;
1290 final short index;
1291 final NamedFunction function;
1292 final Object constraint; // additional type information, if not null
1293 @Stable final Object[] arguments;
1294
1295 private static final Object[] EMPTY_ARGS = new Object[0];
1296
1297 private Name(int index, BasicType type, NamedFunction function, Object[] arguments, Object constraint) {
1298 this.index = (short)index;
1299 this.type = type;
1300 this.function = function;
1301 this.arguments = arguments;
1302 this.constraint = constraint;
1303 assert(this.index == index && typesMatch(function, arguments));
1304 assert(constraint == null || isParam()); // only params have constraints
1305 assert(constraint == null || constraint instanceof ClassSpecializer.SpeciesData || constraint instanceof Class);
1306 }
1307
1308 Name(MethodHandle function, Object... arguments) {
1309 this(new NamedFunction(function), arguments);
1310 }
1311 Name(MethodType functionType, Object... arguments) {
1312 this(new NamedFunction(functionType), arguments);
1313 assert(arguments[0] instanceof Name name && name.type == L_TYPE);
1314 }
1315 Name(MemberName function, Object... arguments) {
1316 this(new NamedFunction(function), arguments);
1317 }
1318 Name(NamedFunction function) {
1319 this(-1, function.returnType(), function, EMPTY_ARGS, null);
1320 }
1321 Name(NamedFunction function, Object arg) {
1322 this(-1, function.returnType(), function, new Object[] { arg }, null);
1323 }
1324 Name(NamedFunction function, Object arg0, Object arg1) {
1325 this(-1, function.returnType(), function, new Object[] { arg0, arg1 }, null);
1326 }
1327 Name(NamedFunction function, Object... arguments) {
1328 this(-1, function.returnType(), function, Arrays.copyOf(arguments, arguments.length, Object[].class), null);
1329 }
1330 /** Create a raw parameter of the given type, with an expected index. */
1331 Name(int index, BasicType type) {
1332 this(index, type, null, null, null);
1333 }
1334 /** Create a raw parameter of the given type. */
1335 Name(BasicType type) { this(-1, type); }
1336
1337 BasicType type() { return type; }
1338 int index() { return index; }
1339
1340 char typeChar() {
1341 return type.btChar;
1342 }
1343
1344 Name withIndex(int i) {
1345 if (i == this.index) return this;
1346 return new Name(i, type, function, arguments, constraint);
1347 }
1348
1349 Name withConstraint(Object constraint) {
1350 if (constraint == this.constraint) return this;
1351 return new Name(index, type, function, arguments, constraint);
1352 }
1353
1354 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1355 if (oldName == newName) return this;
1356 @SuppressWarnings("LocalVariableHidesMemberVariable")
1357 Object[] arguments = this.arguments;
1358 if (arguments == null) return this;
1359 boolean replaced = false;
1360 for (int j = 0; j < arguments.length; j++) {
1361 if (arguments[j] == oldName) {
1362 if (!replaced) {
1363 replaced = true;
1364 arguments = arguments.clone();
1365 }
1366 arguments[j] = newName;
1367 }
1368 }
1369 if (!replaced) return this;
1370 return new Name(function, arguments);
1371 }
1372 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1373 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1374 */
1375 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1376 if (start >= end) return this;
1377 @SuppressWarnings("LocalVariableHidesMemberVariable")
1378 Object[] arguments = this.arguments;
1379 boolean replaced = false;
1380 eachArg:
1381 for (int j = 0; j < arguments.length; j++) {
1382 if (arguments[j] instanceof Name n) {
1383 int check = n.index;
1384 // harmless check to see if the thing is already in newNames:
1385 if (check >= 0 && check < newNames.length && n == newNames[check])
1386 continue eachArg;
1387 // n might not have the correct index: n != oldNames[n.index].
1388 for (int i = start; i < end; i++) {
1389 if (n == oldNames[i]) {
1390 if (n == newNames[i])
1391 continue eachArg;
1392 if (!replaced) {
1393 replaced = true;
1394 arguments = arguments.clone();
1395 }
1396 arguments[j] = newNames[i];
1397 continue eachArg;
1398 }
1399 }
1400 }
1401 }
1402 if (!replaced) return this;
1403 return new Name(function, arguments);
1404 }
1405 void internArguments() {
1406 @SuppressWarnings("LocalVariableHidesMemberVariable")
1407 Object[] arguments = this.arguments;
1408 for (int j = 0; j < arguments.length; j++) {
1409 if (arguments[j] instanceof Name n) {
1410 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1411 arguments[j] = internArgument(n);
1412 }
1413 }
1414 }
1415 boolean isParam() {
1416 return function == null;
1417 }
1418
1419 boolean refersTo(Class<?> declaringClass, String methodName) {
1420 return function != null &&
1421 function.member() != null && function.member().refersTo(declaringClass, methodName);
1422 }
1423
1424 /**
1425 * Check if MemberName is a call to MethodHandle.invokeBasic.
1426 */
1427 boolean isInvokeBasic() {
1428 if (function == null)
1429 return false;
1430 if (arguments.length < 1)
1431 return false; // must have MH argument
1432 MemberName member = function.member();
1433 return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1434 !member.isPublic() && !member.isStatic();
1435 }
1436
1437 /**
1438 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1439 */
1440 boolean isLinkerMethodInvoke() {
1441 if (function == null)
1442 return false;
1443 if (arguments.length < 1)
1444 return false; // must have MH argument
1445 MemberName member = function.member();
1446 return member != null &&
1447 member.getDeclaringClass() == MethodHandle.class &&
1448 !member.isPublic() && member.isStatic() &&
1449 member.getName().startsWith("linkTo");
1450 }
1451
1452 public String toString() {
1453 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1454 }
1455 public String debugString() {
1456 String s = paramString();
1457 return (function == null) ? s : s + "=" + exprString();
1458 }
1459 public String paramString() {
1460 String s = toString();
1461 Object c = constraint;
1462 if (c == null)
1463 return s;
1464 if (c instanceof Class<?> cl) c = cl.getSimpleName();
1465 return s + "/" + c;
1466 }
1467 public String exprString() {
1468 if (function == null) return toString();
1469 StringBuilder buf = new StringBuilder(function.toString());
1470 buf.append("(");
1471 String cma = "";
1472 for (Object a : arguments) {
1473 buf.append(cma); cma = ",";
1474 if (a instanceof Name || a instanceof Integer)
1475 buf.append(a);
1476 else
1477 buf.append("(").append(a).append(")");
1478 }
1479 buf.append(")");
1480 return buf.toString();
1481 }
1482
1483 private boolean typesMatch(NamedFunction function, Object ... arguments) {
1484 if (arguments == null) {
1485 assert(function == null);
1486 return true;
1487 }
1488 assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1489 for (int i = 0; i < arguments.length; i++) {
1490 assert (typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1491 }
1492 return true;
1493 }
1494
1495 private static boolean typesMatch(BasicType parameterType, Object object) {
1496 if (object instanceof Name name) {
1497 return name.type == parameterType;
1498 }
1499 switch (parameterType) {
1500 case I_TYPE: return object instanceof Integer;
1501 case J_TYPE: return object instanceof Long;
1502 case F_TYPE: return object instanceof Float;
1503 case D_TYPE: return object instanceof Double;
1504 }
1505 assert(parameterType == L_TYPE);
1506 return true;
1507 }
1508
1509 /** Return the index of the last occurrence of n in the argument array.
1510 * Return -1 if the name is not used.
1511 */
1512 int lastUseIndex(Name n) {
1513 Object[] arguments = this.arguments;
1514 if (arguments == null) return -1;
1515 for (int i = arguments.length; --i >= 0; ) {
1516 if (arguments[i] == n) return i;
1517 }
1518 return -1;
1519 }
1520
1521 public boolean equals(Name that) {
1522 if (this == that) return true;
1523 if (isParam())
1524 // each parameter is a unique atom
1525 return false; // this != that
1526 return
1527 //this.index == that.index &&
1528 this.type == that.type &&
1529 this.function.equals(that.function) &&
1530 Arrays.equals(this.arguments, that.arguments);
1531 }
1532 @Override
1533 public boolean equals(Object x) {
1534 return x instanceof Name n && equals(n);
1535 }
1536 @Override
1537 public int hashCode() {
1538 if (isParam())
1539 return index | (type.ordinal() << 8);
1540 return function.hashCode() ^ Arrays.hashCode(arguments);
1541 }
1542 }
1543
1544 /** Return the index of the last name which contains n as an argument.
1545 * Return -1 if the name is not used. Return names.length if it is the return value.
1546 */
1547 int lastUseIndex(Name n) {
1548 int ni = n.index, nmax = names.length;
1549 assert(names[ni] == n);
1550 if (result == ni) return nmax; // live all the way beyond the end
1551 for (int i = nmax; --i > ni; ) {
1552 if (names[i].lastUseIndex(n) >= 0)
1553 return i;
1554 }
1555 return -1;
1556 }
1557
1558 /** Return the number of times n is used as an argument or return value. */
1559 int useCount(Name n) {
1560 int count = (result == n.index) ? 1 : 0;
1561 int i = Math.max(n.index + 1, arity);
1562 Name[] names = this.names;
1563 while (i < names.length) {
1564 Object[] arguments = names[i++].arguments;
1565 if (arguments != null) {
1566 for (Object argument : arguments) {
1567 if (argument == n) {
1568 count++;
1569 }
1570 }
1571 }
1572 }
1573 return count;
1574 }
1575
1576 static Name argument(int which, BasicType type) {
1577 if (which >= INTERNED_ARGUMENT_LIMIT)
1578 return new Name(which, type);
1579 return INTERNED_ARGUMENTS[type.ordinal()][which];
1580 }
1581 static Name internArgument(Name n) {
1582 assert(n.isParam()) : "not param: " + n;
1583 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1584 if (n.constraint != null) return n;
1585 return argument(n.index, n.type);
1586 }
1587 static Name[] arguments(int extra, MethodType types) {
1588 int length = types.parameterCount();
1589 Name[] names = new Name[length + extra];
1590 for (int i = 0; i < length; i++)
1591 names[i] = argument(i, basicType(types.parameterType(i)));
1592 return names;
1593 }
1594
1595 static Name[] invokeArguments(int extra, MethodType types) {
1596 int length = types.parameterCount();
1597 Name[] names = new Name[length + extra + 1];
1598 names[0] = argument(0, L_TYPE);
1599 for (int i = 0; i < length; i++)
1600 names[i + 1] = argument(i + 1, basicType(types.parameterType(i)));
1601 return names;
1602 }
1603
1604 static final int INTERNED_ARGUMENT_LIMIT = 10;
1605 private static final Name[][] INTERNED_ARGUMENTS
1606 = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1607 static {
1608 for (BasicType type : BasicType.ARG_TYPES) {
1609 int ord = type.ordinal();
1610 for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1611 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1612 }
1613 }
1614 }
1615
1616 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1617
1618 static LambdaForm identityForm(BasicType type) {
1619 int ord = type.ordinal();
1620 LambdaForm form = LF_identity[ord];
1621 if (form != null) {
1622 return form;
1623 }
1624 createIdentityForm(type);
1625 return LF_identity[ord];
1626 }
1627
1628 static NamedFunction identity(BasicType type) {
1629 int ord = type.ordinal();
1630 NamedFunction function = NF_identity[ord];
1631 if (function != null) {
1632 return function;
1633 }
1634 createIdentityForm(type);
1635 return NF_identity[ord];
1636 }
1637
1638 static LambdaForm constantForm(BasicType type) {
1639 assert type != null && type != V_TYPE : type;
1640 var cached = LF_constant[type.ordinal()];
1641 if (cached != null)
1642 return cached;
1643 return createConstantForm(type);
1644 }
1645
1646 private static LambdaForm createConstantForm(BasicType type) {
1647 UNSAFE.ensureClassInitialized(BoundMethodHandle.class); // defend access to SimpleMethodHandle
1648 var species = SimpleMethodHandle.BMH_SPECIES.extendWith(type);
1649 var carrier = argument(0, L_TYPE).withConstraint(species); // BMH bound with data
1650 Name[] constNames = new Name[] { carrier, new Name(species.getterFunction(0), carrier) };
1651 return LF_constant[type.ordinal()] = create(1, constNames, Kind.CONSTANT);
1652 }
1653
1654 private static final @Stable LambdaForm[] LF_identity = new LambdaForm[TYPE_LIMIT];
1655 private static final @Stable NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1656 private static final @Stable LambdaForm[] LF_constant = new LambdaForm[ARG_TYPE_LIMIT]; // no void
1657
1658 private static final Object createIdentityFormLock = new Object();
1659 private static void createIdentityForm(BasicType type) {
1660 // Avoid racy initialization during bootstrap
1661 UNSAFE.ensureClassInitialized(BoundMethodHandle.class);
1662 synchronized (createIdentityFormLock) {
1663 final int ord = type.ordinal();
1664 LambdaForm idForm = LF_identity[ord];
1665 if (idForm != null) {
1666 return;
1667 }
1668 char btChar = type.basicTypeChar();
1669 boolean isVoid = (type == V_TYPE);
1670 Class<?> btClass = type.btClass;
1671 MethodType idType = (isVoid) ? MethodType.methodType(btClass) : MethodType.methodType(btClass, btClass);
1672
1673 // Look up symbolic names. It might not be necessary to have these,
1674 // but if we need to emit direct references to bytecodes, it helps.
1675 MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1676 try {
1677 idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, LM_TRUSTED, NoSuchMethodException.class);
1678 } catch (IllegalAccessException|NoSuchMethodException ex) {
1679 throw newInternalError(ex);
1680 }
1681
1682 NamedFunction idFun;
1683
1684 // Create the LFs and NamedFunctions. Precompiling LFs to byte code is needed to break circular
1685 // bootstrap dependency on this method in case we're interpreting LFs
1686 if (isVoid) {
1687 Name[] idNames = new Name[] { argument(0, L_TYPE) };
1688 idForm = LambdaForm.create(1, idNames, VOID_RESULT, Kind.IDENTITY);
1689 idForm.compileToBytecode();
1690 idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm));
1691 } else {
1692 Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1693 idForm = LambdaForm.create(2, idNames, 1, Kind.IDENTITY);
1694 idForm.compileToBytecode();
1695 idFun = new NamedFunction(idMem, MethodHandleImpl.makeIntrinsic(idMem.getInvocationType(), idForm,
1696 MethodHandleImpl.Intrinsic.IDENTITY));
1697 }
1698
1699 LF_identity[ord] = idForm;
1700 NF_identity[ord] = idFun;
1701
1702 assert(idFun.isIdentity());
1703 }
1704 }
1705
1706 // Avoid appealing to ValueConversions at bootstrap time:
1707 private static int identity_I(int x) { return x; }
1708 private static long identity_J(long x) { return x; }
1709 private static float identity_F(float x) { return x; }
1710 private static double identity_D(double x) { return x; }
1711 private static Object identity_L(Object x) { return x; }
1712 private static void identity_V() { return; }
1713 /**
1714 * Internal marker for byte-compiled LambdaForms.
1715 */
1716 /*non-public*/
1717 @Target(ElementType.METHOD)
1718 @Retention(RetentionPolicy.RUNTIME)
1719 @interface Compiled {
1720 }
1721
1722 private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1723 private static final HashMap<LambdaForm,String> DEBUG_NAMES;
1724 static {
1725 if (debugEnabled()) {
1726 DEBUG_NAME_COUNTERS = new HashMap<>();
1727 DEBUG_NAMES = new HashMap<>();
1728 } else {
1729 DEBUG_NAME_COUNTERS = null;
1730 DEBUG_NAMES = null;
1731 }
1732 }
1733
1734 static {
1735 // The Holder class will contain pre-generated forms resolved
1736 // using MemberName.getFactory(). However, that doesn't initialize the
1737 // class, which subtly breaks inlining etc. By forcing
1738 // initialization of the Holder class we avoid these issues.
1739 UNSAFE.ensureClassInitialized(Holder.class);
1740 }
1741
1742 /* Placeholder class for identity and constant forms generated ahead of time */
1743 final class Holder {}
1744
1745 // The following hack is necessary in order to suppress TRACE_INTERPRETER
1746 // during execution of the static initializes of this class.
1747 // Turning on TRACE_INTERPRETER too early will cause
1748 // stack overflows and other misbehavior during attempts to trace events
1749 // that occur during LambdaForm.<clinit>.
1750 // Therefore, do not move this line higher in this file, and do not remove.
1751 private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1752 }