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 // Start field forms
267 // IJFDL, instance/static differ in method type, can share form
268 // init form only applicable to static
269 FIELD_ACCESS("fieldAccess"),
270 FIELD_ACCESS_INIT("fieldAccessInit"),
271 VOLATILE_FIELD_ACCESS("volatileFieldAccess"),
272 VOLATILE_FIELD_ACCESS_INIT("volatileFieldAccessInit"),
273 // BCSZ need own forms to avoid clashing with basic type I, +-init/volatile
274 FIELD_ACCESS_B("fieldAccessB"),
275 FIELD_ACCESS_INIT_B("fieldAccessInitB"),
276 VOLATILE_FIELD_ACCESS_B("volatileFieldAccessB"),
277 VOLATILE_FIELD_ACCESS_INIT_B("volatileFieldAccessInitB"),
278 FIELD_ACCESS_C("fieldAccessC"),
279 FIELD_ACCESS_INIT_C("fieldAccessInitC"),
280 VOLATILE_FIELD_ACCESS_C("volatileFieldAccessC"),
281 VOLATILE_FIELD_ACCESS_INIT_C("volatileFieldAccessInitC"),
282 FIELD_ACCESS_S("fieldAccessS"),
283 FIELD_ACCESS_INIT_S("fieldAccessInitS"),
284 VOLATILE_FIELD_ACCESS_S("volatileFieldAccessS"),
285 VOLATILE_FIELD_ACCESS_INIT_S("volatileFieldAccessInitS"),
286 FIELD_ACCESS_Z("fieldAccessZ"),
287 FIELD_ACCESS_INIT_Z("fieldAccessInitZ"),
288 VOLATILE_FIELD_ACCESS_Z("volatileFieldAccessZ"),
289 VOLATILE_FIELD_ACCESS_INIT_Z("volatileFieldAccessInitZ"),
290 // cast, nr, flat need their own forms to avoid clashing with L
291 FIELD_ACCESS_CAST("fieldAccessCast"),
292 FIELD_ACCESS_INIT_CAST("fieldAccessInitCast"),
293 VOLATILE_FIELD_ACCESS_CAST("volatileFieldAccessCast"),
294 VOLATILE_FIELD_ACCESS_INIT_CAST("volatileFieldAccessInitCast"),
295 // null-check and put reference, +-cast, +-init/volatile
296 // non-cast forms serve bytecode emulation purpose, which always enforces null checks
297 PUT_NULL_RESTRICTED_REFERENCE("putNullRestrictedReference"),
298 PUT_NULL_RESTRICTED_REFERENCE_INIT("putNullRestrictedReferenceInit"),
299 VOLATILE_PUT_NULL_RESTRICTED_REFERENCE("volatilePutNullRestrictedReference"),
300 VOLATILE_PUT_NULL_RESTRICTED_REFERENCE_INIT("volatilePutNullRestrictedReferenceInit"),
301 PUT_NULL_RESTRICTED_REFERENCE_CAST("putNullRestrictedReferenceCast"),
302 PUT_NULL_RESTRICTED_REFERENCE_CAST_INIT("putNullRestrictedReferenceInitCast"),
303 VOLATILE_PUT_NULL_RESTRICTED_REFERENCE_CAST("volatilePutNullRestrictedReferenceCast"),
304 VOLATILE_PUT_NULL_RESTRICTED_REFERENCE_CAST_INIT("volatilePutNullRestrictedReferenceCastInit"),
305 // flat implies cast, +-init/volatile
306 FIELD_ACCESS_FLAT("fieldAccessFlat"),
307 FIELD_ACCESS_INIT_FLAT("fieldAccessInitFlat"),
308 VOLATILE_FIELD_ACCESS_FLAT("volatileFieldAccessFlat"),
309 VOLATILE_FIELD_ACCESS_INIT_FLAT("volatileFieldAccessInitFlat"),
310 // write guard NR flat, implies cast; +-volatile; no init forms - no flat in static fields yet
311 PUT_NULL_RESTRICTED_FLAT_VALUE("putNullRestrictedFlatValue"),
312 VOLATILE_PUT_NULL_RESTRICTED_FLAT_VALUE("volatilePutNullRestrictedFlatValue"),
313 // End fields
314 TRY_FINALLY("tryFinally"),
315 TABLE_SWITCH("tableSwitch"),
316 COLLECTOR("collector"),
317 LOOP("loop"),
318 GUARD("guard"),
319 GUARD_WITH_CATCH("guardWithCatch"),
320 VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
321 VARHANDLE_INVOKER("VH.invoker", "invoker"),
322 VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
323
324 final String defaultLambdaName;
325 final String methodName;
326
327 private Kind(String defaultLambdaName) {
328 this(defaultLambdaName, defaultLambdaName);
329 }
330
331 private Kind(String defaultLambdaName, String methodName) {
332 this.defaultLambdaName = defaultLambdaName;
333 this.methodName = methodName;
334 }
335 }
336
337 // private version that doesn't do checks or defensive copies
338 private LambdaForm(int arity, int result, boolean forceInline, MethodHandle customized, Name[] names, Kind kind) {
339 this.arity = arity;
340 this.result = result;
341 this.forceInline = forceInline;
342 this.customized = customized;
343 this.names = names;
344 this.kind = kind;
345 this.vmentry = null;
346 this.isCompiled = false;
347 }
348
349 // root factory pre/post processing and calls simple constructor
350 private static LambdaForm create(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
351 names = names.clone();
352 assert(namesOK(arity, names));
353 result = fixResult(result, names);
354
355 boolean canInterpret = normalizeNames(arity, names);
356 LambdaForm form = new LambdaForm(arity, result, forceInline, customized, names, kind);
357 assert(form.nameRefsAreLegal());
358 if (!canInterpret) {
359 form.compileToBytecode();
360 }
361 return form;
362 }
363
364 // derived factories with defaults
365 private static final int DEFAULT_RESULT = LAST_RESULT;
366 private static final boolean DEFAULT_FORCE_INLINE = true;
367 private static final MethodHandle DEFAULT_CUSTOMIZED = null;
368 private static final Kind DEFAULT_KIND = Kind.GENERIC;
369
370 static LambdaForm create(int arity, Name[] names, int result) {
371 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
372 }
373 static LambdaForm create(int arity, Name[] names, int result, Kind kind) {
374 return create(arity, names, result, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
375 }
376 static LambdaForm create(int arity, Name[] names) {
377 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, DEFAULT_KIND);
378 }
379 static LambdaForm create(int arity, Name[] names, Kind kind) {
380 return create(arity, names, DEFAULT_RESULT, DEFAULT_FORCE_INLINE, DEFAULT_CUSTOMIZED, kind);
381 }
382 static LambdaForm create(int arity, Name[] names, boolean forceInline, Kind kind) {
383 return create(arity, names, DEFAULT_RESULT, forceInline, DEFAULT_CUSTOMIZED, kind);
384 }
385
386 private static int fixResult(int result, Name[] names) {
387 if (result == LAST_RESULT)
388 result = names.length - 1; // might still be void
389 if (result >= 0 && names[result].type == V_TYPE)
390 result = VOID_RESULT;
391 return result;
392 }
393
394 static boolean debugNames() {
395 return DEBUG_NAME_COUNTERS != null;
396 }
397
398 static void associateWithDebugName(LambdaForm form, String name) {
399 assert (debugNames());
400 synchronized (DEBUG_NAMES) {
401 DEBUG_NAMES.put(form, name);
402 }
403 }
404
405 String lambdaName() {
406 if (DEBUG_NAMES != null) {
407 synchronized (DEBUG_NAMES) {
408 String name = DEBUG_NAMES.get(this);
409 if (name == null) {
410 name = generateDebugName();
411 }
412 return name;
413 }
414 }
415 return kind.defaultLambdaName;
416 }
417
418 private String generateDebugName() {
419 assert (debugNames());
420 String debugNameStem = kind.defaultLambdaName;
421 Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
422 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
423 StringBuilder buf = new StringBuilder(debugNameStem);
424 int leadingZero = buf.length();
425 buf.append((int) ctr);
426 for (int i = buf.length() - leadingZero; i < 3; i++) {
427 buf.insert(leadingZero, '0');
428 }
429 buf.append('_');
430 buf.append(basicTypeSignature());
431 String name = buf.toString();
432 associateWithDebugName(this, name);
433 return name;
434 }
435
436 private static boolean namesOK(int arity, Name[] names) {
437 for (int i = 0; i < names.length; i++) {
438 Name n = names[i];
439 assert(n != null) : "n is null";
440 if (i < arity)
441 assert( n.isParam()) : n + " is not param at " + i;
442 else
443 assert(!n.isParam()) : n + " is param at " + i;
444 }
445 return true;
446 }
447
448 /** Customize LambdaForm for a particular MethodHandle */
449 LambdaForm customize(MethodHandle mh) {
450 if (customized == mh) {
451 return this;
452 }
453 LambdaForm customForm = LambdaForm.create(arity, names, result, forceInline, mh, kind);
454 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
455 // If shared LambdaForm has been compiled, compile customized version as well.
456 customForm.compileToBytecode();
457 }
458 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
459 return customForm;
460 }
461
462 /** Get uncustomized flavor of the LambdaForm */
463 LambdaForm uncustomize() {
464 if (customized == null) {
465 return this;
466 }
467 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
468 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
469 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
470 // If customized LambdaForm has been compiled, compile uncustomized version as well.
471 uncustomizedForm.compileToBytecode();
472 }
473 return uncustomizedForm;
474 }
475
476 /** Renumber and/or replace params so that they are interned and canonically numbered.
477 * @return true if we can interpret
478 */
479 private static boolean normalizeNames(int arity, Name[] names) {
480 Name[] oldNames = names.clone();
481 int maxOutArity = 0;
482 for (int i = 0; i < names.length; i++) {
483 Name n = names[i];
484 names[i] = n.withIndex(i);
485 if (n.arguments != null && maxOutArity < n.arguments.length)
486 maxOutArity = n.arguments.length;
487 }
488 if (oldNames != null) {
489 for (int i = Math.max(1, arity); i < names.length; i++) {
490 Name fixed = names[i].replaceNames(oldNames, names, 0, i);
491 names[i] = fixed.withIndex(i);
492 }
493 }
494 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
495 boolean needIntern = false;
496 for (int i = 0; i < maxInterned; i++) {
497 Name n = names[i], n2 = internArgument(n);
498 if (n != n2) {
499 names[i] = n2;
500 needIntern = true;
501 }
502 }
503 if (needIntern) {
504 for (int i = arity; i < names.length; i++) {
505 names[i].internArguments();
506 }
507 }
508
509 // return true if we can interpret
510 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
511 // Cannot use LF interpreter on very high arity expressions.
512 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
513 return false;
514 }
515 return true;
516 }
517
518 /**
519 * Check that all embedded Name references are localizable to this lambda,
520 * and are properly ordered after their corresponding definitions.
521 * <p>
522 * Note that a Name can be local to multiple lambdas, as long as
523 * it possesses the same index in each use site.
524 * This allows Name references to be freely reused to construct
525 * fresh lambdas, without confusion.
526 */
527 boolean nameRefsAreLegal() {
528 assert(arity >= 0 && arity <= names.length);
529 assert(result >= -1 && result < names.length);
530 // Do all names possess an index consistent with their local definition order?
531 for (int i = 0; i < arity; i++) {
532 Name n = names[i];
533 assert(n.index() == i) : Arrays.asList(n.index(), i);
534 assert(n.isParam());
535 }
536 // Also, do all local name references
537 for (int i = arity; i < names.length; i++) {
538 Name n = names[i];
539 assert(n.index() == i);
540 for (Object arg : n.arguments) {
541 if (arg instanceof Name n2) {
542 int i2 = n2.index;
543 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
544 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
545 assert(i2 < i); // ref must come after def!
546 }
547 }
548 }
549 return true;
550 }
551
552 // /** Invoke this form on the given arguments. */
553 // final Object invoke(Object... args) throws Throwable {
554 // // NYI: fit this into the fast path?
555 // return interpretWithArguments(args);
556 // }
557
558 /** Report the return type. */
559 BasicType returnType() {
560 if (result < 0) return V_TYPE;
561 Name n = names[result];
562 return n.type;
563 }
564
565 /** Report the N-th argument type. */
566 BasicType parameterType(int n) {
567 return parameter(n).type;
568 }
569
570 /** Report the N-th argument name. */
571 Name parameter(int n) {
572 Name param = names[n];
573 assert(n < arity && param.isParam());
574 return param;
575 }
576
577 /** Report the N-th argument type constraint. */
578 Object parameterConstraint(int n) {
579 return parameter(n).constraint;
580 }
581
582 /** Report the arity. */
583 int arity() {
584 return arity;
585 }
586
587 /** Report the number of expressions (non-parameter names). */
588 int expressionCount() {
589 return names.length - arity;
590 }
591
592 /** Return the method type corresponding to my basic type signature. */
593 MethodType methodType() {
594 Class<?>[] ptypes = new Class<?>[arity];
595 for (int i = 0; i < arity; ++i) {
596 ptypes[i] = parameterType(i).btClass;
597 }
598 return MethodType.methodType(returnType().btClass, ptypes, true);
599 }
600
601 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
602 final String basicTypeSignature() {
603 StringBuilder buf = new StringBuilder(arity() + 3);
604 for (int i = 0, a = arity(); i < a; i++)
605 buf.append(parameterType(i).basicTypeChar());
606 return buf.append('_').append(returnType().basicTypeChar()).toString();
607 }
608 static int signatureArity(String sig) {
609 assert(isValidSignature(sig));
610 return sig.indexOf('_');
611 }
612 static boolean isValidSignature(String sig) {
613 int arity = sig.indexOf('_');
614 if (arity < 0) return false; // must be of the form *_*
615 int siglen = sig.length();
616 if (siglen != arity + 2) return false; // *_X
617 for (int i = 0; i < siglen; i++) {
618 if (i == arity) continue; // skip '_'
619 char c = sig.charAt(i);
620 if (c == 'V')
621 return (i == siglen - 1 && arity == siglen - 2);
622 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
623 }
624 return true; // [LIJFD]*_[LIJFDV]
625 }
626
627 /**
628 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
629 */
630 boolean isSelectAlternative(int pos) {
631 // selectAlternative idiom:
632 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
633 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
634 if (pos+1 >= names.length) return false;
635 Name name0 = names[pos];
636 Name name1 = names[pos+1];
637 return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
638 name1.isInvokeBasic() &&
639 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
640 lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
641 }
642
643 private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
644 if (pos+2 >= names.length) return false;
645 Name name0 = names[pos];
646 Name name1 = names[pos+1];
647 Name name2 = names[pos+2];
648 return name1.refersTo(MethodHandleImpl.class, idiomName) &&
649 name0.isInvokeBasic() &&
650 name2.isInvokeBasic() &&
651 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
652 lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
653 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
654 lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
655 }
656
657 /**
658 * Check if i-th name is a start of GuardWithCatch idiom.
659 */
660 boolean isGuardWithCatch(int pos) {
661 // GuardWithCatch idiom:
662 // t_{n}:L=MethodHandle.invokeBasic(...)
663 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
664 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
665 return isMatchingIdiom(pos, "guardWithCatch", 3);
666 }
667
668 /**
669 * Check if i-th name is a start of the tryFinally idiom.
670 */
671 boolean isTryFinally(int pos) {
672 // tryFinally idiom:
673 // t_{n}:L=MethodHandle.invokeBasic(...)
674 // t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
675 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
676 return isMatchingIdiom(pos, "tryFinally", 2);
677 }
678
679 /**
680 * Check if i-th name is a start of the tableSwitch idiom.
681 */
682 boolean isTableSwitch(int pos) {
683 // tableSwitch idiom:
684 // t_{n}:L=MethodHandle.invokeBasic(...) // args
685 // t_{n+1}:L=MethodHandleImpl.tableSwitch(*, *, *, t_{n})
686 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
687 if (pos + 2 >= names.length) return false;
688
689 final int POS_COLLECT_ARGS = pos;
690 final int POS_TABLE_SWITCH = pos + 1;
691 final int POS_UNBOX_RESULT = pos + 2;
692
693 Name collectArgs = names[POS_COLLECT_ARGS];
694 Name tableSwitch = names[POS_TABLE_SWITCH];
695 Name unboxResult = names[POS_UNBOX_RESULT];
696 return tableSwitch.refersTo(MethodHandleImpl.class, "tableSwitch") &&
697 collectArgs.isInvokeBasic() &&
698 unboxResult.isInvokeBasic() &&
699 tableSwitch.lastUseIndex(collectArgs) == 3 && // t_{n+1}:L=MethodHandleImpl.<invoker>(*, *, *, t_{n});
700 lastUseIndex(collectArgs) == POS_TABLE_SWITCH && // t_{n} is local: used only in t_{n+1}
701 unboxResult.lastUseIndex(tableSwitch) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
702 lastUseIndex(tableSwitch) == POS_UNBOX_RESULT; // t_{n+1} is local: used only in t_{n+2}
703 }
704
705 /**
706 * Check if i-th name is a start of the loop idiom.
707 */
708 boolean isLoop(int pos) {
709 // loop idiom:
710 // t_{n}:L=MethodHandle.invokeBasic(...)
711 // t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
712 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
713 return isMatchingIdiom(pos, "loop", 2);
714 }
715
716 /*
717 * Code generation issues:
718 *
719 * Compiled LFs should be reusable in general.
720 * The biggest issue is how to decide when to pull a name into
721 * the bytecode, versus loading a reified form from the MH data.
722 *
723 * For example, an asType wrapper may require execution of a cast
724 * after a call to a MH. The target type of the cast can be placed
725 * as a constant in the LF itself. This will force the cast type
726 * to be compiled into the bytecodes and native code for the MH.
727 * Or, the target type of the cast can be erased in the LF, and
728 * loaded from the MH data. (Later on, if the MH as a whole is
729 * inlined, the data will flow into the inlined instance of the LF,
730 * as a constant, and the end result will be an optimal cast.)
731 *
732 * This erasure of cast types can be done with any use of
733 * reference types. It can also be done with whole method
734 * handles. Erasing a method handle might leave behind
735 * LF code that executes correctly for any MH of a given
736 * type, and load the required MH from the enclosing MH's data.
737 * Or, the erasure might even erase the expected MT.
738 *
739 * Also, for direct MHs, the MemberName of the target
740 * could be erased, and loaded from the containing direct MH.
741 * As a simple case, a LF for all int-valued non-static
742 * field getters would perform a cast on its input argument
743 * (to non-constant base type derived from the MemberName)
744 * and load an integer value from the input object
745 * (at a non-constant offset also derived from the MemberName).
746 * Such MN-erased LFs would be inlinable back to optimized
747 * code, whenever a constant enclosing DMH is available
748 * to supply a constant MN from its data.
749 *
750 * The main problem here is to keep LFs reasonably generic,
751 * while ensuring that hot spots will inline good instances.
752 * "Reasonably generic" means that we don't end up with
753 * repeated versions of bytecode or machine code that do
754 * not differ in their optimized form. Repeated versions
755 * of machine would have the undesirable overheads of
756 * (a) redundant compilation work and (b) extra I$ pressure.
757 * To control repeated versions, we need to be ready to
758 * erase details from LFs and move them into MH data,
759 * whenever those details are not relevant to significant
760 * optimization. "Significant" means optimization of
761 * code that is actually hot.
762 *
763 * Achieving this may require dynamic splitting of MHs, by replacing
764 * a generic LF with a more specialized one, on the same MH,
765 * if (a) the MH is frequently executed and (b) the MH cannot
766 * be inlined into a containing caller, such as an invokedynamic.
767 *
768 * Compiled LFs that are no longer used should be GC-able.
769 * If they contain non-BCP references, they should be properly
770 * interlinked with the class loader(s) that their embedded types
771 * depend on. This probably means that reusable compiled LFs
772 * will be tabulated (indexed) on relevant class loaders,
773 * or else that the tables that cache them will have weak links.
774 */
775
776 /**
777 * Make this LF directly executable, as part of a MethodHandle.
778 * Invariant: Every MH which is invoked must prepare its LF
779 * before invocation.
780 * (In principle, the JVM could do this very lazily,
781 * as a sort of pre-invocation linkage step.)
782 */
783 public void prepare() {
784 if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
785 compileToBytecode();
786 }
787 if (this.vmentry != null) {
788 // already prepared (e.g., a primitive DMH invoker form)
789 return;
790 }
791 MethodType mtype = methodType();
792 MethodTypeForm form = mtype.form();
793
794 MemberName entry = form.cachedInterpretEntry();
795 if (entry == null) {
796 assert (isValidSignature(basicTypeSignature()));
797 entry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
798 entry = form.setCachedInterpretEntry(entry);
799 }
800 this.vmentry = entry;
801 // TO DO: Maybe add invokeGeneric, invokeWithArguments
802 }
803
804 private static @Stable PerfCounter LF_FAILED;
805
806 private static PerfCounter failedCompilationCounter() {
807 if (LF_FAILED == null) {
808 LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
809 }
810 return LF_FAILED;
811 }
812
813 /** Generate optimizable bytecode for this form. */
814 void compileToBytecode() {
815 if (forceInterpretation()) {
816 return; // this should not be compiled
817 }
818 if (vmentry != null && isCompiled) {
819 return; // already compiled somehow
820 }
821
822 // Obtain the invoker MethodType outside of the following try block.
823 // This ensures that an IllegalArgumentException is directly thrown if the
824 // type would have 256 or more parameters
825 MethodType invokerType = methodType();
826 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
827 try {
828 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
829 if (TRACE_INTERPRETER)
830 traceInterpreter("compileToBytecode", this);
831 isCompiled = true;
832 } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
833 // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
834 invocationCounter = -1;
835 failedCompilationCounter().increment();
836 if (LOG_LF_COMPILATION_FAILURE) {
837 System.out.println("LambdaForm compilation failed: " + this);
838 bge.printStackTrace(System.out);
839 }
840 } catch (Error e) {
841 // Pass through any error
842 throw e;
843 } catch (Exception e) {
844 // Wrap any exception
845 throw newInternalError(this.toString(), e);
846 }
847 }
848
849 // The next few routines are called only from assert expressions
850 // They verify that the built-in invokers process the correct raw data types.
851 private static boolean argumentTypesMatch(String sig, Object[] av) {
852 int arity = signatureArity(sig);
853 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
854 assert(av[0] instanceof MethodHandle) : "av[0] not instance of MethodHandle: " + av[0];
855 MethodHandle mh = (MethodHandle) av[0];
856 MethodType mt = mh.type();
857 assert(mt.parameterCount() == arity-1);
858 for (int i = 0; i < av.length; i++) {
859 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
860 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
861 }
862 return true;
863 }
864 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
865 // The following line is needed because (...)void method handles can use non-void invokers
866 if (type == void.class) tc = V_TYPE; // can drop any kind of value
867 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
868 switch (tc) {
869 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
870 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
871 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
872 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
873 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
874 case V_TYPE: break; // allow anything here; will be dropped
875 default: assert(false);
876 }
877 return true;
878 }
879 private static boolean checkInt(Class<?> type, Object x) {
880 assert(x instanceof Integer);
881 if (type == int.class) return true;
882 Wrapper w = Wrapper.forBasicType(type);
883 assert(w.isSubwordOrInt());
884 Object x1 = Wrapper.INT.wrap(w.wrap(x));
885 return x.equals(x1);
886 }
887 private static boolean checkRef(Class<?> type, Object x) {
888 assert(!type.isPrimitive());
889 if (x == null) return true;
890 if (type.isInterface()) return true;
891 return type.isInstance(x);
892 }
893
894 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
895 private static final int COMPILE_THRESHOLD;
896 static {
897 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
898 }
899 private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
900
901 private boolean forceInterpretation() {
902 return invocationCounter == -1;
903 }
904
905 /** Interpretively invoke this form on the given arguments. */
906 @Hidden
907 @DontInline
908 Object interpretWithArguments(Object... argumentValues) throws Throwable {
909 if (TRACE_INTERPRETER)
910 return interpretWithArgumentsTracing(argumentValues);
911 checkInvocationCounter();
912 assert(arityCheck(argumentValues));
913 Object[] values = Arrays.copyOf(argumentValues, names.length);
914 for (int i = argumentValues.length; i < values.length; i++) {
915 values[i] = interpretName(names[i], values);
916 }
917 Object rv = (result < 0) ? null : values[result];
918 assert(resultCheck(argumentValues, rv));
919 return rv;
920 }
921
922 /** Evaluate a single Name within this form, applying its function to its arguments. */
923 @Hidden
924 @DontInline
925 Object interpretName(Name name, Object[] values) throws Throwable {
926 if (TRACE_INTERPRETER)
927 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
928 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
929 for (int i = 0; i < arguments.length; i++) {
930 Object a = arguments[i];
931 if (a instanceof Name n) {
932 int i2 = n.index();
933 assert(names[i2] == a);
934 a = values[i2];
935 arguments[i] = a;
936 }
937 }
938 return name.function.invokeWithArguments(arguments);
939 }
940
941 private void checkInvocationCounter() {
942 if (COMPILE_THRESHOLD != 0 &&
943 !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
944 invocationCounter++; // benign race
945 if (invocationCounter >= COMPILE_THRESHOLD) {
946 // Replace vmentry with a bytecode version of this LF.
947 compileToBytecode();
948 }
949 }
950 }
951 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
952 traceInterpreter("[ interpretWithArguments", this, argumentValues);
953 if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
954 int ctr = invocationCounter++; // benign race
955 traceInterpreter("| invocationCounter", ctr);
956 if (invocationCounter >= COMPILE_THRESHOLD) {
957 compileToBytecode();
958 }
959 }
960 Object rval;
961 try {
962 assert(arityCheck(argumentValues));
963 Object[] values = Arrays.copyOf(argumentValues, names.length);
964 for (int i = argumentValues.length; i < values.length; i++) {
965 values[i] = interpretName(names[i], values);
966 }
967 rval = (result < 0) ? null : values[result];
968 } catch (Throwable ex) {
969 traceInterpreter("] throw =>", ex);
970 throw ex;
971 }
972 traceInterpreter("] return =>", rval);
973 return rval;
974 }
975
976 static void traceInterpreter(String event, Object obj, Object... args) {
977 if (TRACE_INTERPRETER) {
978 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
979 }
980 }
981 static void traceInterpreter(String event, Object obj) {
982 traceInterpreter(event, obj, (Object[])null);
983 }
984 private boolean arityCheck(Object[] argumentValues) {
985 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
986 // also check that the leading (receiver) argument is somehow bound to this LF:
987 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
988 MethodHandle mh = (MethodHandle) argumentValues[0];
989 assert(mh.internalForm() == this);
990 // note: argument #0 could also be an interface wrapper, in the future
991 argumentTypesMatch(basicTypeSignature(), argumentValues);
992 return true;
993 }
994 private boolean resultCheck(Object[] argumentValues, Object result) {
995 MethodHandle mh = (MethodHandle) argumentValues[0];
996 MethodType mt = mh.type();
997 assert(valueMatches(returnType(), mt.returnType(), result));
998 return true;
999 }
1000
1001 public String toString() {
1002 return debugString(-1);
1003 }
1004
1005 String debugString(int indentLevel) {
1006 String prefix = MethodHandle.debugPrefix(indentLevel);
1007 String lambdaName = lambdaName();
1008 StringBuilder buf = new StringBuilder(lambdaName);
1009 buf.append("=Lambda(");
1010 for (int i = 0; i < names.length; i++) {
1011 if (i == arity) buf.append(")=>{");
1012 Name n = names[i];
1013 if (i >= arity) buf.append("\n ").append(prefix);
1014 buf.append(n.paramString());
1015 if (i < arity) {
1016 if (i+1 < arity) buf.append(",");
1017 continue;
1018 }
1019 buf.append("=").append(n.exprString());
1020 buf.append(";");
1021 }
1022 if (arity == names.length) buf.append(")=>{");
1023 buf.append(result < 0 ? "void" : names[result]).append("}");
1024 if (TRACE_INTERPRETER) {
1025 // Extra verbosity:
1026 buf.append(":").append(basicTypeSignature());
1027 buf.append("/").append(vmentry);
1028 }
1029 return buf.toString();
1030 }
1031
1032 @Override
1033 public boolean equals(Object obj) {
1034 return obj instanceof LambdaForm lf && equals(lf);
1035 }
1036 public boolean equals(LambdaForm that) {
1037 if (this.result != that.result) return false;
1038 return Arrays.equals(this.names, that.names);
1039 }
1040 public int hashCode() {
1041 return result + 31 * Arrays.hashCode(names);
1042 }
1043 LambdaFormEditor editor() {
1044 return LambdaFormEditor.lambdaFormEditor(this);
1045 }
1046
1047 boolean contains(Name name) {
1048 int pos = name.index();
1049 if (pos >= 0) {
1050 return pos < names.length && name.equals(names[pos]);
1051 }
1052 for (int i = arity; i < names.length; i++) {
1053 if (name.equals(names[i]))
1054 return true;
1055 }
1056 return false;
1057 }
1058
1059 static class NamedFunction {
1060 final MemberName member;
1061 private @Stable MethodHandle resolvedHandle;
1062 private @Stable MethodType type;
1063
1064 NamedFunction(MethodHandle resolvedHandle) {
1065 this(resolvedHandle.internalMemberName(), resolvedHandle);
1066 }
1067 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1068 this.member = member;
1069 this.resolvedHandle = resolvedHandle;
1070 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1071 //assert(!isInvokeBasic(member));
1072 }
1073 NamedFunction(MethodType basicInvokerType) {
1074 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1075 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1076 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1077 this.member = resolvedHandle.internalMemberName();
1078 } else {
1079 // necessary to pass BigArityTest
1080 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1081 }
1082 assert(isInvokeBasic(member));
1083 }
1084
1085 private static boolean isInvokeBasic(MemberName member) {
1086 return member != null &&
1087 member.getDeclaringClass() == MethodHandle.class &&
1088 "invokeBasic".equals(member.getName());
1089 }
1090
1091 // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1092 // Any LambdaForm containing such a member is not interpretable.
1093 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1094 // And even without the resolvedHandle, the name can still be compiled and optimized.
1095 NamedFunction(Method method) {
1096 this(new MemberName(method));
1097 }
1098 NamedFunction(MemberName member) {
1099 this(member, null);
1100 }
1101
1102 MethodHandle resolvedHandle() {
1103 if (resolvedHandle == null) resolve();
1104 return resolvedHandle;
1105 }
1106
1107 synchronized void resolve() {
1108 if (resolvedHandle == null) {
1109 resolvedHandle = DirectMethodHandle.make(member);
1110 }
1111 }
1112
1113 @Override
1114 public boolean equals(Object other) {
1115 if (this == other) return true;
1116 if (other == null) return false;
1117 return (other instanceof NamedFunction that)
1118 && this.member != null
1119 && this.member.equals(that.member);
1120 }
1121
1122 @Override
1123 public int hashCode() {
1124 if (member != null)
1125 return member.hashCode();
1126 return super.hashCode();
1127 }
1128
1129 static final MethodType INVOKER_METHOD_TYPE =
1130 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1131
1132 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1133 typeForm = typeForm.basicType().form(); // normalize to basic type
1134 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1135 if (mh != null) return mh;
1136 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1137 mh = DirectMethodHandle.make(invoker);
1138 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1139 if (mh2 != null) return mh2; // benign race
1140 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1141 throw newInternalError(mh.debugString());
1142 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1143 }
1144
1145 @Hidden
1146 Object invokeWithArguments(Object... arguments) throws Throwable {
1147 // If we have a cached invoker, call it right away.
1148 // NOTE: The invoker always returns a reference value.
1149 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1150 return invoker().invokeBasic(resolvedHandle(), arguments);
1151 }
1152
1153 @Hidden
1154 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1155 Object rval;
1156 try {
1157 traceInterpreter("[ call", this, arguments);
1158 // resolvedHandle might be uninitialized, ok for tracing
1159 if (resolvedHandle == null) {
1160 traceInterpreter("| resolve", this);
1161 resolvedHandle();
1162 }
1163 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1164 } catch (Throwable ex) {
1165 traceInterpreter("] throw =>", ex);
1166 throw ex;
1167 }
1168 traceInterpreter("] return =>", rval);
1169 return rval;
1170 }
1171
1172 private MethodHandle invoker() {
1173 return computeInvoker(methodType().form());
1174 }
1175
1176 MethodType methodType() {
1177 MethodType type = this.type;
1178 if (type == null) {
1179 this.type = type = calculateMethodType(member, resolvedHandle);
1180 }
1181 return type;
1182 }
1183
1184 private static MethodType calculateMethodType(MemberName member, MethodHandle resolvedHandle) {
1185 if (resolvedHandle != null) {
1186 return resolvedHandle.type();
1187 } else {
1188 // only for certain internal LFs during bootstrapping
1189 return member.getInvocationType();
1190 }
1191 }
1192
1193 MemberName member() {
1194 assert(assertMemberIsConsistent());
1195 return member;
1196 }
1197
1198 // Called only from assert.
1199 private boolean assertMemberIsConsistent() {
1200 if (resolvedHandle instanceof DirectMethodHandle) {
1201 MemberName m = resolvedHandle.internalMemberName();
1202 assert(m.equals(member));
1203 }
1204 return true;
1205 }
1206
1207 Class<?> memberDeclaringClassOrNull() {
1208 return (member == null) ? null : member.getDeclaringClass();
1209 }
1210
1211 BasicType returnType() {
1212 return basicType(methodType().returnType());
1213 }
1214
1215 BasicType parameterType(int n) {
1216 return basicType(methodType().parameterType(n));
1217 }
1218
1219 int arity() {
1220 return methodType().parameterCount();
1221 }
1222
1223 public String toString() {
1224 if (member == null) return String.valueOf(resolvedHandle);
1225 return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1226 }
1227
1228 public boolean isIdentity() {
1229 return this.equals(identity(returnType()));
1230 }
1231
1232 public MethodHandleImpl.Intrinsic intrinsicName() {
1233 return resolvedHandle != null
1234 ? resolvedHandle.intrinsicName()
1235 : MethodHandleImpl.Intrinsic.NONE;
1236 }
1237
1238 public Object intrinsicData() {
1239 return resolvedHandle != null
1240 ? resolvedHandle.intrinsicData()
1241 : null;
1242 }
1243 }
1244
1245 public static String basicTypeSignature(MethodType type) {
1246 int params = type.parameterCount();
1247 char[] sig = new char[params + 2];
1248 int sigp = 0;
1249 while (sigp < params) {
1250 sig[sigp] = basicTypeChar(type.parameterType(sigp++));
1251 }
1252 sig[sigp++] = '_';
1253 sig[sigp++] = basicTypeChar(type.returnType());
1254 assert(sigp == sig.length);
1255 return String.valueOf(sig);
1256 }
1257
1258 /** Hack to make signatures more readable when they show up in method names.
1259 * Signature should start with a sequence of uppercase ASCII letters.
1260 * Runs of three or more are replaced by a single letter plus a decimal repeat count.
1261 * A tail of anything other than uppercase ASCII is passed through unchanged.
1262 * @param signature sequence of uppercase ASCII letters with possible repetitions
1263 * @return same sequence, with repetitions counted by decimal numerals
1264 */
1265 public static String shortenSignature(String signature) {
1266 final int NO_CHAR = -1, MIN_RUN = 3;
1267 int c0, c1 = NO_CHAR, c1reps = 0;
1268 StringBuilder buf = null;
1269 int len = signature.length();
1270 if (len < MIN_RUN) return signature;
1271 for (int i = 0; i <= len; i++) {
1272 if (c1 != NO_CHAR && !('A' <= c1 && c1 <= 'Z')) {
1273 // wrong kind of char; bail out here
1274 if (buf != null) {
1275 buf.append(signature, i - c1reps, len);
1276 }
1277 break;
1278 }
1279 // shift in the next char:
1280 c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1281 if (c1 == c0) { ++c1reps; continue; }
1282 // shift in the next count:
1283 int c0reps = c1reps; c1reps = 1;
1284 // end of a character run
1285 if (c0reps < MIN_RUN) {
1286 if (buf != null) {
1287 while (--c0reps >= 0)
1288 buf.append((char)c0);
1289 }
1290 continue;
1291 }
1292 // found three or more in a row
1293 if (buf == null)
1294 buf = new StringBuilder().append(signature, 0, i - c0reps);
1295 buf.append((char)c0).append(c0reps);
1296 }
1297 return (buf == null) ? signature : buf.toString();
1298 }
1299
1300 static final class Name {
1301 final BasicType type;
1302 final short index;
1303 final NamedFunction function;
1304 final Object constraint; // additional type information, if not null
1305 @Stable final Object[] arguments;
1306
1307 private static final Object[] EMPTY_ARGS = new Object[0];
1308
1309 private Name(int index, BasicType type, NamedFunction function, Object[] arguments, Object constraint) {
1310 this.index = (short)index;
1311 this.type = type;
1312 this.function = function;
1313 this.arguments = arguments;
1314 this.constraint = constraint;
1315 assert(this.index == index && typesMatch(function, arguments));
1316 assert(constraint == null || isParam()); // only params have constraints
1317 assert(constraint == null || constraint instanceof ClassSpecializer.SpeciesData || constraint instanceof Class);
1318 }
1319
1320 Name(MethodHandle function, Object... arguments) {
1321 this(new NamedFunction(function), arguments);
1322 }
1323 Name(MethodType functionType, Object... arguments) {
1324 this(new NamedFunction(functionType), arguments);
1325 assert(arguments[0] instanceof Name name && name.type == L_TYPE);
1326 }
1327 Name(MemberName function, Object... arguments) {
1328 this(new NamedFunction(function), arguments);
1329 }
1330 Name(NamedFunction function) {
1331 this(-1, function.returnType(), function, EMPTY_ARGS, null);
1332 }
1333 Name(NamedFunction function, Object arg) {
1334 this(-1, function.returnType(), function, new Object[] { arg }, null);
1335 }
1336 Name(NamedFunction function, Object arg0, Object arg1) {
1337 this(-1, function.returnType(), function, new Object[] { arg0, arg1 }, null);
1338 }
1339 Name(NamedFunction function, Object... arguments) {
1340 this(-1, function.returnType(), function, Arrays.copyOf(arguments, arguments.length, Object[].class), null);
1341 }
1342 /** Create a raw parameter of the given type, with an expected index. */
1343 Name(int index, BasicType type) {
1344 this(index, type, null, null, null);
1345 }
1346 /** Create a raw parameter of the given type. */
1347 Name(BasicType type) { this(-1, type); }
1348
1349 BasicType type() { return type; }
1350 int index() { return index; }
1351
1352 char typeChar() {
1353 return type.btChar;
1354 }
1355
1356 Name withIndex(int i) {
1357 if (i == this.index) return this;
1358 return new Name(i, type, function, arguments, constraint);
1359 }
1360
1361 Name withConstraint(Object constraint) {
1362 if (constraint == this.constraint) return this;
1363 return new Name(index, type, function, arguments, constraint);
1364 }
1365
1366 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1367 if (oldName == newName) return this;
1368 @SuppressWarnings("LocalVariableHidesMemberVariable")
1369 Object[] arguments = this.arguments;
1370 if (arguments == null) return this;
1371 boolean replaced = false;
1372 for (int j = 0; j < arguments.length; j++) {
1373 if (arguments[j] == oldName) {
1374 if (!replaced) {
1375 replaced = true;
1376 arguments = arguments.clone();
1377 }
1378 arguments[j] = newName;
1379 }
1380 }
1381 if (!replaced) return this;
1382 return new Name(function, arguments);
1383 }
1384 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1385 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1386 */
1387 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1388 if (start >= end) return this;
1389 @SuppressWarnings("LocalVariableHidesMemberVariable")
1390 Object[] arguments = this.arguments;
1391 boolean replaced = false;
1392 eachArg:
1393 for (int j = 0; j < arguments.length; j++) {
1394 if (arguments[j] instanceof Name n) {
1395 int check = n.index;
1396 // harmless check to see if the thing is already in newNames:
1397 if (check >= 0 && check < newNames.length && n == newNames[check])
1398 continue eachArg;
1399 // n might not have the correct index: n != oldNames[n.index].
1400 for (int i = start; i < end; i++) {
1401 if (n == oldNames[i]) {
1402 if (n == newNames[i])
1403 continue eachArg;
1404 if (!replaced) {
1405 replaced = true;
1406 arguments = arguments.clone();
1407 }
1408 arguments[j] = newNames[i];
1409 continue eachArg;
1410 }
1411 }
1412 }
1413 }
1414 if (!replaced) return this;
1415 return new Name(function, arguments);
1416 }
1417 void internArguments() {
1418 @SuppressWarnings("LocalVariableHidesMemberVariable")
1419 Object[] arguments = this.arguments;
1420 for (int j = 0; j < arguments.length; j++) {
1421 if (arguments[j] instanceof Name n) {
1422 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1423 arguments[j] = internArgument(n);
1424 }
1425 }
1426 }
1427 boolean isParam() {
1428 return function == null;
1429 }
1430
1431 boolean refersTo(Class<?> declaringClass, String methodName) {
1432 return function != null &&
1433 function.member() != null && function.member().refersTo(declaringClass, methodName);
1434 }
1435
1436 /**
1437 * Check if MemberName is a call to MethodHandle.invokeBasic.
1438 */
1439 boolean isInvokeBasic() {
1440 if (function == null)
1441 return false;
1442 if (arguments.length < 1)
1443 return false; // must have MH argument
1444 MemberName member = function.member();
1445 return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1446 !member.isPublic() && !member.isStatic();
1447 }
1448
1449 /**
1450 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1451 */
1452 boolean isLinkerMethodInvoke() {
1453 if (function == null)
1454 return false;
1455 if (arguments.length < 1)
1456 return false; // must have MH argument
1457 MemberName member = function.member();
1458 return member != null &&
1459 member.getDeclaringClass() == MethodHandle.class &&
1460 !member.isPublic() && member.isStatic() &&
1461 member.getName().startsWith("linkTo");
1462 }
1463
1464 public String toString() {
1465 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1466 }
1467 public String debugString() {
1468 String s = paramString();
1469 return (function == null) ? s : s + "=" + exprString();
1470 }
1471 public String paramString() {
1472 String s = toString();
1473 Object c = constraint;
1474 if (c == null)
1475 return s;
1476 if (c instanceof Class<?> cl) c = cl.getSimpleName();
1477 return s + "/" + c;
1478 }
1479 public String exprString() {
1480 if (function == null) return toString();
1481 StringBuilder buf = new StringBuilder(function.toString());
1482 buf.append("(");
1483 String cma = "";
1484 for (Object a : arguments) {
1485 buf.append(cma); cma = ",";
1486 if (a instanceof Name || a instanceof Integer)
1487 buf.append(a);
1488 else
1489 buf.append("(").append(a).append(")");
1490 }
1491 buf.append(")");
1492 return buf.toString();
1493 }
1494
1495 private boolean typesMatch(NamedFunction function, Object ... arguments) {
1496 if (arguments == null) {
1497 assert(function == null);
1498 return true;
1499 }
1500 assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1501 for (int i = 0; i < arguments.length; i++) {
1502 assert (typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1503 }
1504 return true;
1505 }
1506
1507 private static boolean typesMatch(BasicType parameterType, Object object) {
1508 if (object instanceof Name name) {
1509 return name.type == parameterType;
1510 }
1511 switch (parameterType) {
1512 case I_TYPE: return object instanceof Integer;
1513 case J_TYPE: return object instanceof Long;
1514 case F_TYPE: return object instanceof Float;
1515 case D_TYPE: return object instanceof Double;
1516 }
1517 assert(parameterType == L_TYPE);
1518 return true;
1519 }
1520
1521 /** Return the index of the last occurrence of n in the argument array.
1522 * Return -1 if the name is not used.
1523 */
1524 int lastUseIndex(Name n) {
1525 Object[] arguments = this.arguments;
1526 if (arguments == null) return -1;
1527 for (int i = arguments.length; --i >= 0; ) {
1528 if (arguments[i] == n) return i;
1529 }
1530 return -1;
1531 }
1532
1533 public boolean equals(Name that) {
1534 if (this == that) return true;
1535 if (isParam())
1536 // each parameter is a unique atom
1537 return false; // this != that
1538 return
1539 //this.index == that.index &&
1540 this.type == that.type &&
1541 this.function.equals(that.function) &&
1542 Arrays.equals(this.arguments, that.arguments);
1543 }
1544 @Override
1545 public boolean equals(Object x) {
1546 return x instanceof Name n && equals(n);
1547 }
1548 @Override
1549 public int hashCode() {
1550 if (isParam())
1551 return index | (type.ordinal() << 8);
1552 return function.hashCode() ^ Arrays.hashCode(arguments);
1553 }
1554 }
1555
1556 /** Return the index of the last name which contains n as an argument.
1557 * Return -1 if the name is not used. Return names.length if it is the return value.
1558 */
1559 int lastUseIndex(Name n) {
1560 int ni = n.index, nmax = names.length;
1561 assert(names[ni] == n);
1562 if (result == ni) return nmax; // live all the way beyond the end
1563 for (int i = nmax; --i > ni; ) {
1564 if (names[i].lastUseIndex(n) >= 0)
1565 return i;
1566 }
1567 return -1;
1568 }
1569
1570 /** Return the number of times n is used as an argument or return value. */
1571 int useCount(Name n) {
1572 int count = (result == n.index) ? 1 : 0;
1573 int i = Math.max(n.index + 1, arity);
1574 Name[] names = this.names;
1575 while (i < names.length) {
1576 Object[] arguments = names[i++].arguments;
1577 if (arguments != null) {
1578 for (Object argument : arguments) {
1579 if (argument == n) {
1580 count++;
1581 }
1582 }
1583 }
1584 }
1585 return count;
1586 }
1587
1588 static Name argument(int which, BasicType type) {
1589 if (which >= INTERNED_ARGUMENT_LIMIT)
1590 return new Name(which, type);
1591 return INTERNED_ARGUMENTS[type.ordinal()][which];
1592 }
1593 static Name internArgument(Name n) {
1594 assert(n.isParam()) : "not param: " + n;
1595 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1596 if (n.constraint != null) return n;
1597 return argument(n.index, n.type);
1598 }
1599 static Name[] arguments(int extra, MethodType types) {
1600 int length = types.parameterCount();
1601 Name[] names = new Name[length + extra];
1602 for (int i = 0; i < length; i++)
1603 names[i] = argument(i, basicType(types.parameterType(i)));
1604 return names;
1605 }
1606
1607 static Name[] invokeArguments(int extra, MethodType types) {
1608 int length = types.parameterCount();
1609 Name[] names = new Name[length + extra + 1];
1610 names[0] = argument(0, L_TYPE);
1611 for (int i = 0; i < length; i++)
1612 names[i + 1] = argument(i + 1, basicType(types.parameterType(i)));
1613 return names;
1614 }
1615
1616 static final int INTERNED_ARGUMENT_LIMIT = 10;
1617 private static final Name[][] INTERNED_ARGUMENTS
1618 = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1619 static {
1620 for (BasicType type : BasicType.ARG_TYPES) {
1621 int ord = type.ordinal();
1622 for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1623 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1624 }
1625 }
1626 }
1627
1628 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1629
1630 static LambdaForm identityForm(BasicType type) {
1631 int ord = type.ordinal();
1632 LambdaForm form = LF_identity[ord];
1633 if (form != null) {
1634 return form;
1635 }
1636 createIdentityForm(type);
1637 return LF_identity[ord];
1638 }
1639
1640 static NamedFunction identity(BasicType type) {
1641 int ord = type.ordinal();
1642 NamedFunction function = NF_identity[ord];
1643 if (function != null) {
1644 return function;
1645 }
1646 createIdentityForm(type);
1647 return NF_identity[ord];
1648 }
1649
1650 static LambdaForm constantForm(BasicType type) {
1651 assert type != null && type != V_TYPE : type;
1652 var cached = LF_constant[type.ordinal()];
1653 if (cached != null)
1654 return cached;
1655 return createConstantForm(type);
1656 }
1657
1658 private static LambdaForm createConstantForm(BasicType type) {
1659 UNSAFE.ensureClassInitialized(BoundMethodHandle.class); // defend access to SimpleMethodHandle
1660 var species = SimpleMethodHandle.BMH_SPECIES.extendWith(type);
1661 var carrier = argument(0, L_TYPE).withConstraint(species); // BMH bound with data
1662 Name[] constNames = new Name[] { carrier, new Name(species.getterFunction(0), carrier) };
1663 return LF_constant[type.ordinal()] = create(1, constNames, Kind.CONSTANT);
1664 }
1665
1666 private static final @Stable LambdaForm[] LF_identity = new LambdaForm[TYPE_LIMIT];
1667 private static final @Stable NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1668 private static final @Stable LambdaForm[] LF_constant = new LambdaForm[ARG_TYPE_LIMIT]; // no void
1669
1670 private static final Object createIdentityFormLock = new Object();
1671 private static void createIdentityForm(BasicType type) {
1672 // Avoid racy initialization during bootstrap
1673 UNSAFE.ensureClassInitialized(BoundMethodHandle.class);
1674 synchronized (createIdentityFormLock) {
1675 final int ord = type.ordinal();
1676 LambdaForm idForm = LF_identity[ord];
1677 if (idForm != null) {
1678 return;
1679 }
1680 char btChar = type.basicTypeChar();
1681 boolean isVoid = (type == V_TYPE);
1682 Class<?> btClass = type.btClass;
1683 MethodType idType = (isVoid) ? MethodType.methodType(btClass) : MethodType.methodType(btClass, btClass);
1684
1685 // Look up symbolic names. It might not be necessary to have these,
1686 // but if we need to emit direct references to bytecodes, it helps.
1687 MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1688 try {
1689 idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, LM_TRUSTED, NoSuchMethodException.class);
1690 } catch (IllegalAccessException|NoSuchMethodException ex) {
1691 throw newInternalError(ex);
1692 }
1693
1694 NamedFunction idFun;
1695
1696 // Create the LFs and NamedFunctions. Precompiling LFs to byte code is needed to break circular
1697 // bootstrap dependency on this method in case we're interpreting LFs
1698 if (isVoid) {
1699 Name[] idNames = new Name[] { argument(0, L_TYPE) };
1700 idForm = LambdaForm.create(1, idNames, VOID_RESULT, Kind.IDENTITY);
1701 idForm.compileToBytecode();
1702 idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm));
1703 } else {
1704 Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1705 idForm = LambdaForm.create(2, idNames, 1, Kind.IDENTITY);
1706 idForm.compileToBytecode();
1707 idFun = new NamedFunction(idMem, MethodHandleImpl.makeIntrinsic(idMem.getInvocationType(), idForm,
1708 MethodHandleImpl.Intrinsic.IDENTITY));
1709 }
1710
1711 LF_identity[ord] = idForm;
1712 NF_identity[ord] = idFun;
1713
1714 assert(idFun.isIdentity());
1715 }
1716 }
1717
1718 // Avoid appealing to ValueConversions at bootstrap time:
1719 private static int identity_I(int x) { return x; }
1720 private static long identity_J(long x) { return x; }
1721 private static float identity_F(float x) { return x; }
1722 private static double identity_D(double x) { return x; }
1723 private static Object identity_L(Object x) { return x; }
1724 private static void identity_V() { return; }
1725 /**
1726 * Internal marker for byte-compiled LambdaForms.
1727 */
1728 /*non-public*/
1729 @Target(ElementType.METHOD)
1730 @Retention(RetentionPolicy.RUNTIME)
1731 @interface Compiled {
1732 }
1733
1734 private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1735 private static final HashMap<LambdaForm,String> DEBUG_NAMES;
1736 static {
1737 if (debugEnabled()) {
1738 DEBUG_NAME_COUNTERS = new HashMap<>();
1739 DEBUG_NAMES = new HashMap<>();
1740 } else {
1741 DEBUG_NAME_COUNTERS = null;
1742 DEBUG_NAMES = null;
1743 }
1744 }
1745
1746 static {
1747 // The Holder class will contain pre-generated forms resolved
1748 // using MemberName.getFactory(). However, that doesn't initialize the
1749 // class, which subtly breaks inlining etc. By forcing
1750 // initialization of the Holder class we avoid these issues.
1751 UNSAFE.ensureClassInitialized(Holder.class);
1752 }
1753
1754 /* Placeholder class for identity and constant forms generated ahead of time */
1755 final class Holder {}
1756
1757 // The following hack is necessary in order to suppress TRACE_INTERPRETER
1758 // during execution of the static initializes of this class.
1759 // Turning on TRACE_INTERPRETER too early will cause
1760 // stack overflows and other misbehavior during attempts to trace events
1761 // that occur during LambdaForm.<clinit>.
1762 // Therefore, do not move this line higher in this file, and do not remove.
1763 private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1764 }