1 /*
2 * Copyright (c) 2011, 2013, 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.annotation.*;
29 import java.lang.reflect.Method;
30 import java.util.List;
31 import java.util.Arrays;
32 import java.util.HashMap;
33
34 import sun.invoke.util.Wrapper;
35 import java.lang.reflect.Field;
36
37 import static java.lang.invoke.LambdaForm.BasicType.*;
38 import static java.lang.invoke.MethodHandleStatics.*;
39 import static java.lang.invoke.MethodHandleNatives.Constants.*;
40
41 /**
42 * The symbolic, non-executable form of a method handle's invocation semantics.
43 * It consists of a series of names.
44 * The first N (N=arity) names are parameters,
45 * while any remaining names are temporary values.
46 * Each temporary specifies the application of a function to some arguments.
47 * The functions are method handles, while the arguments are mixes of
48 * constant values and local names.
49 * The result of the lambda is defined as one of the names, often the last one.
50 * <p>
51 * Here is an approximate grammar:
52 * <blockquote><pre>{@code
53 * LambdaForm = "(" ArgName* ")=>{" TempName* Result "}"
54 * ArgName = "a" N ":" T
55 * TempName = "t" N ":" T "=" Function "(" Argument* ");"
56 * Function = ConstantValue
57 * Argument = NameRef | ConstantValue
58 * Result = NameRef | "void"
59 * NameRef = "a" N | "t" N
60 * N = (any whole number)
61 * T = "L" | "I" | "J" | "F" | "D" | "V"
62 * }</pre></blockquote>
63 * Names are numbered consecutively from left to right starting at zero.
64 * (The letters are merely a taste of syntax sugar.)
65 * Thus, the first temporary (if any) is always numbered N (where N=arity).
66 * Every occurrence of a name reference in an argument list must refer to
67 * a name previously defined within the same lambda.
68 * A lambda has a void result if and only if its result index is -1.
69 * If a temporary has the type "V", it cannot be the subject of a NameRef,
70 * even though possesses a number.
71 * Note that all reference types are erased to "L", which stands for {@code Object}.
72 * All subword types (boolean, byte, short, char) are erased to "I" which is {@code int}.
73 * The other types stand for the usual primitive types.
74 * <p>
75 * Function invocation closely follows the static rules of the Java verifier.
76 * Arguments and return values must exactly match when their "Name" types are
77 * considered.
78 * Conversions are allowed only if they do not change the erased type.
79 * <ul>
80 * <li>L = Object: casts are used freely to convert into and out of reference types
81 * <li>I = int: subword types are forcibly narrowed when passed as arguments (see {@code explicitCastArguments})
82 * <li>J = long: no implicit conversions
83 * <li>F = float: no implicit conversions
84 * <li>D = double: no implicit conversions
85 * <li>V = void: a function result may be void if and only if its Name is of type "V"
86 * </ul>
87 * Although implicit conversions are not allowed, explicit ones can easily be
88 * encoded by using temporary expressions which call type-transformed identity functions.
89 * <p>
90 * Examples:
91 * <blockquote><pre>{@code
92 * (a0:J)=>{ a0 }
93 * == identity(long)
94 * (a0:I)=>{ t1:V = System.out#println(a0); void }
95 * == System.out#println(int)
96 * (a0:L)=>{ t1:V = System.out#println(a0); a0 }
97 * == identity, with printing side-effect
98 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
99 * t3:L = BoundMethodHandle#target(a0);
100 * t4:L = MethodHandle#invoke(t3, t2, a1); t4 }
101 * == general invoker for unary insertArgument combination
102 * (a0:L, a1:L)=>{ t2:L = FilterMethodHandle#filter(a0);
103 * t3:L = MethodHandle#invoke(t2, a1);
104 * t4:L = FilterMethodHandle#target(a0);
105 * t5:L = MethodHandle#invoke(t4, t3); t5 }
106 * == general invoker for unary filterArgument combination
107 * (a0:L, a1:L)=>{ ...(same as previous example)...
108 * t5:L = MethodHandle#invoke(t4, t3, a1); t5 }
109 * == general invoker for unary/unary foldArgument combination
110 * (a0:L, a1:I)=>{ t2:I = identity(long).asType((int)->long)(a1); t2 }
111 * == invoker for identity method handle which performs i2l
112 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
113 * t3:L = Class#cast(t2,a1); t3 }
114 * == invoker for identity method handle which performs cast
115 * }</pre></blockquote>
116 * <p>
117 * @author John Rose, JSR 292 EG
118 */
119 class LambdaForm {
120 final int arity;
121 final int result;
122 final boolean forceInline;
123 final MethodHandle customized;
124 @Stable final Name[] names;
125 final String debugName;
126 MemberName vmentry; // low-level behavior, or null if not yet prepared
127 private boolean isCompiled;
128
129 // Either a LambdaForm cache (managed by LambdaFormEditor) or a link to uncustomized version (for customized LF)
130 volatile Object transformCache;
131
132 public static final int VOID_RESULT = -1, LAST_RESULT = -2;
133
134 enum BasicType {
135 L_TYPE('L', Object.class, Wrapper.OBJECT), // all reference types
136 I_TYPE('I', int.class, Wrapper.INT),
137 J_TYPE('J', long.class, Wrapper.LONG),
138 F_TYPE('F', float.class, Wrapper.FLOAT),
139 D_TYPE('D', double.class, Wrapper.DOUBLE), // all primitive types
140 V_TYPE('V', void.class, Wrapper.VOID); // not valid in all contexts
141
142 static final BasicType[] ALL_TYPES = BasicType.values();
143 static final BasicType[] ARG_TYPES = Arrays.copyOf(ALL_TYPES, ALL_TYPES.length-1);
144
145 static final int ARG_TYPE_LIMIT = ARG_TYPES.length;
146 static final int TYPE_LIMIT = ALL_TYPES.length;
147
148 private final char btChar;
149 private final Class<?> btClass;
150 private final Wrapper btWrapper;
151
152 private BasicType(char btChar, Class<?> btClass, Wrapper wrapper) {
153 this.btChar = btChar;
154 this.btClass = btClass;
155 this.btWrapper = wrapper;
156 }
157
158 char basicTypeChar() {
159 return btChar;
160 }
161 Class<?> basicTypeClass() {
162 return btClass;
163 }
164 Wrapper basicTypeWrapper() {
165 return btWrapper;
166 }
167 int basicTypeSlots() {
168 return btWrapper.stackSlots();
169 }
170
171 static BasicType basicType(byte type) {
172 return ALL_TYPES[type];
173 }
174 static BasicType basicType(char type) {
175 switch (type) {
176 case 'L': return L_TYPE;
177 case 'I': return I_TYPE;
178 case 'J': return J_TYPE;
179 case 'F': return F_TYPE;
180 case 'D': return D_TYPE;
181 case 'V': return V_TYPE;
182 // all subword types are represented as ints
183 case 'Z':
184 case 'B':
185 case 'S':
186 case 'C':
187 return I_TYPE;
188 default:
189 throw newInternalError("Unknown type char: '"+type+"'");
190 }
191 }
192 static BasicType basicType(Wrapper type) {
193 char c = type.basicTypeChar();
194 return basicType(c);
195 }
196 static BasicType basicType(Class<?> type) {
197 if (!type.isPrimitive()) return L_TYPE;
198 return basicType(Wrapper.forPrimitiveType(type));
199 }
200
201 static char basicTypeChar(Class<?> type) {
202 return basicType(type).btChar;
203 }
204 static BasicType[] basicTypes(List<Class<?>> types) {
205 BasicType[] btypes = new BasicType[types.size()];
206 for (int i = 0; i < btypes.length; i++) {
207 btypes[i] = basicType(types.get(i));
208 }
209 return btypes;
210 }
211 static BasicType[] basicTypes(String types) {
212 BasicType[] btypes = new BasicType[types.length()];
213 for (int i = 0; i < btypes.length; i++) {
214 btypes[i] = basicType(types.charAt(i));
215 }
216 return btypes;
217 }
218 static byte[] basicTypesOrd(BasicType[] btypes) {
219 byte[] ords = new byte[btypes.length];
220 for (int i = 0; i < btypes.length; i++) {
221 ords[i] = (byte)btypes[i].ordinal();
222 }
223 return ords;
224 }
225 static boolean isBasicTypeChar(char c) {
226 return "LIJFDV".indexOf(c) >= 0;
227 }
228 static boolean isArgBasicTypeChar(char c) {
229 return "LIJFD".indexOf(c) >= 0;
230 }
231
232 static { assert(checkBasicType()); }
233 private static boolean checkBasicType() {
234 for (int i = 0; i < ARG_TYPE_LIMIT; i++) {
235 assert ARG_TYPES[i].ordinal() == i;
236 assert ARG_TYPES[i] == ALL_TYPES[i];
237 }
238 for (int i = 0; i < TYPE_LIMIT; i++) {
239 assert ALL_TYPES[i].ordinal() == i;
240 }
241 assert ALL_TYPES[TYPE_LIMIT - 1] == V_TYPE;
242 assert !Arrays.asList(ARG_TYPES).contains(V_TYPE);
243 return true;
244 }
245 }
246
247 LambdaForm(String debugName,
248 int arity, Name[] names, int result) {
249 this(debugName, arity, names, result, /*forceInline=*/true, /*customized=*/null);
250 }
251 LambdaForm(String debugName,
252 int arity, Name[] names, int result, boolean forceInline, MethodHandle customized) {
253 assert(namesOK(arity, names));
254 this.arity = arity;
255 this.result = fixResult(result, names);
256 this.names = names.clone();
257 this.debugName = fixDebugName(debugName);
258 this.forceInline = forceInline;
259 this.customized = customized;
260 int maxOutArity = normalize();
261 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
262 // Cannot use LF interpreter on very high arity expressions.
263 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
264 compileToBytecode();
265 }
266 }
267 LambdaForm(String debugName,
268 int arity, Name[] names) {
269 this(debugName, arity, names, LAST_RESULT, /*forceInline=*/true, /*customized=*/null);
270 }
271 LambdaForm(String debugName,
272 int arity, Name[] names, boolean forceInline) {
273 this(debugName, arity, names, LAST_RESULT, forceInline, /*customized=*/null);
274 }
275 LambdaForm(String debugName,
276 Name[] formals, Name[] temps, Name result) {
277 this(debugName,
278 formals.length, buildNames(formals, temps, result), LAST_RESULT, /*forceInline=*/true, /*customized=*/null);
279 }
280 LambdaForm(String debugName,
281 Name[] formals, Name[] temps, Name result, boolean forceInline) {
282 this(debugName,
283 formals.length, buildNames(formals, temps, result), LAST_RESULT, forceInline, /*customized=*/null);
284 }
285
286 private static Name[] buildNames(Name[] formals, Name[] temps, Name result) {
287 int arity = formals.length;
288 int length = arity + temps.length + (result == null ? 0 : 1);
289 Name[] names = Arrays.copyOf(formals, length);
290 System.arraycopy(temps, 0, names, arity, temps.length);
291 if (result != null)
292 names[length - 1] = result;
293 return names;
294 }
295
296 private LambdaForm(String sig) {
297 // Make a blank lambda form, which returns a constant zero or null.
298 // It is used as a template for managing the invocation of similar forms that are non-empty.
299 // Called only from getPreparedForm.
300 assert(isValidSignature(sig));
301 this.arity = signatureArity(sig);
302 this.result = (signatureReturn(sig) == V_TYPE ? -1 : arity);
303 this.names = buildEmptyNames(arity, sig);
304 this.debugName = "LF.zero";
305 this.forceInline = true;
306 this.customized = null;
307 assert(nameRefsAreLegal());
308 assert(isEmpty());
309 assert(sig.equals(basicTypeSignature())) : sig + " != " + basicTypeSignature();
310 }
311
312 private static Name[] buildEmptyNames(int arity, String basicTypeSignature) {
313 assert(isValidSignature(basicTypeSignature));
314 int resultPos = arity + 1; // skip '_'
315 if (arity < 0 || basicTypeSignature.length() != resultPos+1)
316 throw new IllegalArgumentException("bad arity for "+basicTypeSignature);
317 int numRes = (basicType(basicTypeSignature.charAt(resultPos)) == V_TYPE ? 0 : 1);
318 Name[] names = arguments(numRes, basicTypeSignature.substring(0, arity));
319 for (int i = 0; i < numRes; i++) {
320 Name zero = new Name(constantZero(basicType(basicTypeSignature.charAt(resultPos + i))));
321 names[arity + i] = zero.newIndex(arity + i);
322 }
323 return names;
324 }
325
326 private static int fixResult(int result, Name[] names) {
327 if (result == LAST_RESULT)
328 result = names.length - 1; // might still be void
329 if (result >= 0 && names[result].type == V_TYPE)
330 result = VOID_RESULT;
331 return result;
332 }
333
334 private static String fixDebugName(String debugName) {
335 if (DEBUG_NAME_COUNTERS != null) {
336 int under = debugName.indexOf('_');
337 int length = debugName.length();
338 if (under < 0) under = length;
339 String debugNameStem = debugName.substring(0, under);
340 Integer ctr;
341 synchronized (DEBUG_NAME_COUNTERS) {
342 ctr = DEBUG_NAME_COUNTERS.get(debugNameStem);
343 if (ctr == null) ctr = 0;
344 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr+1);
345 }
346 StringBuilder buf = new StringBuilder(debugNameStem);
347 buf.append('_');
348 int leadingZero = buf.length();
349 buf.append((int) ctr);
350 for (int i = buf.length() - leadingZero; i < 3; i++)
351 buf.insert(leadingZero, '0');
352 if (under < length) {
353 ++under; // skip "_"
354 while (under < length && Character.isDigit(debugName.charAt(under))) {
355 ++under;
356 }
357 if (under < length && debugName.charAt(under) == '_') ++under;
358 if (under < length)
359 buf.append('_').append(debugName, under, length);
360 }
361 return buf.toString();
362 }
363 return debugName;
364 }
365
366 private static boolean namesOK(int arity, Name[] names) {
367 for (int i = 0; i < names.length; i++) {
368 Name n = names[i];
369 assert(n != null) : "n is null";
370 if (i < arity)
371 assert( n.isParam()) : n + " is not param at " + i;
372 else
373 assert(!n.isParam()) : n + " is param at " + i;
374 }
375 return true;
376 }
377
378 /** Customize LambdaForm for a particular MethodHandle */
379 LambdaForm customize(MethodHandle mh) {
380 LambdaForm customForm = new LambdaForm(debugName, arity, names, result, forceInline, mh);
381 if (COMPILE_THRESHOLD > 0 && isCompiled) {
382 // If shared LambdaForm has been compiled, compile customized version as well.
383 customForm.compileToBytecode();
384 }
385 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
386 return customForm;
387 }
388
389 /** Get uncustomized flavor of the LambdaForm */
390 LambdaForm uncustomize() {
391 if (customized == null) {
392 return this;
393 }
394 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
395 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
396 if (COMPILE_THRESHOLD > 0 && isCompiled) {
397 // If customized LambdaForm has been compiled, compile uncustomized version as well.
398 uncustomizedForm.compileToBytecode();
399 }
400 return uncustomizedForm;
401 }
402
403 /** Renumber and/or replace params so that they are interned and canonically numbered.
404 * @return maximum argument list length among the names (since we have to pass over them anyway)
405 */
406 private int normalize() {
407 Name[] oldNames = null;
408 int maxOutArity = 0;
409 int changesStart = 0;
410 for (int i = 0; i < names.length; i++) {
411 Name n = names[i];
412 if (!n.initIndex(i)) {
413 if (oldNames == null) {
414 oldNames = names.clone();
415 changesStart = i;
416 }
417 names[i] = n.cloneWithIndex(i);
418 }
419 if (n.arguments != null && maxOutArity < n.arguments.length)
420 maxOutArity = n.arguments.length;
421 }
422 if (oldNames != null) {
423 int startFixing = arity;
424 if (startFixing <= changesStart)
425 startFixing = changesStart+1;
426 for (int i = startFixing; i < names.length; i++) {
427 Name fixed = names[i].replaceNames(oldNames, names, changesStart, i);
428 names[i] = fixed.newIndex(i);
429 }
430 }
431 assert(nameRefsAreLegal());
432 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
433 boolean needIntern = false;
434 for (int i = 0; i < maxInterned; i++) {
435 Name n = names[i], n2 = internArgument(n);
436 if (n != n2) {
437 names[i] = n2;
438 needIntern = true;
439 }
440 }
441 if (needIntern) {
442 for (int i = arity; i < names.length; i++) {
443 names[i].internArguments();
444 }
445 }
446 assert(nameRefsAreLegal());
447 return maxOutArity;
448 }
449
450 /**
451 * Check that all embedded Name references are localizable to this lambda,
452 * and are properly ordered after their corresponding definitions.
453 * <p>
454 * Note that a Name can be local to multiple lambdas, as long as
455 * it possesses the same index in each use site.
456 * This allows Name references to be freely reused to construct
457 * fresh lambdas, without confusion.
458 */
459 boolean nameRefsAreLegal() {
460 assert(arity >= 0 && arity <= names.length);
461 assert(result >= -1 && result < names.length);
462 // Do all names possess an index consistent with their local definition order?
463 for (int i = 0; i < arity; i++) {
464 Name n = names[i];
465 assert(n.index() == i) : Arrays.asList(n.index(), i);
466 assert(n.isParam());
467 }
468 // Also, do all local name references
469 for (int i = arity; i < names.length; i++) {
470 Name n = names[i];
471 assert(n.index() == i);
472 for (Object arg : n.arguments) {
473 if (arg instanceof Name) {
474 Name n2 = (Name) arg;
475 int i2 = n2.index;
476 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
477 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
478 assert(i2 < i); // ref must come after def!
479 }
480 }
481 }
482 return true;
483 }
484
485 /** Invoke this form on the given arguments. */
486 // final Object invoke(Object... args) throws Throwable {
487 // // NYI: fit this into the fast path?
488 // return interpretWithArguments(args);
489 // }
490
491 /** Report the return type. */
492 BasicType returnType() {
493 if (result < 0) return V_TYPE;
494 Name n = names[result];
495 return n.type;
496 }
497
498 /** Report the N-th argument type. */
499 BasicType parameterType(int n) {
500 return parameter(n).type;
501 }
502
503 /** Report the N-th argument name. */
504 Name parameter(int n) {
505 assert(n < arity);
506 Name param = names[n];
507 assert(param.isParam());
508 return param;
509 }
510
511 /** Report the N-th argument type constraint. */
512 Object parameterConstraint(int n) {
513 return parameter(n).constraint;
514 }
515
516 /** Report the arity. */
517 int arity() {
518 return arity;
519 }
520
521 /** Report the number of expressions (non-parameter names). */
522 int expressionCount() {
523 return names.length - arity;
524 }
525
526 /** Return the method type corresponding to my basic type signature. */
527 MethodType methodType() {
528 return signatureType(basicTypeSignature());
529 }
530 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
531 final String basicTypeSignature() {
532 StringBuilder buf = new StringBuilder(arity() + 3);
533 for (int i = 0, a = arity(); i < a; i++)
534 buf.append(parameterType(i).basicTypeChar());
535 return buf.append('_').append(returnType().basicTypeChar()).toString();
536 }
537 static int signatureArity(String sig) {
538 assert(isValidSignature(sig));
539 return sig.indexOf('_');
540 }
541 static BasicType signatureReturn(String sig) {
542 return basicType(sig.charAt(signatureArity(sig) + 1));
543 }
544 static boolean isValidSignature(String sig) {
545 int arity = sig.indexOf('_');
546 if (arity < 0) return false; // must be of the form *_*
547 int siglen = sig.length();
548 if (siglen != arity + 2) return false; // *_X
549 for (int i = 0; i < siglen; i++) {
550 if (i == arity) continue; // skip '_'
551 char c = sig.charAt(i);
552 if (c == 'V')
553 return (i == siglen - 1 && arity == siglen - 2);
554 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
555 }
556 return true; // [LIJFD]*_[LIJFDV]
557 }
558 static MethodType signatureType(String sig) {
559 Class<?>[] ptypes = new Class<?>[signatureArity(sig)];
560 for (int i = 0; i < ptypes.length; i++)
561 ptypes[i] = basicType(sig.charAt(i)).btClass;
562 Class<?> rtype = signatureReturn(sig).btClass;
563 return MethodType.methodType(rtype, ptypes);
564 }
565
566 /*
567 * Code generation issues:
568 *
569 * Compiled LFs should be reusable in general.
570 * The biggest issue is how to decide when to pull a name into
571 * the bytecode, versus loading a reified form from the MH data.
572 *
573 * For example, an asType wrapper may require execution of a cast
574 * after a call to a MH. The target type of the cast can be placed
575 * as a constant in the LF itself. This will force the cast type
576 * to be compiled into the bytecodes and native code for the MH.
577 * Or, the target type of the cast can be erased in the LF, and
578 * loaded from the MH data. (Later on, if the MH as a whole is
579 * inlined, the data will flow into the inlined instance of the LF,
580 * as a constant, and the end result will be an optimal cast.)
581 *
582 * This erasure of cast types can be done with any use of
583 * reference types. It can also be done with whole method
584 * handles. Erasing a method handle might leave behind
585 * LF code that executes correctly for any MH of a given
586 * type, and load the required MH from the enclosing MH's data.
587 * Or, the erasure might even erase the expected MT.
588 *
589 * Also, for direct MHs, the MemberName of the target
590 * could be erased, and loaded from the containing direct MH.
591 * As a simple case, a LF for all int-valued non-static
592 * field getters would perform a cast on its input argument
593 * (to non-constant base type derived from the MemberName)
594 * and load an integer value from the input object
595 * (at a non-constant offset also derived from the MemberName).
596 * Such MN-erased LFs would be inlinable back to optimized
597 * code, whenever a constant enclosing DMH is available
598 * to supply a constant MN from its data.
599 *
600 * The main problem here is to keep LFs reasonably generic,
601 * while ensuring that hot spots will inline good instances.
602 * "Reasonably generic" means that we don't end up with
603 * repeated versions of bytecode or machine code that do
604 * not differ in their optimized form. Repeated versions
605 * of machine would have the undesirable overheads of
606 * (a) redundant compilation work and (b) extra I$ pressure.
607 * To control repeated versions, we need to be ready to
608 * erase details from LFs and move them into MH data,
609 * whevener those details are not relevant to significant
610 * optimization. "Significant" means optimization of
611 * code that is actually hot.
612 *
613 * Achieving this may require dynamic splitting of MHs, by replacing
614 * a generic LF with a more specialized one, on the same MH,
615 * if (a) the MH is frequently executed and (b) the MH cannot
616 * be inlined into a containing caller, such as an invokedynamic.
617 *
618 * Compiled LFs that are no longer used should be GC-able.
619 * If they contain non-BCP references, they should be properly
620 * interlinked with the class loader(s) that their embedded types
621 * depend on. This probably means that reusable compiled LFs
622 * will be tabulated (indexed) on relevant class loaders,
623 * or else that the tables that cache them will have weak links.
624 */
625
626 /**
627 * Make this LF directly executable, as part of a MethodHandle.
628 * Invariant: Every MH which is invoked must prepare its LF
629 * before invocation.
630 * (In principle, the JVM could do this very lazily,
631 * as a sort of pre-invocation linkage step.)
632 */
633 public void prepare() {
634 if (COMPILE_THRESHOLD == 0 && !isCompiled) {
635 compileToBytecode();
636 }
637 if (this.vmentry != null) {
638 // already prepared (e.g., a primitive DMH invoker form)
639 return;
640 }
641 LambdaForm prep = getPreparedForm(basicTypeSignature());
642 this.vmentry = prep.vmentry;
643 // TO DO: Maybe add invokeGeneric, invokeWithArguments
644 }
645
646 /** Generate optimizable bytecode for this form. */
647 MemberName compileToBytecode() {
648 if (vmentry != null && isCompiled) {
649 return vmentry; // already compiled somehow
650 }
651 MethodType invokerType = methodType();
652 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
653 try {
654 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
655 if (TRACE_INTERPRETER)
656 traceInterpreter("compileToBytecode", this);
657 isCompiled = true;
658 return vmentry;
659 } catch (Error | Exception ex) {
660 throw newInternalError(this.toString(), ex);
661 }
662 }
663
664 private static void computeInitialPreparedForms() {
665 // Find all predefined invokers and associate them with canonical empty lambda forms.
666 for (MemberName m : MemberName.getFactory().getMethods(LambdaForm.class, false, null, null, null)) {
667 if (!m.isStatic() || !m.isPackage()) continue;
668 MethodType mt = m.getMethodType();
669 if (mt.parameterCount() > 0 &&
670 mt.parameterType(0) == MethodHandle.class &&
671 m.getName().startsWith("interpret_")) {
672 String sig = basicTypeSignature(mt);
673 assert(m.getName().equals("interpret" + sig.substring(sig.indexOf('_'))));
674 LambdaForm form = new LambdaForm(sig);
675 form.vmentry = m;
676 form = mt.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, form);
677 }
678 }
679 }
680
681 // Set this false to disable use of the interpret_L methods defined in this file.
682 private static final boolean USE_PREDEFINED_INTERPRET_METHODS = true;
683
684 // The following are predefined exact invokers. The system must build
685 // a separate invoker for each distinct signature.
686 static Object interpret_L(MethodHandle mh) throws Throwable {
687 Object[] av = {mh};
688 String sig = null;
689 assert(argumentTypesMatch(sig = "L_L", av));
690 Object res = mh.form.interpretWithArguments(av);
691 assert(returnTypesMatch(sig, av, res));
692 return res;
693 }
694 static Object interpret_L(MethodHandle mh, Object x1) throws Throwable {
695 Object[] av = {mh, x1};
696 String sig = null;
697 assert(argumentTypesMatch(sig = "LL_L", av));
698 Object res = mh.form.interpretWithArguments(av);
699 assert(returnTypesMatch(sig, av, res));
700 return res;
701 }
702 static Object interpret_L(MethodHandle mh, Object x1, Object x2) throws Throwable {
703 Object[] av = {mh, x1, x2};
704 String sig = null;
705 assert(argumentTypesMatch(sig = "LLL_L", av));
706 Object res = mh.form.interpretWithArguments(av);
707 assert(returnTypesMatch(sig, av, res));
708 return res;
709 }
710 private static LambdaForm getPreparedForm(String sig) {
711 MethodType mtype = signatureType(sig);
712 LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
713 if (prep != null) return prep;
714 assert(isValidSignature(sig));
715 prep = new LambdaForm(sig);
716 prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(sig);
717 return mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
718 }
719
720 // The next few routines are called only from assert expressions
721 // They verify that the built-in invokers process the correct raw data types.
722 private static boolean argumentTypesMatch(String sig, Object[] av) {
723 int arity = signatureArity(sig);
724 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
725 assert(av[0] instanceof MethodHandle) : "av[0] not instace of MethodHandle: " + av[0];
726 MethodHandle mh = (MethodHandle) av[0];
727 MethodType mt = mh.type();
728 assert(mt.parameterCount() == arity-1);
729 for (int i = 0; i < av.length; i++) {
730 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
731 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
732 }
733 return true;
734 }
735 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
736 // The following line is needed because (...)void method handles can use non-void invokers
737 if (type == void.class) tc = V_TYPE; // can drop any kind of value
738 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
739 switch (tc) {
740 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
741 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
742 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
743 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
744 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
745 case V_TYPE: break; // allow anything here; will be dropped
746 default: assert(false);
747 }
748 return true;
749 }
750 private static boolean returnTypesMatch(String sig, Object[] av, Object res) {
751 MethodHandle mh = (MethodHandle) av[0];
752 return valueMatches(signatureReturn(sig), mh.type().returnType(), res);
753 }
754 private static boolean checkInt(Class<?> type, Object x) {
755 assert(x instanceof Integer);
756 if (type == int.class) return true;
757 Wrapper w = Wrapper.forBasicType(type);
758 assert(w.isSubwordOrInt());
759 Object x1 = Wrapper.INT.wrap(w.wrap(x));
760 return x.equals(x1);
761 }
762 private static boolean checkRef(Class<?> type, Object x) {
763 assert(!type.isPrimitive());
764 if (x == null) return true;
765 if (type.isInterface()) return true;
766 return type.isInstance(x);
767 }
768
769 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
770 private static final int COMPILE_THRESHOLD;
771 static {
772 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
773 }
774 private int invocationCounter = 0;
775
776 @Hidden
777 @DontInline
778 /** Interpretively invoke this form on the given arguments. */
779 Object interpretWithArguments(Object... argumentValues) throws Throwable {
780 if (TRACE_INTERPRETER)
781 return interpretWithArgumentsTracing(argumentValues);
782 checkInvocationCounter();
783 assert(arityCheck(argumentValues));
784 Object[] values = Arrays.copyOf(argumentValues, names.length);
785 for (int i = argumentValues.length; i < values.length; i++) {
786 values[i] = interpretName(names[i], values);
787 }
788 Object rv = (result < 0) ? null : values[result];
789 assert(resultCheck(argumentValues, rv));
790 return rv;
791 }
792
793 @Hidden
794 @DontInline
795 /** Evaluate a single Name within this form, applying its function to its arguments. */
796 Object interpretName(Name name, Object[] values) throws Throwable {
797 if (TRACE_INTERPRETER)
798 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
799 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
800 for (int i = 0; i < arguments.length; i++) {
801 Object a = arguments[i];
802 if (a instanceof Name) {
803 int i2 = ((Name)a).index();
804 assert(names[i2] == a);
805 a = values[i2];
806 arguments[i] = a;
807 }
808 }
809 return name.function.invokeWithArguments(arguments);
810 }
811
812 private void checkInvocationCounter() {
813 if (COMPILE_THRESHOLD != 0 &&
814 invocationCounter < COMPILE_THRESHOLD) {
815 invocationCounter++; // benign race
816 if (invocationCounter >= COMPILE_THRESHOLD) {
817 // Replace vmentry with a bytecode version of this LF.
818 compileToBytecode();
819 }
820 }
821 }
822 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
823 traceInterpreter("[ interpretWithArguments", this, argumentValues);
824 if (invocationCounter < COMPILE_THRESHOLD) {
825 int ctr = invocationCounter++; // benign race
826 traceInterpreter("| invocationCounter", ctr);
827 if (invocationCounter >= COMPILE_THRESHOLD) {
828 compileToBytecode();
829 }
830 }
831 Object rval;
832 try {
833 assert(arityCheck(argumentValues));
834 Object[] values = Arrays.copyOf(argumentValues, names.length);
835 for (int i = argumentValues.length; i < values.length; i++) {
836 values[i] = interpretName(names[i], values);
837 }
838 rval = (result < 0) ? null : values[result];
839 } catch (Throwable ex) {
840 traceInterpreter("] throw =>", ex);
841 throw ex;
842 }
843 traceInterpreter("] return =>", rval);
844 return rval;
845 }
846
847 static void traceInterpreter(String event, Object obj, Object... args) {
848 if (TRACE_INTERPRETER) {
849 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
850 }
851 }
852 static void traceInterpreter(String event, Object obj) {
853 traceInterpreter(event, obj, (Object[])null);
854 }
855 private boolean arityCheck(Object[] argumentValues) {
856 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
857 // also check that the leading (receiver) argument is somehow bound to this LF:
858 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
859 MethodHandle mh = (MethodHandle) argumentValues[0];
860 assert(mh.internalForm() == this);
861 // note: argument #0 could also be an interface wrapper, in the future
862 argumentTypesMatch(basicTypeSignature(), argumentValues);
863 return true;
864 }
865 private boolean resultCheck(Object[] argumentValues, Object result) {
866 MethodHandle mh = (MethodHandle) argumentValues[0];
867 MethodType mt = mh.type();
868 assert(valueMatches(returnType(), mt.returnType(), result));
869 return true;
870 }
871
872 private boolean isEmpty() {
873 if (result < 0)
874 return (names.length == arity);
875 else if (result == arity && names.length == arity + 1)
876 return names[arity].isConstantZero();
877 else
878 return false;
879 }
880
881 public String toString() {
882 StringBuilder buf = new StringBuilder(debugName+"=Lambda(");
883 for (int i = 0; i < names.length; i++) {
884 if (i == arity) buf.append(")=>{");
885 Name n = names[i];
886 if (i >= arity) buf.append("\n ");
887 buf.append(n.paramString());
888 if (i < arity) {
889 if (i+1 < arity) buf.append(",");
890 continue;
891 }
892 buf.append("=").append(n.exprString());
893 buf.append(";");
894 }
895 if (arity == names.length) buf.append(")=>{");
896 buf.append(result < 0 ? "void" : names[result]).append("}");
897 if (TRACE_INTERPRETER) {
898 // Extra verbosity:
899 buf.append(":").append(basicTypeSignature());
900 buf.append("/").append(vmentry);
901 }
902 return buf.toString();
903 }
904
905 @Override
906 public boolean equals(Object obj) {
907 return obj instanceof LambdaForm && equals((LambdaForm)obj);
908 }
909 public boolean equals(LambdaForm that) {
910 if (this.result != that.result) return false;
911 return Arrays.equals(this.names, that.names);
912 }
913 public int hashCode() {
914 return result + 31 * Arrays.hashCode(names);
915 }
916 LambdaFormEditor editor() {
917 return LambdaFormEditor.lambdaFormEditor(this);
918 }
919
920 boolean contains(Name name) {
921 int pos = name.index();
922 if (pos >= 0) {
923 return pos < names.length && name.equals(names[pos]);
924 }
925 for (int i = arity; i < names.length; i++) {
926 if (name.equals(names[i]))
927 return true;
928 }
929 return false;
930 }
931
932 LambdaForm addArguments(int pos, BasicType... types) {
933 // names array has MH in slot 0; skip it.
934 int argpos = pos + 1;
935 assert(argpos <= arity);
936 int length = names.length;
937 int inTypes = types.length;
938 Name[] names2 = Arrays.copyOf(names, length + inTypes);
939 int arity2 = arity + inTypes;
940 int result2 = result;
941 if (result2 >= argpos)
942 result2 += inTypes;
943 // Note: The LF constructor will rename names2[argpos...].
944 // Make space for new arguments (shift temporaries).
945 System.arraycopy(names, argpos, names2, argpos + inTypes, length - argpos);
946 for (int i = 0; i < inTypes; i++) {
947 names2[argpos + i] = new Name(types[i]);
948 }
949 return new LambdaForm(debugName, arity2, names2, result2);
950 }
951
952 LambdaForm addArguments(int pos, List<Class<?>> types) {
953 return addArguments(pos, basicTypes(types));
954 }
955
956 LambdaForm permuteArguments(int skip, int[] reorder, BasicType[] types) {
957 // Note: When inArg = reorder[outArg], outArg is fed by a copy of inArg.
958 // The types are the types of the new (incoming) arguments.
959 int length = names.length;
960 int inTypes = types.length;
961 int outArgs = reorder.length;
962 assert(skip+outArgs == arity);
963 assert(permutedTypesMatch(reorder, types, names, skip));
964 int pos = 0;
965 // skip trivial first part of reordering:
966 while (pos < outArgs && reorder[pos] == pos) pos += 1;
967 Name[] names2 = new Name[length - outArgs + inTypes];
968 System.arraycopy(names, 0, names2, 0, skip+pos);
969 // copy the body:
970 int bodyLength = length - arity;
971 System.arraycopy(names, skip+outArgs, names2, skip+inTypes, bodyLength);
972 int arity2 = names2.length - bodyLength;
973 int result2 = result;
974 if (result2 >= 0) {
975 if (result2 < skip+outArgs) {
976 // return the corresponding inArg
977 result2 = reorder[result2-skip];
978 } else {
979 result2 = result2 - outArgs + inTypes;
980 }
981 }
982 // rework names in the body:
983 for (int j = pos; j < outArgs; j++) {
984 Name n = names[skip+j];
985 int i = reorder[j];
986 // replace names[skip+j] by names2[skip+i]
987 Name n2 = names2[skip+i];
988 if (n2 == null)
989 names2[skip+i] = n2 = new Name(types[i]);
990 else
991 assert(n2.type == types[i]);
992 for (int k = arity2; k < names2.length; k++) {
993 names2[k] = names2[k].replaceName(n, n2);
994 }
995 }
996 // some names are unused, but must be filled in
997 for (int i = skip+pos; i < arity2; i++) {
998 if (names2[i] == null)
999 names2[i] = argument(i, types[i - skip]);
1000 }
1001 for (int j = arity; j < names.length; j++) {
1002 int i = j - arity + arity2;
1003 // replace names2[i] by names[j]
1004 Name n = names[j];
1005 Name n2 = names2[i];
1006 if (n != n2) {
1007 for (int k = i+1; k < names2.length; k++) {
1008 names2[k] = names2[k].replaceName(n, n2);
1009 }
1010 }
1011 }
1012 return new LambdaForm(debugName, arity2, names2, result2);
1013 }
1014
1015 static boolean permutedTypesMatch(int[] reorder, BasicType[] types, Name[] names, int skip) {
1016 int inTypes = types.length;
1017 int outArgs = reorder.length;
1018 for (int i = 0; i < outArgs; i++) {
1019 assert(names[skip+i].isParam());
1020 assert(names[skip+i].type == types[reorder[i]]);
1021 }
1022 return true;
1023 }
1024
1025 static class NamedFunction {
1026 final MemberName member;
1027 @Stable MethodHandle resolvedHandle;
1028 @Stable MethodHandle invoker;
1029
1030 NamedFunction(MethodHandle resolvedHandle) {
1031 this(resolvedHandle.internalMemberName(), resolvedHandle);
1032 }
1033 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1034 this.member = member;
1035 this.resolvedHandle = resolvedHandle;
1036 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1037 //assert(!isInvokeBasic());
1038 }
1039 NamedFunction(MethodType basicInvokerType) {
1040 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1041 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1042 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1043 this.member = resolvedHandle.internalMemberName();
1044 } else {
1045 // necessary to pass BigArityTest
1046 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1047 }
1048 assert(isInvokeBasic());
1049 }
1050
1051 private boolean isInvokeBasic() {
1052 return member != null &&
1053 member.isMethodHandleInvoke() &&
1054 "invokeBasic".equals(member.getName());
1055 }
1056
1057 // The next 3 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1058 // Any LambdaForm containing such a member is not interpretable.
1059 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1060 // And even without the resolvedHandle, the name can still be compiled and optimized.
1061 NamedFunction(Method method) {
1062 this(new MemberName(method));
1063 }
1064 NamedFunction(Field field) {
1065 this(new MemberName(field));
1066 }
1067 NamedFunction(MemberName member) {
1068 this.member = member;
1069 this.resolvedHandle = null;
1070 }
1071
1072 MethodHandle resolvedHandle() {
1073 if (resolvedHandle == null) resolve();
1074 return resolvedHandle;
1075 }
1076
1077 void resolve() {
1078 resolvedHandle = DirectMethodHandle.make(member);
1079 }
1080
1081 @Override
1082 public boolean equals(Object other) {
1083 if (this == other) return true;
1084 if (other == null) return false;
1085 if (!(other instanceof NamedFunction)) return false;
1086 NamedFunction that = (NamedFunction) other;
1087 return this.member != null && this.member.equals(that.member);
1088 }
1089
1090 @Override
1091 public int hashCode() {
1092 if (member != null)
1093 return member.hashCode();
1094 return super.hashCode();
1095 }
1096
1097 // Put the predefined NamedFunction invokers into the table.
1098 static void initializeInvokers() {
1099 for (MemberName m : MemberName.getFactory().getMethods(NamedFunction.class, false, null, null, null)) {
1100 if (!m.isStatic() || !m.isPackage()) continue;
1101 MethodType type = m.getMethodType();
1102 if (type.equals(INVOKER_METHOD_TYPE) &&
1103 m.getName().startsWith("invoke_")) {
1104 String sig = m.getName().substring("invoke_".length());
1105 int arity = LambdaForm.signatureArity(sig);
1106 MethodType srcType = MethodType.genericMethodType(arity);
1107 if (LambdaForm.signatureReturn(sig) == V_TYPE)
1108 srcType = srcType.changeReturnType(void.class);
1109 MethodTypeForm typeForm = srcType.form();
1110 typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, DirectMethodHandle.make(m));
1111 }
1112 }
1113 }
1114
1115 // The following are predefined NamedFunction invokers. The system must build
1116 // a separate invoker for each distinct signature.
1117 /** void return type invokers. */
1118 @Hidden
1119 static Object invoke__V(MethodHandle mh, Object[] a) throws Throwable {
1120 assert(arityCheck(0, void.class, mh, a));
1121 mh.invokeBasic();
1122 return null;
1123 }
1124 @Hidden
1125 static Object invoke_L_V(MethodHandle mh, Object[] a) throws Throwable {
1126 assert(arityCheck(1, void.class, mh, a));
1127 mh.invokeBasic(a[0]);
1128 return null;
1129 }
1130 @Hidden
1131 static Object invoke_LL_V(MethodHandle mh, Object[] a) throws Throwable {
1132 assert(arityCheck(2, void.class, mh, a));
1133 mh.invokeBasic(a[0], a[1]);
1134 return null;
1135 }
1136 @Hidden
1137 static Object invoke_LLL_V(MethodHandle mh, Object[] a) throws Throwable {
1138 assert(arityCheck(3, void.class, mh, a));
1139 mh.invokeBasic(a[0], a[1], a[2]);
1140 return null;
1141 }
1142 @Hidden
1143 static Object invoke_LLLL_V(MethodHandle mh, Object[] a) throws Throwable {
1144 assert(arityCheck(4, void.class, mh, a));
1145 mh.invokeBasic(a[0], a[1], a[2], a[3]);
1146 return null;
1147 }
1148 @Hidden
1149 static Object invoke_LLLLL_V(MethodHandle mh, Object[] a) throws Throwable {
1150 assert(arityCheck(5, void.class, mh, a));
1151 mh.invokeBasic(a[0], a[1], a[2], a[3], a[4]);
1152 return null;
1153 }
1154 /** Object return type invokers. */
1155 @Hidden
1156 static Object invoke__L(MethodHandle mh, Object[] a) throws Throwable {
1157 assert(arityCheck(0, mh, a));
1158 return mh.invokeBasic();
1159 }
1160 @Hidden
1161 static Object invoke_L_L(MethodHandle mh, Object[] a) throws Throwable {
1162 assert(arityCheck(1, mh, a));
1163 return mh.invokeBasic(a[0]);
1164 }
1165 @Hidden
1166 static Object invoke_LL_L(MethodHandle mh, Object[] a) throws Throwable {
1167 assert(arityCheck(2, mh, a));
1168 return mh.invokeBasic(a[0], a[1]);
1169 }
1170 @Hidden
1171 static Object invoke_LLL_L(MethodHandle mh, Object[] a) throws Throwable {
1172 assert(arityCheck(3, mh, a));
1173 return mh.invokeBasic(a[0], a[1], a[2]);
1174 }
1175 @Hidden
1176 static Object invoke_LLLL_L(MethodHandle mh, Object[] a) throws Throwable {
1177 assert(arityCheck(4, mh, a));
1178 return mh.invokeBasic(a[0], a[1], a[2], a[3]);
1179 }
1180 @Hidden
1181 static Object invoke_LLLLL_L(MethodHandle mh, Object[] a) throws Throwable {
1182 assert(arityCheck(5, mh, a));
1183 return mh.invokeBasic(a[0], a[1], a[2], a[3], a[4]);
1184 }
1185 private static boolean arityCheck(int arity, MethodHandle mh, Object[] a) {
1186 return arityCheck(arity, Object.class, mh, a);
1187 }
1188 private static boolean arityCheck(int arity, Class<?> rtype, MethodHandle mh, Object[] a) {
1189 assert(a.length == arity)
1190 : Arrays.asList(a.length, arity);
1191 assert(mh.type().basicType() == MethodType.genericMethodType(arity).changeReturnType(rtype))
1192 : Arrays.asList(mh, rtype, arity);
1193 MemberName member = mh.internalMemberName();
1194 if (member != null && member.getName().equals("invokeBasic") && member.isMethodHandleInvoke()) {
1195 assert(arity > 0);
1196 assert(a[0] instanceof MethodHandle);
1197 MethodHandle mh2 = (MethodHandle) a[0];
1198 assert(mh2.type().basicType() == MethodType.genericMethodType(arity-1).changeReturnType(rtype))
1199 : Arrays.asList(member, mh2, rtype, arity);
1200 }
1201 return true;
1202 }
1203
1204 static final MethodType INVOKER_METHOD_TYPE =
1205 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1206
1207 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1208 typeForm = typeForm.basicType().form(); // normalize to basic type
1209 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1210 if (mh != null) return mh;
1211 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1212 mh = DirectMethodHandle.make(invoker);
1213 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1214 if (mh2 != null) return mh2; // benign race
1215 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1216 throw newInternalError(mh.debugString());
1217 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1218 }
1219
1220 @Hidden
1221 Object invokeWithArguments(Object... arguments) throws Throwable {
1222 // If we have a cached invoker, call it right away.
1223 // NOTE: The invoker always returns a reference value.
1224 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1225 assert(checkArgumentTypes(arguments, methodType()));
1226 return invoker().invokeBasic(resolvedHandle(), arguments);
1227 }
1228
1229 @Hidden
1230 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1231 Object rval;
1232 try {
1233 traceInterpreter("[ call", this, arguments);
1234 if (invoker == null) {
1235 traceInterpreter("| getInvoker", this);
1236 invoker();
1237 }
1238 if (resolvedHandle == null) {
1239 traceInterpreter("| resolve", this);
1240 resolvedHandle();
1241 }
1242 assert(checkArgumentTypes(arguments, methodType()));
1243 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1244 } catch (Throwable ex) {
1245 traceInterpreter("] throw =>", ex);
1246 throw ex;
1247 }
1248 traceInterpreter("] return =>", rval);
1249 return rval;
1250 }
1251
1252 private MethodHandle invoker() {
1253 if (invoker != null) return invoker;
1254 // Get an invoker and cache it.
1255 return invoker = computeInvoker(methodType().form());
1256 }
1257
1258 private static boolean checkArgumentTypes(Object[] arguments, MethodType methodType) {
1259 if (true) return true; // FIXME
1260 MethodType dstType = methodType.form().erasedType();
1261 MethodType srcType = dstType.basicType().wrap();
1262 Class<?>[] ptypes = new Class<?>[arguments.length];
1263 for (int i = 0; i < arguments.length; i++) {
1264 Object arg = arguments[i];
1265 Class<?> ptype = arg == null ? Object.class : arg.getClass();
1266 // If the dest. type is a primitive we keep the
1267 // argument type.
1268 ptypes[i] = dstType.parameterType(i).isPrimitive() ? ptype : Object.class;
1269 }
1270 MethodType argType = MethodType.methodType(srcType.returnType(), ptypes).wrap();
1271 assert(argType.isConvertibleTo(srcType)) : "wrong argument types: cannot convert " + argType + " to " + srcType;
1272 return true;
1273 }
1274
1275 MethodType methodType() {
1276 if (resolvedHandle != null)
1277 return resolvedHandle.type();
1278 else
1279 // only for certain internal LFs during bootstrapping
1280 return member.getInvocationType();
1281 }
1282
1283 MemberName member() {
1284 assert(assertMemberIsConsistent());
1285 return member;
1286 }
1287
1288 // Called only from assert.
1289 private boolean assertMemberIsConsistent() {
1290 if (resolvedHandle instanceof DirectMethodHandle) {
1291 MemberName m = resolvedHandle.internalMemberName();
1292 assert(m.equals(member));
1293 }
1294 return true;
1295 }
1296
1297 Class<?> memberDeclaringClassOrNull() {
1298 return (member == null) ? null : member.getDeclaringClass();
1299 }
1300
1301 BasicType returnType() {
1302 return basicType(methodType().returnType());
1303 }
1304
1305 BasicType parameterType(int n) {
1306 return basicType(methodType().parameterType(n));
1307 }
1308
1309 int arity() {
1310 return methodType().parameterCount();
1311 }
1312
1313 public String toString() {
1314 if (member == null) return String.valueOf(resolvedHandle);
1315 return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1316 }
1317
1318 public boolean isIdentity() {
1319 return this.equals(identity(returnType()));
1320 }
1321
1322 public boolean isConstantZero() {
1323 return this.equals(constantZero(returnType()));
1324 }
1325
1326 public MethodHandleImpl.Intrinsic intrinsicName() {
1327 return resolvedHandle == null ? MethodHandleImpl.Intrinsic.NONE
1328 : resolvedHandle.intrinsicName();
1329 }
1330 }
1331
1332 public static String basicTypeSignature(MethodType type) {
1333 char[] sig = new char[type.parameterCount() + 2];
1334 int sigp = 0;
1335 for (Class<?> pt : type.parameterList()) {
1336 sig[sigp++] = basicTypeChar(pt);
1337 }
1338 sig[sigp++] = '_';
1339 sig[sigp++] = basicTypeChar(type.returnType());
1340 assert(sigp == sig.length);
1341 return String.valueOf(sig);
1342 }
1343 public static String shortenSignature(String signature) {
1344 // Hack to make signatures more readable when they show up in method names.
1345 final int NO_CHAR = -1, MIN_RUN = 3;
1346 int c0, c1 = NO_CHAR, c1reps = 0;
1347 StringBuilder buf = null;
1348 int len = signature.length();
1349 if (len < MIN_RUN) return signature;
1350 for (int i = 0; i <= len; i++) {
1351 // shift in the next char:
1352 c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1353 if (c1 == c0) { ++c1reps; continue; }
1354 // shift in the next count:
1355 int c0reps = c1reps; c1reps = 1;
1356 // end of a character run
1357 if (c0reps < MIN_RUN) {
1358 if (buf != null) {
1359 while (--c0reps >= 0)
1360 buf.append((char)c0);
1361 }
1362 continue;
1363 }
1364 // found three or more in a row
1365 if (buf == null)
1366 buf = new StringBuilder().append(signature, 0, i - c0reps);
1367 buf.append((char)c0).append(c0reps);
1368 }
1369 return (buf == null) ? signature : buf.toString();
1370 }
1371
1372 static final class Name {
1373 final BasicType type;
1374 private short index;
1375 final NamedFunction function;
1376 final Object constraint; // additional type information, if not null
1377 @Stable final Object[] arguments;
1378
1379 private Name(int index, BasicType type, NamedFunction function, Object[] arguments) {
1380 this.index = (short)index;
1381 this.type = type;
1382 this.function = function;
1383 this.arguments = arguments;
1384 this.constraint = null;
1385 assert(this.index == index);
1386 }
1387 private Name(Name that, Object constraint) {
1388 this.index = that.index;
1389 this.type = that.type;
1390 this.function = that.function;
1391 this.arguments = that.arguments;
1392 this.constraint = constraint;
1393 assert(constraint == null || isParam()); // only params have constraints
1394 assert(constraint == null || constraint instanceof BoundMethodHandle.SpeciesData || constraint instanceof Class);
1395 }
1396 Name(MethodHandle function, Object... arguments) {
1397 this(new NamedFunction(function), arguments);
1398 }
1399 Name(MethodType functionType, Object... arguments) {
1400 this(new NamedFunction(functionType), arguments);
1401 assert(arguments[0] instanceof Name && ((Name)arguments[0]).type == L_TYPE);
1402 }
1403 Name(MemberName function, Object... arguments) {
1404 this(new NamedFunction(function), arguments);
1405 }
1406 Name(NamedFunction function, Object... arguments) {
1407 this(-1, function.returnType(), function, arguments = Arrays.copyOf(arguments, arguments.length, Object[].class));
1408 assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1409 for (int i = 0; i < arguments.length; i++)
1410 assert(typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1411 }
1412 /** Create a raw parameter of the given type, with an expected index. */
1413 Name(int index, BasicType type) {
1414 this(index, type, null, null);
1415 }
1416 /** Create a raw parameter of the given type. */
1417 Name(BasicType type) { this(-1, type); }
1418
1419 BasicType type() { return type; }
1420 int index() { return index; }
1421 boolean initIndex(int i) {
1422 if (index != i) {
1423 if (index != -1) return false;
1424 index = (short)i;
1425 }
1426 return true;
1427 }
1428 char typeChar() {
1429 return type.btChar;
1430 }
1431
1432 void resolve() {
1433 if (function != null)
1434 function.resolve();
1435 }
1436
1437 Name newIndex(int i) {
1438 if (initIndex(i)) return this;
1439 return cloneWithIndex(i);
1440 }
1441 Name cloneWithIndex(int i) {
1442 Object[] newArguments = (arguments == null) ? null : arguments.clone();
1443 return new Name(i, type, function, newArguments).withConstraint(constraint);
1444 }
1445 Name withConstraint(Object constraint) {
1446 if (constraint == this.constraint) return this;
1447 return new Name(this, constraint);
1448 }
1449 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1450 if (oldName == newName) return this;
1451 @SuppressWarnings("LocalVariableHidesMemberVariable")
1452 Object[] arguments = this.arguments;
1453 if (arguments == null) return this;
1454 boolean replaced = false;
1455 for (int j = 0; j < arguments.length; j++) {
1456 if (arguments[j] == oldName) {
1457 if (!replaced) {
1458 replaced = true;
1459 arguments = arguments.clone();
1460 }
1461 arguments[j] = newName;
1462 }
1463 }
1464 if (!replaced) return this;
1465 return new Name(function, arguments);
1466 }
1467 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1468 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1469 */
1470 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1471 if (start >= end) return this;
1472 @SuppressWarnings("LocalVariableHidesMemberVariable")
1473 Object[] arguments = this.arguments;
1474 boolean replaced = false;
1475 eachArg:
1476 for (int j = 0; j < arguments.length; j++) {
1477 if (arguments[j] instanceof Name) {
1478 Name n = (Name) arguments[j];
1479 int check = n.index;
1480 // harmless check to see if the thing is already in newNames:
1481 if (check >= 0 && check < newNames.length && n == newNames[check])
1482 continue eachArg;
1483 // n might not have the correct index: n != oldNames[n.index].
1484 for (int i = start; i < end; i++) {
1485 if (n == oldNames[i]) {
1486 if (n == newNames[i])
1487 continue eachArg;
1488 if (!replaced) {
1489 replaced = true;
1490 arguments = arguments.clone();
1491 }
1492 arguments[j] = newNames[i];
1493 continue eachArg;
1494 }
1495 }
1496 }
1497 }
1498 if (!replaced) return this;
1499 return new Name(function, arguments);
1500 }
1501 void internArguments() {
1502 @SuppressWarnings("LocalVariableHidesMemberVariable")
1503 Object[] arguments = this.arguments;
1504 for (int j = 0; j < arguments.length; j++) {
1505 if (arguments[j] instanceof Name) {
1506 Name n = (Name) arguments[j];
1507 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1508 arguments[j] = internArgument(n);
1509 }
1510 }
1511 }
1512 boolean isParam() {
1513 return function == null;
1514 }
1515 boolean isConstantZero() {
1516 return !isParam() && arguments.length == 0 && function.isConstantZero();
1517 }
1518
1519 public String toString() {
1520 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1521 }
1522 public String debugString() {
1523 String s = paramString();
1524 return (function == null) ? s : s + "=" + exprString();
1525 }
1526 public String paramString() {
1527 String s = toString();
1528 Object c = constraint;
1529 if (c == null)
1530 return s;
1531 if (c instanceof Class) c = ((Class<?>)c).getSimpleName();
1532 return s + "/" + c;
1533 }
1534 public String exprString() {
1535 if (function == null) return toString();
1536 StringBuilder buf = new StringBuilder(function.toString());
1537 buf.append("(");
1538 String cma = "";
1539 for (Object a : arguments) {
1540 buf.append(cma); cma = ",";
1541 if (a instanceof Name || a instanceof Integer)
1542 buf.append(a);
1543 else
1544 buf.append("(").append(a).append(")");
1545 }
1546 buf.append(")");
1547 return buf.toString();
1548 }
1549
1550 static boolean typesMatch(BasicType parameterType, Object object) {
1551 if (object instanceof Name) {
1552 return ((Name)object).type == parameterType;
1553 }
1554 switch (parameterType) {
1555 case I_TYPE: return object instanceof Integer;
1556 case J_TYPE: return object instanceof Long;
1557 case F_TYPE: return object instanceof Float;
1558 case D_TYPE: return object instanceof Double;
1559 }
1560 assert(parameterType == L_TYPE);
1561 return true;
1562 }
1563
1564 /** Return the index of the last occurrence of n in the argument array.
1565 * Return -1 if the name is not used.
1566 */
1567 int lastUseIndex(Name n) {
1568 if (arguments == null) return -1;
1569 for (int i = arguments.length; --i >= 0; ) {
1570 if (arguments[i] == n) return i;
1571 }
1572 return -1;
1573 }
1574
1575 /** Return the number of occurrences of n in the argument array.
1576 * Return 0 if the name is not used.
1577 */
1578 int useCount(Name n) {
1579 if (arguments == null) return 0;
1580 int count = 0;
1581 for (int i = arguments.length; --i >= 0; ) {
1582 if (arguments[i] == n) ++count;
1583 }
1584 return count;
1585 }
1586
1587 boolean contains(Name n) {
1588 return this == n || lastUseIndex(n) >= 0;
1589 }
1590
1591 public boolean equals(Name that) {
1592 if (this == that) return true;
1593 if (isParam())
1594 // each parameter is a unique atom
1595 return false; // this != that
1596 return
1597 //this.index == that.index &&
1598 this.type == that.type &&
1599 this.function.equals(that.function) &&
1600 Arrays.equals(this.arguments, that.arguments);
1601 }
1602 @Override
1603 public boolean equals(Object x) {
1604 return x instanceof Name && equals((Name)x);
1605 }
1606 @Override
1607 public int hashCode() {
1608 if (isParam())
1609 return index | (type.ordinal() << 8);
1610 return function.hashCode() ^ Arrays.hashCode(arguments);
1611 }
1612 }
1613
1614 /** Return the index of the last name which contains n as an argument.
1615 * Return -1 if the name is not used. Return names.length if it is the return value.
1616 */
1617 int lastUseIndex(Name n) {
1618 int ni = n.index, nmax = names.length;
1619 assert(names[ni] == n);
1620 if (result == ni) return nmax; // live all the way beyond the end
1621 for (int i = nmax; --i > ni; ) {
1622 if (names[i].lastUseIndex(n) >= 0)
1623 return i;
1624 }
1625 return -1;
1626 }
1627
1628 /** Return the number of times n is used as an argument or return value. */
1629 int useCount(Name n) {
1630 int ni = n.index, nmax = names.length;
1631 int end = lastUseIndex(n);
1632 if (end < 0) return 0;
1633 int count = 0;
1634 if (end == nmax) { count++; end--; }
1635 int beg = n.index() + 1;
1636 if (beg < arity) beg = arity;
1637 for (int i = beg; i <= end; i++) {
1638 count += names[i].useCount(n);
1639 }
1640 return count;
1641 }
1642
1643 static Name argument(int which, char type) {
1644 return argument(which, basicType(type));
1645 }
1646 static Name argument(int which, BasicType type) {
1647 if (which >= INTERNED_ARGUMENT_LIMIT)
1648 return new Name(which, type);
1649 return INTERNED_ARGUMENTS[type.ordinal()][which];
1650 }
1651 static Name internArgument(Name n) {
1652 assert(n.isParam()) : "not param: " + n;
1653 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1654 if (n.constraint != null) return n;
1655 return argument(n.index, n.type);
1656 }
1657 static Name[] arguments(int extra, String types) {
1658 int length = types.length();
1659 Name[] names = new Name[length + extra];
1660 for (int i = 0; i < length; i++)
1661 names[i] = argument(i, types.charAt(i));
1662 return names;
1663 }
1664 static Name[] arguments(int extra, char... types) {
1665 int length = types.length;
1666 Name[] names = new Name[length + extra];
1667 for (int i = 0; i < length; i++)
1668 names[i] = argument(i, types[i]);
1669 return names;
1670 }
1671 static Name[] arguments(int extra, List<Class<?>> types) {
1672 int length = types.size();
1673 Name[] names = new Name[length + extra];
1674 for (int i = 0; i < length; i++)
1675 names[i] = argument(i, basicType(types.get(i)));
1676 return names;
1677 }
1678 static Name[] arguments(int extra, Class<?>... types) {
1679 int length = types.length;
1680 Name[] names = new Name[length + extra];
1681 for (int i = 0; i < length; i++)
1682 names[i] = argument(i, basicType(types[i]));
1683 return names;
1684 }
1685 static Name[] arguments(int extra, MethodType types) {
1686 int length = types.parameterCount();
1687 Name[] names = new Name[length + extra];
1688 for (int i = 0; i < length; i++)
1689 names[i] = argument(i, basicType(types.parameterType(i)));
1690 return names;
1691 }
1692 static final int INTERNED_ARGUMENT_LIMIT = 10;
1693 private static final Name[][] INTERNED_ARGUMENTS
1694 = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1695 static {
1696 for (BasicType type : BasicType.ARG_TYPES) {
1697 int ord = type.ordinal();
1698 for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1699 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1700 }
1701 }
1702 }
1703
1704 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1705
1706 static LambdaForm identityForm(BasicType type) {
1707 return LF_identityForm[type.ordinal()];
1708 }
1709 static LambdaForm zeroForm(BasicType type) {
1710 return LF_zeroForm[type.ordinal()];
1711 }
1712 static NamedFunction identity(BasicType type) {
1713 return NF_identity[type.ordinal()];
1714 }
1715 static NamedFunction constantZero(BasicType type) {
1716 return NF_zero[type.ordinal()];
1717 }
1718 private static final LambdaForm[] LF_identityForm = new LambdaForm[TYPE_LIMIT];
1719 private static final LambdaForm[] LF_zeroForm = new LambdaForm[TYPE_LIMIT];
1720 private static final NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1721 private static final NamedFunction[] NF_zero = new NamedFunction[TYPE_LIMIT];
1722 private static void createIdentityForms() {
1723 for (BasicType type : BasicType.ALL_TYPES) {
1724 int ord = type.ordinal();
1725 char btChar = type.basicTypeChar();
1726 boolean isVoid = (type == V_TYPE);
1727 Class<?> btClass = type.btClass;
1728 MethodType zeType = MethodType.methodType(btClass);
1729 MethodType idType = isVoid ? zeType : zeType.appendParameterTypes(btClass);
1730
1731 // Look up some symbolic names. It might not be necessary to have these,
1732 // but if we need to emit direct references to bytecodes, it helps.
1733 // Zero is built from a call to an identity function with a constant zero input.
1734 MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1735 MemberName zeMem = new MemberName(LambdaForm.class, "zero_"+btChar, zeType, REF_invokeStatic);
1736 try {
1737 zeMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, zeMem, null, NoSuchMethodException.class);
1738 idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, NoSuchMethodException.class);
1739 } catch (IllegalAccessException|NoSuchMethodException ex) {
1740 throw newInternalError(ex);
1741 }
1742
1743 NamedFunction idFun = new NamedFunction(idMem);
1744 LambdaForm idForm;
1745 if (isVoid) {
1746 Name[] idNames = new Name[] { argument(0, L_TYPE) };
1747 idForm = new LambdaForm(idMem.getName(), 1, idNames, VOID_RESULT);
1748 } else {
1749 Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1750 idForm = new LambdaForm(idMem.getName(), 2, idNames, 1);
1751 }
1752 LF_identityForm[ord] = idForm;
1753 NF_identity[ord] = idFun;
1754
1755 NamedFunction zeFun = new NamedFunction(zeMem);
1756 LambdaForm zeForm;
1757 if (isVoid) {
1758 zeForm = idForm;
1759 } else {
1760 Object zeValue = Wrapper.forBasicType(btChar).zero();
1761 Name[] zeNames = new Name[] { argument(0, L_TYPE), new Name(idFun, zeValue) };
1762 zeForm = new LambdaForm(zeMem.getName(), 1, zeNames, 1);
1763 }
1764 LF_zeroForm[ord] = zeForm;
1765 NF_zero[ord] = zeFun;
1766
1767 assert(idFun.isIdentity());
1768 assert(zeFun.isConstantZero());
1769 assert(new Name(zeFun).isConstantZero());
1770 }
1771
1772 // Do this in a separate pass, so that SimpleMethodHandle.make can see the tables.
1773 for (BasicType type : BasicType.ALL_TYPES) {
1774 int ord = type.ordinal();
1775 NamedFunction idFun = NF_identity[ord];
1776 LambdaForm idForm = LF_identityForm[ord];
1777 MemberName idMem = idFun.member;
1778 idFun.resolvedHandle = SimpleMethodHandle.make(idMem.getInvocationType(), idForm);
1779
1780 NamedFunction zeFun = NF_zero[ord];
1781 LambdaForm zeForm = LF_zeroForm[ord];
1782 MemberName zeMem = zeFun.member;
1783 zeFun.resolvedHandle = SimpleMethodHandle.make(zeMem.getInvocationType(), zeForm);
1784
1785 assert(idFun.isIdentity());
1786 assert(zeFun.isConstantZero());
1787 assert(new Name(zeFun).isConstantZero());
1788 }
1789 }
1790
1791 // Avoid appealing to ValueConversions at bootstrap time:
1792 private static int identity_I(int x) { return x; }
1793 private static long identity_J(long x) { return x; }
1794 private static float identity_F(float x) { return x; }
1795 private static double identity_D(double x) { return x; }
1796 private static Object identity_L(Object x) { return x; }
1797 private static void identity_V() { return; } // same as zeroV, but that's OK
1798 private static int zero_I() { return 0; }
1799 private static long zero_J() { return 0; }
1800 private static float zero_F() { return 0; }
1801 private static double zero_D() { return 0; }
1802 private static Object zero_L() { return null; }
1803 private static void zero_V() { return; }
1804
1805 /**
1806 * Internal marker for byte-compiled LambdaForms.
1807 */
1808 /*non-public*/
1809 @Target(ElementType.METHOD)
1810 @Retention(RetentionPolicy.RUNTIME)
1811 @interface Compiled {
1812 }
1813
1814 /**
1815 * Internal marker for LambdaForm interpreter frames.
1816 */
1817 /*non-public*/
1818 @Target(ElementType.METHOD)
1819 @Retention(RetentionPolicy.RUNTIME)
1820 @interface Hidden {
1821 }
1822
1823 private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1824 static {
1825 if (debugEnabled())
1826 DEBUG_NAME_COUNTERS = new HashMap<>();
1827 else
1828 DEBUG_NAME_COUNTERS = null;
1829 }
1830
1831 // Put this last, so that previous static inits can run before.
1832 static {
1833 createIdentityForms();
1834 if (USE_PREDEFINED_INTERPRET_METHODS)
1835 computeInitialPreparedForms();
1836 NamedFunction.initializeInvokers();
1837 }
1838
1839 // The following hack is necessary in order to suppress TRACE_INTERPRETER
1840 // during execution of the static initializes of this class.
1841 // Turning on TRACE_INTERPRETER too early will cause
1842 // stack overflows and other misbehavior during attempts to trace events
1843 // that occur during LambdaForm.<clinit>.
1844 // Therefore, do not move this line higher in this file, and do not remove.
1845 private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1846 }