1 /*
2 * Copyright (c) 2011, 2017, 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 jdk.internal.perf.PerfCounter;
29 import jdk.internal.vm.annotation.DontInline;
30 import jdk.internal.vm.annotation.Stable;
31 import sun.invoke.util.Wrapper;
32
33 import java.lang.annotation.ElementType;
34 import java.lang.annotation.Retention;
35 import java.lang.annotation.RetentionPolicy;
36 import java.lang.annotation.Target;
37 import java.lang.reflect.Method;
38 import java.util.Arrays;
39 import java.util.HashMap;
40
41 import static java.lang.invoke.LambdaForm.BasicType.*;
42 import static java.lang.invoke.MethodHandleNatives.Constants.REF_invokeStatic;
43 import static java.lang.invoke.MethodHandleStatics.*;
44
45 /**
46 * The symbolic, non-executable form of a method handle's invocation semantics.
47 * It consists of a series of names.
48 * The first N (N=arity) names are parameters,
49 * while any remaining names are temporary values.
50 * Each temporary specifies the application of a function to some arguments.
51 * The functions are method handles, while the arguments are mixes of
52 * constant values and local names.
53 * The result of the lambda is defined as one of the names, often the last one.
54 * <p>
55 * Here is an approximate grammar:
56 * <blockquote><pre>{@code
57 * LambdaForm = "(" ArgName* ")=>{" TempName* Result "}"
58 * ArgName = "a" N ":" T
59 * TempName = "t" N ":" T "=" Function "(" Argument* ");"
60 * Function = ConstantValue
61 * Argument = NameRef | ConstantValue
62 * Result = NameRef | "void"
63 * NameRef = "a" N | "t" N
64 * N = (any whole number)
65 * T = "L" | "I" | "J" | "F" | "D" | "V"
66 * }</pre></blockquote>
67 * Names are numbered consecutively from left to right starting at zero.
68 * (The letters are merely a taste of syntax sugar.)
69 * Thus, the first temporary (if any) is always numbered N (where N=arity).
70 * Every occurrence of a name reference in an argument list must refer to
71 * a name previously defined within the same lambda.
72 * A lambda has a void result if and only if its result index is -1.
73 * If a temporary has the type "V", it cannot be the subject of a NameRef,
74 * even though possesses a number.
75 * Note that all reference types are erased to "L", which stands for {@code Object}.
76 * All subword types (boolean, byte, short, char) are erased to "I" which is {@code int}.
77 * The other types stand for the usual primitive types.
78 * <p>
79 * Function invocation closely follows the static rules of the Java verifier.
80 * Arguments and return values must exactly match when their "Name" types are
81 * considered.
82 * Conversions are allowed only if they do not change the erased type.
83 * <ul>
84 * <li>L = Object: casts are used freely to convert into and out of reference types
85 * <li>I = int: subword types are forcibly narrowed when passed as arguments (see {@code explicitCastArguments})
86 * <li>J = long: no implicit conversions
87 * <li>F = float: no implicit conversions
88 * <li>D = double: no implicit conversions
89 * <li>V = void: a function result may be void if and only if its Name is of type "V"
90 * </ul>
91 * Although implicit conversions are not allowed, explicit ones can easily be
92 * encoded by using temporary expressions which call type-transformed identity functions.
93 * <p>
94 * Examples:
95 * <blockquote><pre>{@code
96 * (a0:J)=>{ a0 }
97 * == identity(long)
98 * (a0:I)=>{ t1:V = System.out#println(a0); void }
99 * == System.out#println(int)
100 * (a0:L)=>{ t1:V = System.out#println(a0); a0 }
101 * == identity, with printing side-effect
102 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
103 * t3:L = BoundMethodHandle#target(a0);
104 * t4:L = MethodHandle#invoke(t3, t2, a1); t4 }
105 * == general invoker for unary insertArgument combination
106 * (a0:L, a1:L)=>{ t2:L = FilterMethodHandle#filter(a0);
107 * t3:L = MethodHandle#invoke(t2, a1);
108 * t4:L = FilterMethodHandle#target(a0);
109 * t5:L = MethodHandle#invoke(t4, t3); t5 }
110 * == general invoker for unary filterArgument combination
111 * (a0:L, a1:L)=>{ ...(same as previous example)...
112 * t5:L = MethodHandle#invoke(t4, t3, a1); t5 }
113 * == general invoker for unary/unary foldArgument combination
114 * (a0:L, a1:I)=>{ t2:I = identity(long).asType((int)->long)(a1); t2 }
115 * == invoker for identity method handle which performs i2l
116 * (a0:L, a1:L)=>{ t2:L = BoundMethodHandle#argument(a0);
117 * t3:L = Class#cast(t2,a1); t3 }
118 * == invoker for identity method handle which performs cast
119 * }</pre></blockquote>
120 * <p>
121 * @author John Rose, JSR 292 EG
122 */
123 class LambdaForm {
124 final int arity;
125 final int result;
126 final boolean forceInline;
127 final MethodHandle customized;
128 @Stable final Name[] names;
129 final Kind kind;
130 MemberName vmentry; // low-level behavior, or null if not yet prepared
131 private boolean isCompiled;
132
133 // Either a LambdaForm cache (managed by LambdaFormEditor) or a link to uncustomized version (for customized LF)
134 volatile Object transformCache;
135
136 public static final int VOID_RESULT = -1, LAST_RESULT = -2;
137
138 enum BasicType {
139 L_TYPE('L', Object.class, Wrapper.OBJECT), // all reference types
140 I_TYPE('I', int.class, Wrapper.INT),
141 J_TYPE('J', long.class, Wrapper.LONG),
142 F_TYPE('F', float.class, Wrapper.FLOAT),
143 D_TYPE('D', double.class, Wrapper.DOUBLE), // all primitive types
144 V_TYPE('V', void.class, Wrapper.VOID); // not valid in all contexts
145
146 static final @Stable BasicType[] ALL_TYPES = BasicType.values();
147 static final @Stable BasicType[] ARG_TYPES = Arrays.copyOf(ALL_TYPES, ALL_TYPES.length-1);
148
149 static final int ARG_TYPE_LIMIT = ARG_TYPES.length;
150 static final int TYPE_LIMIT = ALL_TYPES.length;
151
152 // Derived int constants, which (unlike the enums) can be constant folded.
153 // We can remove them when JDK-8161245 is fixed.
154 static final byte
155 L_TYPE_NUM = (byte) L_TYPE.ordinal(),
156 I_TYPE_NUM = (byte) I_TYPE.ordinal(),
157 J_TYPE_NUM = (byte) J_TYPE.ordinal(),
158 F_TYPE_NUM = (byte) F_TYPE.ordinal(),
159 D_TYPE_NUM = (byte) D_TYPE.ordinal(),
160 V_TYPE_NUM = (byte) V_TYPE.ordinal();
161
162 final char btChar;
163 final Class<?> btClass;
164 final Wrapper btWrapper;
165
166 private BasicType(char btChar, Class<?> btClass, Wrapper wrapper) {
167 this.btChar = btChar;
168 this.btClass = btClass;
169 this.btWrapper = wrapper;
170 }
171
172 char basicTypeChar() {
173 return btChar;
174 }
175 Class<?> basicTypeClass() {
176 return btClass;
177 }
178 Wrapper basicTypeWrapper() {
179 return btWrapper;
180 }
181 int basicTypeSlots() {
182 return btWrapper.stackSlots();
183 }
184
185 static BasicType basicType(byte type) {
186 return ALL_TYPES[type];
187 }
188 static BasicType basicType(char type) {
189 switch (type) {
190 case 'L': return L_TYPE;
191 case 'I': return I_TYPE;
192 case 'J': return J_TYPE;
193 case 'F': return F_TYPE;
194 case 'D': return D_TYPE;
195 case 'V': return V_TYPE;
196 // all subword types are represented as ints
197 case 'Z':
198 case 'B':
199 case 'S':
200 case 'C':
201 return I_TYPE;
202 default:
203 throw newInternalError("Unknown type char: '"+type+"'");
204 }
205 }
206 static BasicType basicType(Wrapper type) {
207 char c = type.basicTypeChar();
208 return basicType(c);
209 }
210 static BasicType basicType(Class<?> type) {
211 if (!type.isPrimitive()) return L_TYPE;
212 return basicType(Wrapper.forPrimitiveType(type));
213 }
214 static BasicType[] basicTypes(String types) {
215 BasicType[] btypes = new BasicType[types.length()];
216 for (int i = 0; i < btypes.length; i++) {
217 btypes[i] = basicType(types.charAt(i));
218 }
219 return btypes;
220 }
221 static String basicTypeDesc(BasicType[] types) {
222 if (types == null) {
223 return null;
224 }
225 if (types.length == 0) {
226 return "";
227 }
228 StringBuilder sb = new StringBuilder();
229 for (BasicType bt : types) {
230 sb.append(bt.basicTypeChar());
231 }
232 return sb.toString();
233 }
234 static int[] basicTypeOrds(BasicType[] types) {
235 if (types == null) {
236 return null;
237 }
238 int[] a = new int[types.length];
239 for(int i = 0; i < types.length; ++i) {
240 a[i] = types[i].ordinal();
241 }
242 return a;
243 }
244
245 static char basicTypeChar(Class<?> type) {
246 return basicType(type).btChar;
247 }
248
249 static byte[] basicTypesOrd(Class<?>[] types) {
250 byte[] ords = new byte[types.length];
251 for (int i = 0; i < ords.length; i++) {
252 ords[i] = (byte)basicType(types[i]).ordinal();
253 }
254 return ords;
255 }
256
257 static boolean isBasicTypeChar(char c) {
258 return "LIJFDV".indexOf(c) >= 0;
259 }
260 static boolean isArgBasicTypeChar(char c) {
261 return "LIJFD".indexOf(c) >= 0;
262 }
263
264 static { assert(checkBasicType()); }
265 private static boolean checkBasicType() {
266 for (int i = 0; i < ARG_TYPE_LIMIT; i++) {
267 assert ARG_TYPES[i].ordinal() == i;
268 assert ARG_TYPES[i] == ALL_TYPES[i];
269 }
270 for (int i = 0; i < TYPE_LIMIT; i++) {
271 assert ALL_TYPES[i].ordinal() == i;
272 }
273 assert ALL_TYPES[TYPE_LIMIT - 1] == V_TYPE;
274 assert !Arrays.asList(ARG_TYPES).contains(V_TYPE);
275 return true;
276 }
277 }
278
279 enum Kind {
280 GENERIC("invoke"),
281 ZERO("zero"),
282 IDENTITY("identity"),
283 BOUND_REINVOKER("BMH.reinvoke", "reinvoke"),
284 REINVOKER("MH.reinvoke", "reinvoke"),
285 DELEGATE("MH.delegate", "delegate"),
286 EXACT_LINKER("MH.invokeExact_MT", "invokeExact_MT"),
287 EXACT_INVOKER("MH.exactInvoker", "exactInvoker"),
288 GENERIC_LINKER("MH.invoke_MT", "invoke_MT"),
289 GENERIC_INVOKER("MH.invoker", "invoker"),
290 LINK_TO_TARGET_METHOD("linkToTargetMethod"),
291 LINK_TO_CALL_SITE("linkToCallSite"),
292 DIRECT_INVOKE_VIRTUAL("DMH.invokeVirtual", "invokeVirtual"),
293 DIRECT_INVOKE_SPECIAL("DMH.invokeSpecial", "invokeSpecial"),
294 DIRECT_INVOKE_STATIC("DMH.invokeStatic", "invokeStatic"),
295 DIRECT_NEW_INVOKE_SPECIAL("DMH.newInvokeSpecial", "newInvokeSpecial"),
296 DIRECT_INVOKE_INTERFACE("DMH.invokeInterface", "invokeInterface"),
297 DIRECT_INVOKE_STATIC_INIT("DMH.invokeStaticInit", "invokeStaticInit"),
298 GET_OBJECT("getObject"),
299 PUT_OBJECT("putObject"),
300 GET_OBJECT_VOLATILE("getObjectVolatile"),
301 PUT_OBJECT_VOLATILE("putObjectVolatile"),
302 GET_INT("getInt"),
303 PUT_INT("putInt"),
304 GET_INT_VOLATILE("getIntVolatile"),
305 PUT_INT_VOLATILE("putIntVolatile"),
306 GET_BOOLEAN("getBoolean"),
307 PUT_BOOLEAN("putBoolean"),
308 GET_BOOLEAN_VOLATILE("getBooleanVolatile"),
309 PUT_BOOLEAN_VOLATILE("putBooleanVolatile"),
310 GET_BYTE("getByte"),
311 PUT_BYTE("putByte"),
312 GET_BYTE_VOLATILE("getByteVolatile"),
313 PUT_BYTE_VOLATILE("putByteVolatile"),
314 GET_CHAR("getChar"),
315 PUT_CHAR("putChar"),
316 GET_CHAR_VOLATILE("getCharVolatile"),
317 PUT_CHAR_VOLATILE("putCharVolatile"),
318 GET_SHORT("getShort"),
319 PUT_SHORT("putShort"),
320 GET_SHORT_VOLATILE("getShortVolatile"),
321 PUT_SHORT_VOLATILE("putShortVolatile"),
322 GET_LONG("getLong"),
323 PUT_LONG("putLong"),
324 GET_LONG_VOLATILE("getLongVolatile"),
325 PUT_LONG_VOLATILE("putLongVolatile"),
326 GET_FLOAT("getFloat"),
327 PUT_FLOAT("putFloat"),
328 GET_FLOAT_VOLATILE("getFloatVolatile"),
329 PUT_FLOAT_VOLATILE("putFloatVolatile"),
330 GET_DOUBLE("getDouble"),
331 PUT_DOUBLE("putDouble"),
332 GET_DOUBLE_VOLATILE("getDoubleVolatile"),
333 PUT_DOUBLE_VOLATILE("putDoubleVolatile"),
334 TRY_FINALLY("tryFinally"),
335 COLLECT("collect"),
336 CONVERT("convert"),
337 SPREAD("spread"),
338 LOOP("loop"),
339 FIELD("field"),
340 GUARD("guard"),
341 GUARD_WITH_CATCH("guardWithCatch"),
342 VARHANDLE_EXACT_INVOKER("VH.exactInvoker"),
343 VARHANDLE_INVOKER("VH.invoker", "invoker"),
344 VARHANDLE_LINKER("VH.invoke_MT", "invoke_MT");
345
346 final String defaultLambdaName;
347 final String methodName;
348
349 private Kind(String defaultLambdaName) {
350 this(defaultLambdaName, defaultLambdaName);
351 }
352
353 private Kind(String defaultLambdaName, String methodName) {
354 this.defaultLambdaName = defaultLambdaName;
355 this.methodName = methodName;
356 }
357 }
358
359 LambdaForm(int arity, Name[] names, int result) {
360 this(arity, names, result, /*forceInline=*/true, /*customized=*/null, Kind.GENERIC);
361 }
362 LambdaForm(int arity, Name[] names, int result, Kind kind) {
363 this(arity, names, result, /*forceInline=*/true, /*customized=*/null, kind);
364 }
365 LambdaForm(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized) {
366 this(arity, names, result, forceInline, customized, Kind.GENERIC);
367 }
368 LambdaForm(int arity, Name[] names, int result, boolean forceInline, MethodHandle customized, Kind kind) {
369 assert(namesOK(arity, names));
370 this.arity = arity;
371 this.result = fixResult(result, names);
372 this.names = names.clone();
373 this.forceInline = forceInline;
374 this.customized = customized;
375 this.kind = kind;
376 int maxOutArity = normalize();
377 if (maxOutArity > MethodType.MAX_MH_INVOKER_ARITY) {
378 // Cannot use LF interpreter on very high arity expressions.
379 assert(maxOutArity <= MethodType.MAX_JVM_ARITY);
380 compileToBytecode();
381 }
382 }
383 LambdaForm(int arity, Name[] names) {
384 this(arity, names, LAST_RESULT, /*forceInline=*/true, /*customized=*/null, Kind.GENERIC);
385 }
386 LambdaForm(int arity, Name[] names, Kind kind) {
387 this(arity, names, LAST_RESULT, /*forceInline=*/true, /*customized=*/null, kind);
388 }
389 LambdaForm(int arity, Name[] names, boolean forceInline) {
390 this(arity, names, LAST_RESULT, forceInline, /*customized=*/null, Kind.GENERIC);
391 }
392 LambdaForm(int arity, Name[] names, boolean forceInline, Kind kind) {
393 this(arity, names, LAST_RESULT, forceInline, /*customized=*/null, kind);
394 }
395 LambdaForm(Name[] formals, Name[] temps, Name result) {
396 this(formals.length, buildNames(formals, temps, result), LAST_RESULT, /*forceInline=*/true, /*customized=*/null);
397 }
398 LambdaForm(Name[] formals, Name[] temps, Name result, boolean forceInline) {
399 this(formals.length, buildNames(formals, temps, result), LAST_RESULT, forceInline, /*customized=*/null);
400 }
401
402 private static Name[] buildNames(Name[] formals, Name[] temps, Name result) {
403 int arity = formals.length;
404 int length = arity + temps.length + (result == null ? 0 : 1);
405 Name[] names = Arrays.copyOf(formals, length);
406 System.arraycopy(temps, 0, names, arity, temps.length);
407 if (result != null)
408 names[length - 1] = result;
409 return names;
410 }
411
412 private LambdaForm(MethodType mt) {
413 // Make a blank lambda form, which returns a constant zero or null.
414 // It is used as a template for managing the invocation of similar forms that are non-empty.
415 // Called only from getPreparedForm.
416 this.arity = mt.parameterCount();
417 this.result = (mt.returnType() == void.class || mt.returnType() == Void.class) ? -1 : arity;
418 this.names = buildEmptyNames(arity, mt, result == -1);
419 this.forceInline = true;
420 this.customized = null;
421 this.kind = Kind.ZERO;
422 assert(nameRefsAreLegal());
423 assert(isEmpty());
424 String sig = null;
425 assert(isValidSignature(sig = basicTypeSignature()));
426 assert(sig.equals(basicTypeSignature())) : sig + " != " + basicTypeSignature();
427 }
428
429 private static Name[] buildEmptyNames(int arity, MethodType mt, boolean isVoid) {
430 Name[] names = arguments(isVoid ? 0 : 1, mt);
431 if (!isVoid) {
432 Name zero = new Name(constantZero(basicType(mt.returnType())));
433 names[arity] = zero.newIndex(arity);
434 }
435 return names;
436 }
437
438 private static int fixResult(int result, Name[] names) {
439 if (result == LAST_RESULT)
440 result = names.length - 1; // might still be void
441 if (result >= 0 && names[result].type == V_TYPE)
442 result = VOID_RESULT;
443 return result;
444 }
445
446 static boolean debugNames() {
447 return DEBUG_NAME_COUNTERS != null;
448 }
449
450 static void associateWithDebugName(LambdaForm form, String name) {
451 assert (debugNames());
452 synchronized (DEBUG_NAMES) {
453 DEBUG_NAMES.put(form, name);
454 }
455 }
456
457 String lambdaName() {
458 if (DEBUG_NAMES != null) {
459 synchronized (DEBUG_NAMES) {
460 String name = DEBUG_NAMES.get(this);
461 if (name == null) {
462 name = generateDebugName();
463 }
464 return name;
465 }
466 }
467 return kind.defaultLambdaName;
468 }
469
470 private String generateDebugName() {
471 assert (debugNames());
472 String debugNameStem = kind.defaultLambdaName;
473 Integer ctr = DEBUG_NAME_COUNTERS.getOrDefault(debugNameStem, 0);
474 DEBUG_NAME_COUNTERS.put(debugNameStem, ctr + 1);
475 StringBuilder buf = new StringBuilder(debugNameStem);
476 int leadingZero = buf.length();
477 buf.append((int) ctr);
478 for (int i = buf.length() - leadingZero; i < 3; i++) {
479 buf.insert(leadingZero, '0');
480 }
481 buf.append('_');
482 buf.append(basicTypeSignature());
483 String name = buf.toString();
484 associateWithDebugName(this, name);
485 return name;
486 }
487
488 private static boolean namesOK(int arity, Name[] names) {
489 for (int i = 0; i < names.length; i++) {
490 Name n = names[i];
491 assert(n != null) : "n is null";
492 if (i < arity)
493 assert( n.isParam()) : n + " is not param at " + i;
494 else
495 assert(!n.isParam()) : n + " is param at " + i;
496 }
497 return true;
498 }
499
500 /** Customize LambdaForm for a particular MethodHandle */
501 LambdaForm customize(MethodHandle mh) {
502 LambdaForm customForm = new LambdaForm(arity, names, result, forceInline, mh, kind);
503 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
504 // If shared LambdaForm has been compiled, compile customized version as well.
505 customForm.compileToBytecode();
506 }
507 customForm.transformCache = this; // LambdaFormEditor should always use uncustomized form.
508 return customForm;
509 }
510
511 /** Get uncustomized flavor of the LambdaForm */
512 LambdaForm uncustomize() {
513 if (customized == null) {
514 return this;
515 }
516 assert(transformCache != null); // Customized LambdaForm should always has a link to uncustomized version.
517 LambdaForm uncustomizedForm = (LambdaForm)transformCache;
518 if (COMPILE_THRESHOLD >= 0 && isCompiled) {
519 // If customized LambdaForm has been compiled, compile uncustomized version as well.
520 uncustomizedForm.compileToBytecode();
521 }
522 return uncustomizedForm;
523 }
524
525 /** Renumber and/or replace params so that they are interned and canonically numbered.
526 * @return maximum argument list length among the names (since we have to pass over them anyway)
527 */
528 private int normalize() {
529 Name[] oldNames = null;
530 int maxOutArity = 0;
531 int changesStart = 0;
532 for (int i = 0; i < names.length; i++) {
533 Name n = names[i];
534 if (!n.initIndex(i)) {
535 if (oldNames == null) {
536 oldNames = names.clone();
537 changesStart = i;
538 }
539 names[i] = n.cloneWithIndex(i);
540 }
541 if (n.arguments != null && maxOutArity < n.arguments.length)
542 maxOutArity = n.arguments.length;
543 }
544 if (oldNames != null) {
545 int startFixing = arity;
546 if (startFixing <= changesStart)
547 startFixing = changesStart+1;
548 for (int i = startFixing; i < names.length; i++) {
549 Name fixed = names[i].replaceNames(oldNames, names, changesStart, i);
550 names[i] = fixed.newIndex(i);
551 }
552 }
553 assert(nameRefsAreLegal());
554 int maxInterned = Math.min(arity, INTERNED_ARGUMENT_LIMIT);
555 boolean needIntern = false;
556 for (int i = 0; i < maxInterned; i++) {
557 Name n = names[i], n2 = internArgument(n);
558 if (n != n2) {
559 names[i] = n2;
560 needIntern = true;
561 }
562 }
563 if (needIntern) {
564 for (int i = arity; i < names.length; i++) {
565 names[i].internArguments();
566 }
567 }
568 assert(nameRefsAreLegal());
569 return maxOutArity;
570 }
571
572 /**
573 * Check that all embedded Name references are localizable to this lambda,
574 * and are properly ordered after their corresponding definitions.
575 * <p>
576 * Note that a Name can be local to multiple lambdas, as long as
577 * it possesses the same index in each use site.
578 * This allows Name references to be freely reused to construct
579 * fresh lambdas, without confusion.
580 */
581 boolean nameRefsAreLegal() {
582 assert(arity >= 0 && arity <= names.length);
583 assert(result >= -1 && result < names.length);
584 // Do all names possess an index consistent with their local definition order?
585 for (int i = 0; i < arity; i++) {
586 Name n = names[i];
587 assert(n.index() == i) : Arrays.asList(n.index(), i);
588 assert(n.isParam());
589 }
590 // Also, do all local name references
591 for (int i = arity; i < names.length; i++) {
592 Name n = names[i];
593 assert(n.index() == i);
594 for (Object arg : n.arguments) {
595 if (arg instanceof Name) {
596 Name n2 = (Name) arg;
597 int i2 = n2.index;
598 assert(0 <= i2 && i2 < names.length) : n.debugString() + ": 0 <= i2 && i2 < names.length: 0 <= " + i2 + " < " + names.length;
599 assert(names[i2] == n2) : Arrays.asList("-1-", i, "-2-", n.debugString(), "-3-", i2, "-4-", n2.debugString(), "-5-", names[i2].debugString(), "-6-", this);
600 assert(i2 < i); // ref must come after def!
601 }
602 }
603 }
604 return true;
605 }
606
607 /** Invoke this form on the given arguments. */
608 // final Object invoke(Object... args) throws Throwable {
609 // // NYI: fit this into the fast path?
610 // return interpretWithArguments(args);
611 // }
612
613 /** Report the return type. */
614 BasicType returnType() {
615 if (result < 0) return V_TYPE;
616 Name n = names[result];
617 return n.type;
618 }
619
620 /** Report the N-th argument type. */
621 BasicType parameterType(int n) {
622 return parameter(n).type;
623 }
624
625 /** Report the N-th argument name. */
626 Name parameter(int n) {
627 assert(n < arity);
628 Name param = names[n];
629 assert(param.isParam());
630 return param;
631 }
632
633 /** Report the N-th argument type constraint. */
634 Object parameterConstraint(int n) {
635 return parameter(n).constraint;
636 }
637
638 /** Report the arity. */
639 int arity() {
640 return arity;
641 }
642
643 /** Report the number of expressions (non-parameter names). */
644 int expressionCount() {
645 return names.length - arity;
646 }
647
648 /** Return the method type corresponding to my basic type signature. */
649 MethodType methodType() {
650 Class<?>[] ptypes = new Class<?>[arity];
651 for (int i = 0; i < arity; ++i) {
652 ptypes[i] = parameterType(i).btClass;
653 }
654 return MethodType.makeImpl(returnType().btClass, ptypes, true);
655 }
656
657 /** Return ABC_Z, where the ABC are parameter type characters, and Z is the return type character. */
658 final String basicTypeSignature() {
659 StringBuilder buf = new StringBuilder(arity() + 3);
660 for (int i = 0, a = arity(); i < a; i++)
661 buf.append(parameterType(i).basicTypeChar());
662 return buf.append('_').append(returnType().basicTypeChar()).toString();
663 }
664 static int signatureArity(String sig) {
665 assert(isValidSignature(sig));
666 return sig.indexOf('_');
667 }
668 static BasicType signatureReturn(String sig) {
669 return basicType(sig.charAt(signatureArity(sig) + 1));
670 }
671 static boolean isValidSignature(String sig) {
672 int arity = sig.indexOf('_');
673 if (arity < 0) return false; // must be of the form *_*
674 int siglen = sig.length();
675 if (siglen != arity + 2) return false; // *_X
676 for (int i = 0; i < siglen; i++) {
677 if (i == arity) continue; // skip '_'
678 char c = sig.charAt(i);
679 if (c == 'V')
680 return (i == siglen - 1 && arity == siglen - 2);
681 if (!isArgBasicTypeChar(c)) return false; // must be [LIJFD]
682 }
683 return true; // [LIJFD]*_[LIJFDV]
684 }
685 static MethodType signatureType(String sig) {
686 Class<?>[] ptypes = new Class<?>[signatureArity(sig)];
687 for (int i = 0; i < ptypes.length; i++)
688 ptypes[i] = basicType(sig.charAt(i)).btClass;
689 Class<?> rtype = signatureReturn(sig).btClass;
690 return MethodType.makeImpl(rtype, ptypes, true);
691 }
692 static MethodType basicMethodType(MethodType mt) {
693 return signatureType(basicTypeSignature(mt));
694 }
695
696 /**
697 * Check if i-th name is a call to MethodHandleImpl.selectAlternative.
698 */
699 boolean isSelectAlternative(int pos) {
700 // selectAlternative idiom:
701 // t_{n}:L=MethodHandleImpl.selectAlternative(...)
702 // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
703 if (pos+1 >= names.length) return false;
704 Name name0 = names[pos];
705 Name name1 = names[pos+1];
706 return name0.refersTo(MethodHandleImpl.class, "selectAlternative") &&
707 name1.isInvokeBasic() &&
708 name1.lastUseIndex(name0) == 0 && // t_{n+1}:?=MethodHandle.invokeBasic(t_{n}, ...)
709 lastUseIndex(name0) == pos+1; // t_{n} is local: used only in t_{n+1}
710 }
711
712 private boolean isMatchingIdiom(int pos, String idiomName, int nArgs) {
713 if (pos+2 >= names.length) return false;
714 Name name0 = names[pos];
715 Name name1 = names[pos+1];
716 Name name2 = names[pos+2];
717 return name1.refersTo(MethodHandleImpl.class, idiomName) &&
718 name0.isInvokeBasic() &&
719 name2.isInvokeBasic() &&
720 name1.lastUseIndex(name0) == nArgs && // t_{n+1}:L=MethodHandleImpl.<invoker>(<args>, t_{n});
721 lastUseIndex(name0) == pos+1 && // t_{n} is local: used only in t_{n+1}
722 name2.lastUseIndex(name1) == 1 && // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
723 lastUseIndex(name1) == pos+2; // t_{n+1} is local: used only in t_{n+2}
724 }
725
726 /**
727 * Check if i-th name is a start of GuardWithCatch idiom.
728 */
729 boolean isGuardWithCatch(int pos) {
730 // GuardWithCatch idiom:
731 // t_{n}:L=MethodHandle.invokeBasic(...)
732 // t_{n+1}:L=MethodHandleImpl.guardWithCatch(*, *, *, t_{n});
733 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
734 return isMatchingIdiom(pos, "guardWithCatch", 3);
735 }
736
737 /**
738 * Check if i-th name is a start of the tryFinally idiom.
739 */
740 boolean isTryFinally(int pos) {
741 // tryFinally idiom:
742 // t_{n}:L=MethodHandle.invokeBasic(...)
743 // t_{n+1}:L=MethodHandleImpl.tryFinally(*, *, t_{n})
744 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
745 return isMatchingIdiom(pos, "tryFinally", 2);
746 }
747
748 /**
749 * Check if i-th name is a start of the loop idiom.
750 */
751 boolean isLoop(int pos) {
752 // loop idiom:
753 // t_{n}:L=MethodHandle.invokeBasic(...)
754 // t_{n+1}:L=MethodHandleImpl.loop(types, *, t_{n})
755 // t_{n+2}:?=MethodHandle.invokeBasic(*, t_{n+1})
756 return isMatchingIdiom(pos, "loop", 2);
757 }
758
759 /*
760 * Code generation issues:
761 *
762 * Compiled LFs should be reusable in general.
763 * The biggest issue is how to decide when to pull a name into
764 * the bytecode, versus loading a reified form from the MH data.
765 *
766 * For example, an asType wrapper may require execution of a cast
767 * after a call to a MH. The target type of the cast can be placed
768 * as a constant in the LF itself. This will force the cast type
769 * to be compiled into the bytecodes and native code for the MH.
770 * Or, the target type of the cast can be erased in the LF, and
771 * loaded from the MH data. (Later on, if the MH as a whole is
772 * inlined, the data will flow into the inlined instance of the LF,
773 * as a constant, and the end result will be an optimal cast.)
774 *
775 * This erasure of cast types can be done with any use of
776 * reference types. It can also be done with whole method
777 * handles. Erasing a method handle might leave behind
778 * LF code that executes correctly for any MH of a given
779 * type, and load the required MH from the enclosing MH's data.
780 * Or, the erasure might even erase the expected MT.
781 *
782 * Also, for direct MHs, the MemberName of the target
783 * could be erased, and loaded from the containing direct MH.
784 * As a simple case, a LF for all int-valued non-static
785 * field getters would perform a cast on its input argument
786 * (to non-constant base type derived from the MemberName)
787 * and load an integer value from the input object
788 * (at a non-constant offset also derived from the MemberName).
789 * Such MN-erased LFs would be inlinable back to optimized
790 * code, whenever a constant enclosing DMH is available
791 * to supply a constant MN from its data.
792 *
793 * The main problem here is to keep LFs reasonably generic,
794 * while ensuring that hot spots will inline good instances.
795 * "Reasonably generic" means that we don't end up with
796 * repeated versions of bytecode or machine code that do
797 * not differ in their optimized form. Repeated versions
798 * of machine would have the undesirable overheads of
799 * (a) redundant compilation work and (b) extra I$ pressure.
800 * To control repeated versions, we need to be ready to
801 * erase details from LFs and move them into MH data,
802 * whevener those details are not relevant to significant
803 * optimization. "Significant" means optimization of
804 * code that is actually hot.
805 *
806 * Achieving this may require dynamic splitting of MHs, by replacing
807 * a generic LF with a more specialized one, on the same MH,
808 * if (a) the MH is frequently executed and (b) the MH cannot
809 * be inlined into a containing caller, such as an invokedynamic.
810 *
811 * Compiled LFs that are no longer used should be GC-able.
812 * If they contain non-BCP references, they should be properly
813 * interlinked with the class loader(s) that their embedded types
814 * depend on. This probably means that reusable compiled LFs
815 * will be tabulated (indexed) on relevant class loaders,
816 * or else that the tables that cache them will have weak links.
817 */
818
819 /**
820 * Make this LF directly executable, as part of a MethodHandle.
821 * Invariant: Every MH which is invoked must prepare its LF
822 * before invocation.
823 * (In principle, the JVM could do this very lazily,
824 * as a sort of pre-invocation linkage step.)
825 */
826 public void prepare() {
827 if (COMPILE_THRESHOLD == 0 && !forceInterpretation() && !isCompiled) {
828 compileToBytecode();
829 }
830 if (this.vmentry != null) {
831 // already prepared (e.g., a primitive DMH invoker form)
832 return;
833 }
834 MethodType mtype = methodType();
835 LambdaForm prep = mtype.form().cachedLambdaForm(MethodTypeForm.LF_INTERPRET);
836 if (prep == null) {
837 assert (isValidSignature(basicTypeSignature()));
838 prep = new LambdaForm(mtype);
839 prep.vmentry = InvokerBytecodeGenerator.generateLambdaFormInterpreterEntryPoint(mtype);
840 prep = mtype.form().setCachedLambdaForm(MethodTypeForm.LF_INTERPRET, prep);
841 }
842 this.vmentry = prep.vmentry;
843 // TO DO: Maybe add invokeGeneric, invokeWithArguments
844 }
845
846 private static @Stable PerfCounter LF_FAILED;
847
848 private static PerfCounter failedCompilationCounter() {
849 if (LF_FAILED == null) {
850 LF_FAILED = PerfCounter.newPerfCounter("java.lang.invoke.failedLambdaFormCompilations");
851 }
852 return LF_FAILED;
853 }
854
855 /** Generate optimizable bytecode for this form. */
856 void compileToBytecode() {
857 if (forceInterpretation()) {
858 return; // this should not be compiled
859 }
860 if (vmentry != null && isCompiled) {
861 return; // already compiled somehow
862 }
863
864 // Obtain the invoker MethodType outside of the following try block.
865 // This ensures that an IllegalArgumentException is directly thrown if the
866 // type would have 256 or more parameters
867 MethodType invokerType = methodType();
868 assert(vmentry == null || vmentry.getMethodType().basicType().equals(invokerType));
869 try {
870 vmentry = InvokerBytecodeGenerator.generateCustomizedCode(this, invokerType);
871 if (TRACE_INTERPRETER)
872 traceInterpreter("compileToBytecode", this);
873 isCompiled = true;
874 } catch (InvokerBytecodeGenerator.BytecodeGenerationException bge) {
875 // bytecode generation failed - mark this LambdaForm as to be run in interpretation mode only
876 invocationCounter = -1;
877 failedCompilationCounter().increment();
878 if (LOG_LF_COMPILATION_FAILURE) {
879 System.out.println("LambdaForm compilation failed: " + this);
880 bge.printStackTrace(System.out);
881 }
882 } catch (Error e) {
883 // Pass through any error
884 throw e;
885 } catch (Exception e) {
886 // Wrap any exception
887 throw newInternalError(this.toString(), e);
888 }
889 }
890
891 // The next few routines are called only from assert expressions
892 // They verify that the built-in invokers process the correct raw data types.
893 private static boolean argumentTypesMatch(String sig, Object[] av) {
894 int arity = signatureArity(sig);
895 assert(av.length == arity) : "av.length == arity: av.length=" + av.length + ", arity=" + arity;
896 assert(av[0] instanceof MethodHandle) : "av[0] not instace of MethodHandle: " + av[0];
897 MethodHandle mh = (MethodHandle) av[0];
898 MethodType mt = mh.type();
899 assert(mt.parameterCount() == arity-1);
900 for (int i = 0; i < av.length; i++) {
901 Class<?> pt = (i == 0 ? MethodHandle.class : mt.parameterType(i-1));
902 assert(valueMatches(basicType(sig.charAt(i)), pt, av[i]));
903 }
904 return true;
905 }
906 private static boolean valueMatches(BasicType tc, Class<?> type, Object x) {
907 // The following line is needed because (...)void method handles can use non-void invokers
908 if (type == void.class) tc = V_TYPE; // can drop any kind of value
909 assert tc == basicType(type) : tc + " == basicType(" + type + ")=" + basicType(type);
910 switch (tc) {
911 case I_TYPE: assert checkInt(type, x) : "checkInt(" + type + "," + x +")"; break;
912 case J_TYPE: assert x instanceof Long : "instanceof Long: " + x; break;
913 case F_TYPE: assert x instanceof Float : "instanceof Float: " + x; break;
914 case D_TYPE: assert x instanceof Double : "instanceof Double: " + x; break;
915 case L_TYPE: assert checkRef(type, x) : "checkRef(" + type + "," + x + ")"; break;
916 case V_TYPE: break; // allow anything here; will be dropped
917 default: assert(false);
918 }
919 return true;
920 }
921 private static boolean checkInt(Class<?> type, Object x) {
922 assert(x instanceof Integer);
923 if (type == int.class) return true;
924 Wrapper w = Wrapper.forBasicType(type);
925 assert(w.isSubwordOrInt());
926 Object x1 = Wrapper.INT.wrap(w.wrap(x));
927 return x.equals(x1);
928 }
929 private static boolean checkRef(Class<?> type, Object x) {
930 assert(!type.isPrimitive());
931 if (x == null) return true;
932 if (type.isInterface()) return true;
933 return type.isInstance(x);
934 }
935
936 /** If the invocation count hits the threshold we spin bytecodes and call that subsequently. */
937 private static final int COMPILE_THRESHOLD;
938 static {
939 COMPILE_THRESHOLD = Math.max(-1, MethodHandleStatics.COMPILE_THRESHOLD);
940 }
941 private int invocationCounter = 0; // a value of -1 indicates LambdaForm interpretation mode forever
942
943 private boolean forceInterpretation() {
944 return invocationCounter == -1;
945 }
946
947 @Hidden
948 @DontInline
949 /** Interpretively invoke this form on the given arguments. */
950 Object interpretWithArguments(Object... argumentValues) throws Throwable {
951 if (TRACE_INTERPRETER)
952 return interpretWithArgumentsTracing(argumentValues);
953 checkInvocationCounter();
954 assert(arityCheck(argumentValues));
955 Object[] values = Arrays.copyOf(argumentValues, names.length);
956 for (int i = argumentValues.length; i < values.length; i++) {
957 values[i] = interpretName(names[i], values);
958 }
959 Object rv = (result < 0) ? null : values[result];
960 assert(resultCheck(argumentValues, rv));
961 return rv;
962 }
963
964 @Hidden
965 @DontInline
966 /** Evaluate a single Name within this form, applying its function to its arguments. */
967 Object interpretName(Name name, Object[] values) throws Throwable {
968 if (TRACE_INTERPRETER)
969 traceInterpreter("| interpretName", name.debugString(), (Object[]) null);
970 Object[] arguments = Arrays.copyOf(name.arguments, name.arguments.length, Object[].class);
971 for (int i = 0; i < arguments.length; i++) {
972 Object a = arguments[i];
973 if (a instanceof Name) {
974 int i2 = ((Name)a).index();
975 assert(names[i2] == a);
976 a = values[i2];
977 arguments[i] = a;
978 }
979 }
980 return name.function.invokeWithArguments(arguments);
981 }
982
983 private void checkInvocationCounter() {
984 if (COMPILE_THRESHOLD != 0 &&
985 !forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
986 invocationCounter++; // benign race
987 if (invocationCounter >= COMPILE_THRESHOLD) {
988 // Replace vmentry with a bytecode version of this LF.
989 compileToBytecode();
990 }
991 }
992 }
993 Object interpretWithArgumentsTracing(Object... argumentValues) throws Throwable {
994 traceInterpreter("[ interpretWithArguments", this, argumentValues);
995 if (!forceInterpretation() && invocationCounter < COMPILE_THRESHOLD) {
996 int ctr = invocationCounter++; // benign race
997 traceInterpreter("| invocationCounter", ctr);
998 if (invocationCounter >= COMPILE_THRESHOLD) {
999 compileToBytecode();
1000 }
1001 }
1002 Object rval;
1003 try {
1004 assert(arityCheck(argumentValues));
1005 Object[] values = Arrays.copyOf(argumentValues, names.length);
1006 for (int i = argumentValues.length; i < values.length; i++) {
1007 values[i] = interpretName(names[i], values);
1008 }
1009 rval = (result < 0) ? null : values[result];
1010 } catch (Throwable ex) {
1011 traceInterpreter("] throw =>", ex);
1012 throw ex;
1013 }
1014 traceInterpreter("] return =>", rval);
1015 return rval;
1016 }
1017
1018 static void traceInterpreter(String event, Object obj, Object... args) {
1019 if (TRACE_INTERPRETER) {
1020 System.out.println("LFI: "+event+" "+(obj != null ? obj : "")+(args != null && args.length != 0 ? Arrays.asList(args) : ""));
1021 }
1022 }
1023 static void traceInterpreter(String event, Object obj) {
1024 traceInterpreter(event, obj, (Object[])null);
1025 }
1026 private boolean arityCheck(Object[] argumentValues) {
1027 assert(argumentValues.length == arity) : arity+"!="+Arrays.asList(argumentValues)+".length";
1028 // also check that the leading (receiver) argument is somehow bound to this LF:
1029 assert(argumentValues[0] instanceof MethodHandle) : "not MH: " + argumentValues[0];
1030 MethodHandle mh = (MethodHandle) argumentValues[0];
1031 assert(mh.internalForm() == this);
1032 // note: argument #0 could also be an interface wrapper, in the future
1033 argumentTypesMatch(basicTypeSignature(), argumentValues);
1034 return true;
1035 }
1036 private boolean resultCheck(Object[] argumentValues, Object result) {
1037 MethodHandle mh = (MethodHandle) argumentValues[0];
1038 MethodType mt = mh.type();
1039 assert(valueMatches(returnType(), mt.returnType(), result));
1040 return true;
1041 }
1042
1043 private boolean isEmpty() {
1044 if (result < 0)
1045 return (names.length == arity);
1046 else if (result == arity && names.length == arity + 1)
1047 return names[arity].isConstantZero();
1048 else
1049 return false;
1050 }
1051
1052 public String toString() {
1053 String lambdaName = lambdaName();
1054 StringBuilder buf = new StringBuilder(lambdaName + "=Lambda(");
1055 for (int i = 0; i < names.length; i++) {
1056 if (i == arity) buf.append(")=>{");
1057 Name n = names[i];
1058 if (i >= arity) buf.append("\n ");
1059 buf.append(n.paramString());
1060 if (i < arity) {
1061 if (i+1 < arity) buf.append(",");
1062 continue;
1063 }
1064 buf.append("=").append(n.exprString());
1065 buf.append(";");
1066 }
1067 if (arity == names.length) buf.append(")=>{");
1068 buf.append(result < 0 ? "void" : names[result]).append("}");
1069 if (TRACE_INTERPRETER) {
1070 // Extra verbosity:
1071 buf.append(":").append(basicTypeSignature());
1072 buf.append("/").append(vmentry);
1073 }
1074 return buf.toString();
1075 }
1076
1077 @Override
1078 public boolean equals(Object obj) {
1079 return obj instanceof LambdaForm && equals((LambdaForm)obj);
1080 }
1081 public boolean equals(LambdaForm that) {
1082 if (this.result != that.result) return false;
1083 return Arrays.equals(this.names, that.names);
1084 }
1085 public int hashCode() {
1086 return result + 31 * Arrays.hashCode(names);
1087 }
1088 LambdaFormEditor editor() {
1089 return LambdaFormEditor.lambdaFormEditor(this);
1090 }
1091
1092 boolean contains(Name name) {
1093 int pos = name.index();
1094 if (pos >= 0) {
1095 return pos < names.length && name.equals(names[pos]);
1096 }
1097 for (int i = arity; i < names.length; i++) {
1098 if (name.equals(names[i]))
1099 return true;
1100 }
1101 return false;
1102 }
1103
1104 static class NamedFunction {
1105 final MemberName member;
1106 private @Stable MethodHandle resolvedHandle;
1107 @Stable MethodHandle invoker;
1108 private final MethodHandleImpl.Intrinsic intrinsicName;
1109
1110 NamedFunction(MethodHandle resolvedHandle) {
1111 this(resolvedHandle.internalMemberName(), resolvedHandle, MethodHandleImpl.Intrinsic.NONE);
1112 }
1113 NamedFunction(MethodHandle resolvedHandle, MethodHandleImpl.Intrinsic intrinsic) {
1114 this(resolvedHandle.internalMemberName(), resolvedHandle, intrinsic);
1115 }
1116 NamedFunction(MemberName member, MethodHandle resolvedHandle) {
1117 this(member, resolvedHandle, MethodHandleImpl.Intrinsic.NONE);
1118 }
1119 NamedFunction(MemberName member, MethodHandle resolvedHandle, MethodHandleImpl.Intrinsic intrinsic) {
1120 this.member = member;
1121 this.resolvedHandle = resolvedHandle;
1122 this.intrinsicName = intrinsic;
1123 assert(resolvedHandle == null ||
1124 resolvedHandle.intrinsicName() == MethodHandleImpl.Intrinsic.NONE ||
1125 resolvedHandle.intrinsicName() == intrinsic) : resolvedHandle.intrinsicName() + " != " + intrinsic;
1126 // The following assert is almost always correct, but will fail for corner cases, such as PrivateInvokeTest.
1127 //assert(!isInvokeBasic(member));
1128 }
1129 NamedFunction(MethodType basicInvokerType) {
1130 assert(basicInvokerType == basicInvokerType.basicType()) : basicInvokerType;
1131 if (basicInvokerType.parameterSlotCount() < MethodType.MAX_MH_INVOKER_ARITY) {
1132 this.resolvedHandle = basicInvokerType.invokers().basicInvoker();
1133 this.member = resolvedHandle.internalMemberName();
1134 } else {
1135 // necessary to pass BigArityTest
1136 this.member = Invokers.invokeBasicMethod(basicInvokerType);
1137 }
1138 this.intrinsicName = MethodHandleImpl.Intrinsic.NONE;
1139 assert(isInvokeBasic(member));
1140 }
1141
1142 private static boolean isInvokeBasic(MemberName member) {
1143 return member != null &&
1144 member.getDeclaringClass() == MethodHandle.class &&
1145 "invokeBasic".equals(member.getName());
1146 }
1147
1148 // The next 2 constructors are used to break circular dependencies on MH.invokeStatic, etc.
1149 // Any LambdaForm containing such a member is not interpretable.
1150 // This is OK, since all such LFs are prepared with special primitive vmentry points.
1151 // And even without the resolvedHandle, the name can still be compiled and optimized.
1152 NamedFunction(Method method) {
1153 this(new MemberName(method));
1154 }
1155 NamedFunction(MemberName member) {
1156 this(member, null);
1157 }
1158
1159 MethodHandle resolvedHandle() {
1160 if (resolvedHandle == null) resolve();
1161 return resolvedHandle;
1162 }
1163
1164 synchronized void resolve() {
1165 if (resolvedHandle == null) {
1166 resolvedHandle = DirectMethodHandle.make(member);
1167 }
1168 }
1169
1170 @Override
1171 public boolean equals(Object other) {
1172 if (this == other) return true;
1173 if (other == null) return false;
1174 if (!(other instanceof NamedFunction)) return false;
1175 NamedFunction that = (NamedFunction) other;
1176 return this.member != null && this.member.equals(that.member);
1177 }
1178
1179 @Override
1180 public int hashCode() {
1181 if (member != null)
1182 return member.hashCode();
1183 return super.hashCode();
1184 }
1185
1186 static final MethodType INVOKER_METHOD_TYPE =
1187 MethodType.methodType(Object.class, MethodHandle.class, Object[].class);
1188
1189 private static MethodHandle computeInvoker(MethodTypeForm typeForm) {
1190 typeForm = typeForm.basicType().form(); // normalize to basic type
1191 MethodHandle mh = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1192 if (mh != null) return mh;
1193 MemberName invoker = InvokerBytecodeGenerator.generateNamedFunctionInvoker(typeForm); // this could take a while
1194 mh = DirectMethodHandle.make(invoker);
1195 MethodHandle mh2 = typeForm.cachedMethodHandle(MethodTypeForm.MH_NF_INV);
1196 if (mh2 != null) return mh2; // benign race
1197 if (!mh.type().equals(INVOKER_METHOD_TYPE))
1198 throw newInternalError(mh.debugString());
1199 return typeForm.setCachedMethodHandle(MethodTypeForm.MH_NF_INV, mh);
1200 }
1201
1202 @Hidden
1203 Object invokeWithArguments(Object... arguments) throws Throwable {
1204 // If we have a cached invoker, call it right away.
1205 // NOTE: The invoker always returns a reference value.
1206 if (TRACE_INTERPRETER) return invokeWithArgumentsTracing(arguments);
1207 return invoker().invokeBasic(resolvedHandle(), arguments);
1208 }
1209
1210 @Hidden
1211 Object invokeWithArgumentsTracing(Object[] arguments) throws Throwable {
1212 Object rval;
1213 try {
1214 traceInterpreter("[ call", this, arguments);
1215 if (invoker == null) {
1216 traceInterpreter("| getInvoker", this);
1217 invoker();
1218 }
1219 // resolvedHandle might be uninitialized, ok for tracing
1220 if (resolvedHandle == null) {
1221 traceInterpreter("| resolve", this);
1222 resolvedHandle();
1223 }
1224 rval = invoker().invokeBasic(resolvedHandle(), arguments);
1225 } catch (Throwable ex) {
1226 traceInterpreter("] throw =>", ex);
1227 throw ex;
1228 }
1229 traceInterpreter("] return =>", rval);
1230 return rval;
1231 }
1232
1233 private MethodHandle invoker() {
1234 if (invoker != null) return invoker;
1235 // Get an invoker and cache it.
1236 return invoker = computeInvoker(methodType().form());
1237 }
1238
1239 MethodType methodType() {
1240 if (resolvedHandle != null)
1241 return resolvedHandle.type();
1242 else
1243 // only for certain internal LFs during bootstrapping
1244 return member.getInvocationType();
1245 }
1246
1247 MemberName member() {
1248 assert(assertMemberIsConsistent());
1249 return member;
1250 }
1251
1252 // Called only from assert.
1253 private boolean assertMemberIsConsistent() {
1254 if (resolvedHandle instanceof DirectMethodHandle) {
1255 MemberName m = resolvedHandle.internalMemberName();
1256 assert(m.equals(member));
1257 }
1258 return true;
1259 }
1260
1261 Class<?> memberDeclaringClassOrNull() {
1262 return (member == null) ? null : member.getDeclaringClass();
1263 }
1264
1265 BasicType returnType() {
1266 return basicType(methodType().returnType());
1267 }
1268
1269 BasicType parameterType(int n) {
1270 return basicType(methodType().parameterType(n));
1271 }
1272
1273 int arity() {
1274 return methodType().parameterCount();
1275 }
1276
1277 public String toString() {
1278 if (member == null) return String.valueOf(resolvedHandle);
1279 return member.getDeclaringClass().getSimpleName()+"."+member.getName();
1280 }
1281
1282 public boolean isIdentity() {
1283 return this.equals(identity(returnType()));
1284 }
1285
1286 public boolean isConstantZero() {
1287 return this.equals(constantZero(returnType()));
1288 }
1289
1290 public MethodHandleImpl.Intrinsic intrinsicName() {
1291 return intrinsicName;
1292 }
1293 }
1294
1295 public static String basicTypeSignature(MethodType type) {
1296 int params = type.parameterCount();
1297 char[] sig = new char[params + 2];
1298 int sigp = 0;
1299 while (sigp < params) {
1300 sig[sigp] = basicTypeChar(type.parameterType(sigp++));
1301 }
1302 sig[sigp++] = '_';
1303 sig[sigp++] = basicTypeChar(type.returnType());
1304 assert(sigp == sig.length);
1305 return String.valueOf(sig);
1306 }
1307
1308 /** Hack to make signatures more readable when they show up in method names.
1309 * Signature should start with a sequence of uppercase ASCII letters.
1310 * Runs of three or more are replaced by a single letter plus a decimal repeat count.
1311 * A tail of anything other than uppercase ASCII is passed through unchanged.
1312 * @param signature sequence of uppercase ASCII letters with possible repetitions
1313 * @return same sequence, with repetitions counted by decimal numerals
1314 */
1315 public static String shortenSignature(String signature) {
1316 final int NO_CHAR = -1, MIN_RUN = 3;
1317 int c0, c1 = NO_CHAR, c1reps = 0;
1318 StringBuilder buf = null;
1319 int len = signature.length();
1320 if (len < MIN_RUN) return signature;
1321 for (int i = 0; i <= len; i++) {
1322 if (c1 != NO_CHAR && !('A' <= c1 && c1 <= 'Z')) {
1323 // wrong kind of char; bail out here
1324 if (buf != null) {
1325 buf.append(signature.substring(i - c1reps, len));
1326 }
1327 break;
1328 }
1329 // shift in the next char:
1330 c0 = c1; c1 = (i == len ? NO_CHAR : signature.charAt(i));
1331 if (c1 == c0) { ++c1reps; continue; }
1332 // shift in the next count:
1333 int c0reps = c1reps; c1reps = 1;
1334 // end of a character run
1335 if (c0reps < MIN_RUN) {
1336 if (buf != null) {
1337 while (--c0reps >= 0)
1338 buf.append((char)c0);
1339 }
1340 continue;
1341 }
1342 // found three or more in a row
1343 if (buf == null)
1344 buf = new StringBuilder().append(signature, 0, i - c0reps);
1345 buf.append((char)c0).append(c0reps);
1346 }
1347 return (buf == null) ? signature : buf.toString();
1348 }
1349
1350 static final class Name {
1351 final BasicType type;
1352 @Stable short index;
1353 final NamedFunction function;
1354 final Object constraint; // additional type information, if not null
1355 @Stable final Object[] arguments;
1356
1357 private Name(int index, BasicType type, NamedFunction function, Object[] arguments) {
1358 this.index = (short)index;
1359 this.type = type;
1360 this.function = function;
1361 this.arguments = arguments;
1362 this.constraint = null;
1363 assert(this.index == index);
1364 }
1365 private Name(Name that, Object constraint) {
1366 this.index = that.index;
1367 this.type = that.type;
1368 this.function = that.function;
1369 this.arguments = that.arguments;
1370 this.constraint = constraint;
1371 assert(constraint == null || isParam()); // only params have constraints
1372 assert(constraint == null || constraint instanceof ClassSpecializer.SpeciesData || constraint instanceof Class);
1373 }
1374 Name(MethodHandle function, Object... arguments) {
1375 this(new NamedFunction(function), arguments);
1376 }
1377 Name(MethodType functionType, Object... arguments) {
1378 this(new NamedFunction(functionType), arguments);
1379 assert(arguments[0] instanceof Name && ((Name)arguments[0]).type == L_TYPE);
1380 }
1381 Name(MemberName function, Object... arguments) {
1382 this(new NamedFunction(function), arguments);
1383 }
1384 Name(NamedFunction function, Object... arguments) {
1385 this(-1, function.returnType(), function, arguments = Arrays.copyOf(arguments, arguments.length, Object[].class));
1386 assert(typesMatch(function, arguments));
1387 }
1388 /** Create a raw parameter of the given type, with an expected index. */
1389 Name(int index, BasicType type) {
1390 this(index, type, null, null);
1391 }
1392 /** Create a raw parameter of the given type. */
1393 Name(BasicType type) { this(-1, type); }
1394
1395 BasicType type() { return type; }
1396 int index() { return index; }
1397 boolean initIndex(int i) {
1398 if (index != i) {
1399 if (index != -1) return false;
1400 index = (short)i;
1401 }
1402 return true;
1403 }
1404 char typeChar() {
1405 return type.btChar;
1406 }
1407
1408 void resolve() {
1409 if (function != null)
1410 function.resolve();
1411 }
1412
1413 Name newIndex(int i) {
1414 if (initIndex(i)) return this;
1415 return cloneWithIndex(i);
1416 }
1417 Name cloneWithIndex(int i) {
1418 Object[] newArguments = (arguments == null) ? null : arguments.clone();
1419 return new Name(i, type, function, newArguments).withConstraint(constraint);
1420 }
1421 Name withConstraint(Object constraint) {
1422 if (constraint == this.constraint) return this;
1423 return new Name(this, constraint);
1424 }
1425 Name replaceName(Name oldName, Name newName) { // FIXME: use replaceNames uniformly
1426 if (oldName == newName) return this;
1427 @SuppressWarnings("LocalVariableHidesMemberVariable")
1428 Object[] arguments = this.arguments;
1429 if (arguments == null) return this;
1430 boolean replaced = false;
1431 for (int j = 0; j < arguments.length; j++) {
1432 if (arguments[j] == oldName) {
1433 if (!replaced) {
1434 replaced = true;
1435 arguments = arguments.clone();
1436 }
1437 arguments[j] = newName;
1438 }
1439 }
1440 if (!replaced) return this;
1441 return new Name(function, arguments);
1442 }
1443 /** In the arguments of this Name, replace oldNames[i] pairwise by newNames[i].
1444 * Limit such replacements to {@code start<=i<end}. Return possibly changed self.
1445 */
1446 Name replaceNames(Name[] oldNames, Name[] newNames, int start, int end) {
1447 if (start >= end) return this;
1448 @SuppressWarnings("LocalVariableHidesMemberVariable")
1449 Object[] arguments = this.arguments;
1450 boolean replaced = false;
1451 eachArg:
1452 for (int j = 0; j < arguments.length; j++) {
1453 if (arguments[j] instanceof Name) {
1454 Name n = (Name) arguments[j];
1455 int check = n.index;
1456 // harmless check to see if the thing is already in newNames:
1457 if (check >= 0 && check < newNames.length && n == newNames[check])
1458 continue eachArg;
1459 // n might not have the correct index: n != oldNames[n.index].
1460 for (int i = start; i < end; i++) {
1461 if (n == oldNames[i]) {
1462 if (n == newNames[i])
1463 continue eachArg;
1464 if (!replaced) {
1465 replaced = true;
1466 arguments = arguments.clone();
1467 }
1468 arguments[j] = newNames[i];
1469 continue eachArg;
1470 }
1471 }
1472 }
1473 }
1474 if (!replaced) return this;
1475 return new Name(function, arguments);
1476 }
1477 void internArguments() {
1478 @SuppressWarnings("LocalVariableHidesMemberVariable")
1479 Object[] arguments = this.arguments;
1480 for (int j = 0; j < arguments.length; j++) {
1481 if (arguments[j] instanceof Name) {
1482 Name n = (Name) arguments[j];
1483 if (n.isParam() && n.index < INTERNED_ARGUMENT_LIMIT)
1484 arguments[j] = internArgument(n);
1485 }
1486 }
1487 }
1488 boolean isParam() {
1489 return function == null;
1490 }
1491 boolean isConstantZero() {
1492 return !isParam() && arguments.length == 0 && function.isConstantZero();
1493 }
1494
1495 boolean refersTo(Class<?> declaringClass, String methodName) {
1496 return function != null &&
1497 function.member() != null && function.member().refersTo(declaringClass, methodName);
1498 }
1499
1500 /**
1501 * Check if MemberName is a call to MethodHandle.invokeBasic.
1502 */
1503 boolean isInvokeBasic() {
1504 if (function == null)
1505 return false;
1506 if (arguments.length < 1)
1507 return false; // must have MH argument
1508 MemberName member = function.member();
1509 return member != null && member.refersTo(MethodHandle.class, "invokeBasic") &&
1510 !member.isPublic() && !member.isStatic();
1511 }
1512
1513 /**
1514 * Check if MemberName is a call to MethodHandle.linkToStatic, etc.
1515 */
1516 boolean isLinkerMethodInvoke() {
1517 if (function == null)
1518 return false;
1519 if (arguments.length < 1)
1520 return false; // must have MH argument
1521 MemberName member = function.member();
1522 return member != null &&
1523 member.getDeclaringClass() == MethodHandle.class &&
1524 !member.isPublic() && member.isStatic() &&
1525 member.getName().startsWith("linkTo");
1526 }
1527
1528 public String toString() {
1529 return (isParam()?"a":"t")+(index >= 0 ? index : System.identityHashCode(this))+":"+typeChar();
1530 }
1531 public String debugString() {
1532 String s = paramString();
1533 return (function == null) ? s : s + "=" + exprString();
1534 }
1535 public String paramString() {
1536 String s = toString();
1537 Object c = constraint;
1538 if (c == null)
1539 return s;
1540 if (c instanceof Class) c = ((Class<?>)c).getSimpleName();
1541 return s + "/" + c;
1542 }
1543 public String exprString() {
1544 if (function == null) return toString();
1545 StringBuilder buf = new StringBuilder(function.toString());
1546 buf.append("(");
1547 String cma = "";
1548 for (Object a : arguments) {
1549 buf.append(cma); cma = ",";
1550 if (a instanceof Name || a instanceof Integer)
1551 buf.append(a);
1552 else
1553 buf.append("(").append(a).append(")");
1554 }
1555 buf.append(")");
1556 return buf.toString();
1557 }
1558
1559 private boolean typesMatch(NamedFunction function, Object ... arguments) {
1560 assert(arguments.length == function.arity()) : "arity mismatch: arguments.length=" + arguments.length + " == function.arity()=" + function.arity() + " in " + debugString();
1561 for (int i = 0; i < arguments.length; i++) {
1562 assert (typesMatch(function.parameterType(i), arguments[i])) : "types don't match: function.parameterType(" + i + ")=" + function.parameterType(i) + ", arguments[" + i + "]=" + arguments[i] + " in " + debugString();
1563 }
1564 return true;
1565 }
1566
1567 private static boolean typesMatch(BasicType parameterType, Object object) {
1568 if (object instanceof Name) {
1569 return ((Name)object).type == parameterType;
1570 }
1571 switch (parameterType) {
1572 case I_TYPE: return object instanceof Integer;
1573 case J_TYPE: return object instanceof Long;
1574 case F_TYPE: return object instanceof Float;
1575 case D_TYPE: return object instanceof Double;
1576 }
1577 assert(parameterType == L_TYPE);
1578 return true;
1579 }
1580
1581 /** Return the index of the last occurrence of n in the argument array.
1582 * Return -1 if the name is not used.
1583 */
1584 int lastUseIndex(Name n) {
1585 if (arguments == null) return -1;
1586 for (int i = arguments.length; --i >= 0; ) {
1587 if (arguments[i] == n) return i;
1588 }
1589 return -1;
1590 }
1591
1592 /** Return the number of occurrences of n in the argument array.
1593 * Return 0 if the name is not used.
1594 */
1595 int useCount(Name n) {
1596 if (arguments == null) return 0;
1597 int count = 0;
1598 for (int i = arguments.length; --i >= 0; ) {
1599 if (arguments[i] == n) ++count;
1600 }
1601 return count;
1602 }
1603
1604 boolean contains(Name n) {
1605 return this == n || lastUseIndex(n) >= 0;
1606 }
1607
1608 public boolean equals(Name that) {
1609 if (this == that) return true;
1610 if (isParam())
1611 // each parameter is a unique atom
1612 return false; // this != that
1613 return
1614 //this.index == that.index &&
1615 this.type == that.type &&
1616 this.function.equals(that.function) &&
1617 Arrays.equals(this.arguments, that.arguments);
1618 }
1619 @Override
1620 public boolean equals(Object x) {
1621 return x instanceof Name && equals((Name)x);
1622 }
1623 @Override
1624 public int hashCode() {
1625 if (isParam())
1626 return index | (type.ordinal() << 8);
1627 return function.hashCode() ^ Arrays.hashCode(arguments);
1628 }
1629 }
1630
1631 /** Return the index of the last name which contains n as an argument.
1632 * Return -1 if the name is not used. Return names.length if it is the return value.
1633 */
1634 int lastUseIndex(Name n) {
1635 int ni = n.index, nmax = names.length;
1636 assert(names[ni] == n);
1637 if (result == ni) return nmax; // live all the way beyond the end
1638 for (int i = nmax; --i > ni; ) {
1639 if (names[i].lastUseIndex(n) >= 0)
1640 return i;
1641 }
1642 return -1;
1643 }
1644
1645 /** Return the number of times n is used as an argument or return value. */
1646 int useCount(Name n) {
1647 int nmax = names.length;
1648 int end = lastUseIndex(n);
1649 if (end < 0) return 0;
1650 int count = 0;
1651 if (end == nmax) { count++; end--; }
1652 int beg = n.index() + 1;
1653 if (beg < arity) beg = arity;
1654 for (int i = beg; i <= end; i++) {
1655 count += names[i].useCount(n);
1656 }
1657 return count;
1658 }
1659
1660 static Name argument(int which, BasicType type) {
1661 if (which >= INTERNED_ARGUMENT_LIMIT)
1662 return new Name(which, type);
1663 return INTERNED_ARGUMENTS[type.ordinal()][which];
1664 }
1665 static Name internArgument(Name n) {
1666 assert(n.isParam()) : "not param: " + n;
1667 assert(n.index < INTERNED_ARGUMENT_LIMIT);
1668 if (n.constraint != null) return n;
1669 return argument(n.index, n.type);
1670 }
1671 static Name[] arguments(int extra, MethodType types) {
1672 int length = types.parameterCount();
1673 Name[] names = new Name[length + extra];
1674 for (int i = 0; i < length; i++)
1675 names[i] = argument(i, basicType(types.parameterType(i)));
1676 return names;
1677 }
1678 static final int INTERNED_ARGUMENT_LIMIT = 10;
1679 private static final Name[][] INTERNED_ARGUMENTS
1680 = new Name[ARG_TYPE_LIMIT][INTERNED_ARGUMENT_LIMIT];
1681 static {
1682 for (BasicType type : BasicType.ARG_TYPES) {
1683 int ord = type.ordinal();
1684 for (int i = 0; i < INTERNED_ARGUMENTS[ord].length; i++) {
1685 INTERNED_ARGUMENTS[ord][i] = new Name(i, type);
1686 }
1687 }
1688 }
1689
1690 private static final MemberName.Factory IMPL_NAMES = MemberName.getFactory();
1691
1692 static LambdaForm identityForm(BasicType type) {
1693 int ord = type.ordinal();
1694 LambdaForm form = LF_identity[ord];
1695 if (form != null) {
1696 return form;
1697 }
1698 createFormsFor(type);
1699 return LF_identity[ord];
1700 }
1701
1702 static LambdaForm zeroForm(BasicType type) {
1703 int ord = type.ordinal();
1704 LambdaForm form = LF_zero[ord];
1705 if (form != null) {
1706 return form;
1707 }
1708 createFormsFor(type);
1709 return LF_zero[ord];
1710 }
1711
1712 static NamedFunction identity(BasicType type) {
1713 int ord = type.ordinal();
1714 NamedFunction function = NF_identity[ord];
1715 if (function != null) {
1716 return function;
1717 }
1718 createFormsFor(type);
1719 return NF_identity[ord];
1720 }
1721
1722 static NamedFunction constantZero(BasicType type) {
1723 int ord = type.ordinal();
1724 NamedFunction function = NF_zero[ord];
1725 if (function != null) {
1726 return function;
1727 }
1728 createFormsFor(type);
1729 return NF_zero[ord];
1730 }
1731
1732 private static final @Stable LambdaForm[] LF_identity = new LambdaForm[TYPE_LIMIT];
1733 private static final @Stable LambdaForm[] LF_zero = new LambdaForm[TYPE_LIMIT];
1734 private static final @Stable NamedFunction[] NF_identity = new NamedFunction[TYPE_LIMIT];
1735 private static final @Stable NamedFunction[] NF_zero = new NamedFunction[TYPE_LIMIT];
1736
1737 private static synchronized void createFormsFor(BasicType type) {
1738 final int ord = type.ordinal();
1739 LambdaForm idForm = LF_identity[ord];
1740 if (idForm != null) {
1741 return;
1742 }
1743 char btChar = type.basicTypeChar();
1744 boolean isVoid = (type == V_TYPE);
1745 Class<?> btClass = type.btClass;
1746 MethodType zeType = MethodType.methodType(btClass);
1747 MethodType idType = (isVoid) ? zeType : MethodType.methodType(btClass, btClass);
1748
1749 // Look up symbolic names. It might not be necessary to have these,
1750 // but if we need to emit direct references to bytecodes, it helps.
1751 // Zero is built from a call to an identity function with a constant zero input.
1752 MemberName idMem = new MemberName(LambdaForm.class, "identity_"+btChar, idType, REF_invokeStatic);
1753 MemberName zeMem = null;
1754 try {
1755 idMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, idMem, null, NoSuchMethodException.class);
1756 if (!isVoid) {
1757 zeMem = new MemberName(LambdaForm.class, "zero_"+btChar, zeType, REF_invokeStatic);
1758 zeMem = IMPL_NAMES.resolveOrFail(REF_invokeStatic, zeMem, null, NoSuchMethodException.class);
1759 }
1760 } catch (IllegalAccessException|NoSuchMethodException ex) {
1761 throw newInternalError(ex);
1762 }
1763
1764 NamedFunction idFun;
1765 LambdaForm zeForm;
1766 NamedFunction zeFun;
1767
1768 // Create the LFs and NamedFunctions. Precompiling LFs to byte code is needed to break circular
1769 // bootstrap dependency on this method in case we're interpreting LFs
1770 if (isVoid) {
1771 Name[] idNames = new Name[] { argument(0, L_TYPE) };
1772 idForm = new LambdaForm(1, idNames, VOID_RESULT, Kind.IDENTITY);
1773 idForm.compileToBytecode();
1774 idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm));
1775
1776 zeForm = idForm;
1777 zeFun = idFun;
1778 } else {
1779 Name[] idNames = new Name[] { argument(0, L_TYPE), argument(1, type) };
1780 idForm = new LambdaForm(2, idNames, 1, Kind.IDENTITY);
1781 idForm.compileToBytecode();
1782 idFun = new NamedFunction(idMem, SimpleMethodHandle.make(idMem.getInvocationType(), idForm),
1783 MethodHandleImpl.Intrinsic.IDENTITY);
1784
1785 Object zeValue = Wrapper.forBasicType(btChar).zero();
1786 Name[] zeNames = new Name[] { argument(0, L_TYPE), new Name(idFun, zeValue) };
1787 zeForm = new LambdaForm(1, zeNames, 1, Kind.ZERO);
1788 zeForm.compileToBytecode();
1789 zeFun = new NamedFunction(zeMem, SimpleMethodHandle.make(zeMem.getInvocationType(), zeForm),
1790 MethodHandleImpl.Intrinsic.ZERO);
1791 }
1792
1793 LF_zero[ord] = zeForm;
1794 NF_zero[ord] = zeFun;
1795 LF_identity[ord] = idForm;
1796 NF_identity[ord] = idFun;
1797
1798 assert(idFun.isIdentity());
1799 assert(zeFun.isConstantZero());
1800 assert(new Name(zeFun).isConstantZero());
1801 }
1802
1803 // Avoid appealing to ValueConversions at bootstrap time:
1804 private static int identity_I(int x) { return x; }
1805 private static long identity_J(long x) { return x; }
1806 private static float identity_F(float x) { return x; }
1807 private static double identity_D(double x) { return x; }
1808 private static Object identity_L(Object x) { return x; }
1809 private static void identity_V() { return; }
1810 private static int zero_I() { return 0; }
1811 private static long zero_J() { return 0; }
1812 private static float zero_F() { return 0; }
1813 private static double zero_D() { return 0; }
1814 private static Object zero_L() { return null; }
1815
1816 /**
1817 * Internal marker for byte-compiled LambdaForms.
1818 */
1819 /*non-public*/
1820 @Target(ElementType.METHOD)
1821 @Retention(RetentionPolicy.RUNTIME)
1822 @interface Compiled {
1823 }
1824
1825 /**
1826 * Internal marker for LambdaForm interpreter frames.
1827 */
1828 /*non-public*/
1829 @Target(ElementType.METHOD)
1830 @Retention(RetentionPolicy.RUNTIME)
1831 @interface Hidden {
1832 }
1833
1834 private static final HashMap<String,Integer> DEBUG_NAME_COUNTERS;
1835 private static final HashMap<LambdaForm,String> DEBUG_NAMES;
1836 static {
1837 if (debugEnabled()) {
1838 DEBUG_NAME_COUNTERS = new HashMap<>();
1839 DEBUG_NAMES = new HashMap<>();
1840 } else {
1841 DEBUG_NAME_COUNTERS = null;
1842 DEBUG_NAMES = null;
1843 }
1844 }
1845
1846 static {
1847 // The Holder class will contain pre-generated forms resolved
1848 // using MemberName.getFactory(). However, that doesn't initialize the
1849 // class, which subtly breaks inlining etc. By forcing
1850 // initialization of the Holder class we avoid these issues.
1851 UNSAFE.ensureClassInitialized(Holder.class);
1852 }
1853
1854 /* Placeholder class for zero and identity forms generated ahead of time */
1855 final class Holder {}
1856
1857 // The following hack is necessary in order to suppress TRACE_INTERPRETER
1858 // during execution of the static initializes of this class.
1859 // Turning on TRACE_INTERPRETER too early will cause
1860 // stack overflows and other misbehavior during attempts to trace events
1861 // that occur during LambdaForm.<clinit>.
1862 // Therefore, do not move this line higher in this file, and do not remove.
1863 private static final boolean TRACE_INTERPRETER = MethodHandleStatics.TRACE_INTERPRETER;
1864 }