1 /*
2 * Copyright (c) 2010, 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 jdk.nashorn.internal.runtime;
27
28 import static jdk.nashorn.internal.lookup.Lookup.MH;
29 import static jdk.nashorn.internal.runtime.ECMAErrors.typeError;
30 import static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;
31
32 import java.io.IOException;
33 import java.io.ObjectInputStream;
34 import java.io.Serializable;
35 import java.lang.invoke.MethodHandle;
36 import java.lang.invoke.MethodHandles;
37 import java.lang.invoke.MethodType;
38 import java.util.Collection;
39 import java.util.LinkedList;
40 import java.util.List;
41 import jdk.nashorn.internal.runtime.linker.LinkerCallSite;
42
43
44 /**
45 * A container for data needed to instantiate a specific {@link ScriptFunction} at runtime.
46 * Instances of this class are created during codegen and stored in script classes'
47 * constants array to reduce function instantiation overhead during runtime.
48 */
49 public abstract class ScriptFunctionData implements Serializable {
50 static final int MAX_ARITY = LinkerCallSite.ARGLIMIT;
51 static {
52 // Assert it fits in a byte, as that's what we store it in. It's just a size optimization though, so if needed
53 // "byte arity" field can be widened.
54 assert MAX_ARITY < 256;
55 }
56
57 /** Name of the function or "" for anonymous functions */
58 protected final String name;
59
60 /**
61 * A list of code versions of a function sorted in ascending order of generic descriptors.
62 */
63 protected transient LinkedList<CompiledFunction> code = new LinkedList<>();
64
65 /** Function flags */
66 protected int flags;
67
68 // Parameter arity of the function, corresponding to "f.length". E.g. "function f(a, b, c) { ... }" arity is 3, and
69 // some built-in ECMAScript functions have their arity declared by the specification. Note that regardless of this
70 // value, the function might still be capable of receiving variable number of arguments, see isVariableArity.
71 private int arity;
72
73 // this may be null, if not available
74 private String documentation;
75
76 /**
77 * A pair of method handles used for generic invoker and constructor. Field is volatile as it can be initialized by
78 * multiple threads concurrently, but we still tolerate a race condition in it as all values stored into it are
79 * idempotent.
80 */
81 private volatile transient GenericInvokers genericInvokers;
82
83 private static final MethodHandle BIND_VAR_ARGS = findOwnMH("bindVarArgs", Object[].class, Object[].class, Object[].class);
84
85 /** Is this a strict mode function? */
86 public static final int IS_STRICT = 1 << 0;
87 /** Is this a built-in function? */
88 public static final int IS_BUILTIN = 1 << 1;
89 /** Is this a constructor function? */
90 public static final int IS_CONSTRUCTOR = 1 << 2;
91 /** Does this function expect a callee argument? */
92 public static final int NEEDS_CALLEE = 1 << 3;
93 /** Does this function make use of the this-object argument? */
94 public static final int USES_THIS = 1 << 4;
95 /** Is this a variable arity function? */
96 public static final int IS_VARIABLE_ARITY = 1 << 5;
97 /** Is this a object literal property getter or setter? */
98 public static final int IS_PROPERTY_ACCESSOR = 1 << 6;
99
100 /** Flag for strict or built-in functions */
101 public static final int IS_STRICT_OR_BUILTIN = IS_STRICT | IS_BUILTIN;
102 /** Flag for built-in constructors */
103 public static final int IS_BUILTIN_CONSTRUCTOR = IS_BUILTIN | IS_CONSTRUCTOR;
104
105 private static final long serialVersionUID = 4252901245508769114L;
106
107 /**
108 * Constructor
109 *
110 * @param name script function name
111 * @param arity arity
112 * @param flags the function flags
113 */
114 ScriptFunctionData(final String name, final int arity, final int flags) {
115 this.name = name;
116 this.flags = flags;
117 setArity(arity);
118 }
119
120 final int getArity() {
121 return arity;
122 }
123
124 final String getDocumentation() {
125 return documentation != null? documentation : toSource();
126 }
127
128 final boolean isVariableArity() {
129 return (flags & IS_VARIABLE_ARITY) != 0;
130 }
131
132 final boolean isPropertyAccessor() {
133 return (flags & IS_PROPERTY_ACCESSOR) != 0;
134 }
135
136 /**
137 * Used from e.g. Native*$Constructors as an explicit call. TODO - make arity immutable and final
138 * @param arity new arity
139 */
140 void setArity(final int arity) {
141 if(arity < 0 || arity > MAX_ARITY) {
142 throw new IllegalArgumentException(String.valueOf(arity));
143 }
144 this.arity = arity;
145 }
146
147 /**
148 * Used from nasgen generated code.
149 *
150 * @param doc documentation for this function
151 */
152 void setDocumentation(final String doc) {
153 this.documentation = doc;
154 }
155
156 CompiledFunction bind(final CompiledFunction originalInv, final ScriptFunction fn, final Object self, final Object[] args) {
157 final MethodHandle boundInvoker = bindInvokeHandle(originalInv.createComposableInvoker(), fn, self, args);
158
159 if (isConstructor()) {
160 return new CompiledFunction(boundInvoker, bindConstructHandle(originalInv.createComposableConstructor(), fn, args), null);
161 }
162
163 return new CompiledFunction(boundInvoker);
164 }
165
166 /**
167 * Is this a ScriptFunction generated with strict semantics?
168 * @return true if strict, false otherwise
169 */
170 public final boolean isStrict() {
171 return (flags & IS_STRICT) != 0;
172 }
173
174 /**
175 * Return the complete internal function name for this
176 * data, not anonymous or similar. May be identical
177 * @return internal function name
178 */
179 protected String getFunctionName() {
180 return getName();
181 }
182
183 final boolean isBuiltin() {
184 return (flags & IS_BUILTIN) != 0;
185 }
186
187 final boolean isConstructor() {
188 return (flags & IS_CONSTRUCTOR) != 0;
189 }
190
191 abstract boolean needsCallee();
192
193 /**
194 * Returns true if this is a non-strict, non-built-in function that requires non-primitive this argument
195 * according to ECMA 10.4.3.
196 * @return true if this argument must be an object
197 */
198 final boolean needsWrappedThis() {
199 return (flags & USES_THIS) != 0 && (flags & IS_STRICT_OR_BUILTIN) == 0;
200 }
201
202 String toSource() {
203 return "function " + (name == null ? "" : name) + "() { [native code] }";
204 }
205
206 String getName() {
207 return name;
208 }
209
210 /**
211 * Get this function as a String containing its source code. If no source code
212 * exists in this ScriptFunction, its contents will be displayed as {@code [native code]}
213 *
214 * @return string representation of this function
215 */
216 @Override
217 public String toString() {
218 return name.isEmpty() ? "<anonymous>" : name;
219 }
220
221 /**
222 * Verbose description of data
223 * @return verbose description
224 */
225 public String toStringVerbose() {
226 final StringBuilder sb = new StringBuilder();
227
228 sb.append("name='").
229 append(name.isEmpty() ? "<anonymous>" : name).
230 append("' ").
231 append(code.size()).
232 append(" invokers=").
233 append(code);
234
235 return sb.toString();
236 }
237
238 /**
239 * Pick the best invoker, i.e. the one version of this method with as narrow and specific
240 * types as possible. If the call site arguments are objects, but boxed primitives we can
241 * also try to get a primitive version of the method and do an unboxing filter, but then
242 * we need to insert a guard that checks the argument is really always a boxed primitive
243 * and not suddenly a "real" object
244 *
245 * @param callSiteType callsite type
246 * @return compiled function object representing the best invoker.
247 */
248 final CompiledFunction getBestInvoker(final MethodType callSiteType, final ScriptObject runtimeScope) {
249 return getBestInvoker(callSiteType, runtimeScope, CompiledFunction.NO_FUNCTIONS);
250 }
251
252 final CompiledFunction getBestInvoker(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden) {
253 final CompiledFunction cf = getBest(callSiteType, runtimeScope, forbidden);
254 assert cf != null;
255 return cf;
256 }
257
258 final CompiledFunction getBestConstructor(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden) {
259 if (!isConstructor()) {
260 throw typeError("not.a.constructor", toSource());
261 }
262 // Constructor call sites don't have a "this", but getBest is meant to operate on "callee, this, ..." style
263 final CompiledFunction cf = getBest(callSiteType.insertParameterTypes(1, Object.class), runtimeScope, forbidden);
264 return cf;
265 }
266
267 /**
268 * If we can have lazy code generation, this is a hook to ensure that the code has been compiled.
269 * This does not guarantee the code been installed in this {@code ScriptFunctionData} instance
270 */
271 protected void ensureCompiled() {
272 //empty
273 }
274
275 /**
276 * Return a generic Object/Object invoker for this method. It will ensure code
277 * is generated, get the most generic of all versions of this function and adapt it
278 * to Objects.
279 *
280 * @param runtimeScope the runtime scope. It can be used to evaluate types of scoped variables to guide the
281 * optimistic compilation, should the call to this method trigger code compilation. Can be null if current runtime
282 * scope is not known, but that might cause compilation of code that will need more deoptimization passes.
283 * @return generic invoker of this script function
284 */
285 final MethodHandle getGenericInvoker(final ScriptObject runtimeScope) {
286 // This method has race conditions both on genericsInvoker and genericsInvoker.invoker, but even if invoked
287 // concurrently, they'll create idempotent results, so it doesn't matter. We could alternatively implement this
288 // using java.util.concurrent.AtomicReferenceFieldUpdater, but it's hardly worth it.
289 final GenericInvokers lgenericInvokers = ensureGenericInvokers();
290 MethodHandle invoker = lgenericInvokers.invoker;
291 if(invoker == null) {
292 lgenericInvokers.invoker = invoker = createGenericInvoker(runtimeScope);
293 }
294 return invoker;
295 }
296
297 private MethodHandle createGenericInvoker(final ScriptObject runtimeScope) {
298 return makeGenericMethod(getGeneric(runtimeScope).createComposableInvoker());
299 }
300
301 final MethodHandle getGenericConstructor(final ScriptObject runtimeScope) {
302 // This method has race conditions both on genericsInvoker and genericsInvoker.constructor, but even if invoked
303 // concurrently, they'll create idempotent results, so it doesn't matter. We could alternatively implement this
304 // using java.util.concurrent.AtomicReferenceFieldUpdater, but it's hardly worth it.
305 final GenericInvokers lgenericInvokers = ensureGenericInvokers();
306 MethodHandle constructor = lgenericInvokers.constructor;
307 if(constructor == null) {
308 lgenericInvokers.constructor = constructor = createGenericConstructor(runtimeScope);
309 }
310 return constructor;
311 }
312
313 private MethodHandle createGenericConstructor(final ScriptObject runtimeScope) {
314 return makeGenericMethod(getGeneric(runtimeScope).createComposableConstructor());
315 }
316
317 private GenericInvokers ensureGenericInvokers() {
318 GenericInvokers lgenericInvokers = genericInvokers;
319 if(lgenericInvokers == null) {
320 genericInvokers = lgenericInvokers = new GenericInvokers();
321 }
322 return lgenericInvokers;
323 }
324
325 private static MethodType widen(final MethodType cftype) {
326 final Class<?>[] paramTypes = new Class<?>[cftype.parameterCount()];
327 for (int i = 0; i < cftype.parameterCount(); i++) {
328 paramTypes[i] = cftype.parameterType(i).isPrimitive() ? cftype.parameterType(i) : Object.class;
329 }
330 return MH.type(cftype.returnType(), paramTypes);
331 }
332
333 /**
334 * Used to find an apply to call version that fits this callsite.
335 * We cannot just, as in the normal matcher case, return e.g. (Object, Object, int)
336 * for (Object, Object, int, int, int) or we will destroy the semantics and get
337 * a function that, when padded with undefined values, behaves differently
338 * @param type actual call site type
339 * @return apply to call that perfectly fits this callsite or null if none found
340 */
341 CompiledFunction lookupExactApplyToCall(final MethodType type) {
342 for (final CompiledFunction cf : code) {
343 if (!cf.isApplyToCall()) {
344 continue;
345 }
346
347 final MethodType cftype = cf.type();
348 if (cftype.parameterCount() != type.parameterCount()) {
349 continue;
350 }
351
352 if (widen(cftype).equals(widen(type))) {
353 return cf;
354 }
355 }
356
357 return null;
358 }
359
360 CompiledFunction pickFunction(final MethodType callSiteType, final boolean canPickVarArg) {
361 for (final CompiledFunction candidate : code) {
362 if (candidate.matchesCallSite(callSiteType, canPickVarArg)) {
363 return candidate;
364 }
365 }
366 return null;
367 }
368
369 /**
370 * Returns the best function for the specified call site type.
371 * @param callSiteType The call site type. Call site types are expected to have the form
372 * {@code (callee, this[, args...])}.
373 * @param runtimeScope the runtime scope. It can be used to evaluate types of scoped variables to guide the
374 * optimistic compilation, should the call to this method trigger code compilation. Can be null if current runtime
375 * scope is not known, but that might cause compilation of code that will need more deoptimization passes.
376 * @return the best function for the specified call site type.
377 */
378 abstract CompiledFunction getBest(final MethodType callSiteType, final ScriptObject runtimeScope, final Collection<CompiledFunction> forbidden);
379
380 boolean isValidCallSite(final MethodType callSiteType) {
381 return callSiteType.parameterCount() >= 2 && // Must have at least (callee, this)
382 callSiteType.parameterType(0).isAssignableFrom(ScriptFunction.class); // Callee must be assignable from script function
383 }
384
385 CompiledFunction getGeneric(final ScriptObject runtimeScope) {
386 return getBest(getGenericType(), runtimeScope, CompiledFunction.NO_FUNCTIONS);
387 }
388
389 /**
390 * Get a method type for a generic invoker.
391 * @return the method type for the generic invoker
392 */
393 abstract MethodType getGenericType();
394
395 /**
396 * Allocates an object using this function's allocator.
397 *
398 * @param map the property map for the allocated object.
399 * @return the object allocated using this function's allocator, or null if the function doesn't have an allocator.
400 */
401 ScriptObject allocate(final PropertyMap map) {
402 return null;
403 }
404
405 /**
406 * Get the property map to use for objects allocated by this function.
407 *
408 * @param prototype the prototype of the allocated object
409 * @return the property map for allocated objects.
410 */
411 PropertyMap getAllocatorMap(final ScriptObject prototype) {
412 return null;
413 }
414
415 /**
416 * This method is used to create the immutable portion of a bound function.
417 * See {@link ScriptFunction#createBound(Object, Object[])}
418 *
419 * @param fn the original function being bound
420 * @param self this reference to bind. Can be null.
421 * @param args additional arguments to bind. Can be null.
422 */
423 ScriptFunctionData makeBoundFunctionData(final ScriptFunction fn, final Object self, final Object[] args) {
424 final Object[] allArgs = args == null ? ScriptRuntime.EMPTY_ARRAY : args;
425 final int length = args == null ? 0 : args.length;
426 // Clear the callee and this flags
427 final int boundFlags = flags & ~NEEDS_CALLEE & ~USES_THIS;
428
429 final List<CompiledFunction> boundList = new LinkedList<>();
430 final ScriptObject runtimeScope = fn.getScope();
431 final CompiledFunction bindTarget = new CompiledFunction(getGenericInvoker(runtimeScope), getGenericConstructor(runtimeScope), null);
432 boundList.add(bind(bindTarget, fn, self, allArgs));
433
434 return new FinalScriptFunctionData(name, Math.max(0, getArity() - length), boundList, boundFlags);
435 }
436
437 /**
438 * Convert this argument for non-strict functions according to ES 10.4.3
439 *
440 * @param thiz the this argument
441 *
442 * @return the converted this object
443 */
444 private Object convertThisObject(final Object thiz) {
445 return needsWrappedThis() ? wrapThis(thiz) : thiz;
446 }
447
448 static Object wrapThis(final Object thiz) {
449 if (!(thiz instanceof ScriptObject)) {
450 if (JSType.nullOrUndefined(thiz)) {
451 return Context.getGlobal();
452 }
453
454 if (isPrimitiveThis(thiz)) {
455 return Context.getGlobal().wrapAsObject(thiz);
456 }
457 }
458
459 return thiz;
460 }
461
462 static boolean isPrimitiveThis(final Object obj) {
463 return JSType.isString(obj) || obj instanceof Number || obj instanceof Boolean;
464 }
465
466 /**
467 * Creates an invoker method handle for a bound function.
468 *
469 * @param targetFn the function being bound
470 * @param originalInvoker an original invoker method handle for the function. This can be its generic invoker or
471 * any of its specializations.
472 * @param self the "this" value being bound
473 * @param args additional arguments being bound
474 *
475 * @return a bound invoker method handle that will bind the self value and the specified arguments. The resulting
476 * invoker never needs a callee; if the original invoker needed it, it will be bound to {@code fn}. The resulting
477 * invoker still takes an initial {@code this} parameter, but it is always dropped and the bound {@code self} passed
478 * to the original invoker on invocation.
479 */
480 private MethodHandle bindInvokeHandle(final MethodHandle originalInvoker, final ScriptFunction targetFn, final Object self, final Object[] args) {
481 // Is the target already bound? If it is, we won't bother binding either callee or self as they're already bound
482 // in the target and will be ignored anyway.
483 final boolean isTargetBound = targetFn.isBoundFunction();
484
485 final boolean needsCallee = needsCallee(originalInvoker);
486 assert needsCallee == needsCallee() : "callee contract violation 2";
487 assert !(isTargetBound && needsCallee); // already bound functions don't need a callee
488
489 final Object boundSelf = isTargetBound ? null : convertThisObject(self);
490 final MethodHandle boundInvoker;
491
492 if (isVarArg(originalInvoker)) {
493 // First, bind callee and this without arguments
494 final MethodHandle noArgBoundInvoker;
495
496 if (isTargetBound) {
497 // Don't bind either callee or this
498 noArgBoundInvoker = originalInvoker;
499 } else if (needsCallee) {
500 // Bind callee and this
501 noArgBoundInvoker = MH.insertArguments(originalInvoker, 0, targetFn, boundSelf);
502 } else {
503 // Only bind this
504 noArgBoundInvoker = MH.bindTo(originalInvoker, boundSelf);
505 }
506 // Now bind arguments
507 if (args.length > 0) {
508 boundInvoker = varArgBinder(noArgBoundInvoker, args);
509 } else {
510 boundInvoker = noArgBoundInvoker;
511 }
512 } else {
513 // If target is already bound, insert additional bound arguments after "this" argument, at position 1.
514 final int argInsertPos = isTargetBound ? 1 : 0;
515 final Object[] boundArgs = new Object[Math.min(originalInvoker.type().parameterCount() - argInsertPos, args.length + (isTargetBound ? 0 : needsCallee ? 2 : 1))];
516 int next = 0;
517 if (!isTargetBound) {
518 if (needsCallee) {
519 boundArgs[next++] = targetFn;
520 }
521 boundArgs[next++] = boundSelf;
522 }
523 // If more bound args were specified than the function can take, we'll just drop those.
524 System.arraycopy(args, 0, boundArgs, next, boundArgs.length - next);
525 // If target is already bound, insert additional bound arguments after "this" argument, at position 1;
526 // "this" will get dropped anyway by the target invoker. We previously asserted that already bound functions
527 // don't take a callee parameter, so we can know that the signature is (this[, args...]) therefore args
528 // start at position 1. If the function is not bound, we start inserting arguments at position 0.
529 boundInvoker = MH.insertArguments(originalInvoker, argInsertPos, boundArgs);
530 }
531
532 if (isTargetBound) {
533 return boundInvoker;
534 }
535
536 // If the target is not already bound, add a dropArguments that'll throw away the passed this
537 return MH.dropArguments(boundInvoker, 0, Object.class);
538 }
539
540 /**
541 * Creates a constructor method handle for a bound function using the passed constructor handle.
542 *
543 * @param originalConstructor the constructor handle to bind. It must be a composed constructor.
544 * @param fn the function being bound
545 * @param args arguments being bound
546 *
547 * @return a bound constructor method handle that will bind the specified arguments. The resulting constructor never
548 * needs a callee; if the original constructor needed it, it will be bound to {@code fn}. The resulting constructor
549 * still takes an initial {@code this} parameter and passes it to the underlying original constructor. Finally, if
550 * this script function data object has no constructor handle, null is returned.
551 */
552 private static MethodHandle bindConstructHandle(final MethodHandle originalConstructor, final ScriptFunction fn, final Object[] args) {
553 assert originalConstructor != null;
554
555 // If target function is already bound, don't bother binding the callee.
556 final MethodHandle calleeBoundConstructor = fn.isBoundFunction() ? originalConstructor :
557 MH.dropArguments(MH.bindTo(originalConstructor, fn), 0, ScriptFunction.class);
558
559 if (args.length == 0) {
560 return calleeBoundConstructor;
561 }
562
563 if (isVarArg(calleeBoundConstructor)) {
564 return varArgBinder(calleeBoundConstructor, args);
565 }
566
567 final Object[] boundArgs;
568
569 final int maxArgCount = calleeBoundConstructor.type().parameterCount() - 1;
570 if (args.length <= maxArgCount) {
571 boundArgs = args;
572 } else {
573 boundArgs = new Object[maxArgCount];
574 System.arraycopy(args, 0, boundArgs, 0, maxArgCount);
575 }
576
577 return MH.insertArguments(calleeBoundConstructor, 1, boundArgs);
578 }
579
580 /**
581 * Takes a method handle, and returns a potentially different method handle that can be used in
582 * {@code ScriptFunction#invoke(Object, Object...)} or {code ScriptFunction#construct(Object, Object...)}.
583 * The returned method handle will be sure to return {@code Object}, and will have all its parameters turned into
584 * {@code Object} as well, except for the following ones:
585 * <ul>
586 * <li>a last parameter of type {@code Object[]} which is used for vararg functions,</li>
587 * <li>the first argument, which is forced to be {@link ScriptFunction}, in case the function receives itself
588 * (callee) as an argument.</li>
589 * </ul>
590 *
591 * @param mh the original method handle
592 *
593 * @return the new handle, conforming to the rules above.
594 */
595 private static MethodHandle makeGenericMethod(final MethodHandle mh) {
596 final MethodType type = mh.type();
597 final MethodType newType = makeGenericType(type);
598 return type.equals(newType) ? mh : mh.asType(newType);
599 }
600
601 private static MethodType makeGenericType(final MethodType type) {
602 MethodType newType = type.generic();
603 if (isVarArg(type)) {
604 newType = newType.changeParameterType(type.parameterCount() - 1, Object[].class);
605 }
606 if (needsCallee(type)) {
607 newType = newType.changeParameterType(0, ScriptFunction.class);
608 }
609 return newType;
610 }
611
612 /**
613 * Execute this script function.
614 *
615 * @param self Target object.
616 * @param arguments Call arguments.
617 * @return ScriptFunction result.
618 *
619 * @throws Throwable if there is an exception/error with the invocation or thrown from it
620 */
621 Object invoke(final ScriptFunction fn, final Object self, final Object... arguments) throws Throwable {
622 final MethodHandle mh = getGenericInvoker(fn.getScope());
623 final Object selfObj = convertThisObject(self);
624 final Object[] args = arguments == null ? ScriptRuntime.EMPTY_ARRAY : arguments;
625
626 DebuggerSupport.notifyInvoke(mh);
627
628 if (isVarArg(mh)) {
629 if (needsCallee(mh)) {
630 return mh.invokeExact(fn, selfObj, args);
631 }
632 return mh.invokeExact(selfObj, args);
633 }
634
635 final int paramCount = mh.type().parameterCount();
636 if (needsCallee(mh)) {
637 switch (paramCount) {
638 case 2:
639 return mh.invokeExact(fn, selfObj);
640 case 3:
641 return mh.invokeExact(fn, selfObj, getArg(args, 0));
642 case 4:
643 return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1));
644 case 5:
645 return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2));
646 case 6:
647 return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
648 case 7:
649 return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
650 case 8:
651 return mh.invokeExact(fn, selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
652 default:
653 return mh.invokeWithArguments(withArguments(fn, selfObj, paramCount, args));
654 }
655 }
656
657 switch (paramCount) {
658 case 1:
659 return mh.invokeExact(selfObj);
660 case 2:
661 return mh.invokeExact(selfObj, getArg(args, 0));
662 case 3:
663 return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1));
664 case 4:
665 return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2));
666 case 5:
667 return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
668 case 6:
669 return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
670 case 7:
671 return mh.invokeExact(selfObj, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
672 default:
673 return mh.invokeWithArguments(withArguments(null, selfObj, paramCount, args));
674 }
675 }
676
677 Object construct(final ScriptFunction fn, final Object... arguments) throws Throwable {
678 final MethodHandle mh = getGenericConstructor(fn.getScope());
679 final Object[] args = arguments == null ? ScriptRuntime.EMPTY_ARRAY : arguments;
680
681 DebuggerSupport.notifyInvoke(mh);
682
683 if (isVarArg(mh)) {
684 if (needsCallee(mh)) {
685 return mh.invokeExact(fn, args);
686 }
687 return mh.invokeExact(args);
688 }
689
690 final int paramCount = mh.type().parameterCount();
691 if (needsCallee(mh)) {
692 switch (paramCount) {
693 case 1:
694 return mh.invokeExact(fn);
695 case 2:
696 return mh.invokeExact(fn, getArg(args, 0));
697 case 3:
698 return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1));
699 case 4:
700 return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2));
701 case 5:
702 return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
703 case 6:
704 return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
705 case 7:
706 return mh.invokeExact(fn, getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
707 default:
708 return mh.invokeWithArguments(withArguments(fn, paramCount, args));
709 }
710 }
711
712 switch (paramCount) {
713 case 0:
714 return mh.invokeExact();
715 case 1:
716 return mh.invokeExact(getArg(args, 0));
717 case 2:
718 return mh.invokeExact(getArg(args, 0), getArg(args, 1));
719 case 3:
720 return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2));
721 case 4:
722 return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3));
723 case 5:
724 return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4));
725 case 6:
726 return mh.invokeExact(getArg(args, 0), getArg(args, 1), getArg(args, 2), getArg(args, 3), getArg(args, 4), getArg(args, 5));
727 default:
728 return mh.invokeWithArguments(withArguments(null, paramCount, args));
729 }
730 }
731
732 private static Object getArg(final Object[] args, final int i) {
733 return i < args.length ? args[i] : UNDEFINED;
734 }
735
736 private static Object[] withArguments(final ScriptFunction fn, final int argCount, final Object[] args) {
737 final Object[] finalArgs = new Object[argCount];
738
739 int nextArg = 0;
740 if (fn != null) {
741 //needs callee
742 finalArgs[nextArg++] = fn;
743 }
744
745 // Don't add more args that there is argCount in the handle (including self and callee).
746 for (int i = 0; i < args.length && nextArg < argCount;) {
747 finalArgs[nextArg++] = args[i++];
748 }
749
750 // If we have fewer args than argCount, pad with undefined.
751 while (nextArg < argCount) {
752 finalArgs[nextArg++] = UNDEFINED;
753 }
754
755 return finalArgs;
756 }
757
758 private static Object[] withArguments(final ScriptFunction fn, final Object self, final int argCount, final Object[] args) {
759 final Object[] finalArgs = new Object[argCount];
760
761 int nextArg = 0;
762 if (fn != null) {
763 //needs callee
764 finalArgs[nextArg++] = fn;
765 }
766 finalArgs[nextArg++] = self;
767
768 // Don't add more args that there is argCount in the handle (including self and callee).
769 for (int i = 0; i < args.length && nextArg < argCount;) {
770 finalArgs[nextArg++] = args[i++];
771 }
772
773 // If we have fewer args than argCount, pad with undefined.
774 while (nextArg < argCount) {
775 finalArgs[nextArg++] = UNDEFINED;
776 }
777
778 return finalArgs;
779 }
780 /**
781 * Takes a variable-arity method and binds a variable number of arguments in it. The returned method will filter the
782 * vararg array and pass a different array that prepends the bound arguments in front of the arguments passed on
783 * invocation
784 *
785 * @param mh the handle
786 * @param args the bound arguments
787 *
788 * @return the bound method handle
789 */
790 private static MethodHandle varArgBinder(final MethodHandle mh, final Object[] args) {
791 assert args != null;
792 assert args.length > 0;
793 return MH.filterArguments(mh, mh.type().parameterCount() - 1, MH.bindTo(BIND_VAR_ARGS, args));
794 }
795
796 /**
797 * Heuristic to figure out if the method handle has a callee argument. If it's type is
798 * {@code (ScriptFunction, ...)}, then we'll assume it has a callee argument. We need this as
799 * the constructor above is not passed this information, and can't just blindly assume it's false
800 * (notably, it's being invoked for creation of new scripts, and scripts have scopes, therefore
801 * they also always receive a callee).
802 *
803 * @param mh the examined method handle
804 *
805 * @return true if the method handle expects a callee, false otherwise
806 */
807 protected static boolean needsCallee(final MethodHandle mh) {
808 return needsCallee(mh.type());
809 }
810
811 static boolean needsCallee(final MethodType type) {
812 final int length = type.parameterCount();
813
814 if (length == 0) {
815 return false;
816 }
817
818 final Class<?> param0 = type.parameterType(0);
819 return param0 == ScriptFunction.class || param0 == boolean.class && length > 1 && type.parameterType(1) == ScriptFunction.class;
820 }
821
822 /**
823 * Check if a javascript function methodhandle is a vararg handle
824 *
825 * @param mh method handle to check
826 *
827 * @return true if vararg
828 */
829 protected static boolean isVarArg(final MethodHandle mh) {
830 return isVarArg(mh.type());
831 }
832
833 static boolean isVarArg(final MethodType type) {
834 return type.parameterType(type.parameterCount() - 1).isArray();
835 }
836
837 /**
838 * Is this ScriptFunction declared in a dynamic context
839 * @return true if in dynamic context, false if not or irrelevant
840 */
841 public boolean inDynamicContext() {
842 return false;
843 }
844
845 @SuppressWarnings("unused")
846 private static Object[] bindVarArgs(final Object[] array1, final Object[] array2) {
847 if (array2 == null) {
848 // Must clone it, as we can't allow the receiving method to alter the array
849 return array1.clone();
850 }
851
852 final int l2 = array2.length;
853 if (l2 == 0) {
854 return array1.clone();
855 }
856
857 final int l1 = array1.length;
858 final Object[] concat = new Object[l1 + l2];
859 System.arraycopy(array1, 0, concat, 0, l1);
860 System.arraycopy(array2, 0, concat, l1, l2);
861
862 return concat;
863 }
864
865 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
866 return MH.findStatic(MethodHandles.lookup(), ScriptFunctionData.class, name, MH.type(rtype, types));
867 }
868
869 /**
870 * This class is used to hold the generic invoker and generic constructor pair. It is structured in this way since
871 * most functions will never use them, so this way ScriptFunctionData only pays storage cost for one null reference
872 * to the GenericInvokers object, instead of two null references for the two method handles.
873 */
874 private static final class GenericInvokers {
875 volatile MethodHandle invoker;
876 volatile MethodHandle constructor;
877 }
878
879 private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
880 in.defaultReadObject();
881 code = new LinkedList<>();
882 }
883 }