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 package jdk.nashorn.internal.runtime;
26
27 import static jdk.nashorn.internal.lookup.Lookup.MH;
28 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.INVALID_PROGRAM_POINT;
29 import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid;
30 import java.lang.invoke.CallSite;
31 import java.lang.invoke.MethodHandle;
32 import java.lang.invoke.MethodHandles;
33 import java.lang.invoke.MethodType;
34 import java.lang.invoke.MutableCallSite;
35 import java.lang.invoke.SwitchPoint;
36 import java.util.ArrayList;
37 import java.util.Collection;
38 import java.util.Collections;
39 import java.util.Iterator;
40 import java.util.List;
41 import java.util.Map;
42 import java.util.TreeMap;
43 import java.util.function.Supplier;
44 import java.util.logging.Level;
45 import jdk.internal.dynalink.linker.GuardedInvocation;
46 import jdk.nashorn.internal.codegen.Compiler;
47 import jdk.nashorn.internal.codegen.Compiler.CompilationPhases;
48 import jdk.nashorn.internal.codegen.TypeMap;
49 import jdk.nashorn.internal.codegen.types.ArrayType;
50 import jdk.nashorn.internal.codegen.types.Type;
51 import jdk.nashorn.internal.ir.FunctionNode;
52 import jdk.nashorn.internal.objects.annotations.SpecializedFunction.LinkLogic;
53 import jdk.nashorn.internal.runtime.events.RecompilationEvent;
54 import jdk.nashorn.internal.runtime.linker.Bootstrap;
55 import jdk.nashorn.internal.runtime.logging.DebugLogger;
56
57 /**
58 * An version of a JavaScript function, native or JavaScript.
59 * Supports lazily generating a constructor version of the invocation.
60 */
61 final class CompiledFunction {
62
63 private static final MethodHandle NEWFILTER = findOwnMH("newFilter", Object.class, Object.class, Object.class);
64 private static final MethodHandle RELINK_COMPOSABLE_INVOKER = findOwnMH("relinkComposableInvoker", void.class, CallSite.class, CompiledFunction.class, boolean.class);
65 private static final MethodHandle HANDLE_REWRITE_EXCEPTION = findOwnMH("handleRewriteException", MethodHandle.class, CompiledFunction.class, OptimismInfo.class, RewriteException.class);
66 private static final MethodHandle RESTOF_INVOKER = MethodHandles.exactInvoker(MethodType.methodType(Object.class, RewriteException.class));
67
68 private final DebugLogger log;
69
70 static final Collection<CompiledFunction> NO_FUNCTIONS = Collections.emptySet();
71
72 /**
73 * The method type may be more specific than the invoker, if. e.g.
74 * the invoker is guarded, and a guard with a generic object only
75 * fallback, while the target is more specific, we still need the
76 * more specific type for sorting
77 */
78 private MethodHandle invoker;
79 private MethodHandle constructor;
80 private OptimismInfo optimismInfo;
81 private final int flags; // from FunctionNode
82 private final MethodType callSiteType;
83
84 private final Specialization specialization;
85
86 CompiledFunction(final MethodHandle invoker) {
87 this(invoker, null, null);
88 }
89
90 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker, final Specialization specialization) {
91 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), specialization);
92 }
93
94 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final Specialization specialization) {
95 this(invoker, constructor, 0, null, specialization, DebugLogger.DISABLED_LOGGER);
96 }
97
98 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final int flags, final MethodType callSiteType, final Specialization specialization, final DebugLogger log) {
99 this.specialization = specialization;
100 if (specialization != null && specialization.isOptimistic()) {
101 /*
102 * An optimistic builtin with isOptimistic=true works like any optimistic generated function, i.e. it
103 * can throw unwarranted optimism exceptions. As native functions trivially can't have parts of them
104 * regenerated as restof methods, this only works if the methods are atomic/functional in their behavior
105 * and doesn't modify state before an UOE can be thrown. If they aren't, we can reexecute a wider version
106 * of the same builtin in a recompilation handler for FinalScriptFunctionData. There are several
107 * candidate methods in Native* that would benefit from this, but I haven't had time to implement any
108 * of them currently. In order to fit in with the relinking framework, the current thinking is
109 * that the methods still take a program point to fit in with other optimistic functions, but
110 * it is set to "first", which is the beginning of the method. The relinker can tell the difference
111 * between builtin and JavaScript functions. This might change. TODO
112 */
113 this.invoker = MH.insertArguments(invoker, invoker.type().parameterCount() - 1, UnwarrantedOptimismException.FIRST_PROGRAM_POINT);
114 throw new AssertionError("Optimistic (UnwarrantedOptimismException throwing) builtin functions are currently not in use");
115 }
116 this.invoker = invoker;
117 this.constructor = constructor;
118 this.flags = flags;
119 this.callSiteType = callSiteType;
120 this.log = log;
121 }
122
123 CompiledFunction(final MethodHandle invoker, final RecompilableScriptFunctionData functionData,
124 final Map<Integer, Type> invalidatedProgramPoints, final MethodType callSiteType, final int flags) {
125 this(invoker, null, flags, callSiteType, null, functionData.getLogger());
126 if ((flags & FunctionNode.IS_DEOPTIMIZABLE) != 0) {
127 optimismInfo = new OptimismInfo(functionData, invalidatedProgramPoints);
128 } else {
129 optimismInfo = null;
130 }
131 }
132
133 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker) {
134 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), null);
135 }
136
137 boolean isSpecialization() {
138 return specialization != null;
139 }
140
141 boolean hasLinkLogic() {
142 return getLinkLogicClass() != null;
143 }
144
145 Class<? extends LinkLogic> getLinkLogicClass() {
146 if (isSpecialization()) {
147 final Class<? extends LinkLogic> linkLogicClass = specialization.getLinkLogicClass();
148 assert !LinkLogic.isEmpty(linkLogicClass) : "empty link logic classes should have been removed by nasgen";
149 return linkLogicClass;
150 }
151 return null;
152 }
153
154 int getFlags() {
155 return flags;
156 }
157
158 /**
159 * An optimistic specialization is one that can throw UnwarrantedOptimismException.
160 * This is allowed for native methods, as long as they are functional, i.e. don't change
161 * any state between entering and throwing the UOE. Then we can re-execute a wider version
162 * of the method in the continuation. Rest-of method generation for optimistic builtins is
163 * of course not possible, but this approach works and fits into the same relinking
164 * framework
165 *
166 * @return true if optimistic builtin
167 */
168 boolean isOptimistic() {
169 return isSpecialization() ? specialization.isOptimistic() : false;
170 }
171
172 boolean isApplyToCall() {
173 return (flags & FunctionNode.HAS_APPLY_TO_CALL_SPECIALIZATION) != 0;
174 }
175
176 boolean isVarArg() {
177 return isVarArgsType(invoker.type());
178 }
179
180 @Override
181 public String toString() {
182 final StringBuilder sb = new StringBuilder();
183 final Class<? extends LinkLogic> linkLogicClass = getLinkLogicClass();
184
185 sb.append("[invokerType=").
186 append(invoker.type()).
187 append(" ctor=").
188 append(constructor).
189 append(" weight=").
190 append(weight()).
191 append(" linkLogic=").
192 append(linkLogicClass != null ? linkLogicClass.getSimpleName() : "none");
193
194 return sb.toString();
195 }
196
197 boolean needsCallee() {
198 return ScriptFunctionData.needsCallee(invoker);
199 }
200
201 /**
202 * Returns an invoker method handle for this function. Note that the handle is safely composable in
203 * the sense that you can compose it with other handles using any combinators even if you can't affect call site
204 * invalidation. If this compiled function is non-optimistic, then it returns the same value as
205 * {@link #getInvokerOrConstructor(boolean)}. However, if the function is optimistic, then this handle will
206 * incur an overhead as it will add an intermediate internal call site that can relink itself when the function
207 * needs to regenerate its code to always point at the latest generated code version.
208 * @return a guaranteed composable invoker method handle for this function.
209 */
210 MethodHandle createComposableInvoker() {
211 return createComposableInvoker(false);
212 }
213
214 /**
215 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle should be
216 * considered non-composable in the sense that you can only compose it with other handles using any combinators if
217 * you can ensure that the composition is guarded by {@link #getOptimisticAssumptionsSwitchPoint()} if it's
218 * non-null, and that you can relink the call site it is set into as a target if the switch point is invalidated. In
219 * all other cases, use {@link #createComposableConstructor()}.
220 * @return a direct constructor method handle for this function.
221 */
222 private MethodHandle getConstructor() {
223 if (constructor == null) {
224 constructor = createConstructorFromInvoker(createInvokerForPessimisticCaller());
225 }
226
227 return constructor;
228 }
229
230 /**
231 * Creates a version of the invoker intended for a pessimistic caller (return type is Object, no caller optimistic
232 * program point available).
233 * @return a version of the invoker intended for a pessimistic caller.
234 */
235 private MethodHandle createInvokerForPessimisticCaller() {
236 return createInvoker(Object.class, INVALID_PROGRAM_POINT);
237 }
238
239 /**
240 * Compose a constructor from an invoker.
241 *
242 * @param invoker invoker
243 * @return the composed constructor
244 */
245 private static MethodHandle createConstructorFromInvoker(final MethodHandle invoker) {
246 final boolean needsCallee = ScriptFunctionData.needsCallee(invoker);
247 // If it was (callee, this, args...), permute it to (this, callee, args...). We're doing this because having
248 // "this" in the first argument position is what allows the elegant folded composition of
249 // (newFilter x constructor x allocator) further down below in the code. Also, ensure the composite constructor
250 // always returns Object.
251 final MethodHandle swapped = needsCallee ? swapCalleeAndThis(invoker) : invoker;
252
253 final MethodHandle returnsObject = MH.asType(swapped, swapped.type().changeReturnType(Object.class));
254
255 final MethodType ctorType = returnsObject.type();
256
257 // Construct a dropping type list for NEWFILTER, but don't include constructor "this" into it, so it's actually
258 // captured as "allocation" parameter of NEWFILTER after we fold the constructor into it.
259 // (this, [callee, ]args...) => ([callee, ]args...)
260 final Class<?>[] ctorArgs = ctorType.dropParameterTypes(0, 1).parameterArray();
261
262 // Fold constructor into newFilter that replaces the return value from the constructor with the originally
263 // allocated value when the originally allocated value is a JS primitive (String, Boolean, Number).
264 // (result, this, [callee, ]args...) x (this, [callee, ]args...) => (this, [callee, ]args...)
265 final MethodHandle filtered = MH.foldArguments(MH.dropArguments(NEWFILTER, 2, ctorArgs), returnsObject);
266
267 // allocate() takes a ScriptFunction and returns a newly allocated ScriptObject...
268 if (needsCallee) {
269 // ...we either fold it into the previous composition, if we need both the ScriptFunction callee object and
270 // the newly allocated object in the arguments, so (this, callee, args...) x (callee) => (callee, args...),
271 // or...
272 return MH.foldArguments(filtered, ScriptFunction.ALLOCATE);
273 }
274
275 // ...replace the ScriptFunction argument with the newly allocated object, if it doesn't need the callee
276 // (this, args...) filter (callee) => (callee, args...)
277 return MH.filterArguments(filtered, 0, ScriptFunction.ALLOCATE);
278 }
279
280 /**
281 * Permutes the parameters in the method handle from {@code (callee, this, ...)} to {@code (this, callee, ...)}.
282 * Used when creating a constructor handle.
283 * @param mh a method handle with order of arguments {@code (callee, this, ...)}
284 * @return a method handle with order of arguments {@code (this, callee, ...)}
285 */
286 private static MethodHandle swapCalleeAndThis(final MethodHandle mh) {
287 final MethodType type = mh.type();
288 assert type.parameterType(0) == ScriptFunction.class : type;
289 assert type.parameterType(1) == Object.class : type;
290 final MethodType newType = type.changeParameterType(0, Object.class).changeParameterType(1, ScriptFunction.class);
291 final int[] reorder = new int[type.parameterCount()];
292 reorder[0] = 1;
293 assert reorder[1] == 0;
294 for (int i = 2; i < reorder.length; ++i) {
295 reorder[i] = i;
296 }
297 return MethodHandles.permuteArguments(mh, newType, reorder);
298 }
299
300 /**
301 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle is safely
302 * composable in the sense that you can compose it with other handles using any combinators even if you can't affect
303 * call site invalidation. If this compiled function is non-optimistic, then it returns the same value as
304 * {@link #getConstructor()}. However, if the function is optimistic, then this handle will incur an overhead as it
305 * will add an intermediate internal call site that can relink itself when the function needs to regenerate its code
306 * to always point at the latest generated code version.
307 * @return a guaranteed composable constructor method handle for this function.
308 */
309 MethodHandle createComposableConstructor() {
310 return createComposableInvoker(true);
311 }
312
313 boolean hasConstructor() {
314 return constructor != null;
315 }
316
317 MethodType type() {
318 return invoker.type();
319 }
320
321 int weight() {
322 return weight(type());
323 }
324
325 private static int weight(final MethodType type) {
326 if (isVarArgsType(type)) {
327 return Integer.MAX_VALUE; //if there is a varargs it should be the heavist and last fallback
328 }
329
330 int weight = Type.typeFor(type.returnType()).getWeight();
331 for (int i = 0 ; i < type.parameterCount() ; i++) {
332 final Class<?> paramType = type.parameterType(i);
333 final int pweight = Type.typeFor(paramType).getWeight() * 2; //params are more important than call types as return values are always specialized
334 weight += pweight;
335 }
336
337 weight += type.parameterCount(); //more params outweigh few parameters
338
339 return weight;
340 }
341
342 static boolean isVarArgsType(final MethodType type) {
343 assert type.parameterCount() >= 1 : type;
344 return type.parameterType(type.parameterCount() - 1) == Object[].class;
345 }
346
347 static boolean moreGenericThan(final MethodType mt0, final MethodType mt1) {
348 return weight(mt0) > weight(mt1);
349 }
350
351 boolean betterThanFinal(final CompiledFunction other, final MethodType callSiteMethodType) {
352 // Prefer anything over nothing, as we can't compile new versions.
353 if (other == null) {
354 return true;
355 }
356 return betterThanFinal(this, other, callSiteMethodType);
357 }
358
359 private static boolean betterThanFinal(final CompiledFunction cf, final CompiledFunction other, final MethodType callSiteMethodType) {
360 final MethodType thisMethodType = cf.type();
361 final MethodType otherMethodType = other.type();
362 final int thisParamCount = getParamCount(thisMethodType);
363 final int otherParamCount = getParamCount(otherMethodType);
364 final int callSiteRawParamCount = getParamCount(callSiteMethodType);
365 final boolean csVarArg = callSiteRawParamCount == Integer.MAX_VALUE;
366 // Subtract 1 for callee for non-vararg call sites
367 final int callSiteParamCount = csVarArg ? callSiteRawParamCount : callSiteRawParamCount - 1;
368
369 // Prefer the function that discards less parameters
370 final int thisDiscardsParams = Math.max(callSiteParamCount - thisParamCount, 0);
371 final int otherDiscardsParams = Math.max(callSiteParamCount - otherParamCount, 0);
372 if(thisDiscardsParams < otherDiscardsParams) {
373 return true;
374 }
375 if(thisDiscardsParams > otherDiscardsParams) {
376 return false;
377 }
378
379 final boolean thisVarArg = thisParamCount == Integer.MAX_VALUE;
380 final boolean otherVarArg = otherParamCount == Integer.MAX_VALUE;
381 if(!(thisVarArg && otherVarArg && csVarArg)) {
382 // At least one of them isn't vararg
383 final Type[] thisType = toTypeWithoutCallee(thisMethodType, 0); // Never has callee
384 final Type[] otherType = toTypeWithoutCallee(otherMethodType, 0); // Never has callee
385 final Type[] callSiteType = toTypeWithoutCallee(callSiteMethodType, 1); // Always has callee
386
387 int narrowWeightDelta = 0;
388 int widenWeightDelta = 0;
389 final int minParamsCount = Math.min(Math.min(thisParamCount, otherParamCount), callSiteParamCount);
390 for(int i = 0; i < minParamsCount; ++i) {
391 final int callSiteParamWeight = getParamType(i, callSiteType, csVarArg).getWeight();
392 // Delta is negative for narrowing, positive for widening
393 final int thisParamWeightDelta = getParamType(i, thisType, thisVarArg).getWeight() - callSiteParamWeight;
394 final int otherParamWeightDelta = getParamType(i, otherType, otherVarArg).getWeight() - callSiteParamWeight;
395 // Only count absolute values of narrowings
396 narrowWeightDelta += Math.max(-thisParamWeightDelta, 0) - Math.max(-otherParamWeightDelta, 0);
397 // Only count absolute values of widenings
398 widenWeightDelta += Math.max(thisParamWeightDelta, 0) - Math.max(otherParamWeightDelta, 0);
399 }
400
401 // If both functions accept more arguments than what is passed at the call site, account for ability
402 // to receive Undefined un-narrowed in the remaining arguments.
403 if(!thisVarArg) {
404 for(int i = callSiteParamCount; i < thisParamCount; ++i) {
405 narrowWeightDelta += Math.max(Type.OBJECT.getWeight() - thisType[i].getWeight(), 0);
406 }
407 }
408 if(!otherVarArg) {
409 for(int i = callSiteParamCount; i < otherParamCount; ++i) {
410 narrowWeightDelta -= Math.max(Type.OBJECT.getWeight() - otherType[i].getWeight(), 0);
411 }
412 }
413
414 // Prefer function that narrows less
415 if(narrowWeightDelta < 0) {
416 return true;
417 }
418 if(narrowWeightDelta > 0) {
419 return false;
420 }
421
422 // Prefer function that widens less
423 if(widenWeightDelta < 0) {
424 return true;
425 }
426 if(widenWeightDelta > 0) {
427 return false;
428 }
429 }
430
431 // Prefer the function that exactly matches the arity of the call site.
432 if(thisParamCount == callSiteParamCount && otherParamCount != callSiteParamCount) {
433 return true;
434 }
435 if(thisParamCount != callSiteParamCount && otherParamCount == callSiteParamCount) {
436 return false;
437 }
438
439 // Otherwise, neither function matches arity exactly. We also know that at this point, they both can receive
440 // more arguments than call site, otherwise we would've already chosen the one that discards less parameters.
441 // Note that variable arity methods are preferred, as they actually match the call site arity better, since they
442 // really have arbitrary arity.
443 if(thisVarArg) {
444 if(!otherVarArg) {
445 return true; //
446 }
447 } else if(otherVarArg) {
448 return false;
449 }
450
451 // Neither is variable arity; chose the one that has less extra parameters.
452 final int fnParamDelta = thisParamCount - otherParamCount;
453 if(fnParamDelta < 0) {
454 return true;
455 }
456 if(fnParamDelta > 0) {
457 return false;
458 }
459
460 final int callSiteRetWeight = Type.typeFor(callSiteMethodType.returnType()).getWeight();
461 // Delta is negative for narrower return type, positive for wider return type
462 final int thisRetWeightDelta = Type.typeFor(thisMethodType.returnType()).getWeight() - callSiteRetWeight;
463 final int otherRetWeightDelta = Type.typeFor(otherMethodType.returnType()).getWeight() - callSiteRetWeight;
464
465 // Prefer function that returns a less wide return type
466 final int widenRetDelta = Math.max(thisRetWeightDelta, 0) - Math.max(otherRetWeightDelta, 0);
467 if(widenRetDelta < 0) {
468 return true;
469 }
470 if(widenRetDelta > 0) {
471 return false;
472 }
473
474 // Prefer function that returns a less narrow return type
475 final int narrowRetDelta = Math.max(-thisRetWeightDelta, 0) - Math.max(-otherRetWeightDelta, 0);
476 if(narrowRetDelta < 0) {
477 return true;
478 }
479 if(narrowRetDelta > 0) {
480 return false;
481 }
482
483 //if they are equal, pick the specialized one first
484 if (cf.isSpecialization() != other.isSpecialization()) {
485 return cf.isSpecialization(); //always pick the specialized version if we can
486 }
487
488 if (cf.isSpecialization() && other.isSpecialization()) {
489 return cf.getLinkLogicClass() != null; //pick link logic specialization above generic specializations
490 }
491
492 // Signatures are identical
493 throw new AssertionError(thisMethodType + " identically applicable to " + otherMethodType + " for " + callSiteMethodType);
494 }
495
496 private static Type[] toTypeWithoutCallee(final MethodType type, final int thisIndex) {
497 final int paramCount = type.parameterCount();
498 final Type[] t = new Type[paramCount - thisIndex];
499 for(int i = thisIndex; i < paramCount; ++i) {
500 t[i - thisIndex] = Type.typeFor(type.parameterType(i));
501 }
502 return t;
503 }
504
505 private static Type getParamType(final int i, final Type[] paramTypes, final boolean isVarArg) {
506 final int fixParamCount = paramTypes.length - (isVarArg ? 1 : 0);
507 if(i < fixParamCount) {
508 return paramTypes[i];
509 }
510 assert isVarArg;
511 return ((ArrayType)paramTypes[paramTypes.length - 1]).getElementType();
512 }
513
514 boolean matchesCallSite(final MethodType other, final boolean pickVarArg) {
515 if (other.equals(this.callSiteType)) {
516 return true;
517 }
518 final MethodType type = type();
519 final int fnParamCount = getParamCount(type);
520 final boolean isVarArg = fnParamCount == Integer.MAX_VALUE;
521 if (isVarArg) {
522 return pickVarArg;
523 }
524
525 final int csParamCount = getParamCount(other);
526 final boolean csIsVarArg = csParamCount == Integer.MAX_VALUE;
527 final int thisThisIndex = needsCallee() ? 1 : 0; // Index of "this" parameter in this function's type
528
529 final int fnParamCountNoCallee = fnParamCount - thisThisIndex;
530 final int minParams = Math.min(csParamCount - 1, fnParamCountNoCallee); // callSiteType always has callee, so subtract 1
531 // We must match all incoming parameters, including "this". "this" will usually be Object, but there
532 // are exceptions, e.g. when calling functions with primitive "this" in strict mode or through call/apply.
533 for(int i = 0; i < minParams; ++i) {
534 final Type fnType = Type.typeFor(type.parameterType(i + thisThisIndex));
535 final Type csType = csIsVarArg ? Type.OBJECT : Type.typeFor(other.parameterType(i + 1));
536 if(!fnType.isEquivalentTo(csType)) {
537 return false;
538 }
539 }
540
541 // Must match any undefined parameters to Object type.
542 for(int i = minParams; i < fnParamCountNoCallee; ++i) {
543 if(!Type.typeFor(type.parameterType(i + thisThisIndex)).isEquivalentTo(Type.OBJECT)) {
544 return false;
545 }
546 }
547
548 return true;
549 }
550
551 private static int getParamCount(final MethodType type) {
552 final int paramCount = type.parameterCount();
553 return type.parameterType(paramCount - 1).isArray() ? Integer.MAX_VALUE : paramCount;
554 }
555
556 private boolean canBeDeoptimized() {
557 return optimismInfo != null;
558 }
559
560 private MethodHandle createComposableInvoker(final boolean isConstructor) {
561 final MethodHandle handle = getInvokerOrConstructor(isConstructor);
562
563 // If compiled function is not optimistic, it can't ever change its invoker/constructor, so just return them
564 // directly.
565 if(!canBeDeoptimized()) {
566 return handle;
567 }
568
569 // Otherwise, we need a new level of indirection; need to introduce a mutable call site that can relink itslef
570 // to the compiled function's changed target whenever the optimistic assumptions are invalidated.
571 final CallSite cs = new MutableCallSite(handle.type());
572 relinkComposableInvoker(cs, this, isConstructor);
573 return cs.dynamicInvoker();
574 }
575
576 private static class HandleAndAssumptions {
577 final MethodHandle handle;
578 final SwitchPoint assumptions;
579
580 HandleAndAssumptions(final MethodHandle handle, final SwitchPoint assumptions) {
581 this.handle = handle;
582 this.assumptions = assumptions;
583 }
584
585 GuardedInvocation createInvocation() {
586 return new GuardedInvocation(handle, assumptions);
587 }
588 }
589
590 /**
591 * Returns a pair of an invocation created with a passed-in supplier and a non-invalidated switch point for
592 * optimistic assumptions (or null for the switch point if the function can not be deoptimized). While the method
593 * makes a best effort to return a non-invalidated switch point (compensating for possible deoptimizing
594 * recompilation happening on another thread) it is still possible that by the time this method returns the
595 * switchpoint has been invalidated by a {@code RewriteException} triggered on another thread for this function.
596 * This is not a problem, though, as these switch points are always used to produce call sites that fall back to
597 * relinking when they are invalidated, and in this case the execution will end up here again. What this method
598 * basically does is minimize such busy-loop relinking while the function is being recompiled on a different thread.
599 * @param invocationSupplier the supplier that constructs the actual invocation method handle; should use the
600 * {@code CompiledFunction} method itself in some capacity.
601 * @return a tuple object containing the method handle as created by the supplier and an optimistic assumptions
602 * switch point that is guaranteed to not have been invalidated before the call to this method (or null if the
603 * function can't be further deoptimized).
604 */
605 private synchronized HandleAndAssumptions getValidOptimisticInvocation(final Supplier<MethodHandle> invocationSupplier) {
606 for(;;) {
607 final MethodHandle handle = invocationSupplier.get();
608 final SwitchPoint assumptions = canBeDeoptimized() ? optimismInfo.optimisticAssumptions : null;
609 if(assumptions != null && assumptions.hasBeenInvalidated()) {
610 // We can be in a situation where one thread is in the middle of a deoptimizing compilation when we hit
611 // this and thus, it has invalidated the old switch point, but hasn't created the new one yet. Note that
612 // the behavior of invalidating the old switch point before recompilation, and only creating the new one
613 // after recompilation is by design. If we didn't wait here for the recompilation to complete, we would
614 // be busy looping through the fallback path of the invalidated switch point, relinking the call site
615 // again with the same invalidated switch point, invoking the fallback, etc. stealing CPU cycles from
616 // the recompilation task we're dependent on. This can still happen if the switch point gets invalidated
617 // after we grabbed it here, in which case we'll indeed do one busy relink immediately.
618 try {
619 wait();
620 } catch (final InterruptedException e) {
621 // Intentionally ignored. There's nothing meaningful we can do if we're interrupted
622 }
623 } else {
624 return new HandleAndAssumptions(handle, assumptions);
625 }
626 }
627 }
628
629 private static void relinkComposableInvoker(final CallSite cs, final CompiledFunction inv, final boolean constructor) {
630 final HandleAndAssumptions handleAndAssumptions = inv.getValidOptimisticInvocation(new Supplier<MethodHandle>() {
631 @Override
632 public MethodHandle get() {
633 return inv.getInvokerOrConstructor(constructor);
634 }
635 });
636 final MethodHandle handle = handleAndAssumptions.handle;
637 final SwitchPoint assumptions = handleAndAssumptions.assumptions;
638 final MethodHandle target;
639 if(assumptions == null) {
640 target = handle;
641 } else {
642 final MethodHandle relink = MethodHandles.insertArguments(RELINK_COMPOSABLE_INVOKER, 0, cs, inv, constructor);
643 target = assumptions.guardWithTest(handle, MethodHandles.foldArguments(cs.dynamicInvoker(), relink));
644 }
645 cs.setTarget(target.asType(cs.type()));
646 }
647
648 private MethodHandle getInvokerOrConstructor(final boolean selectCtor) {
649 return selectCtor ? getConstructor() : createInvokerForPessimisticCaller();
650 }
651
652 /**
653 * Returns a guarded invocation for this function when not invoked as a constructor. The guarded invocation has no
654 * guard but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a
655 * final guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and
656 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to
657 * continue to use the switch point. If that is not possible, use {@link #createComposableInvoker()} instead.
658 * @return a guarded invocation for an ordinary (non-constructor) invocation of this function.
659 */
660 GuardedInvocation createFunctionInvocation(final Class<?> callSiteReturnType, final int callerProgramPoint) {
661 return getValidOptimisticInvocation(new Supplier<MethodHandle>() {
662 @Override
663 public MethodHandle get() {
664 return createInvoker(callSiteReturnType, callerProgramPoint);
665 }
666 }).createInvocation();
667 }
668
669 /**
670 * Returns a guarded invocation for this function when invoked as a constructor. The guarded invocation has no guard
671 * but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a final
672 * guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and
673 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to
674 * continue to use the switch point. If that is not possible, use {@link #createComposableConstructor()} instead.
675 * @return a guarded invocation for invocation of this function as a constructor.
676 */
677 GuardedInvocation createConstructorInvocation() {
678 return getValidOptimisticInvocation(new Supplier<MethodHandle>() {
679 @Override
680 public MethodHandle get() {
681 return getConstructor();
682 }
683 }).createInvocation();
684 }
685
686 private MethodHandle createInvoker(final Class<?> callSiteReturnType, final int callerProgramPoint) {
687 final boolean isOptimistic = canBeDeoptimized();
688 MethodHandle handleRewriteException = isOptimistic ? createRewriteExceptionHandler() : null;
689
690 MethodHandle inv = invoker;
691 if(isValid(callerProgramPoint)) {
692 inv = OptimisticReturnFilters.filterOptimisticReturnValue(inv, callSiteReturnType, callerProgramPoint);
693 inv = changeReturnType(inv, callSiteReturnType);
694 if(callSiteReturnType.isPrimitive() && handleRewriteException != null) {
695 // because handleRewriteException always returns Object
696 handleRewriteException = OptimisticReturnFilters.filterOptimisticReturnValue(handleRewriteException,
697 callSiteReturnType, callerProgramPoint);
698 }
699 } else if(isOptimistic) {
700 // Required so that rewrite exception has the same return type. It'd be okay to do it even if we weren't
701 // optimistic, but it isn't necessary as the linker upstream will eventually convert the return type.
702 inv = changeReturnType(inv, callSiteReturnType);
703 }
704
705 if(isOptimistic) {
706 assert handleRewriteException != null;
707 final MethodHandle typedHandleRewriteException = changeReturnType(handleRewriteException, inv.type().returnType());
708 return MH.catchException(inv, RewriteException.class, typedHandleRewriteException);
709 }
710 return inv;
711 }
712
713 private MethodHandle createRewriteExceptionHandler() {
714 return MH.foldArguments(RESTOF_INVOKER, MH.insertArguments(HANDLE_REWRITE_EXCEPTION, 0, this, optimismInfo));
715 }
716
717 private static MethodHandle changeReturnType(final MethodHandle mh, final Class<?> newReturnType) {
718 return Bootstrap.getLinkerServices().asType(mh, mh.type().changeReturnType(newReturnType));
719 }
720
721 @SuppressWarnings("unused")
722 private static MethodHandle handleRewriteException(final CompiledFunction function, final OptimismInfo oldOptimismInfo, final RewriteException re) {
723 return function.handleRewriteException(oldOptimismInfo, re);
724 }
725
726 /**
727 * Debug function for printing out all invalidated program points and their
728 * invalidation mapping to next type
729 * @param ipp
730 * @return string describing the ipp map
731 */
732 private static List<String> toStringInvalidations(final Map<Integer, Type> ipp) {
733 if (ipp == null) {
734 return Collections.emptyList();
735 }
736
737 final List<String> list = new ArrayList<>();
738
739 for (final Iterator<Map.Entry<Integer, Type>> iter = ipp.entrySet().iterator(); iter.hasNext(); ) {
740 final Map.Entry<Integer, Type> entry = iter.next();
741 final char bct = entry.getValue().getBytecodeStackType();
742 final String type;
743
744 switch (entry.getValue().getBytecodeStackType()) {
745 case 'A':
746 type = "object";
747 break;
748 case 'I':
749 type = "int";
750 break;
751 case 'J':
752 type = "long";
753 break;
754 case 'D':
755 type = "double";
756 break;
757 default:
758 type = String.valueOf(bct);
759 break;
760 }
761
762 final StringBuilder sb = new StringBuilder();
763 sb.append('[').
764 append("program point: ").
765 append(entry.getKey()).
766 append(" -> ").
767 append(type).
768 append(']');
769
770 list.add(sb.toString());
771 }
772
773 return list;
774 }
775
776 private void logRecompile(final String reason, final FunctionNode fn, final MethodType type, final Map<Integer, Type> ipp) {
777 if (log.isEnabled()) {
778 log.info(reason, DebugLogger.quote(fn.getName()), " signature: ", type);
779 log.indent();
780 for (final String str : toStringInvalidations(ipp)) {
781 log.fine(str);
782 }
783 log.unindent();
784 }
785 }
786
787 /**
788 * Handles a {@link RewriteException} raised during the execution of this function by recompiling (if needed) the
789 * function with an optimistic assumption invalidated at the program point indicated by the exception, and then
790 * executing a rest-of method to complete the execution with the deoptimized version.
791 * @param oldOptInfo the optimism info of this function. We must store it explicitly as a bound argument in the
792 * method handle, otherwise it could be null for handling a rewrite exception in an outer invocation of a recursive
793 * function when recursive invocations of the function have completely deoptimized it.
794 * @param re the rewrite exception that was raised
795 * @return the method handle for the rest-of method, for folding composition.
796 */
797 private synchronized MethodHandle handleRewriteException(final OptimismInfo oldOptInfo, final RewriteException re) {
798 if (log.isEnabled()) {
799 log.info(
800 new RecompilationEvent(
801 Level.INFO,
802 re,
803 re.getReturnValueNonDestructive()),
804 "caught RewriteException ",
805 re.getMessageShort());
806 log.indent();
807 }
808
809 final MethodType type = type();
810
811 // Compiler needs a call site type as its input, which always has a callee parameter, so we must add it if
812 // this function doesn't have a callee parameter.
813 final MethodType ct = type.parameterType(0) == ScriptFunction.class ?
814 type :
815 type.insertParameterTypes(0, ScriptFunction.class);
816 final OptimismInfo currentOptInfo = optimismInfo;
817 final boolean shouldRecompile = currentOptInfo != null && currentOptInfo.requestRecompile(re);
818
819 // Effective optimism info, for subsequent use. We'll normally try to use the current (latest) one, but if it
820 // isn't available, we'll use the old one bound into the call site.
821 final OptimismInfo effectiveOptInfo = currentOptInfo != null ? currentOptInfo : oldOptInfo;
822 FunctionNode fn = effectiveOptInfo.reparse();
823 final boolean serialized = effectiveOptInfo.isSerialized();
824 final Compiler compiler = effectiveOptInfo.getCompiler(fn, ct, re); //set to non rest-of
825
826 if (!shouldRecompile) {
827 // It didn't necessarily recompile, e.g. for an outer invocation of a recursive function if we already
828 // recompiled a deoptimized version for an inner invocation.
829 // We still need to do the rest of from the beginning
830 logRecompile("Rest-of compilation [STANDALONE] ", fn, ct, effectiveOptInfo.invalidatedProgramPoints);
831 return restOfHandle(effectiveOptInfo, compiler.compile(fn, serialized ? CompilationPhases.COMPILE_SERIALIZED_RESTOF : CompilationPhases.COMPILE_ALL_RESTOF), currentOptInfo != null);
832 }
833
834 logRecompile("Deoptimizing recompilation (up to bytecode) ", fn, ct, effectiveOptInfo.invalidatedProgramPoints);
835 fn = compiler.compile(fn, serialized ? CompilationPhases.RECOMPILE_SERIALIZED_UPTO_BYTECODE : CompilationPhases.COMPILE_UPTO_BYTECODE);
836 log.fine("Reusable IR generated");
837
838 // compile the rest of the function, and install it
839 log.info("Generating and installing bytecode from reusable IR...");
840 logRecompile("Rest-of compilation [CODE PIPELINE REUSE] ", fn, ct, effectiveOptInfo.invalidatedProgramPoints);
841 final FunctionNode normalFn = compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL);
842
843 if (effectiveOptInfo.data.usePersistentCodeCache()) {
844 final RecompilableScriptFunctionData data = effectiveOptInfo.data;
845 final int functionNodeId = data.getFunctionNodeId();
846 final TypeMap typeMap = data.typeMap(ct);
847 final Type[] paramTypes = typeMap == null ? null : typeMap.getParameterTypes(functionNodeId);
848 final String cacheKey = CodeStore.getCacheKey(functionNodeId, paramTypes);
849 compiler.persistClassInfo(cacheKey, normalFn);
850 }
851
852 final boolean canBeDeoptimized = normalFn.canBeDeoptimized();
853
854 if (log.isEnabled()) {
855 log.unindent();
856 log.info("Done.");
857
858 log.info("Recompiled '", fn.getName(), "' (", Debug.id(this), ") ", canBeDeoptimized ? "can still be deoptimized." : " is completely deoptimized.");
859 log.finest("Looking up invoker...");
860 }
861
862 final MethodHandle newInvoker = effectiveOptInfo.data.lookup(fn);
863 invoker = newInvoker.asType(type.changeReturnType(newInvoker.type().returnType()));
864 constructor = null; // Will be regenerated when needed
865
866 log.info("Done: ", invoker);
867 final MethodHandle restOf = restOfHandle(effectiveOptInfo, compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL_RESTOF), canBeDeoptimized);
868
869 // Note that we only adjust the switch point after we set the invoker/constructor. This is important.
870 if (canBeDeoptimized) {
871 effectiveOptInfo.newOptimisticAssumptions(); // Otherwise, set a new switch point.
872 } else {
873 optimismInfo = null; // If we got to a point where we no longer have optimistic assumptions, let the optimism info go.
874 }
875 notifyAll();
876
877 return restOf;
878 }
879
880 private MethodHandle restOfHandle(final OptimismInfo info, final FunctionNode restOfFunction, final boolean canBeDeoptimized) {
881 assert info != null;
882 assert restOfFunction.getCompileUnit().getUnitClassName().contains("restOf");
883 final MethodHandle restOf =
884 changeReturnType(
885 info.data.lookupCodeMethod(
886 restOfFunction.getCompileUnit().getCode(),
887 MH.type(restOfFunction.getReturnType().getTypeClass(),
888 RewriteException.class)),
889 Object.class);
890
891 if (!canBeDeoptimized) {
892 return restOf;
893 }
894
895 // If rest-of is itself optimistic, we must make sure that we can repeat a deoptimization if it, too hits an exception.
896 return MH.catchException(restOf, RewriteException.class, createRewriteExceptionHandler());
897
898 }
899
900 private static class OptimismInfo {
901 // TODO: this is pointing to its owning ScriptFunctionData. Re-evaluate if that's okay.
902 private final RecompilableScriptFunctionData data;
903 private final Map<Integer, Type> invalidatedProgramPoints;
904 private SwitchPoint optimisticAssumptions;
905 private final DebugLogger log;
906
907 OptimismInfo(final RecompilableScriptFunctionData data, final Map<Integer, Type> invalidatedProgramPoints) {
908 this.data = data;
909 this.log = data.getLogger();
910 this.invalidatedProgramPoints = invalidatedProgramPoints == null ? new TreeMap<>() : invalidatedProgramPoints;
911 newOptimisticAssumptions();
912 }
913
914 private void newOptimisticAssumptions() {
915 optimisticAssumptions = new SwitchPoint();
916 }
917
918 boolean requestRecompile(final RewriteException e) {
919 final Type retType = e.getReturnType();
920 final Type previousFailedType = invalidatedProgramPoints.put(e.getProgramPoint(), retType);
921
922 if (previousFailedType != null && !previousFailedType.narrowerThan(retType)) {
923 final StackTraceElement[] stack = e.getStackTrace();
924 final String functionId = stack.length == 0 ?
925 data.getName() :
926 stack[0].getClassName() + "." + stack[0].getMethodName();
927
928 log.info("RewriteException for an already invalidated program point ", e.getProgramPoint(), " in ", functionId, ". This is okay for a recursive function invocation, but a bug otherwise.");
929
930 return false;
931 }
932
933 SwitchPoint.invalidateAll(new SwitchPoint[] { optimisticAssumptions });
934
935 return true;
936 }
937
938 Compiler getCompiler(final FunctionNode fn, final MethodType actualCallSiteType, final RewriteException e) {
939 return data.getCompiler(fn, actualCallSiteType, e.getRuntimeScope(), invalidatedProgramPoints, getEntryPoints(e));
940 }
941
942 private static int[] getEntryPoints(final RewriteException e) {
943 final int[] prevEntryPoints = e.getPreviousContinuationEntryPoints();
944 final int[] entryPoints;
945 if (prevEntryPoints == null) {
946 entryPoints = new int[1];
947 } else {
948 final int l = prevEntryPoints.length;
949 entryPoints = new int[l + 1];
950 System.arraycopy(prevEntryPoints, 0, entryPoints, 1, l);
951 }
952 entryPoints[0] = e.getProgramPoint();
953 return entryPoints;
954 }
955
956 FunctionNode reparse() {
957 return data.reparse();
958 }
959
960 boolean isSerialized() {
961 return data.isSerialized();
962 }
963 }
964
965 @SuppressWarnings("unused")
966 private static Object newFilter(final Object result, final Object allocation) {
967 return (result instanceof ScriptObject || !JSType.isPrimitive(result))? result : allocation;
968 }
969
970 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) {
971 return MH.findStatic(MethodHandles.lookup(), CompiledFunction.class, name, MH.type(rtype, types));
972 }
973 }
--- EOF ---