CompiledFunction.java revision 1036:f0b5e3900a10
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 */ 25package jdk.nashorn.internal.runtime; 26 27import static jdk.nashorn.internal.lookup.Lookup.MH; 28import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.INVALID_PROGRAM_POINT; 29import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid; 30import java.lang.invoke.CallSite; 31import java.lang.invoke.MethodHandle; 32import java.lang.invoke.MethodHandles; 33import java.lang.invoke.MethodType; 34import java.lang.invoke.MutableCallSite; 35import java.lang.invoke.SwitchPoint; 36import java.util.Collection; 37import java.util.Collections; 38import java.util.Iterator; 39import java.util.Map; 40import java.util.TreeMap; 41import java.util.function.Supplier; 42import java.util.logging.Level; 43import jdk.internal.dynalink.linker.GuardedInvocation; 44import jdk.nashorn.internal.codegen.Compiler; 45import jdk.nashorn.internal.codegen.Compiler.CompilationPhases; 46import jdk.nashorn.internal.codegen.TypeMap; 47import jdk.nashorn.internal.codegen.types.ArrayType; 48import jdk.nashorn.internal.codegen.types.Type; 49import jdk.nashorn.internal.ir.FunctionNode; 50import jdk.nashorn.internal.objects.annotations.SpecializedFunction.LinkLogic; 51import jdk.nashorn.internal.runtime.events.RecompilationEvent; 52import jdk.nashorn.internal.runtime.linker.Bootstrap; 53import jdk.nashorn.internal.runtime.logging.DebugLogger; 54 55/** 56 * An version of a JavaScript function, native or JavaScript. 57 * Supports lazily generating a constructor version of the invocation. 58 */ 59final class CompiledFunction { 60 61 private static final MethodHandle NEWFILTER = findOwnMH("newFilter", Object.class, Object.class, Object.class); 62 private static final MethodHandle RELINK_COMPOSABLE_INVOKER = findOwnMH("relinkComposableInvoker", void.class, CallSite.class, CompiledFunction.class, boolean.class); 63 private static final MethodHandle HANDLE_REWRITE_EXCEPTION = findOwnMH("handleRewriteException", MethodHandle.class, CompiledFunction.class, OptimismInfo.class, RewriteException.class); 64 private static final MethodHandle RESTOF_INVOKER = MethodHandles.exactInvoker(MethodType.methodType(Object.class, RewriteException.class)); 65 66 private final DebugLogger log; 67 68 static final Collection<CompiledFunction> NO_FUNCTIONS = Collections.emptySet(); 69 70 /** 71 * The method type may be more specific than the invoker, if. e.g. 72 * the invoker is guarded, and a guard with a generic object only 73 * fallback, while the target is more specific, we still need the 74 * more specific type for sorting 75 */ 76 private MethodHandle invoker; 77 private MethodHandle constructor; 78 private OptimismInfo optimismInfo; 79 private final int flags; // from FunctionNode 80 private final MethodType callSiteType; 81 82 private final Specialization specialization; 83 84 CompiledFunction(final MethodHandle invoker) { 85 this(invoker, null, null); 86 } 87 88 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker, final Specialization specialization) { 89 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), specialization); 90 } 91 92 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final Specialization specialization) { 93 this(invoker, constructor, 0, null, specialization, DebugLogger.DISABLED_LOGGER); 94 } 95 96 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final int flags, final MethodType callSiteType, final Specialization specialization, final DebugLogger log) { 97 this.specialization = specialization; 98 if (specialization != null && specialization.isOptimistic()) { 99 /* 100 * An optimistic builtin with isOptimistic=true works like any optimistic generated function, i.e. it 101 * can throw unwarranted optimism exceptions. As native functions trivially can't have parts of them 102 * regenerated as restof methods, this only works if the methods are atomic/functional in their behavior 103 * and doesn't modify state before an UOE can be thrown. If they aren't, we can reexecute a wider version 104 * of the same builtin in a recompilation handler for FinalScriptFunctionData. There are several 105 * candidate methods in Native* that would benefit from this, but I haven't had time to implement any 106 * of them currently. In order to fit in with the relinking framework, the current thinking is 107 * that the methods still take a program point to fit in with other optimistic functions, but 108 * it is set to "first", which is the beginning of the method. The relinker can tell the difference 109 * between builtin and JavaScript functions. This might change. TODO 110 */ 111 this.invoker = MH.insertArguments(invoker, invoker.type().parameterCount() - 1, UnwarrantedOptimismException.FIRST_PROGRAM_POINT); 112 throw new AssertionError("Optimistic (UnwarrantedOptimismException throwing) builtin functions are currently not in use"); 113 } else { 114 this.invoker = invoker; 115 } 116 this.constructor = constructor; 117 this.flags = flags; 118 this.callSiteType = callSiteType; 119 this.log = log; 120 } 121 122 CompiledFunction(final MethodHandle invoker, final RecompilableScriptFunctionData functionData, 123 final Map<Integer, Type> invalidatedProgramPoints, final MethodType callSiteType, final int flags) { 124 this(invoker, null, flags, callSiteType, null, functionData.getLogger()); 125 if ((flags & FunctionNode.IS_DEOPTIMIZABLE) != 0) { 126 optimismInfo = new OptimismInfo(functionData, invalidatedProgramPoints); 127 } else { 128 optimismInfo = null; 129 } 130 } 131 132 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker) { 133 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), null); 134 } 135 136 boolean isSpecialization() { 137 return specialization != null; 138 } 139 140 boolean hasLinkLogic() { 141 return getLinkLogicClass() != null; 142 } 143 144 Class<? extends LinkLogic> getLinkLogicClass() { 145 if (isSpecialization()) { 146 final Class<? extends LinkLogic> linkLogicClass = specialization.getLinkLogicClass(); 147 assert !LinkLogic.isEmpty(linkLogicClass) : "empty link logic classes should have been removed by nasgen"; 148 return linkLogicClass; 149 } 150 return null; 151 } 152 153 int getFlags() { 154 return flags; 155 } 156 157 /** 158 * An optimistic specialization is one that can throw UnwarrantedOptimismException. 159 * This is allowed for native methods, as long as they are functional, i.e. don't change 160 * any state between entering and throwing the UOE. Then we can re-execute a wider version 161 * of the method in the continuation. Rest-of method generation for optimistic builtins is 162 * of course not possible, but this approach works and fits into the same relinking 163 * framework 164 * 165 * @return true if optimistic builtin 166 */ 167 boolean isOptimistic() { 168 return isSpecialization() ? specialization.isOptimistic() : false; 169 } 170 171 boolean isApplyToCall() { 172 return (flags & FunctionNode.HAS_APPLY_TO_CALL_SPECIALIZATION) != 0; 173 } 174 175 boolean isVarArg() { 176 return isVarArgsType(invoker.type()); 177 } 178 179 @Override 180 public String toString() { 181 final StringBuilder sb = new StringBuilder(); 182 final Class<? extends LinkLogic> linkLogicClass = getLinkLogicClass(); 183 184 sb.append("[invokerType="). 185 append(invoker.type()). 186 append(" ctor="). 187 append(constructor). 188 append(" weight="). 189 append(weight()). 190 append(" linkLogic="). 191 append(linkLogicClass != null ? linkLogicClass.getSimpleName() : "none"); 192 193 return sb.toString(); 194 } 195 196 boolean needsCallee() { 197 return ScriptFunctionData.needsCallee(invoker); 198 } 199 200 /** 201 * Returns an invoker method handle for this function. Note that the handle is safely composable in 202 * the sense that you can compose it with other handles using any combinators even if you can't affect call site 203 * invalidation. If this compiled function is non-optimistic, then it returns the same value as 204 * {@link #getInvokerOrConstructor(boolean)}. However, if the function is optimistic, then this handle will 205 * incur an overhead as it will add an intermediate internal call site that can relink itself when the function 206 * needs to regenerate its code to always point at the latest generated code version. 207 * @return a guaranteed composable invoker method handle for this function. 208 */ 209 MethodHandle createComposableInvoker() { 210 return createComposableInvoker(false); 211 } 212 213 /** 214 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle should be 215 * considered non-composable in the sense that you can only compose it with other handles using any combinators if 216 * you can ensure that the composition is guarded by {@link #getOptimisticAssumptionsSwitchPoint()} if it's 217 * non-null, and that you can relink the call site it is set into as a target if the switch point is invalidated. In 218 * all other cases, use {@link #createComposableConstructor()}. 219 * @return a direct constructor method handle for this function. 220 */ 221 private MethodHandle getConstructor() { 222 if (constructor == null) { 223 constructor = createConstructorFromInvoker(createInvokerForPessimisticCaller()); 224 } 225 226 return constructor; 227 } 228 229 /** 230 * Creates a version of the invoker intended for a pessimistic caller (return type is Object, no caller optimistic 231 * program point available). 232 * @return a version of the invoker intended for a pessimistic caller. 233 */ 234 private MethodHandle createInvokerForPessimisticCaller() { 235 return createInvoker(Object.class, INVALID_PROGRAM_POINT); 236 } 237 238 /** 239 * Compose a constructor from an invoker. 240 * 241 * @param invoker invoker 242 * @return the composed constructor 243 */ 244 private static MethodHandle createConstructorFromInvoker(final MethodHandle invoker) { 245 final boolean needsCallee = ScriptFunctionData.needsCallee(invoker); 246 // If it was (callee, this, args...), permute it to (this, callee, args...). We're doing this because having 247 // "this" in the first argument position is what allows the elegant folded composition of 248 // (newFilter x constructor x allocator) further down below in the code. Also, ensure the composite constructor 249 // always returns Object. 250 final MethodHandle swapped = needsCallee ? swapCalleeAndThis(invoker) : invoker; 251 252 final MethodHandle returnsObject = MH.asType(swapped, swapped.type().changeReturnType(Object.class)); 253 254 final MethodType ctorType = returnsObject.type(); 255 256 // Construct a dropping type list for NEWFILTER, but don't include constructor "this" into it, so it's actually 257 // captured as "allocation" parameter of NEWFILTER after we fold the constructor into it. 258 // (this, [callee, ]args...) => ([callee, ]args...) 259 final Class<?>[] ctorArgs = ctorType.dropParameterTypes(0, 1).parameterArray(); 260 261 // Fold constructor into newFilter that replaces the return value from the constructor with the originally 262 // allocated value when the originally allocated value is a JS primitive (String, Boolean, Number). 263 // (result, this, [callee, ]args...) x (this, [callee, ]args...) => (this, [callee, ]args...) 264 final MethodHandle filtered = MH.foldArguments(MH.dropArguments(NEWFILTER, 2, ctorArgs), returnsObject); 265 266 // allocate() takes a ScriptFunction and returns a newly allocated ScriptObject... 267 if (needsCallee) { 268 // ...we either fold it into the previous composition, if we need both the ScriptFunction callee object and 269 // the newly allocated object in the arguments, so (this, callee, args...) x (callee) => (callee, args...), 270 // or... 271 return MH.foldArguments(filtered, ScriptFunction.ALLOCATE); 272 } 273 274 // ...replace the ScriptFunction argument with the newly allocated object, if it doesn't need the callee 275 // (this, args...) filter (callee) => (callee, args...) 276 return MH.filterArguments(filtered, 0, ScriptFunction.ALLOCATE); 277 } 278 279 /** 280 * Permutes the parameters in the method handle from {@code (callee, this, ...)} to {@code (this, callee, ...)}. 281 * Used when creating a constructor handle. 282 * @param mh a method handle with order of arguments {@code (callee, this, ...)} 283 * @return a method handle with order of arguments {@code (this, callee, ...)} 284 */ 285 private static MethodHandle swapCalleeAndThis(final MethodHandle mh) { 286 final MethodType type = mh.type(); 287 assert type.parameterType(0) == ScriptFunction.class : type; 288 assert type.parameterType(1) == Object.class : type; 289 final MethodType newType = type.changeParameterType(0, Object.class).changeParameterType(1, ScriptFunction.class); 290 final int[] reorder = new int[type.parameterCount()]; 291 reorder[0] = 1; 292 assert reorder[1] == 0; 293 for (int i = 2; i < reorder.length; ++i) { 294 reorder[i] = i; 295 } 296 return MethodHandles.permuteArguments(mh, newType, reorder); 297 } 298 299 /** 300 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle is safely 301 * composable in the sense that you can compose it with other handles using any combinators even if you can't affect 302 * call site invalidation. If this compiled function is non-optimistic, then it returns the same value as 303 * {@link #getConstructor()}. However, if the function is optimistic, then this handle will incur an overhead as it 304 * will add an intermediate internal call site that can relink itself when the function needs to regenerate its code 305 * to always point at the latest generated code version. 306 * @return a guaranteed composable constructor method handle for this function. 307 */ 308 MethodHandle createComposableConstructor() { 309 return createComposableInvoker(true); 310 } 311 312 boolean hasConstructor() { 313 return constructor != null; 314 } 315 316 MethodType type() { 317 return invoker.type(); 318 } 319 320 int weight() { 321 return weight(type()); 322 } 323 324 private static int weight(final MethodType type) { 325 if (isVarArgsType(type)) { 326 return Integer.MAX_VALUE; //if there is a varargs it should be the heavist and last fallback 327 } 328 329 int weight = Type.typeFor(type.returnType()).getWeight(); 330 for (int i = 0 ; i < type.parameterCount() ; i++) { 331 final Class<?> paramType = type.parameterType(i); 332 final int pweight = Type.typeFor(paramType).getWeight() * 2; //params are more important than call types as return values are always specialized 333 weight += pweight; 334 } 335 336 weight += type.parameterCount(); //more params outweigh few parameters 337 338 return weight; 339 } 340 341 static boolean isVarArgsType(final MethodType type) { 342 assert type.parameterCount() >= 1 : type; 343 return type.parameterType(type.parameterCount() - 1) == Object[].class; 344 } 345 346 static boolean moreGenericThan(final MethodType mt0, final MethodType mt1) { 347 return weight(mt0) > weight(mt1); 348 } 349 350 boolean betterThanFinal(final CompiledFunction other, final MethodType callSiteMethodType) { 351 // Prefer anything over nothing, as we can't compile new versions. 352 if (other == null) { 353 return true; 354 } 355 return betterThanFinal(this, other, callSiteMethodType); 356 } 357 358 private static boolean betterThanFinal(final CompiledFunction cf, final CompiledFunction other, final MethodType callSiteMethodType) { 359 final MethodType thisMethodType = cf.type(); 360 final MethodType otherMethodType = other.type(); 361 final int thisParamCount = getParamCount(thisMethodType); 362 final int otherParamCount = getParamCount(otherMethodType); 363 final int callSiteRawParamCount = getParamCount(callSiteMethodType); 364 final boolean csVarArg = callSiteRawParamCount == Integer.MAX_VALUE; 365 // Subtract 1 for callee for non-vararg call sites 366 final int callSiteParamCount = csVarArg ? callSiteRawParamCount : callSiteRawParamCount - 1; 367 368 // Prefer the function that discards less parameters 369 final int thisDiscardsParams = Math.max(callSiteParamCount - thisParamCount, 0); 370 final int otherDiscardsParams = Math.max(callSiteParamCount - otherParamCount, 0); 371 if(thisDiscardsParams < otherDiscardsParams) { 372 return true; 373 } 374 if(thisDiscardsParams > otherDiscardsParams) { 375 return false; 376 } 377 378 final boolean thisVarArg = thisParamCount == Integer.MAX_VALUE; 379 final boolean otherVarArg = otherParamCount == Integer.MAX_VALUE; 380 if(!(thisVarArg && otherVarArg && csVarArg)) { 381 // At least one of them isn't vararg 382 final Type[] thisType = toTypeWithoutCallee(thisMethodType, 0); // Never has callee 383 final Type[] otherType = toTypeWithoutCallee(otherMethodType, 0); // Never has callee 384 final Type[] callSiteType = toTypeWithoutCallee(callSiteMethodType, 1); // Always has callee 385 386 int narrowWeightDelta = 0; 387 int widenWeightDelta = 0; 388 final int minParamsCount = Math.min(Math.min(thisParamCount, otherParamCount), callSiteParamCount); 389 for(int i = 0; i < minParamsCount; ++i) { 390 final int callSiteParamWeight = getParamType(i, callSiteType, csVarArg).getWeight(); 391 // Delta is negative for narrowing, positive for widening 392 final int thisParamWeightDelta = getParamType(i, thisType, thisVarArg).getWeight() - callSiteParamWeight; 393 final int otherParamWeightDelta = getParamType(i, otherType, otherVarArg).getWeight() - callSiteParamWeight; 394 // Only count absolute values of narrowings 395 narrowWeightDelta += Math.max(-thisParamWeightDelta, 0) - Math.max(-otherParamWeightDelta, 0); 396 // Only count absolute values of widenings 397 widenWeightDelta += Math.max(thisParamWeightDelta, 0) - Math.max(otherParamWeightDelta, 0); 398 } 399 400 // If both functions accept more arguments than what is passed at the call site, account for ability 401 // to receive Undefined un-narrowed in the remaining arguments. 402 if(!thisVarArg) { 403 for(int i = callSiteParamCount; i < thisParamCount; ++i) { 404 narrowWeightDelta += Math.max(Type.OBJECT.getWeight() - thisType[i].getWeight(), 0); 405 } 406 } 407 if(!otherVarArg) { 408 for(int i = callSiteParamCount; i < otherParamCount; ++i) { 409 narrowWeightDelta -= Math.max(Type.OBJECT.getWeight() - otherType[i].getWeight(), 0); 410 } 411 } 412 413 // Prefer function that narrows less 414 if(narrowWeightDelta < 0) { 415 return true; 416 } 417 if(narrowWeightDelta > 0) { 418 return false; 419 } 420 421 // Prefer function that widens less 422 if(widenWeightDelta < 0) { 423 return true; 424 } 425 if(widenWeightDelta > 0) { 426 return false; 427 } 428 } 429 430 // Prefer the function that exactly matches the arity of the call site. 431 if(thisParamCount == callSiteParamCount && otherParamCount != callSiteParamCount) { 432 return true; 433 } 434 if(thisParamCount != callSiteParamCount && otherParamCount == callSiteParamCount) { 435 return false; 436 } 437 438 // Otherwise, neither function matches arity exactly. We also know that at this point, they both can receive 439 // more arguments than call site, otherwise we would've already chosen the one that discards less parameters. 440 // Note that variable arity methods are preferred, as they actually match the call site arity better, since they 441 // really have arbitrary arity. 442 if(thisVarArg) { 443 if(!otherVarArg) { 444 return true; // 445 } 446 } else if(otherVarArg) { 447 return false; 448 } 449 450 // Neither is variable arity; chose the one that has less extra parameters. 451 final int fnParamDelta = thisParamCount - otherParamCount; 452 if(fnParamDelta < 0) { 453 return true; 454 } 455 if(fnParamDelta > 0) { 456 return false; 457 } 458 459 final int callSiteRetWeight = Type.typeFor(callSiteMethodType.returnType()).getWeight(); 460 // Delta is negative for narrower return type, positive for wider return type 461 final int thisRetWeightDelta = Type.typeFor(thisMethodType.returnType()).getWeight() - callSiteRetWeight; 462 final int otherRetWeightDelta = Type.typeFor(otherMethodType.returnType()).getWeight() - callSiteRetWeight; 463 464 // Prefer function that returns a less wide return type 465 final int widenRetDelta = Math.max(thisRetWeightDelta, 0) - Math.max(otherRetWeightDelta, 0); 466 if(widenRetDelta < 0) { 467 return true; 468 } 469 if(widenRetDelta > 0) { 470 return false; 471 } 472 473 // Prefer function that returns a less narrow return type 474 final int narrowRetDelta = Math.max(-thisRetWeightDelta, 0) - Math.max(-otherRetWeightDelta, 0); 475 if(narrowRetDelta < 0) { 476 return true; 477 } 478 if(narrowRetDelta > 0) { 479 return false; 480 } 481 482 //if they are equal, pick the specialized one first 483 if (cf.isSpecialization() != other.isSpecialization()) { 484 return cf.isSpecialization(); //always pick the specialized version if we can 485 } 486 487 if (cf.isSpecialization() && other.isSpecialization()) { 488 return cf.getLinkLogicClass() != null; //pick link logic specialization above generic specializations 489 } 490 491 // Signatures are identical 492 throw new AssertionError(thisMethodType + " identically applicable to " + otherMethodType + " for " + callSiteMethodType); 493 } 494 495 private static Type[] toTypeWithoutCallee(final MethodType type, final int thisIndex) { 496 final int paramCount = type.parameterCount(); 497 final Type[] t = new Type[paramCount - thisIndex]; 498 for(int i = thisIndex; i < paramCount; ++i) { 499 t[i - thisIndex] = Type.typeFor(type.parameterType(i)); 500 } 501 return t; 502 } 503 504 private static Type getParamType(final int i, final Type[] paramTypes, final boolean isVarArg) { 505 final int fixParamCount = paramTypes.length - (isVarArg ? 1 : 0); 506 if(i < fixParamCount) { 507 return paramTypes[i]; 508 } 509 assert isVarArg; 510 return ((ArrayType)paramTypes[paramTypes.length - 1]).getElementType(); 511 } 512 513 boolean matchesCallSite(final MethodType callSiteType, final boolean pickVarArg) { 514 if (callSiteType.equals(this.callSiteType)) { 515 return true; 516 } 517 final MethodType type = type(); 518 final int fnParamCount = getParamCount(type); 519 final boolean isVarArg = fnParamCount == Integer.MAX_VALUE; 520 if (isVarArg) { 521 return pickVarArg; 522 } 523 524 final int csParamCount = getParamCount(callSiteType); 525 final boolean csIsVarArg = csParamCount == Integer.MAX_VALUE; 526 final int thisThisIndex = needsCallee() ? 1 : 0; // Index of "this" parameter in this function's type 527 528 final int fnParamCountNoCallee = fnParamCount - thisThisIndex; 529 final int minParams = Math.min(csParamCount - 1, fnParamCountNoCallee); // callSiteType always has callee, so subtract 1 530 // We must match all incoming parameters, except "this". Starting from 1 to skip "this". 531 for(int i = 1; i < minParams; ++i) { 532 final Type fnType = Type.typeFor(type.parameterType(i + thisThisIndex)); 533 final Type csType = csIsVarArg ? Type.OBJECT : Type.typeFor(callSiteType.parameterType(i + 1)); 534 if(!fnType.isEquivalentTo(csType)) { 535 return false; 536 } 537 } 538 539 // Must match any undefined parameters to Object type. 540 for(int i = minParams; i < fnParamCountNoCallee; ++i) { 541 if(!Type.typeFor(type.parameterType(i + thisThisIndex)).isEquivalentTo(Type.OBJECT)) { 542 return false; 543 } 544 } 545 546 return true; 547 } 548 549 private static int getParamCount(final MethodType type) { 550 final int paramCount = type.parameterCount(); 551 return type.parameterType(paramCount - 1).isArray() ? Integer.MAX_VALUE : paramCount; 552 } 553 554 private boolean canBeDeoptimized() { 555 return optimismInfo != null; 556 } 557 558 private MethodHandle createComposableInvoker(final boolean isConstructor) { 559 final MethodHandle handle = getInvokerOrConstructor(isConstructor); 560 561 // If compiled function is not optimistic, it can't ever change its invoker/constructor, so just return them 562 // directly. 563 if(!canBeDeoptimized()) { 564 return handle; 565 } 566 567 // Otherwise, we need a new level of indirection; need to introduce a mutable call site that can relink itslef 568 // to the compiled function's changed target whenever the optimistic assumptions are invalidated. 569 final CallSite cs = new MutableCallSite(handle.type()); 570 relinkComposableInvoker(cs, this, isConstructor); 571 return cs.dynamicInvoker(); 572 } 573 574 private static class HandleAndAssumptions { 575 final MethodHandle handle; 576 final SwitchPoint assumptions; 577 578 HandleAndAssumptions(final MethodHandle handle, final SwitchPoint assumptions) { 579 this.handle = handle; 580 this.assumptions = assumptions; 581 } 582 583 GuardedInvocation createInvocation() { 584 return new GuardedInvocation(handle, assumptions); 585 } 586 } 587 588 /** 589 * Returns a pair of an invocation created with a passed-in supplier and a non-invalidated switch point for 590 * optimistic assumptions (or null for the switch point if the function can not be deoptimized). While the method 591 * makes a best effort to return a non-invalidated switch point (compensating for possible deoptimizing 592 * recompilation happening on another thread) it is still possible that by the time this method returns the 593 * switchpoint has been invalidated by a {@code RewriteException} triggered on another thread for this function. 594 * This is not a problem, though, as these switch points are always used to produce call sites that fall back to 595 * relinking when they are invalidated, and in this case the execution will end up here again. What this method 596 * basically does is minimize such busy-loop relinking while the function is being recompiled on a different thread. 597 * @param invocationSupplier the supplier that constructs the actual invocation method handle; should use the 598 * {@code CompiledFunction} method itself in some capacity. 599 * @return a tuple object containing the method handle as created by the supplier and an optimistic assumptions 600 * switch point that is guaranteed to not have been invalidated before the call to this method (or null if the 601 * function can't be further deoptimized). 602 */ 603 private synchronized HandleAndAssumptions getValidOptimisticInvocation(final Supplier<MethodHandle> invocationSupplier) { 604 for(;;) { 605 final MethodHandle handle = invocationSupplier.get(); 606 final SwitchPoint assumptions = canBeDeoptimized() ? optimismInfo.optimisticAssumptions : null; 607 if(assumptions != null && assumptions.hasBeenInvalidated()) { 608 // We can be in a situation where one thread is in the middle of a deoptimizing compilation when we hit 609 // this and thus, it has invalidated the old switch point, but hasn't created the new one yet. Note that 610 // the behavior of invalidating the old switch point before recompilation, and only creating the new one 611 // after recompilation is by design. If we didn't wait here for the recompilation to complete, we would 612 // be busy looping through the fallback path of the invalidated switch point, relinking the call site 613 // again with the same invalidated switch point, invoking the fallback, etc. stealing CPU cycles from 614 // the recompilation task we're dependent on. This can still happen if the switch point gets invalidated 615 // after we grabbed it here, in which case we'll indeed do one busy relink immediately. 616 try { 617 wait(); 618 } catch (final InterruptedException e) { 619 // Intentionally ignored. There's nothing meaningful we can do if we're interrupted 620 } 621 } else { 622 return new HandleAndAssumptions(handle, assumptions); 623 } 624 } 625 } 626 627 private static void relinkComposableInvoker(final CallSite cs, final CompiledFunction inv, final boolean constructor) { 628 final HandleAndAssumptions handleAndAssumptions = inv.getValidOptimisticInvocation(new Supplier<MethodHandle>() { 629 @Override 630 public MethodHandle get() { 631 return inv.getInvokerOrConstructor(constructor); 632 } 633 }); 634 final MethodHandle handle = handleAndAssumptions.handle; 635 final SwitchPoint assumptions = handleAndAssumptions.assumptions; 636 final MethodHandle target; 637 if(assumptions == null) { 638 target = handle; 639 } else { 640 final MethodHandle relink = MethodHandles.insertArguments(RELINK_COMPOSABLE_INVOKER, 0, cs, inv, constructor); 641 target = assumptions.guardWithTest(handle, MethodHandles.foldArguments(cs.dynamicInvoker(), relink)); 642 } 643 cs.setTarget(target.asType(cs.type())); 644 } 645 646 private MethodHandle getInvokerOrConstructor(final boolean selectCtor) { 647 return selectCtor ? getConstructor() : createInvokerForPessimisticCaller(); 648 } 649 650 /** 651 * Returns a guarded invocation for this function when not invoked as a constructor. The guarded invocation has no 652 * guard but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a 653 * final guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 654 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 655 * continue to use the switch point. If that is not possible, use {@link #createComposableInvoker()} instead. 656 * @return a guarded invocation for an ordinary (non-constructor) invocation of this function. 657 */ 658 GuardedInvocation createFunctionInvocation(final Class<?> callSiteReturnType, final int callerProgramPoint) { 659 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 660 @Override 661 public MethodHandle get() { 662 return createInvoker(callSiteReturnType, callerProgramPoint); 663 } 664 }).createInvocation(); 665 } 666 667 /** 668 * Returns a guarded invocation for this function when invoked as a constructor. The guarded invocation has no guard 669 * but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a final 670 * guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 671 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 672 * continue to use the switch point. If that is not possible, use {@link #createComposableConstructor()} instead. 673 * @return a guarded invocation for invocation of this function as a constructor. 674 */ 675 GuardedInvocation createConstructorInvocation() { 676 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 677 @Override 678 public MethodHandle get() { 679 return getConstructor(); 680 } 681 }).createInvocation(); 682 } 683 684 private MethodHandle createInvoker(final Class<?> callSiteReturnType, final int callerProgramPoint) { 685 final boolean isOptimistic = canBeDeoptimized(); 686 MethodHandle handleRewriteException = isOptimistic ? createRewriteExceptionHandler() : null; 687 688 MethodHandle inv = invoker; 689 if(isValid(callerProgramPoint)) { 690 inv = OptimisticReturnFilters.filterOptimisticReturnValue(inv, callSiteReturnType, callerProgramPoint); 691 inv = changeReturnType(inv, callSiteReturnType); 692 if(callSiteReturnType.isPrimitive() && handleRewriteException != null) { 693 // because handleRewriteException always returns Object 694 handleRewriteException = OptimisticReturnFilters.filterOptimisticReturnValue(handleRewriteException, 695 callSiteReturnType, callerProgramPoint); 696 } 697 } else if(isOptimistic) { 698 // Required so that rewrite exception has the same return type. It'd be okay to do it even if we weren't 699 // optimistic, but it isn't necessary as the linker upstream will eventually convert the return type. 700 inv = changeReturnType(inv, callSiteReturnType); 701 } 702 703 if(isOptimistic) { 704 assert handleRewriteException != null; 705 final MethodHandle typedHandleRewriteException = changeReturnType(handleRewriteException, inv.type().returnType()); 706 return MH.catchException(inv, RewriteException.class, typedHandleRewriteException); 707 } 708 return inv; 709 } 710 711 private MethodHandle createRewriteExceptionHandler() { 712 return MH.foldArguments(RESTOF_INVOKER, MH.insertArguments(HANDLE_REWRITE_EXCEPTION, 0, this, optimismInfo)); 713 } 714 715 private static MethodHandle changeReturnType(final MethodHandle mh, final Class<?> newReturnType) { 716 return Bootstrap.getLinkerServices().asType(mh, mh.type().changeReturnType(newReturnType)); 717 } 718 719 @SuppressWarnings("unused") 720 private static MethodHandle handleRewriteException(final CompiledFunction function, final OptimismInfo oldOptimismInfo, final RewriteException re) { 721 return function.handleRewriteException(oldOptimismInfo, re); 722 } 723 724 /** 725 * Debug function for printing out all invalidated program points and their 726 * invalidation mapping to next type 727 * @param ipp 728 * @return string describing the ipp map 729 */ 730 private static String toStringInvalidations(final Map<Integer, Type> ipp) { 731 if (ipp == null) { 732 return ""; 733 } 734 735 final StringBuilder sb = new StringBuilder(); 736 737 for (final Iterator<Map.Entry<Integer, Type>> iter = ipp.entrySet().iterator(); iter.hasNext(); ) { 738 final Map.Entry<Integer, Type> entry = iter.next(); 739 final char bct = entry.getValue().getBytecodeStackType(); 740 741 sb.append('['). 742 append(entry.getKey()). 743 append("->"). 744 append(bct == 'A' ? 'O' : bct). 745 append(']'); 746 747 if (iter.hasNext()) { 748 sb.append(' '); 749 } 750 } 751 752 return sb.toString(); 753 } 754 755 private void logRecompile(final String reason, final FunctionNode fn, final MethodType callSiteType, final Map<Integer, Type> ipp) { 756 if (log.isEnabled()) { 757 log.info(reason, DebugLogger.quote(fn.getName()), " signature: ", callSiteType, " ", toStringInvalidations(ipp)); 758 } 759 } 760 761 /** 762 * Handles a {@link RewriteException} raised during the execution of this function by recompiling (if needed) the 763 * function with an optimistic assumption invalidated at the program point indicated by the exception, and then 764 * executing a rest-of method to complete the execution with the deoptimized version. 765 * @param oldOptInfo the optimism info of this function. We must store it explicitly as a bound argument in the 766 * method handle, otherwise it could be null for handling a rewrite exception in an outer invocation of a recursive 767 * function when recursive invocations of the function have completely deoptimized it. 768 * @param re the rewrite exception that was raised 769 * @return the method handle for the rest-of method, for folding composition. 770 */ 771 private synchronized MethodHandle handleRewriteException(final OptimismInfo oldOptInfo, final RewriteException re) { 772 if (log.isEnabled()) { 773 log.info(new RecompilationEvent(Level.INFO, re, re.getReturnValueNonDestructive()), "RewriteException ", re.getMessageShort()); 774 } 775 776 final MethodType type = type(); 777 778 // Compiler needs a call site type as its input, which always has a callee parameter, so we must add it if 779 // this function doesn't have a callee parameter. 780 final MethodType callSiteType = type.parameterType(0) == ScriptFunction.class ? 781 type : 782 type.insertParameterTypes(0, ScriptFunction.class); 783 final OptimismInfo currentOptInfo = optimismInfo; 784 final boolean shouldRecompile = currentOptInfo != null && currentOptInfo.requestRecompile(re); 785 786 // Effective optimism info, for subsequent use. We'll normally try to use the current (latest) one, but if it 787 // isn't available, we'll use the old one bound into the call site. 788 final OptimismInfo effectiveOptInfo = currentOptInfo != null ? currentOptInfo : oldOptInfo; 789 FunctionNode fn = effectiveOptInfo.reparse(); 790 final Compiler compiler = effectiveOptInfo.getCompiler(fn, callSiteType, re); //set to non rest-of 791 792 if (!shouldRecompile) { 793 // It didn't necessarily recompile, e.g. for an outer invocation of a recursive function if we already 794 // recompiled a deoptimized version for an inner invocation. 795 // We still need to do the rest of from the beginning 796 logRecompile("Rest-of compilation [STANDALONE] ", fn, callSiteType, effectiveOptInfo.invalidatedProgramPoints); 797 return restOfHandle(effectiveOptInfo, compiler.compile(fn, CompilationPhases.COMPILE_ALL_RESTOF), currentOptInfo != null); 798 } 799 800 logRecompile("Deoptimizing recompilation (up to bytecode) ", fn, callSiteType, effectiveOptInfo.invalidatedProgramPoints); 801 fn = compiler.compile(fn, CompilationPhases.COMPILE_UPTO_BYTECODE); 802 log.info("Reusable IR generated"); 803 804 // compile the rest of the function, and install it 805 log.info("Generating and installing bytecode from reusable IR..."); 806 logRecompile("Rest-of compilation [CODE PIPELINE REUSE] ", fn, callSiteType, effectiveOptInfo.invalidatedProgramPoints); 807 final FunctionNode normalFn = compiler.compile(fn, CompilationPhases.COMPILE_FROM_BYTECODE); 808 809 if (effectiveOptInfo.data.usePersistentCodeCache()) { 810 final RecompilableScriptFunctionData data = effectiveOptInfo.data; 811 final int functionNodeId = data.getFunctionNodeId(); 812 final TypeMap typeMap = data.typeMap(callSiteType); 813 final Type[] paramTypes = typeMap == null ? null : typeMap.getParameterTypes(functionNodeId); 814 final String cacheKey = CodeStore.getCacheKey(functionNodeId, paramTypes); 815 compiler.persistClassInfo(cacheKey, normalFn); 816 } 817 818 FunctionNode fn2 = effectiveOptInfo.reparse(); 819 fn2 = compiler.compile(fn2, CompilationPhases.COMPILE_UPTO_BYTECODE); 820 log.info("Done."); 821 822 final boolean canBeDeoptimized = normalFn.canBeDeoptimized(); 823 824 if (log.isEnabled()) { 825 log.info("Recompiled '", fn.getName(), "' (", Debug.id(this), ") ", canBeDeoptimized ? " can still be deoptimized." : " is completely deoptimized."); 826 } 827 828 log.info("Looking up invoker..."); 829 830 final MethodHandle newInvoker = effectiveOptInfo.data.lookup(fn); 831 invoker = newInvoker.asType(type.changeReturnType(newInvoker.type().returnType())); 832 constructor = null; // Will be regenerated when needed 833 834 log.info("Done: ", invoker); 835 final MethodHandle restOf = restOfHandle(effectiveOptInfo, compiler.compile(fn, CompilationPhases.COMPILE_FROM_BYTECODE_RESTOF), canBeDeoptimized); 836 837 // Note that we only adjust the switch point after we set the invoker/constructor. This is important. 838 if (canBeDeoptimized) { 839 effectiveOptInfo.newOptimisticAssumptions(); // Otherwise, set a new switch point. 840 } else { 841 optimismInfo = null; // If we got to a point where we no longer have optimistic assumptions, let the optimism info go. 842 } 843 notifyAll(); 844 845 return restOf; 846 } 847 848 private MethodHandle restOfHandle(final OptimismInfo info, final FunctionNode restOfFunction, final boolean canBeDeoptimized) { 849 assert info != null; 850 assert restOfFunction.getCompileUnit().getUnitClassName().contains("restOf"); 851 final MethodHandle restOf = 852 changeReturnType( 853 info.data.lookupCodeMethod( 854 restOfFunction.getCompileUnit().getCode(), 855 MH.type(restOfFunction.getReturnType().getTypeClass(), 856 RewriteException.class)), 857 Object.class); 858 859 if (!canBeDeoptimized) { 860 return restOf; 861 } 862 863 // If rest-of is itself optimistic, we must make sure that we can repeat a deoptimization if it, too hits an exception. 864 return MH.catchException(restOf, RewriteException.class, createRewriteExceptionHandler()); 865 866 } 867 868 private static class OptimismInfo { 869 // TODO: this is pointing to its owning ScriptFunctionData. Re-evaluate if that's okay. 870 private final RecompilableScriptFunctionData data; 871 private final Map<Integer, Type> invalidatedProgramPoints; 872 private SwitchPoint optimisticAssumptions; 873 private final DebugLogger log; 874 875 OptimismInfo(final RecompilableScriptFunctionData data, final Map<Integer, Type> invalidatedProgramPoints) { 876 this.data = data; 877 this.log = data.getLogger(); 878 this.invalidatedProgramPoints = invalidatedProgramPoints == null ? new TreeMap<Integer, Type>() : invalidatedProgramPoints; 879 newOptimisticAssumptions(); 880 } 881 882 private void newOptimisticAssumptions() { 883 optimisticAssumptions = new SwitchPoint(); 884 } 885 886 boolean requestRecompile(final RewriteException e) { 887 final Type retType = e.getReturnType(); 888 final Type previousFailedType = invalidatedProgramPoints.put(e.getProgramPoint(), retType); 889 890 if (previousFailedType != null && !previousFailedType.narrowerThan(retType)) { 891 final StackTraceElement[] stack = e.getStackTrace(); 892 final String functionId = stack.length == 0 ? 893 data.getName() : 894 stack[0].getClassName() + "." + stack[0].getMethodName(); 895 896 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."); 897 898 return false; 899 } 900 901 SwitchPoint.invalidateAll(new SwitchPoint[] { optimisticAssumptions }); 902 903 return true; 904 } 905 906 Compiler getCompiler(final FunctionNode fn, final MethodType actualCallSiteType, final RewriteException e) { 907 return data.getCompiler(fn, actualCallSiteType, e.getRuntimeScope(), invalidatedProgramPoints, getEntryPoints(e)); 908 } 909 910 private static int[] getEntryPoints(final RewriteException e) { 911 final int[] prevEntryPoints = e.getPreviousContinuationEntryPoints(); 912 final int[] entryPoints; 913 if (prevEntryPoints == null) { 914 entryPoints = new int[1]; 915 } else { 916 final int l = prevEntryPoints.length; 917 entryPoints = new int[l + 1]; 918 System.arraycopy(prevEntryPoints, 0, entryPoints, 1, l); 919 } 920 entryPoints[0] = e.getProgramPoint(); 921 return entryPoints; 922 } 923 924 FunctionNode reparse() { 925 return data.reparse(); 926 } 927 } 928 929 @SuppressWarnings("unused") 930 private static Object newFilter(final Object result, final Object allocation) { 931 return (result instanceof ScriptObject || !JSType.isPrimitive(result))? result : allocation; 932 } 933 934 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 935 return MH.findStatic(MethodHandles.lookup(), CompiledFunction.class, name, MH.type(rtype, types)); 936 } 937} 938