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; 30 31import java.lang.invoke.CallSite; 32import java.lang.invoke.MethodHandle; 33import java.lang.invoke.MethodHandles; 34import java.lang.invoke.MethodType; 35import java.lang.invoke.MutableCallSite; 36import java.lang.invoke.SwitchPoint; 37import java.util.ArrayList; 38import java.util.Collection; 39import java.util.Collections; 40import java.util.Iterator; 41import java.util.List; 42import java.util.Map; 43import java.util.TreeMap; 44import java.util.function.Supplier; 45import java.util.logging.Level; 46import jdk.dynalink.linker.GuardedInvocation; 47import jdk.nashorn.internal.codegen.Compiler; 48import jdk.nashorn.internal.codegen.Compiler.CompilationPhases; 49import jdk.nashorn.internal.codegen.TypeMap; 50import jdk.nashorn.internal.codegen.types.ArrayType; 51import jdk.nashorn.internal.codegen.types.Type; 52import jdk.nashorn.internal.ir.FunctionNode; 53import jdk.nashorn.internal.objects.annotations.SpecializedFunction.LinkLogic; 54import jdk.nashorn.internal.runtime.events.RecompilationEvent; 55import jdk.nashorn.internal.runtime.linker.Bootstrap; 56import jdk.nashorn.internal.runtime.logging.DebugLogger; 57 58/** 59 * An version of a JavaScript function, native or JavaScript. 60 * Supports lazily generating a constructor version of the invocation. 61 */ 62final class CompiledFunction { 63 64 private static final MethodHandle NEWFILTER = findOwnMH("newFilter", Object.class, Object.class, Object.class); 65 private static final MethodHandle RELINK_COMPOSABLE_INVOKER = findOwnMH("relinkComposableInvoker", void.class, CallSite.class, CompiledFunction.class, boolean.class); 66 private static final MethodHandle HANDLE_REWRITE_EXCEPTION = findOwnMH("handleRewriteException", MethodHandle.class, CompiledFunction.class, OptimismInfo.class, RewriteException.class); 67 private static final MethodHandle RESTOF_INVOKER = MethodHandles.exactInvoker(MethodType.methodType(Object.class, RewriteException.class)); 68 69 private final DebugLogger log; 70 71 static final Collection<CompiledFunction> NO_FUNCTIONS = Collections.emptySet(); 72 73 /** 74 * The method type may be more specific than the invoker, if. e.g. 75 * the invoker is guarded, and a guard with a generic object only 76 * fallback, while the target is more specific, we still need the 77 * more specific type for sorting 78 */ 79 private MethodHandle invoker; 80 private MethodHandle constructor; 81 private OptimismInfo optimismInfo; 82 private final int flags; // from FunctionNode 83 private final MethodType callSiteType; 84 85 private final Specialization specialization; 86 87 CompiledFunction(final MethodHandle invoker) { 88 this(invoker, null, null); 89 } 90 91 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker, final Specialization specialization) { 92 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), specialization); 93 } 94 95 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final Specialization specialization) { 96 this(invoker, constructor, 0, null, specialization, DebugLogger.DISABLED_LOGGER); 97 } 98 99 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final int flags, final MethodType callSiteType, final Specialization specialization, final DebugLogger log) { 100 this.specialization = specialization; 101 if (specialization != null && specialization.isOptimistic()) { 102 /* 103 * An optimistic builtin with isOptimistic=true works like any optimistic generated function, i.e. it 104 * can throw unwarranted optimism exceptions. As native functions trivially can't have parts of them 105 * regenerated as "restOf" methods, this only works if the methods are atomic/functional in their behavior 106 * and doesn't modify state before an UOE can be thrown. If they aren't, we can reexecute a wider version 107 * of the same builtin in a recompilation handler for FinalScriptFunctionData. There are several 108 * candidate methods in Native* that would benefit from this, but I haven't had time to implement any 109 * of them currently. In order to fit in with the relinking framework, the current thinking is 110 * that the methods still take a program point to fit in with other optimistic functions, but 111 * it is set to "first", which is the beginning of the method. The relinker can tell the difference 112 * between builtin and JavaScript functions. This might change. TODO 113 */ 114 this.invoker = MH.insertArguments(invoker, invoker.type().parameterCount() - 1, UnwarrantedOptimismException.FIRST_PROGRAM_POINT); 115 throw new AssertionError("Optimistic (UnwarrantedOptimismException throwing) builtin functions are currently not in use"); 116 } 117 this.invoker = invoker; 118 this.constructor = constructor; 119 this.flags = flags; 120 this.callSiteType = callSiteType; 121 this.log = log; 122 } 123 124 CompiledFunction(final MethodHandle invoker, final RecompilableScriptFunctionData functionData, 125 final Map<Integer, Type> invalidatedProgramPoints, final MethodType callSiteType, final int flags) { 126 this(invoker, null, flags, callSiteType, null, functionData.getLogger()); 127 if ((flags & FunctionNode.IS_DEOPTIMIZABLE) != 0) { 128 optimismInfo = new OptimismInfo(functionData, invalidatedProgramPoints); 129 } else { 130 optimismInfo = null; 131 } 132 } 133 134 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker) { 135 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), null); 136 } 137 138 boolean isSpecialization() { 139 return specialization != null; 140 } 141 142 boolean hasLinkLogic() { 143 return getLinkLogicClass() != null; 144 } 145 146 Class<? extends LinkLogic> getLinkLogicClass() { 147 if (isSpecialization()) { 148 final Class<? extends LinkLogic> linkLogicClass = specialization.getLinkLogicClass(); 149 assert !LinkLogic.isEmpty(linkLogicClass) : "empty link logic classes should have been removed by nasgen"; 150 return linkLogicClass; 151 } 152 return null; 153 } 154 155 boolean convertsNumericArgs() { 156 return isSpecialization() && specialization.convertsNumericArgs(); 157 } 158 159 int getFlags() { 160 return flags; 161 } 162 163 /** 164 * An optimistic specialization is one that can throw UnwarrantedOptimismException. 165 * This is allowed for native methods, as long as they are functional, i.e. don't change 166 * any state between entering and throwing the UOE. Then we can re-execute a wider version 167 * of the method in the continuation. Rest-of method generation for optimistic builtins is 168 * of course not possible, but this approach works and fits into the same relinking 169 * framework 170 * 171 * @return true if optimistic builtin 172 */ 173 boolean isOptimistic() { 174 return isSpecialization() ? specialization.isOptimistic() : false; 175 } 176 177 boolean isApplyToCall() { 178 return (flags & FunctionNode.HAS_APPLY_TO_CALL_SPECIALIZATION) != 0; 179 } 180 181 boolean isVarArg() { 182 return isVarArgsType(invoker.type()); 183 } 184 185 @Override 186 public String toString() { 187 final StringBuilder sb = new StringBuilder(); 188 final Class<? extends LinkLogic> linkLogicClass = getLinkLogicClass(); 189 190 sb.append("[invokerType="). 191 append(invoker.type()). 192 append(" ctor="). 193 append(constructor). 194 append(" weight="). 195 append(weight()). 196 append(" linkLogic="). 197 append(linkLogicClass != null ? linkLogicClass.getSimpleName() : "none"); 198 199 return sb.toString(); 200 } 201 202 boolean needsCallee() { 203 return ScriptFunctionData.needsCallee(invoker); 204 } 205 206 /** 207 * Returns an invoker method handle for this function. Note that the handle is safely composable in 208 * the sense that you can compose it with other handles using any combinators even if you can't affect call site 209 * invalidation. If this compiled function is non-optimistic, then it returns the same value as 210 * {@link #getInvokerOrConstructor(boolean)}. However, if the function is optimistic, then this handle will 211 * incur an overhead as it will add an intermediate internal call site that can relink itself when the function 212 * needs to regenerate its code to always point at the latest generated code version. 213 * @return a guaranteed composable invoker method handle for this function. 214 */ 215 MethodHandle createComposableInvoker() { 216 return createComposableInvoker(false); 217 } 218 219 /** 220 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle should be 221 * considered non-composable in the sense that you can only compose it with other handles using any combinators if 222 * you can ensure that the composition is guarded by {@link #getOptimisticAssumptionsSwitchPoint()} if it's 223 * non-null, and that you can relink the call site it is set into as a target if the switch point is invalidated. In 224 * all other cases, use {@link #createComposableConstructor()}. 225 * @return a direct constructor method handle for this function. 226 */ 227 private MethodHandle getConstructor() { 228 if (constructor == null) { 229 constructor = createConstructorFromInvoker(createInvokerForPessimisticCaller()); 230 } 231 232 return constructor; 233 } 234 235 /** 236 * Creates a version of the invoker intended for a pessimistic caller (return type is Object, no caller optimistic 237 * program point available). 238 * @return a version of the invoker intended for a pessimistic caller. 239 */ 240 private MethodHandle createInvokerForPessimisticCaller() { 241 return createInvoker(Object.class, INVALID_PROGRAM_POINT); 242 } 243 244 /** 245 * Compose a constructor from an invoker. 246 * 247 * @param invoker invoker 248 * @return the composed constructor 249 */ 250 private static MethodHandle createConstructorFromInvoker(final MethodHandle invoker) { 251 final boolean needsCallee = ScriptFunctionData.needsCallee(invoker); 252 // If it was (callee, this, args...), permute it to (this, callee, args...). We're doing this because having 253 // "this" in the first argument position is what allows the elegant folded composition of 254 // (newFilter x constructor x allocator) further down below in the code. Also, ensure the composite constructor 255 // always returns Object. 256 final MethodHandle swapped = needsCallee ? swapCalleeAndThis(invoker) : invoker; 257 258 final MethodHandle returnsObject = MH.asType(swapped, swapped.type().changeReturnType(Object.class)); 259 260 final MethodType ctorType = returnsObject.type(); 261 262 // Construct a dropping type list for NEWFILTER, but don't include constructor "this" into it, so it's actually 263 // captured as "allocation" parameter of NEWFILTER after we fold the constructor into it. 264 // (this, [callee, ]args...) => ([callee, ]args...) 265 final Class<?>[] ctorArgs = ctorType.dropParameterTypes(0, 1).parameterArray(); 266 267 // Fold constructor into newFilter that replaces the return value from the constructor with the originally 268 // allocated value when the originally allocated value is a JS primitive (String, Boolean, Number). 269 // (result, this, [callee, ]args...) x (this, [callee, ]args...) => (this, [callee, ]args...) 270 final MethodHandle filtered = MH.foldArguments(MH.dropArguments(NEWFILTER, 2, ctorArgs), returnsObject); 271 272 // allocate() takes a ScriptFunction and returns a newly allocated ScriptObject... 273 if (needsCallee) { 274 // ...we either fold it into the previous composition, if we need both the ScriptFunction callee object and 275 // the newly allocated object in the arguments, so (this, callee, args...) x (callee) => (callee, args...), 276 // or... 277 return MH.foldArguments(filtered, ScriptFunction.ALLOCATE); 278 } 279 280 // ...replace the ScriptFunction argument with the newly allocated object, if it doesn't need the callee 281 // (this, args...) filter (callee) => (callee, args...) 282 return MH.filterArguments(filtered, 0, ScriptFunction.ALLOCATE); 283 } 284 285 /** 286 * Permutes the parameters in the method handle from {@code (callee, this, ...)} to {@code (this, callee, ...)}. 287 * Used when creating a constructor handle. 288 * @param mh a method handle with order of arguments {@code (callee, this, ...)} 289 * @return a method handle with order of arguments {@code (this, callee, ...)} 290 */ 291 private static MethodHandle swapCalleeAndThis(final MethodHandle mh) { 292 final MethodType type = mh.type(); 293 assert type.parameterType(0) == ScriptFunction.class : type; 294 assert type.parameterType(1) == Object.class : type; 295 final MethodType newType = type.changeParameterType(0, Object.class).changeParameterType(1, ScriptFunction.class); 296 final int[] reorder = new int[type.parameterCount()]; 297 reorder[0] = 1; 298 assert reorder[1] == 0; 299 for (int i = 2; i < reorder.length; ++i) { 300 reorder[i] = i; 301 } 302 return MethodHandles.permuteArguments(mh, newType, reorder); 303 } 304 305 /** 306 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle is safely 307 * composable in the sense that you can compose it with other handles using any combinators even if you can't affect 308 * call site invalidation. If this compiled function is non-optimistic, then it returns the same value as 309 * {@link #getConstructor()}. However, if the function is optimistic, then this handle will incur an overhead as it 310 * will add an intermediate internal call site that can relink itself when the function needs to regenerate its code 311 * to always point at the latest generated code version. 312 * @return a guaranteed composable constructor method handle for this function. 313 */ 314 MethodHandle createComposableConstructor() { 315 return createComposableInvoker(true); 316 } 317 318 boolean hasConstructor() { 319 return constructor != null; 320 } 321 322 MethodType type() { 323 return invoker.type(); 324 } 325 326 int weight() { 327 return weight(type()); 328 } 329 330 private static int weight(final MethodType type) { 331 if (isVarArgsType(type)) { 332 return Integer.MAX_VALUE; //if there is a varargs it should be the heavist and last fallback 333 } 334 335 int weight = Type.typeFor(type.returnType()).getWeight(); 336 for (int i = 0 ; i < type.parameterCount() ; i++) { 337 final Class<?> paramType = type.parameterType(i); 338 final int pweight = Type.typeFor(paramType).getWeight() * 2; //params are more important than call types as return values are always specialized 339 weight += pweight; 340 } 341 342 weight += type.parameterCount(); //more params outweigh few parameters 343 344 return weight; 345 } 346 347 static boolean isVarArgsType(final MethodType type) { 348 assert type.parameterCount() >= 1 : type; 349 return type.parameterType(type.parameterCount() - 1) == Object[].class; 350 } 351 352 static boolean moreGenericThan(final MethodType mt0, final MethodType mt1) { 353 return weight(mt0) > weight(mt1); 354 } 355 356 boolean betterThanFinal(final CompiledFunction other, final MethodType callSiteMethodType) { 357 // Prefer anything over nothing, as we can't compile new versions. 358 if (other == null) { 359 return true; 360 } 361 return betterThanFinal(this, other, callSiteMethodType); 362 } 363 364 private static boolean betterThanFinal(final CompiledFunction cf, final CompiledFunction other, final MethodType callSiteMethodType) { 365 final MethodType thisMethodType = cf.type(); 366 final MethodType otherMethodType = other.type(); 367 final int thisParamCount = getParamCount(thisMethodType); 368 final int otherParamCount = getParamCount(otherMethodType); 369 final int callSiteRawParamCount = getParamCount(callSiteMethodType); 370 final boolean csVarArg = callSiteRawParamCount == Integer.MAX_VALUE; 371 // Subtract 1 for callee for non-vararg call sites 372 final int callSiteParamCount = csVarArg ? callSiteRawParamCount : callSiteRawParamCount - 1; 373 374 // Prefer the function that discards less parameters 375 final int thisDiscardsParams = Math.max(callSiteParamCount - thisParamCount, 0); 376 final int otherDiscardsParams = Math.max(callSiteParamCount - otherParamCount, 0); 377 if(thisDiscardsParams < otherDiscardsParams) { 378 return true; 379 } 380 if(thisDiscardsParams > otherDiscardsParams) { 381 return false; 382 } 383 384 final boolean thisVarArg = thisParamCount == Integer.MAX_VALUE; 385 final boolean otherVarArg = otherParamCount == Integer.MAX_VALUE; 386 if(!(thisVarArg && otherVarArg && csVarArg)) { 387 // At least one of them isn't vararg 388 final Type[] thisType = toTypeWithoutCallee(thisMethodType, 0); // Never has callee 389 final Type[] otherType = toTypeWithoutCallee(otherMethodType, 0); // Never has callee 390 final Type[] callSiteType = toTypeWithoutCallee(callSiteMethodType, 1); // Always has callee 391 392 int narrowWeightDelta = 0; 393 int widenWeightDelta = 0; 394 final int minParamsCount = Math.min(Math.min(thisParamCount, otherParamCount), callSiteParamCount); 395 final boolean convertsNumericArgs = cf.convertsNumericArgs(); 396 for(int i = 0; i < minParamsCount; ++i) { 397 final Type callSiteParamType = getParamType(i, callSiteType, csVarArg); 398 final Type thisParamType = getParamType(i, thisType, thisVarArg); 399 if (!convertsNumericArgs && callSiteParamType.isBoolean() && thisParamType.isNumeric()) { 400 // When an argument is converted to number by a function it is safe to "widen" booleans to numeric types. 401 // However, we must avoid this conversion for generic functions such as Array.prototype.push. 402 return false; 403 } 404 final int callSiteParamWeight = callSiteParamType.getWeight(); 405 // Delta is negative for narrowing, positive for widening 406 final int thisParamWeightDelta = thisParamType.getWeight() - callSiteParamWeight; 407 final int otherParamWeightDelta = getParamType(i, otherType, otherVarArg).getWeight() - callSiteParamWeight; 408 // Only count absolute values of narrowings 409 narrowWeightDelta += Math.max(-thisParamWeightDelta, 0) - Math.max(-otherParamWeightDelta, 0); 410 // Only count absolute values of widenings 411 widenWeightDelta += Math.max(thisParamWeightDelta, 0) - Math.max(otherParamWeightDelta, 0); 412 } 413 414 // If both functions accept more arguments than what is passed at the call site, account for ability 415 // to receive Undefined un-narrowed in the remaining arguments. 416 if(!thisVarArg) { 417 for(int i = callSiteParamCount; i < thisParamCount; ++i) { 418 narrowWeightDelta += Math.max(Type.OBJECT.getWeight() - thisType[i].getWeight(), 0); 419 } 420 } 421 if(!otherVarArg) { 422 for(int i = callSiteParamCount; i < otherParamCount; ++i) { 423 narrowWeightDelta -= Math.max(Type.OBJECT.getWeight() - otherType[i].getWeight(), 0); 424 } 425 } 426 427 // Prefer function that narrows less 428 if(narrowWeightDelta < 0) { 429 return true; 430 } 431 if(narrowWeightDelta > 0) { 432 return false; 433 } 434 435 // Prefer function that widens less 436 if(widenWeightDelta < 0) { 437 return true; 438 } 439 if(widenWeightDelta > 0) { 440 return false; 441 } 442 } 443 444 // Prefer the function that exactly matches the arity of the call site. 445 if(thisParamCount == callSiteParamCount && otherParamCount != callSiteParamCount) { 446 return true; 447 } 448 if(thisParamCount != callSiteParamCount && otherParamCount == callSiteParamCount) { 449 return false; 450 } 451 452 // Otherwise, neither function matches arity exactly. We also know that at this point, they both can receive 453 // more arguments than call site, otherwise we would've already chosen the one that discards less parameters. 454 // Note that variable arity methods are preferred, as they actually match the call site arity better, since they 455 // really have arbitrary arity. 456 if(thisVarArg) { 457 if(!otherVarArg) { 458 return true; // 459 } 460 } else if(otherVarArg) { 461 return false; 462 } 463 464 // Neither is variable arity; chose the one that has less extra parameters. 465 final int fnParamDelta = thisParamCount - otherParamCount; 466 if(fnParamDelta < 0) { 467 return true; 468 } 469 if(fnParamDelta > 0) { 470 return false; 471 } 472 473 final int callSiteRetWeight = Type.typeFor(callSiteMethodType.returnType()).getWeight(); 474 // Delta is negative for narrower return type, positive for wider return type 475 final int thisRetWeightDelta = Type.typeFor(thisMethodType.returnType()).getWeight() - callSiteRetWeight; 476 final int otherRetWeightDelta = Type.typeFor(otherMethodType.returnType()).getWeight() - callSiteRetWeight; 477 478 // Prefer function that returns a less wide return type 479 final int widenRetDelta = Math.max(thisRetWeightDelta, 0) - Math.max(otherRetWeightDelta, 0); 480 if(widenRetDelta < 0) { 481 return true; 482 } 483 if(widenRetDelta > 0) { 484 return false; 485 } 486 487 // Prefer function that returns a less narrow return type 488 final int narrowRetDelta = Math.max(-thisRetWeightDelta, 0) - Math.max(-otherRetWeightDelta, 0); 489 if(narrowRetDelta < 0) { 490 return true; 491 } 492 if(narrowRetDelta > 0) { 493 return false; 494 } 495 496 //if they are equal, pick the specialized one first 497 if (cf.isSpecialization() != other.isSpecialization()) { 498 return cf.isSpecialization(); //always pick the specialized version if we can 499 } 500 501 if (cf.isSpecialization() && other.isSpecialization()) { 502 return cf.getLinkLogicClass() != null; //pick link logic specialization above generic specializations 503 } 504 505 // Signatures are identical 506 throw new AssertionError(thisMethodType + " identically applicable to " + otherMethodType + " for " + callSiteMethodType); 507 } 508 509 private static Type[] toTypeWithoutCallee(final MethodType type, final int thisIndex) { 510 final int paramCount = type.parameterCount(); 511 final Type[] t = new Type[paramCount - thisIndex]; 512 for(int i = thisIndex; i < paramCount; ++i) { 513 t[i - thisIndex] = Type.typeFor(type.parameterType(i)); 514 } 515 return t; 516 } 517 518 private static Type getParamType(final int i, final Type[] paramTypes, final boolean isVarArg) { 519 final int fixParamCount = paramTypes.length - (isVarArg ? 1 : 0); 520 if(i < fixParamCount) { 521 return paramTypes[i]; 522 } 523 assert isVarArg; 524 return ((ArrayType)paramTypes[paramTypes.length - 1]).getElementType(); 525 } 526 527 boolean matchesCallSite(final MethodType other, final boolean pickVarArg) { 528 if (other.equals(this.callSiteType)) { 529 return true; 530 } 531 final MethodType type = type(); 532 final int fnParamCount = getParamCount(type); 533 final boolean isVarArg = fnParamCount == Integer.MAX_VALUE; 534 if (isVarArg) { 535 return pickVarArg; 536 } 537 538 final int csParamCount = getParamCount(other); 539 final boolean csIsVarArg = csParamCount == Integer.MAX_VALUE; 540 final int thisThisIndex = needsCallee() ? 1 : 0; // Index of "this" parameter in this function's type 541 542 final int fnParamCountNoCallee = fnParamCount - thisThisIndex; 543 final int minParams = Math.min(csParamCount - 1, fnParamCountNoCallee); // callSiteType always has callee, so subtract 1 544 // We must match all incoming parameters, including "this". "this" will usually be Object, but there 545 // are exceptions, e.g. when calling functions with primitive "this" in strict mode or through call/apply. 546 for(int i = 0; i < minParams; ++i) { 547 final Type fnType = Type.typeFor(type.parameterType(i + thisThisIndex)); 548 final Type csType = csIsVarArg ? Type.OBJECT : Type.typeFor(other.parameterType(i + 1)); 549 if(!fnType.isEquivalentTo(csType)) { 550 return false; 551 } 552 } 553 554 // Must match any undefined parameters to Object type. 555 for(int i = minParams; i < fnParamCountNoCallee; ++i) { 556 if(!Type.typeFor(type.parameterType(i + thisThisIndex)).isEquivalentTo(Type.OBJECT)) { 557 return false; 558 } 559 } 560 561 return true; 562 } 563 564 private static int getParamCount(final MethodType type) { 565 final int paramCount = type.parameterCount(); 566 return type.parameterType(paramCount - 1).isArray() ? Integer.MAX_VALUE : paramCount; 567 } 568 569 private boolean canBeDeoptimized() { 570 return optimismInfo != null; 571 } 572 573 private MethodHandle createComposableInvoker(final boolean isConstructor) { 574 final MethodHandle handle = getInvokerOrConstructor(isConstructor); 575 576 // If compiled function is not optimistic, it can't ever change its invoker/constructor, so just return them 577 // directly. 578 if(!canBeDeoptimized()) { 579 return handle; 580 } 581 582 // Otherwise, we need a new level of indirection; need to introduce a mutable call site that can relink itself 583 // to the compiled function's changed target whenever the optimistic assumptions are invalidated. 584 final CallSite cs = new MutableCallSite(handle.type()); 585 relinkComposableInvoker(cs, this, isConstructor); 586 return cs.dynamicInvoker(); 587 } 588 589 private static class HandleAndAssumptions { 590 final MethodHandle handle; 591 final SwitchPoint assumptions; 592 593 HandleAndAssumptions(final MethodHandle handle, final SwitchPoint assumptions) { 594 this.handle = handle; 595 this.assumptions = assumptions; 596 } 597 598 GuardedInvocation createInvocation() { 599 return new GuardedInvocation(handle, assumptions); 600 } 601 } 602 603 /** 604 * Returns a pair of an invocation created with a passed-in supplier and a non-invalidated switch point for 605 * optimistic assumptions (or null for the switch point if the function can not be deoptimized). While the method 606 * makes a best effort to return a non-invalidated switch point (compensating for possible deoptimizing 607 * recompilation happening on another thread) it is still possible that by the time this method returns the 608 * switchpoint has been invalidated by a {@code RewriteException} triggered on another thread for this function. 609 * This is not a problem, though, as these switch points are always used to produce call sites that fall back to 610 * relinking when they are invalidated, and in this case the execution will end up here again. What this method 611 * basically does is minimize such busy-loop relinking while the function is being recompiled on a different thread. 612 * @param invocationSupplier the supplier that constructs the actual invocation method handle; should use the 613 * {@code CompiledFunction} method itself in some capacity. 614 * @return a tuple object containing the method handle as created by the supplier and an optimistic assumptions 615 * switch point that is guaranteed to not have been invalidated before the call to this method (or null if the 616 * function can't be further deoptimized). 617 */ 618 private synchronized HandleAndAssumptions getValidOptimisticInvocation(final Supplier<MethodHandle> invocationSupplier) { 619 for(;;) { 620 final MethodHandle handle = invocationSupplier.get(); 621 final SwitchPoint assumptions = canBeDeoptimized() ? optimismInfo.optimisticAssumptions : null; 622 if(assumptions != null && assumptions.hasBeenInvalidated()) { 623 // We can be in a situation where one thread is in the middle of a deoptimizing compilation when we hit 624 // this and thus, it has invalidated the old switch point, but hasn't created the new one yet. Note that 625 // the behavior of invalidating the old switch point before recompilation, and only creating the new one 626 // after recompilation is by design. If we didn't wait here for the recompilation to complete, we would 627 // be busy looping through the fallback path of the invalidated switch point, relinking the call site 628 // again with the same invalidated switch point, invoking the fallback, etc. stealing CPU cycles from 629 // the recompilation task we're dependent on. This can still happen if the switch point gets invalidated 630 // after we grabbed it here, in which case we'll indeed do one busy relink immediately. 631 try { 632 wait(); 633 } catch (final InterruptedException e) { 634 // Intentionally ignored. There's nothing meaningful we can do if we're interrupted 635 } 636 } else { 637 return new HandleAndAssumptions(handle, assumptions); 638 } 639 } 640 } 641 642 private static void relinkComposableInvoker(final CallSite cs, final CompiledFunction inv, final boolean constructor) { 643 final HandleAndAssumptions handleAndAssumptions = inv.getValidOptimisticInvocation(new Supplier<MethodHandle>() { 644 @Override 645 public MethodHandle get() { 646 return inv.getInvokerOrConstructor(constructor); 647 } 648 }); 649 final MethodHandle handle = handleAndAssumptions.handle; 650 final SwitchPoint assumptions = handleAndAssumptions.assumptions; 651 final MethodHandle target; 652 if(assumptions == null) { 653 target = handle; 654 } else { 655 final MethodHandle relink = MethodHandles.insertArguments(RELINK_COMPOSABLE_INVOKER, 0, cs, inv, constructor); 656 target = assumptions.guardWithTest(handle, MethodHandles.foldArguments(cs.dynamicInvoker(), relink)); 657 } 658 cs.setTarget(target.asType(cs.type())); 659 } 660 661 private MethodHandle getInvokerOrConstructor(final boolean selectCtor) { 662 return selectCtor ? getConstructor() : createInvokerForPessimisticCaller(); 663 } 664 665 /** 666 * Returns a guarded invocation for this function when not invoked as a constructor. The guarded invocation has no 667 * guard but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a 668 * final guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 669 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 670 * continue to use the switch point. If that is not possible, use {@link #createComposableInvoker()} instead. 671 * @return a guarded invocation for an ordinary (non-constructor) invocation of this function. 672 */ 673 GuardedInvocation createFunctionInvocation(final Class<?> callSiteReturnType, final int callerProgramPoint) { 674 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 675 @Override 676 public MethodHandle get() { 677 return createInvoker(callSiteReturnType, callerProgramPoint); 678 } 679 }).createInvocation(); 680 } 681 682 /** 683 * Returns a guarded invocation for this function when invoked as a constructor. The guarded invocation has no guard 684 * but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a final 685 * guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 686 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 687 * continue to use the switch point. If that is not possible, use {@link #createComposableConstructor()} instead. 688 * @return a guarded invocation for invocation of this function as a constructor. 689 */ 690 GuardedInvocation createConstructorInvocation() { 691 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 692 @Override 693 public MethodHandle get() { 694 return getConstructor(); 695 } 696 }).createInvocation(); 697 } 698 699 private MethodHandle createInvoker(final Class<?> callSiteReturnType, final int callerProgramPoint) { 700 final boolean isOptimistic = canBeDeoptimized(); 701 MethodHandle handleRewriteException = isOptimistic ? createRewriteExceptionHandler() : null; 702 703 MethodHandle inv = invoker; 704 if(isValid(callerProgramPoint)) { 705 inv = OptimisticReturnFilters.filterOptimisticReturnValue(inv, callSiteReturnType, callerProgramPoint); 706 inv = changeReturnType(inv, callSiteReturnType); 707 if(callSiteReturnType.isPrimitive() && handleRewriteException != null) { 708 // because handleRewriteException always returns Object 709 handleRewriteException = OptimisticReturnFilters.filterOptimisticReturnValue(handleRewriteException, 710 callSiteReturnType, callerProgramPoint); 711 } 712 } else if(isOptimistic) { 713 // Required so that rewrite exception has the same return type. It'd be okay to do it even if we weren't 714 // optimistic, but it isn't necessary as the linker upstream will eventually convert the return type. 715 inv = changeReturnType(inv, callSiteReturnType); 716 } 717 718 if(isOptimistic) { 719 assert handleRewriteException != null; 720 final MethodHandle typedHandleRewriteException = changeReturnType(handleRewriteException, inv.type().returnType()); 721 return MH.catchException(inv, RewriteException.class, typedHandleRewriteException); 722 } 723 return inv; 724 } 725 726 private MethodHandle createRewriteExceptionHandler() { 727 return MH.foldArguments(RESTOF_INVOKER, MH.insertArguments(HANDLE_REWRITE_EXCEPTION, 0, this, optimismInfo)); 728 } 729 730 private static MethodHandle changeReturnType(final MethodHandle mh, final Class<?> newReturnType) { 731 return Bootstrap.getLinkerServices().asType(mh, mh.type().changeReturnType(newReturnType)); 732 } 733 734 @SuppressWarnings("unused") 735 private static MethodHandle handleRewriteException(final CompiledFunction function, final OptimismInfo oldOptimismInfo, final RewriteException re) { 736 return function.handleRewriteException(oldOptimismInfo, re); 737 } 738 739 /** 740 * Debug function for printing out all invalidated program points and their 741 * invalidation mapping to next type 742 * @param ipp 743 * @return string describing the ipp map 744 */ 745 private static List<String> toStringInvalidations(final Map<Integer, Type> ipp) { 746 if (ipp == null) { 747 return Collections.emptyList(); 748 } 749 750 final List<String> list = new ArrayList<>(); 751 752 for (final Iterator<Map.Entry<Integer, Type>> iter = ipp.entrySet().iterator(); iter.hasNext(); ) { 753 final Map.Entry<Integer, Type> entry = iter.next(); 754 final char bct = entry.getValue().getBytecodeStackType(); 755 final String type; 756 757 switch (entry.getValue().getBytecodeStackType()) { 758 case 'A': 759 type = "object"; 760 break; 761 case 'I': 762 type = "int"; 763 break; 764 case 'J': 765 type = "long"; 766 break; 767 case 'D': 768 type = "double"; 769 break; 770 default: 771 type = String.valueOf(bct); 772 break; 773 } 774 775 final StringBuilder sb = new StringBuilder(); 776 sb.append('['). 777 append("program point: "). 778 append(entry.getKey()). 779 append(" -> "). 780 append(type). 781 append(']'); 782 783 list.add(sb.toString()); 784 } 785 786 return list; 787 } 788 789 private void logRecompile(final String reason, final FunctionNode fn, final MethodType type, final Map<Integer, Type> ipp) { 790 if (log.isEnabled()) { 791 log.info(reason, DebugLogger.quote(fn.getName()), " signature: ", type); 792 log.indent(); 793 for (final String str : toStringInvalidations(ipp)) { 794 log.fine(str); 795 } 796 log.unindent(); 797 } 798 } 799 800 /** 801 * Handles a {@link RewriteException} raised during the execution of this function by recompiling (if needed) the 802 * function with an optimistic assumption invalidated at the program point indicated by the exception, and then 803 * executing a rest-of method to complete the execution with the deoptimized version. 804 * @param oldOptInfo the optimism info of this function. We must store it explicitly as a bound argument in the 805 * method handle, otherwise it could be null for handling a rewrite exception in an outer invocation of a recursive 806 * function when recursive invocations of the function have completely deoptimized it. 807 * @param re the rewrite exception that was raised 808 * @return the method handle for the rest-of method, for folding composition. 809 */ 810 private synchronized MethodHandle handleRewriteException(final OptimismInfo oldOptInfo, final RewriteException re) { 811 if (log.isEnabled()) { 812 log.info( 813 new RecompilationEvent( 814 Level.INFO, 815 re, 816 re.getReturnValueNonDestructive()), 817 "caught RewriteException ", 818 re.getMessageShort()); 819 log.indent(); 820 } 821 822 final MethodType type = type(); 823 824 // Compiler needs a call site type as its input, which always has a callee parameter, so we must add it if 825 // this function doesn't have a callee parameter. 826 final MethodType ct = type.parameterType(0) == ScriptFunction.class ? 827 type : 828 type.insertParameterTypes(0, ScriptFunction.class); 829 final OptimismInfo currentOptInfo = optimismInfo; 830 final boolean shouldRecompile = currentOptInfo != null && currentOptInfo.requestRecompile(re); 831 832 // Effective optimism info, for subsequent use. We'll normally try to use the current (latest) one, but if it 833 // isn't available, we'll use the old one bound into the call site. 834 final OptimismInfo effectiveOptInfo = currentOptInfo != null ? currentOptInfo : oldOptInfo; 835 FunctionNode fn = effectiveOptInfo.reparse(); 836 final boolean cached = fn.isCached(); 837 final Compiler compiler = effectiveOptInfo.getCompiler(fn, ct, re); //set to non rest-of 838 839 if (!shouldRecompile) { 840 // It didn't necessarily recompile, e.g. for an outer invocation of a recursive function if we already 841 // recompiled a deoptimized version for an inner invocation. 842 // We still need to do the rest of from the beginning 843 logRecompile("Rest-of compilation [STANDALONE] ", fn, ct, effectiveOptInfo.invalidatedProgramPoints); 844 return restOfHandle(effectiveOptInfo, compiler.compile(fn, cached ? CompilationPhases.COMPILE_CACHED_RESTOF : CompilationPhases.COMPILE_ALL_RESTOF), currentOptInfo != null); 845 } 846 847 logRecompile("Deoptimizing recompilation (up to bytecode) ", fn, ct, effectiveOptInfo.invalidatedProgramPoints); 848 fn = compiler.compile(fn, cached ? CompilationPhases.RECOMPILE_CACHED_UPTO_BYTECODE : CompilationPhases.COMPILE_UPTO_BYTECODE); 849 log.fine("Reusable IR generated"); 850 851 // compile the rest of the function, and install it 852 log.info("Generating and installing bytecode from reusable IR..."); 853 logRecompile("Rest-of compilation [CODE PIPELINE REUSE] ", fn, ct, effectiveOptInfo.invalidatedProgramPoints); 854 final FunctionNode normalFn = compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL); 855 856 if (effectiveOptInfo.data.usePersistentCodeCache()) { 857 final RecompilableScriptFunctionData data = effectiveOptInfo.data; 858 final int functionNodeId = data.getFunctionNodeId(); 859 final TypeMap typeMap = data.typeMap(ct); 860 final Type[] paramTypes = typeMap == null ? null : typeMap.getParameterTypes(functionNodeId); 861 final String cacheKey = CodeStore.getCacheKey(functionNodeId, paramTypes); 862 compiler.persistClassInfo(cacheKey, normalFn); 863 } 864 865 final boolean canBeDeoptimized = normalFn.canBeDeoptimized(); 866 867 if (log.isEnabled()) { 868 log.unindent(); 869 log.info("Done."); 870 871 log.info("Recompiled '", fn.getName(), "' (", Debug.id(this), ") ", canBeDeoptimized ? "can still be deoptimized." : " is completely deoptimized."); 872 log.finest("Looking up invoker..."); 873 } 874 875 final MethodHandle newInvoker = effectiveOptInfo.data.lookup(fn); 876 invoker = newInvoker.asType(type.changeReturnType(newInvoker.type().returnType())); 877 constructor = null; // Will be regenerated when needed 878 879 log.info("Done: ", invoker); 880 final MethodHandle restOf = restOfHandle(effectiveOptInfo, compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL_RESTOF), canBeDeoptimized); 881 882 // Note that we only adjust the switch point after we set the invoker/constructor. This is important. 883 if (canBeDeoptimized) { 884 effectiveOptInfo.newOptimisticAssumptions(); // Otherwise, set a new switch point. 885 } else { 886 optimismInfo = null; // If we got to a point where we no longer have optimistic assumptions, let the optimism info go. 887 } 888 notifyAll(); 889 890 return restOf; 891 } 892 893 private MethodHandle restOfHandle(final OptimismInfo info, final FunctionNode restOfFunction, final boolean canBeDeoptimized) { 894 assert info != null; 895 assert restOfFunction.getCompileUnit().getUnitClassName().contains("restOf"); 896 final MethodHandle restOf = 897 changeReturnType( 898 info.data.lookupCodeMethod( 899 restOfFunction.getCompileUnit().getCode(), 900 MH.type(restOfFunction.getReturnType().getTypeClass(), 901 RewriteException.class)), 902 Object.class); 903 904 if (!canBeDeoptimized) { 905 return restOf; 906 } 907 908 // If rest-of is itself optimistic, we must make sure that we can repeat a deoptimization if it, too hits an exception. 909 return MH.catchException(restOf, RewriteException.class, createRewriteExceptionHandler()); 910 911 } 912 913 private static class OptimismInfo { 914 // TODO: this is pointing to its owning ScriptFunctionData. Re-evaluate if that's okay. 915 private final RecompilableScriptFunctionData data; 916 private final Map<Integer, Type> invalidatedProgramPoints; 917 private SwitchPoint optimisticAssumptions; 918 private final DebugLogger log; 919 920 OptimismInfo(final RecompilableScriptFunctionData data, final Map<Integer, Type> invalidatedProgramPoints) { 921 this.data = data; 922 this.log = data.getLogger(); 923 this.invalidatedProgramPoints = invalidatedProgramPoints == null ? new TreeMap<>() : invalidatedProgramPoints; 924 newOptimisticAssumptions(); 925 } 926 927 private void newOptimisticAssumptions() { 928 optimisticAssumptions = new SwitchPoint(); 929 } 930 931 boolean requestRecompile(final RewriteException e) { 932 final Type retType = e.getReturnType(); 933 final Type previousFailedType = invalidatedProgramPoints.put(e.getProgramPoint(), retType); 934 935 if (previousFailedType != null && !previousFailedType.narrowerThan(retType)) { 936 final StackTraceElement[] stack = e.getStackTrace(); 937 final String functionId = stack.length == 0 ? 938 data.getName() : 939 stack[0].getClassName() + "." + stack[0].getMethodName(); 940 941 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."); 942 943 return false; 944 } 945 946 SwitchPoint.invalidateAll(new SwitchPoint[] { optimisticAssumptions }); 947 948 return true; 949 } 950 951 Compiler getCompiler(final FunctionNode fn, final MethodType actualCallSiteType, final RewriteException e) { 952 return data.getCompiler(fn, actualCallSiteType, e.getRuntimeScope(), invalidatedProgramPoints, getEntryPoints(e)); 953 } 954 955 private static int[] getEntryPoints(final RewriteException e) { 956 final int[] prevEntryPoints = e.getPreviousContinuationEntryPoints(); 957 final int[] entryPoints; 958 if (prevEntryPoints == null) { 959 entryPoints = new int[1]; 960 } else { 961 final int l = prevEntryPoints.length; 962 entryPoints = new int[l + 1]; 963 System.arraycopy(prevEntryPoints, 0, entryPoints, 1, l); 964 } 965 entryPoints[0] = e.getProgramPoint(); 966 return entryPoints; 967 } 968 969 FunctionNode reparse() { 970 return data.reparse(); 971 } 972 } 973 974 @SuppressWarnings("unused") 975 private static Object newFilter(final Object result, final Object allocation) { 976 return (result instanceof ScriptObject || !JSType.isPrimitive(result))? result : allocation; 977 } 978 979 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 980 return MH.findStatic(MethodHandles.lookup(), CompiledFunction.class, name, MH.type(rtype, types)); 981 } 982} 983