CompiledFunction.java revision 1088:7e62d98d4625
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 } 114 this.invoker = invoker; 115 this.constructor = constructor; 116 this.flags = flags; 117 this.callSiteType = callSiteType; 118 this.log = log; 119 } 120 121 CompiledFunction(final MethodHandle invoker, final RecompilableScriptFunctionData functionData, 122 final Map<Integer, Type> invalidatedProgramPoints, final MethodType callSiteType, final int flags) { 123 this(invoker, null, flags, callSiteType, null, functionData.getLogger()); 124 if ((flags & FunctionNode.IS_DEOPTIMIZABLE) != 0) { 125 optimismInfo = new OptimismInfo(functionData, invalidatedProgramPoints); 126 } else { 127 optimismInfo = null; 128 } 129 } 130 131 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker) { 132 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), null); 133 } 134 135 boolean isSpecialization() { 136 return specialization != null; 137 } 138 139 boolean hasLinkLogic() { 140 return getLinkLogicClass() != null; 141 } 142 143 Class<? extends LinkLogic> getLinkLogicClass() { 144 if (isSpecialization()) { 145 final Class<? extends LinkLogic> linkLogicClass = specialization.getLinkLogicClass(); 146 assert !LinkLogic.isEmpty(linkLogicClass) : "empty link logic classes should have been removed by nasgen"; 147 return linkLogicClass; 148 } 149 return null; 150 } 151 152 int getFlags() { 153 return flags; 154 } 155 156 /** 157 * An optimistic specialization is one that can throw UnwarrantedOptimismException. 158 * This is allowed for native methods, as long as they are functional, i.e. don't change 159 * any state between entering and throwing the UOE. Then we can re-execute a wider version 160 * of the method in the continuation. Rest-of method generation for optimistic builtins is 161 * of course not possible, but this approach works and fits into the same relinking 162 * framework 163 * 164 * @return true if optimistic builtin 165 */ 166 boolean isOptimistic() { 167 return isSpecialization() ? specialization.isOptimistic() : false; 168 } 169 170 boolean isApplyToCall() { 171 return (flags & FunctionNode.HAS_APPLY_TO_CALL_SPECIALIZATION) != 0; 172 } 173 174 boolean isVarArg() { 175 return isVarArgsType(invoker.type()); 176 } 177 178 @Override 179 public String toString() { 180 final StringBuilder sb = new StringBuilder(); 181 final Class<? extends LinkLogic> linkLogicClass = getLinkLogicClass(); 182 183 sb.append("[invokerType="). 184 append(invoker.type()). 185 append(" ctor="). 186 append(constructor). 187 append(" weight="). 188 append(weight()). 189 append(" linkLogic="). 190 append(linkLogicClass != null ? linkLogicClass.getSimpleName() : "none"); 191 192 return sb.toString(); 193 } 194 195 boolean needsCallee() { 196 return ScriptFunctionData.needsCallee(invoker); 197 } 198 199 /** 200 * Returns an invoker method handle for this function. Note that the handle is safely composable in 201 * the sense that you can compose it with other handles using any combinators even if you can't affect call site 202 * invalidation. If this compiled function is non-optimistic, then it returns the same value as 203 * {@link #getInvokerOrConstructor(boolean)}. However, if the function is optimistic, then this handle will 204 * incur an overhead as it will add an intermediate internal call site that can relink itself when the function 205 * needs to regenerate its code to always point at the latest generated code version. 206 * @return a guaranteed composable invoker method handle for this function. 207 */ 208 MethodHandle createComposableInvoker() { 209 return createComposableInvoker(false); 210 } 211 212 /** 213 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle should be 214 * considered non-composable in the sense that you can only compose it with other handles using any combinators if 215 * you can ensure that the composition is guarded by {@link #getOptimisticAssumptionsSwitchPoint()} if it's 216 * non-null, and that you can relink the call site it is set into as a target if the switch point is invalidated. In 217 * all other cases, use {@link #createComposableConstructor()}. 218 * @return a direct constructor method handle for this function. 219 */ 220 private MethodHandle getConstructor() { 221 if (constructor == null) { 222 constructor = createConstructorFromInvoker(createInvokerForPessimisticCaller()); 223 } 224 225 return constructor; 226 } 227 228 /** 229 * Creates a version of the invoker intended for a pessimistic caller (return type is Object, no caller optimistic 230 * program point available). 231 * @return a version of the invoker intended for a pessimistic caller. 232 */ 233 private MethodHandle createInvokerForPessimisticCaller() { 234 return createInvoker(Object.class, INVALID_PROGRAM_POINT); 235 } 236 237 /** 238 * Compose a constructor from an invoker. 239 * 240 * @param invoker invoker 241 * @return the composed constructor 242 */ 243 private static MethodHandle createConstructorFromInvoker(final MethodHandle invoker) { 244 final boolean needsCallee = ScriptFunctionData.needsCallee(invoker); 245 // If it was (callee, this, args...), permute it to (this, callee, args...). We're doing this because having 246 // "this" in the first argument position is what allows the elegant folded composition of 247 // (newFilter x constructor x allocator) further down below in the code. Also, ensure the composite constructor 248 // always returns Object. 249 final MethodHandle swapped = needsCallee ? swapCalleeAndThis(invoker) : invoker; 250 251 final MethodHandle returnsObject = MH.asType(swapped, swapped.type().changeReturnType(Object.class)); 252 253 final MethodType ctorType = returnsObject.type(); 254 255 // Construct a dropping type list for NEWFILTER, but don't include constructor "this" into it, so it's actually 256 // captured as "allocation" parameter of NEWFILTER after we fold the constructor into it. 257 // (this, [callee, ]args...) => ([callee, ]args...) 258 final Class<?>[] ctorArgs = ctorType.dropParameterTypes(0, 1).parameterArray(); 259 260 // Fold constructor into newFilter that replaces the return value from the constructor with the originally 261 // allocated value when the originally allocated value is a JS primitive (String, Boolean, Number). 262 // (result, this, [callee, ]args...) x (this, [callee, ]args...) => (this, [callee, ]args...) 263 final MethodHandle filtered = MH.foldArguments(MH.dropArguments(NEWFILTER, 2, ctorArgs), returnsObject); 264 265 // allocate() takes a ScriptFunction and returns a newly allocated ScriptObject... 266 if (needsCallee) { 267 // ...we either fold it into the previous composition, if we need both the ScriptFunction callee object and 268 // the newly allocated object in the arguments, so (this, callee, args...) x (callee) => (callee, args...), 269 // or... 270 return MH.foldArguments(filtered, ScriptFunction.ALLOCATE); 271 } 272 273 // ...replace the ScriptFunction argument with the newly allocated object, if it doesn't need the callee 274 // (this, args...) filter (callee) => (callee, args...) 275 return MH.filterArguments(filtered, 0, ScriptFunction.ALLOCATE); 276 } 277 278 /** 279 * Permutes the parameters in the method handle from {@code (callee, this, ...)} to {@code (this, callee, ...)}. 280 * Used when creating a constructor handle. 281 * @param mh a method handle with order of arguments {@code (callee, this, ...)} 282 * @return a method handle with order of arguments {@code (this, callee, ...)} 283 */ 284 private static MethodHandle swapCalleeAndThis(final MethodHandle mh) { 285 final MethodType type = mh.type(); 286 assert type.parameterType(0) == ScriptFunction.class : type; 287 assert type.parameterType(1) == Object.class : type; 288 final MethodType newType = type.changeParameterType(0, Object.class).changeParameterType(1, ScriptFunction.class); 289 final int[] reorder = new int[type.parameterCount()]; 290 reorder[0] = 1; 291 assert reorder[1] == 0; 292 for (int i = 2; i < reorder.length; ++i) { 293 reorder[i] = i; 294 } 295 return MethodHandles.permuteArguments(mh, newType, reorder); 296 } 297 298 /** 299 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle is safely 300 * composable in the sense that you can compose it with other handles using any combinators even if you can't affect 301 * call site invalidation. If this compiled function is non-optimistic, then it returns the same value as 302 * {@link #getConstructor()}. However, if the function is optimistic, then this handle will incur an overhead as it 303 * will add an intermediate internal call site that can relink itself when the function needs to regenerate its code 304 * to always point at the latest generated code version. 305 * @return a guaranteed composable constructor method handle for this function. 306 */ 307 MethodHandle createComposableConstructor() { 308 return createComposableInvoker(true); 309 } 310 311 boolean hasConstructor() { 312 return constructor != null; 313 } 314 315 MethodType type() { 316 return invoker.type(); 317 } 318 319 int weight() { 320 return weight(type()); 321 } 322 323 private static int weight(final MethodType type) { 324 if (isVarArgsType(type)) { 325 return Integer.MAX_VALUE; //if there is a varargs it should be the heavist and last fallback 326 } 327 328 int weight = Type.typeFor(type.returnType()).getWeight(); 329 for (int i = 0 ; i < type.parameterCount() ; i++) { 330 final Class<?> paramType = type.parameterType(i); 331 final int pweight = Type.typeFor(paramType).getWeight() * 2; //params are more important than call types as return values are always specialized 332 weight += pweight; 333 } 334 335 weight += type.parameterCount(); //more params outweigh few parameters 336 337 return weight; 338 } 339 340 static boolean isVarArgsType(final MethodType type) { 341 assert type.parameterCount() >= 1 : type; 342 return type.parameterType(type.parameterCount() - 1) == Object[].class; 343 } 344 345 static boolean moreGenericThan(final MethodType mt0, final MethodType mt1) { 346 return weight(mt0) > weight(mt1); 347 } 348 349 boolean betterThanFinal(final CompiledFunction other, final MethodType callSiteMethodType) { 350 // Prefer anything over nothing, as we can't compile new versions. 351 if (other == null) { 352 return true; 353 } 354 return betterThanFinal(this, other, callSiteMethodType); 355 } 356 357 private static boolean betterThanFinal(final CompiledFunction cf, final CompiledFunction other, final MethodType callSiteMethodType) { 358 final MethodType thisMethodType = cf.type(); 359 final MethodType otherMethodType = other.type(); 360 final int thisParamCount = getParamCount(thisMethodType); 361 final int otherParamCount = getParamCount(otherMethodType); 362 final int callSiteRawParamCount = getParamCount(callSiteMethodType); 363 final boolean csVarArg = callSiteRawParamCount == Integer.MAX_VALUE; 364 // Subtract 1 for callee for non-vararg call sites 365 final int callSiteParamCount = csVarArg ? callSiteRawParamCount : callSiteRawParamCount - 1; 366 367 // Prefer the function that discards less parameters 368 final int thisDiscardsParams = Math.max(callSiteParamCount - thisParamCount, 0); 369 final int otherDiscardsParams = Math.max(callSiteParamCount - otherParamCount, 0); 370 if(thisDiscardsParams < otherDiscardsParams) { 371 return true; 372 } 373 if(thisDiscardsParams > otherDiscardsParams) { 374 return false; 375 } 376 377 final boolean thisVarArg = thisParamCount == Integer.MAX_VALUE; 378 final boolean otherVarArg = otherParamCount == Integer.MAX_VALUE; 379 if(!(thisVarArg && otherVarArg && csVarArg)) { 380 // At least one of them isn't vararg 381 final Type[] thisType = toTypeWithoutCallee(thisMethodType, 0); // Never has callee 382 final Type[] otherType = toTypeWithoutCallee(otherMethodType, 0); // Never has callee 383 final Type[] callSiteType = toTypeWithoutCallee(callSiteMethodType, 1); // Always has callee 384 385 int narrowWeightDelta = 0; 386 int widenWeightDelta = 0; 387 final int minParamsCount = Math.min(Math.min(thisParamCount, otherParamCount), callSiteParamCount); 388 for(int i = 0; i < minParamsCount; ++i) { 389 final int callSiteParamWeight = getParamType(i, callSiteType, csVarArg).getWeight(); 390 // Delta is negative for narrowing, positive for widening 391 final int thisParamWeightDelta = getParamType(i, thisType, thisVarArg).getWeight() - callSiteParamWeight; 392 final int otherParamWeightDelta = getParamType(i, otherType, otherVarArg).getWeight() - callSiteParamWeight; 393 // Only count absolute values of narrowings 394 narrowWeightDelta += Math.max(-thisParamWeightDelta, 0) - Math.max(-otherParamWeightDelta, 0); 395 // Only count absolute values of widenings 396 widenWeightDelta += Math.max(thisParamWeightDelta, 0) - Math.max(otherParamWeightDelta, 0); 397 } 398 399 // If both functions accept more arguments than what is passed at the call site, account for ability 400 // to receive Undefined un-narrowed in the remaining arguments. 401 if(!thisVarArg) { 402 for(int i = callSiteParamCount; i < thisParamCount; ++i) { 403 narrowWeightDelta += Math.max(Type.OBJECT.getWeight() - thisType[i].getWeight(), 0); 404 } 405 } 406 if(!otherVarArg) { 407 for(int i = callSiteParamCount; i < otherParamCount; ++i) { 408 narrowWeightDelta -= Math.max(Type.OBJECT.getWeight() - otherType[i].getWeight(), 0); 409 } 410 } 411 412 // Prefer function that narrows less 413 if(narrowWeightDelta < 0) { 414 return true; 415 } 416 if(narrowWeightDelta > 0) { 417 return false; 418 } 419 420 // Prefer function that widens less 421 if(widenWeightDelta < 0) { 422 return true; 423 } 424 if(widenWeightDelta > 0) { 425 return false; 426 } 427 } 428 429 // Prefer the function that exactly matches the arity of the call site. 430 if(thisParamCount == callSiteParamCount && otherParamCount != callSiteParamCount) { 431 return true; 432 } 433 if(thisParamCount != callSiteParamCount && otherParamCount == callSiteParamCount) { 434 return false; 435 } 436 437 // Otherwise, neither function matches arity exactly. We also know that at this point, they both can receive 438 // more arguments than call site, otherwise we would've already chosen the one that discards less parameters. 439 // Note that variable arity methods are preferred, as they actually match the call site arity better, since they 440 // really have arbitrary arity. 441 if(thisVarArg) { 442 if(!otherVarArg) { 443 return true; // 444 } 445 } else if(otherVarArg) { 446 return false; 447 } 448 449 // Neither is variable arity; chose the one that has less extra parameters. 450 final int fnParamDelta = thisParamCount - otherParamCount; 451 if(fnParamDelta < 0) { 452 return true; 453 } 454 if(fnParamDelta > 0) { 455 return false; 456 } 457 458 final int callSiteRetWeight = Type.typeFor(callSiteMethodType.returnType()).getWeight(); 459 // Delta is negative for narrower return type, positive for wider return type 460 final int thisRetWeightDelta = Type.typeFor(thisMethodType.returnType()).getWeight() - callSiteRetWeight; 461 final int otherRetWeightDelta = Type.typeFor(otherMethodType.returnType()).getWeight() - callSiteRetWeight; 462 463 // Prefer function that returns a less wide return type 464 final int widenRetDelta = Math.max(thisRetWeightDelta, 0) - Math.max(otherRetWeightDelta, 0); 465 if(widenRetDelta < 0) { 466 return true; 467 } 468 if(widenRetDelta > 0) { 469 return false; 470 } 471 472 // Prefer function that returns a less narrow return type 473 final int narrowRetDelta = Math.max(-thisRetWeightDelta, 0) - Math.max(-otherRetWeightDelta, 0); 474 if(narrowRetDelta < 0) { 475 return true; 476 } 477 if(narrowRetDelta > 0) { 478 return false; 479 } 480 481 //if they are equal, pick the specialized one first 482 if (cf.isSpecialization() != other.isSpecialization()) { 483 return cf.isSpecialization(); //always pick the specialized version if we can 484 } 485 486 if (cf.isSpecialization() && other.isSpecialization()) { 487 return cf.getLinkLogicClass() != null; //pick link logic specialization above generic specializations 488 } 489 490 // Signatures are identical 491 throw new AssertionError(thisMethodType + " identically applicable to " + otherMethodType + " for " + callSiteMethodType); 492 } 493 494 private static Type[] toTypeWithoutCallee(final MethodType type, final int thisIndex) { 495 final int paramCount = type.parameterCount(); 496 final Type[] t = new Type[paramCount - thisIndex]; 497 for(int i = thisIndex; i < paramCount; ++i) { 498 t[i - thisIndex] = Type.typeFor(type.parameterType(i)); 499 } 500 return t; 501 } 502 503 private static Type getParamType(final int i, final Type[] paramTypes, final boolean isVarArg) { 504 final int fixParamCount = paramTypes.length - (isVarArg ? 1 : 0); 505 if(i < fixParamCount) { 506 return paramTypes[i]; 507 } 508 assert isVarArg; 509 return ((ArrayType)paramTypes[paramTypes.length - 1]).getElementType(); 510 } 511 512 boolean matchesCallSite(final MethodType other, final boolean pickVarArg) { 513 if (other.equals(this.callSiteType)) { 514 return true; 515 } 516 final MethodType type = type(); 517 final int fnParamCount = getParamCount(type); 518 final boolean isVarArg = fnParamCount == Integer.MAX_VALUE; 519 if (isVarArg) { 520 return pickVarArg; 521 } 522 523 final int csParamCount = getParamCount(other); 524 final boolean csIsVarArg = csParamCount == Integer.MAX_VALUE; 525 final int thisThisIndex = needsCallee() ? 1 : 0; // Index of "this" parameter in this function's type 526 527 final int fnParamCountNoCallee = fnParamCount - thisThisIndex; 528 final int minParams = Math.min(csParamCount - 1, fnParamCountNoCallee); // callSiteType always has callee, so subtract 1 529 // We must match all incoming parameters, except "this". Starting from 1 to skip "this". 530 for(int i = 1; i < minParams; ++i) { 531 final Type fnType = Type.typeFor(type.parameterType(i + thisThisIndex)); 532 final Type csType = csIsVarArg ? Type.OBJECT : Type.typeFor(other.parameterType(i + 1)); 533 if(!fnType.isEquivalentTo(csType)) { 534 return false; 535 } 536 } 537 538 // Must match any undefined parameters to Object type. 539 for(int i = minParams; i < fnParamCountNoCallee; ++i) { 540 if(!Type.typeFor(type.parameterType(i + thisThisIndex)).isEquivalentTo(Type.OBJECT)) { 541 return false; 542 } 543 } 544 545 return true; 546 } 547 548 private static int getParamCount(final MethodType type) { 549 final int paramCount = type.parameterCount(); 550 return type.parameterType(paramCount - 1).isArray() ? Integer.MAX_VALUE : paramCount; 551 } 552 553 private boolean canBeDeoptimized() { 554 return optimismInfo != null; 555 } 556 557 private MethodHandle createComposableInvoker(final boolean isConstructor) { 558 final MethodHandle handle = getInvokerOrConstructor(isConstructor); 559 560 // If compiled function is not optimistic, it can't ever change its invoker/constructor, so just return them 561 // directly. 562 if(!canBeDeoptimized()) { 563 return handle; 564 } 565 566 // Otherwise, we need a new level of indirection; need to introduce a mutable call site that can relink itslef 567 // to the compiled function's changed target whenever the optimistic assumptions are invalidated. 568 final CallSite cs = new MutableCallSite(handle.type()); 569 relinkComposableInvoker(cs, this, isConstructor); 570 return cs.dynamicInvoker(); 571 } 572 573 private static class HandleAndAssumptions { 574 final MethodHandle handle; 575 final SwitchPoint assumptions; 576 577 HandleAndAssumptions(final MethodHandle handle, final SwitchPoint assumptions) { 578 this.handle = handle; 579 this.assumptions = assumptions; 580 } 581 582 GuardedInvocation createInvocation() { 583 return new GuardedInvocation(handle, assumptions); 584 } 585 } 586 587 /** 588 * Returns a pair of an invocation created with a passed-in supplier and a non-invalidated switch point for 589 * optimistic assumptions (or null for the switch point if the function can not be deoptimized). While the method 590 * makes a best effort to return a non-invalidated switch point (compensating for possible deoptimizing 591 * recompilation happening on another thread) it is still possible that by the time this method returns the 592 * switchpoint has been invalidated by a {@code RewriteException} triggered on another thread for this function. 593 * This is not a problem, though, as these switch points are always used to produce call sites that fall back to 594 * relinking when they are invalidated, and in this case the execution will end up here again. What this method 595 * basically does is minimize such busy-loop relinking while the function is being recompiled on a different thread. 596 * @param invocationSupplier the supplier that constructs the actual invocation method handle; should use the 597 * {@code CompiledFunction} method itself in some capacity. 598 * @return a tuple object containing the method handle as created by the supplier and an optimistic assumptions 599 * switch point that is guaranteed to not have been invalidated before the call to this method (or null if the 600 * function can't be further deoptimized). 601 */ 602 private synchronized HandleAndAssumptions getValidOptimisticInvocation(final Supplier<MethodHandle> invocationSupplier) { 603 for(;;) { 604 final MethodHandle handle = invocationSupplier.get(); 605 final SwitchPoint assumptions = canBeDeoptimized() ? optimismInfo.optimisticAssumptions : null; 606 if(assumptions != null && assumptions.hasBeenInvalidated()) { 607 // We can be in a situation where one thread is in the middle of a deoptimizing compilation when we hit 608 // this and thus, it has invalidated the old switch point, but hasn't created the new one yet. Note that 609 // the behavior of invalidating the old switch point before recompilation, and only creating the new one 610 // after recompilation is by design. If we didn't wait here for the recompilation to complete, we would 611 // be busy looping through the fallback path of the invalidated switch point, relinking the call site 612 // again with the same invalidated switch point, invoking the fallback, etc. stealing CPU cycles from 613 // the recompilation task we're dependent on. This can still happen if the switch point gets invalidated 614 // after we grabbed it here, in which case we'll indeed do one busy relink immediately. 615 try { 616 wait(); 617 } catch (final InterruptedException e) { 618 // Intentionally ignored. There's nothing meaningful we can do if we're interrupted 619 } 620 } else { 621 return new HandleAndAssumptions(handle, assumptions); 622 } 623 } 624 } 625 626 private static void relinkComposableInvoker(final CallSite cs, final CompiledFunction inv, final boolean constructor) { 627 final HandleAndAssumptions handleAndAssumptions = inv.getValidOptimisticInvocation(new Supplier<MethodHandle>() { 628 @Override 629 public MethodHandle get() { 630 return inv.getInvokerOrConstructor(constructor); 631 } 632 }); 633 final MethodHandle handle = handleAndAssumptions.handle; 634 final SwitchPoint assumptions = handleAndAssumptions.assumptions; 635 final MethodHandle target; 636 if(assumptions == null) { 637 target = handle; 638 } else { 639 final MethodHandle relink = MethodHandles.insertArguments(RELINK_COMPOSABLE_INVOKER, 0, cs, inv, constructor); 640 target = assumptions.guardWithTest(handle, MethodHandles.foldArguments(cs.dynamicInvoker(), relink)); 641 } 642 cs.setTarget(target.asType(cs.type())); 643 } 644 645 private MethodHandle getInvokerOrConstructor(final boolean selectCtor) { 646 return selectCtor ? getConstructor() : createInvokerForPessimisticCaller(); 647 } 648 649 /** 650 * Returns a guarded invocation for this function when not invoked as a constructor. The guarded invocation has no 651 * guard but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a 652 * final guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 653 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 654 * continue to use the switch point. If that is not possible, use {@link #createComposableInvoker()} instead. 655 * @return a guarded invocation for an ordinary (non-constructor) invocation of this function. 656 */ 657 GuardedInvocation createFunctionInvocation(final Class<?> callSiteReturnType, final int callerProgramPoint) { 658 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 659 @Override 660 public MethodHandle get() { 661 return createInvoker(callSiteReturnType, callerProgramPoint); 662 } 663 }).createInvocation(); 664 } 665 666 /** 667 * Returns a guarded invocation for this function when invoked as a constructor. The guarded invocation has no guard 668 * but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a final 669 * guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 670 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 671 * continue to use the switch point. If that is not possible, use {@link #createComposableConstructor()} instead. 672 * @return a guarded invocation for invocation of this function as a constructor. 673 */ 674 GuardedInvocation createConstructorInvocation() { 675 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 676 @Override 677 public MethodHandle get() { 678 return getConstructor(); 679 } 680 }).createInvocation(); 681 } 682 683 private MethodHandle createInvoker(final Class<?> callSiteReturnType, final int callerProgramPoint) { 684 final boolean isOptimistic = canBeDeoptimized(); 685 MethodHandle handleRewriteException = isOptimistic ? createRewriteExceptionHandler() : null; 686 687 MethodHandle inv = invoker; 688 if(isValid(callerProgramPoint)) { 689 inv = OptimisticReturnFilters.filterOptimisticReturnValue(inv, callSiteReturnType, callerProgramPoint); 690 inv = changeReturnType(inv, callSiteReturnType); 691 if(callSiteReturnType.isPrimitive() && handleRewriteException != null) { 692 // because handleRewriteException always returns Object 693 handleRewriteException = OptimisticReturnFilters.filterOptimisticReturnValue(handleRewriteException, 694 callSiteReturnType, callerProgramPoint); 695 } 696 } else if(isOptimistic) { 697 // Required so that rewrite exception has the same return type. It'd be okay to do it even if we weren't 698 // optimistic, but it isn't necessary as the linker upstream will eventually convert the return type. 699 inv = changeReturnType(inv, callSiteReturnType); 700 } 701 702 if(isOptimistic) { 703 assert handleRewriteException != null; 704 final MethodHandle typedHandleRewriteException = changeReturnType(handleRewriteException, inv.type().returnType()); 705 return MH.catchException(inv, RewriteException.class, typedHandleRewriteException); 706 } 707 return inv; 708 } 709 710 private MethodHandle createRewriteExceptionHandler() { 711 return MH.foldArguments(RESTOF_INVOKER, MH.insertArguments(HANDLE_REWRITE_EXCEPTION, 0, this, optimismInfo)); 712 } 713 714 private static MethodHandle changeReturnType(final MethodHandle mh, final Class<?> newReturnType) { 715 return Bootstrap.getLinkerServices().asType(mh, mh.type().changeReturnType(newReturnType)); 716 } 717 718 @SuppressWarnings("unused") 719 private static MethodHandle handleRewriteException(final CompiledFunction function, final OptimismInfo oldOptimismInfo, final RewriteException re) { 720 return function.handleRewriteException(oldOptimismInfo, re); 721 } 722 723 /** 724 * Debug function for printing out all invalidated program points and their 725 * invalidation mapping to next type 726 * @param ipp 727 * @return string describing the ipp map 728 */ 729 private static String toStringInvalidations(final Map<Integer, Type> ipp) { 730 if (ipp == null) { 731 return ""; 732 } 733 734 final StringBuilder sb = new StringBuilder(); 735 736 for (final Iterator<Map.Entry<Integer, Type>> iter = ipp.entrySet().iterator(); iter.hasNext(); ) { 737 final Map.Entry<Integer, Type> entry = iter.next(); 738 final char bct = entry.getValue().getBytecodeStackType(); 739 740 sb.append('['). 741 append(entry.getKey()). 742 append("->"). 743 append(bct == 'A' ? 'O' : bct). 744 append(']'); 745 746 if (iter.hasNext()) { 747 sb.append(' '); 748 } 749 } 750 751 return sb.toString(); 752 } 753 754 private void logRecompile(final String reason, final FunctionNode fn, final MethodType type, final Map<Integer, Type> ipp) { 755 if (log.isEnabled()) { 756 log.info(reason, DebugLogger.quote(fn.getName()), " signature: ", type, " ", toStringInvalidations(ipp)); 757 } 758 } 759 760 /** 761 * Handles a {@link RewriteException} raised during the execution of this function by recompiling (if needed) the 762 * function with an optimistic assumption invalidated at the program point indicated by the exception, and then 763 * executing a rest-of method to complete the execution with the deoptimized version. 764 * @param oldOptInfo the optimism info of this function. We must store it explicitly as a bound argument in the 765 * method handle, otherwise it could be null for handling a rewrite exception in an outer invocation of a recursive 766 * function when recursive invocations of the function have completely deoptimized it. 767 * @param re the rewrite exception that was raised 768 * @return the method handle for the rest-of method, for folding composition. 769 */ 770 private synchronized MethodHandle handleRewriteException(final OptimismInfo oldOptInfo, final RewriteException re) { 771 if (log.isEnabled()) { 772 log.info(new RecompilationEvent(Level.INFO, re, re.getReturnValueNonDestructive()), "RewriteException ", re.getMessageShort()); 773 } 774 775 final MethodType type = type(); 776 777 // Compiler needs a call site type as its input, which always has a callee parameter, so we must add it if 778 // this function doesn't have a callee parameter. 779 final MethodType ct = type.parameterType(0) == ScriptFunction.class ? 780 type : 781 type.insertParameterTypes(0, ScriptFunction.class); 782 final OptimismInfo currentOptInfo = optimismInfo; 783 final boolean shouldRecompile = currentOptInfo != null && currentOptInfo.requestRecompile(re); 784 785 // Effective optimism info, for subsequent use. We'll normally try to use the current (latest) one, but if it 786 // isn't available, we'll use the old one bound into the call site. 787 final OptimismInfo effectiveOptInfo = currentOptInfo != null ? currentOptInfo : oldOptInfo; 788 FunctionNode fn = effectiveOptInfo.reparse(); 789 final boolean serialized = effectiveOptInfo.isSerialized(); 790 final Compiler compiler = effectiveOptInfo.getCompiler(fn, ct, 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, ct, effectiveOptInfo.invalidatedProgramPoints); 797 return restOfHandle(effectiveOptInfo, compiler.compile(fn, serialized ? CompilationPhases.COMPILE_SERIALIZED_RESTOF : CompilationPhases.COMPILE_ALL_RESTOF), currentOptInfo != null); 798 } 799 800 logRecompile("Deoptimizing recompilation (up to bytecode) ", fn, ct, effectiveOptInfo.invalidatedProgramPoints); 801 fn = compiler.compile(fn, serialized ? CompilationPhases.RECOMPILE_SERIALIZED_UPTO_BYTECODE : 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, ct, effectiveOptInfo.invalidatedProgramPoints); 807 final FunctionNode normalFn = compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL); 808 809 if (effectiveOptInfo.data.usePersistentCodeCache()) { 810 final RecompilableScriptFunctionData data = effectiveOptInfo.data; 811 final int functionNodeId = data.getFunctionNodeId(); 812 final TypeMap typeMap = data.typeMap(ct); 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 log.info("Done."); 819 820 final boolean canBeDeoptimized = normalFn.canBeDeoptimized(); 821 822 if (log.isEnabled()) { 823 log.info("Recompiled '", fn.getName(), "' (", Debug.id(this), ") ", canBeDeoptimized ? " can still be deoptimized." : " is completely deoptimized."); 824 } 825 826 log.info("Looking up invoker..."); 827 828 final MethodHandle newInvoker = effectiveOptInfo.data.lookup(fn); 829 invoker = newInvoker.asType(type.changeReturnType(newInvoker.type().returnType())); 830 constructor = null; // Will be regenerated when needed 831 832 log.info("Done: ", invoker); 833 final MethodHandle restOf = restOfHandle(effectiveOptInfo, compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL_RESTOF), canBeDeoptimized); 834 835 // Note that we only adjust the switch point after we set the invoker/constructor. This is important. 836 if (canBeDeoptimized) { 837 effectiveOptInfo.newOptimisticAssumptions(); // Otherwise, set a new switch point. 838 } else { 839 optimismInfo = null; // If we got to a point where we no longer have optimistic assumptions, let the optimism info go. 840 } 841 notifyAll(); 842 843 return restOf; 844 } 845 846 private MethodHandle restOfHandle(final OptimismInfo info, final FunctionNode restOfFunction, final boolean canBeDeoptimized) { 847 assert info != null; 848 assert restOfFunction.getCompileUnit().getUnitClassName().contains("restOf"); 849 final MethodHandle restOf = 850 changeReturnType( 851 info.data.lookupCodeMethod( 852 restOfFunction.getCompileUnit().getCode(), 853 MH.type(restOfFunction.getReturnType().getTypeClass(), 854 RewriteException.class)), 855 Object.class); 856 857 if (!canBeDeoptimized) { 858 return restOf; 859 } 860 861 // If rest-of is itself optimistic, we must make sure that we can repeat a deoptimization if it, too hits an exception. 862 return MH.catchException(restOf, RewriteException.class, createRewriteExceptionHandler()); 863 864 } 865 866 private static class OptimismInfo { 867 // TODO: this is pointing to its owning ScriptFunctionData. Re-evaluate if that's okay. 868 private final RecompilableScriptFunctionData data; 869 private final Map<Integer, Type> invalidatedProgramPoints; 870 private SwitchPoint optimisticAssumptions; 871 private final DebugLogger log; 872 873 @SuppressWarnings("unused") 874 OptimismInfo(final RecompilableScriptFunctionData data, final Map<Integer, Type> invalidatedProgramPoints) { 875 this.data = data; 876 this.log = data.getLogger(); 877 this.invalidatedProgramPoints = invalidatedProgramPoints == null ? new TreeMap<Integer, Type>() : invalidatedProgramPoints; 878 newOptimisticAssumptions(); 879 } 880 881 private void newOptimisticAssumptions() { 882 optimisticAssumptions = new SwitchPoint(); 883 } 884 885 boolean requestRecompile(final RewriteException e) { 886 final Type retType = e.getReturnType(); 887 final Type previousFailedType = invalidatedProgramPoints.put(e.getProgramPoint(), retType); 888 889 if (previousFailedType != null && !previousFailedType.narrowerThan(retType)) { 890 final StackTraceElement[] stack = e.getStackTrace(); 891 final String functionId = stack.length == 0 ? 892 data.getName() : 893 stack[0].getClassName() + "." + stack[0].getMethodName(); 894 895 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."); 896 897 return false; 898 } 899 900 SwitchPoint.invalidateAll(new SwitchPoint[] { optimisticAssumptions }); 901 902 return true; 903 } 904 905 Compiler getCompiler(final FunctionNode fn, final MethodType actualCallSiteType, final RewriteException e) { 906 return data.getCompiler(fn, actualCallSiteType, e.getRuntimeScope(), invalidatedProgramPoints, getEntryPoints(e)); 907 } 908 909 private static int[] getEntryPoints(final RewriteException e) { 910 final int[] prevEntryPoints = e.getPreviousContinuationEntryPoints(); 911 final int[] entryPoints; 912 if (prevEntryPoints == null) { 913 entryPoints = new int[1]; 914 } else { 915 final int l = prevEntryPoints.length; 916 entryPoints = new int[l + 1]; 917 System.arraycopy(prevEntryPoints, 0, entryPoints, 1, l); 918 } 919 entryPoints[0] = e.getProgramPoint(); 920 return entryPoints; 921 } 922 923 FunctionNode reparse() { 924 return data.reparse(); 925 } 926 927 boolean isSerialized() { 928 return data.isSerialized(); 929 } 930 } 931 932 @SuppressWarnings("unused") 933 private static Object newFilter(final Object result, final Object allocation) { 934 return (result instanceof ScriptObject || !JSType.isPrimitive(result))? result : allocation; 935 } 936 937 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 938 return MH.findStatic(MethodHandles.lookup(), CompiledFunction.class, name, MH.type(rtype, types)); 939 } 940} 941