CompiledFunction.java revision 1349:1261d91a9e28
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.ArrayList; 37import java.util.Collection; 38import java.util.Collections; 39import java.util.Iterator; 40import java.util.List; 41import java.util.Map; 42import java.util.TreeMap; 43import java.util.function.Supplier; 44import java.util.logging.Level; 45import jdk.internal.dynalink.linker.GuardedInvocation; 46import jdk.nashorn.internal.codegen.Compiler; 47import jdk.nashorn.internal.codegen.Compiler.CompilationPhases; 48import jdk.nashorn.internal.codegen.TypeMap; 49import jdk.nashorn.internal.codegen.types.ArrayType; 50import jdk.nashorn.internal.codegen.types.Type; 51import jdk.nashorn.internal.ir.FunctionNode; 52import jdk.nashorn.internal.objects.annotations.SpecializedFunction.LinkLogic; 53import jdk.nashorn.internal.runtime.events.RecompilationEvent; 54import jdk.nashorn.internal.runtime.linker.Bootstrap; 55import jdk.nashorn.internal.runtime.logging.DebugLogger; 56 57/** 58 * An version of a JavaScript function, native or JavaScript. 59 * Supports lazily generating a constructor version of the invocation. 60 */ 61final class CompiledFunction { 62 63 private static final MethodHandle NEWFILTER = findOwnMH("newFilter", Object.class, Object.class, Object.class); 64 private static final MethodHandle RELINK_COMPOSABLE_INVOKER = findOwnMH("relinkComposableInvoker", void.class, CallSite.class, CompiledFunction.class, boolean.class); 65 private static final MethodHandle HANDLE_REWRITE_EXCEPTION = findOwnMH("handleRewriteException", MethodHandle.class, CompiledFunction.class, OptimismInfo.class, RewriteException.class); 66 private static final MethodHandle RESTOF_INVOKER = MethodHandles.exactInvoker(MethodType.methodType(Object.class, RewriteException.class)); 67 68 private final DebugLogger log; 69 70 static final Collection<CompiledFunction> NO_FUNCTIONS = Collections.emptySet(); 71 72 /** 73 * The method type may be more specific than the invoker, if. e.g. 74 * the invoker is guarded, and a guard with a generic object only 75 * fallback, while the target is more specific, we still need the 76 * more specific type for sorting 77 */ 78 private MethodHandle invoker; 79 private MethodHandle constructor; 80 private OptimismInfo optimismInfo; 81 private final int flags; // from FunctionNode 82 private final MethodType callSiteType; 83 84 private final Specialization specialization; 85 86 CompiledFunction(final MethodHandle invoker) { 87 this(invoker, null, null); 88 } 89 90 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker, final Specialization specialization) { 91 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), specialization); 92 } 93 94 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final Specialization specialization) { 95 this(invoker, constructor, 0, null, specialization, DebugLogger.DISABLED_LOGGER); 96 } 97 98 CompiledFunction(final MethodHandle invoker, final MethodHandle constructor, final int flags, final MethodType callSiteType, final Specialization specialization, final DebugLogger log) { 99 this.specialization = specialization; 100 if (specialization != null && specialization.isOptimistic()) { 101 /* 102 * An optimistic builtin with isOptimistic=true works like any optimistic generated function, i.e. it 103 * can throw unwarranted optimism exceptions. As native functions trivially can't have parts of them 104 * regenerated as restof methods, this only works if the methods are atomic/functional in their behavior 105 * and doesn't modify state before an UOE can be thrown. If they aren't, we can reexecute a wider version 106 * of the same builtin in a recompilation handler for FinalScriptFunctionData. There are several 107 * candidate methods in Native* that would benefit from this, but I haven't had time to implement any 108 * of them currently. In order to fit in with the relinking framework, the current thinking is 109 * that the methods still take a program point to fit in with other optimistic functions, but 110 * it is set to "first", which is the beginning of the method. The relinker can tell the difference 111 * between builtin and JavaScript functions. This might change. TODO 112 */ 113 this.invoker = MH.insertArguments(invoker, invoker.type().parameterCount() - 1, UnwarrantedOptimismException.FIRST_PROGRAM_POINT); 114 throw new AssertionError("Optimistic (UnwarrantedOptimismException throwing) builtin functions are currently not in use"); 115 } 116 this.invoker = invoker; 117 this.constructor = constructor; 118 this.flags = flags; 119 this.callSiteType = callSiteType; 120 this.log = log; 121 } 122 123 CompiledFunction(final MethodHandle invoker, final RecompilableScriptFunctionData functionData, 124 final Map<Integer, Type> invalidatedProgramPoints, final MethodType callSiteType, final int flags) { 125 this(invoker, null, flags, callSiteType, null, functionData.getLogger()); 126 if ((flags & FunctionNode.IS_DEOPTIMIZABLE) != 0) { 127 optimismInfo = new OptimismInfo(functionData, invalidatedProgramPoints); 128 } else { 129 optimismInfo = null; 130 } 131 } 132 133 static CompiledFunction createBuiltInConstructor(final MethodHandle invoker) { 134 return new CompiledFunction(MH.insertArguments(invoker, 0, false), createConstructorFromInvoker(MH.insertArguments(invoker, 0, true)), null); 135 } 136 137 boolean isSpecialization() { 138 return specialization != null; 139 } 140 141 boolean hasLinkLogic() { 142 return getLinkLogicClass() != null; 143 } 144 145 Class<? extends LinkLogic> getLinkLogicClass() { 146 if (isSpecialization()) { 147 final Class<? extends LinkLogic> linkLogicClass = specialization.getLinkLogicClass(); 148 assert !LinkLogic.isEmpty(linkLogicClass) : "empty link logic classes should have been removed by nasgen"; 149 return linkLogicClass; 150 } 151 return null; 152 } 153 154 int getFlags() { 155 return flags; 156 } 157 158 /** 159 * An optimistic specialization is one that can throw UnwarrantedOptimismException. 160 * This is allowed for native methods, as long as they are functional, i.e. don't change 161 * any state between entering and throwing the UOE. Then we can re-execute a wider version 162 * of the method in the continuation. Rest-of method generation for optimistic builtins is 163 * of course not possible, but this approach works and fits into the same relinking 164 * framework 165 * 166 * @return true if optimistic builtin 167 */ 168 boolean isOptimistic() { 169 return isSpecialization() ? specialization.isOptimistic() : false; 170 } 171 172 boolean isApplyToCall() { 173 return (flags & FunctionNode.HAS_APPLY_TO_CALL_SPECIALIZATION) != 0; 174 } 175 176 boolean isVarArg() { 177 return isVarArgsType(invoker.type()); 178 } 179 180 @Override 181 public String toString() { 182 final StringBuilder sb = new StringBuilder(); 183 final Class<? extends LinkLogic> linkLogicClass = getLinkLogicClass(); 184 185 sb.append("[invokerType="). 186 append(invoker.type()). 187 append(" ctor="). 188 append(constructor). 189 append(" weight="). 190 append(weight()). 191 append(" linkLogic="). 192 append(linkLogicClass != null ? linkLogicClass.getSimpleName() : "none"); 193 194 return sb.toString(); 195 } 196 197 boolean needsCallee() { 198 return ScriptFunctionData.needsCallee(invoker); 199 } 200 201 /** 202 * Returns an invoker method handle for this function. Note that the handle is safely composable in 203 * the sense that you can compose it with other handles using any combinators even if you can't affect call site 204 * invalidation. If this compiled function is non-optimistic, then it returns the same value as 205 * {@link #getInvokerOrConstructor(boolean)}. However, if the function is optimistic, then this handle will 206 * incur an overhead as it will add an intermediate internal call site that can relink itself when the function 207 * needs to regenerate its code to always point at the latest generated code version. 208 * @return a guaranteed composable invoker method handle for this function. 209 */ 210 MethodHandle createComposableInvoker() { 211 return createComposableInvoker(false); 212 } 213 214 /** 215 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle should be 216 * considered non-composable in the sense that you can only compose it with other handles using any combinators if 217 * you can ensure that the composition is guarded by {@link #getOptimisticAssumptionsSwitchPoint()} if it's 218 * non-null, and that you can relink the call site it is set into as a target if the switch point is invalidated. In 219 * all other cases, use {@link #createComposableConstructor()}. 220 * @return a direct constructor method handle for this function. 221 */ 222 private MethodHandle getConstructor() { 223 if (constructor == null) { 224 constructor = createConstructorFromInvoker(createInvokerForPessimisticCaller()); 225 } 226 227 return constructor; 228 } 229 230 /** 231 * Creates a version of the invoker intended for a pessimistic caller (return type is Object, no caller optimistic 232 * program point available). 233 * @return a version of the invoker intended for a pessimistic caller. 234 */ 235 private MethodHandle createInvokerForPessimisticCaller() { 236 return createInvoker(Object.class, INVALID_PROGRAM_POINT); 237 } 238 239 /** 240 * Compose a constructor from an invoker. 241 * 242 * @param invoker invoker 243 * @return the composed constructor 244 */ 245 private static MethodHandle createConstructorFromInvoker(final MethodHandle invoker) { 246 final boolean needsCallee = ScriptFunctionData.needsCallee(invoker); 247 // If it was (callee, this, args...), permute it to (this, callee, args...). We're doing this because having 248 // "this" in the first argument position is what allows the elegant folded composition of 249 // (newFilter x constructor x allocator) further down below in the code. Also, ensure the composite constructor 250 // always returns Object. 251 final MethodHandle swapped = needsCallee ? swapCalleeAndThis(invoker) : invoker; 252 253 final MethodHandle returnsObject = MH.asType(swapped, swapped.type().changeReturnType(Object.class)); 254 255 final MethodType ctorType = returnsObject.type(); 256 257 // Construct a dropping type list for NEWFILTER, but don't include constructor "this" into it, so it's actually 258 // captured as "allocation" parameter of NEWFILTER after we fold the constructor into it. 259 // (this, [callee, ]args...) => ([callee, ]args...) 260 final Class<?>[] ctorArgs = ctorType.dropParameterTypes(0, 1).parameterArray(); 261 262 // Fold constructor into newFilter that replaces the return value from the constructor with the originally 263 // allocated value when the originally allocated value is a JS primitive (String, Boolean, Number). 264 // (result, this, [callee, ]args...) x (this, [callee, ]args...) => (this, [callee, ]args...) 265 final MethodHandle filtered = MH.foldArguments(MH.dropArguments(NEWFILTER, 2, ctorArgs), returnsObject); 266 267 // allocate() takes a ScriptFunction and returns a newly allocated ScriptObject... 268 if (needsCallee) { 269 // ...we either fold it into the previous composition, if we need both the ScriptFunction callee object and 270 // the newly allocated object in the arguments, so (this, callee, args...) x (callee) => (callee, args...), 271 // or... 272 return MH.foldArguments(filtered, ScriptFunction.ALLOCATE); 273 } 274 275 // ...replace the ScriptFunction argument with the newly allocated object, if it doesn't need the callee 276 // (this, args...) filter (callee) => (callee, args...) 277 return MH.filterArguments(filtered, 0, ScriptFunction.ALLOCATE); 278 } 279 280 /** 281 * Permutes the parameters in the method handle from {@code (callee, this, ...)} to {@code (this, callee, ...)}. 282 * Used when creating a constructor handle. 283 * @param mh a method handle with order of arguments {@code (callee, this, ...)} 284 * @return a method handle with order of arguments {@code (this, callee, ...)} 285 */ 286 private static MethodHandle swapCalleeAndThis(final MethodHandle mh) { 287 final MethodType type = mh.type(); 288 assert type.parameterType(0) == ScriptFunction.class : type; 289 assert type.parameterType(1) == Object.class : type; 290 final MethodType newType = type.changeParameterType(0, Object.class).changeParameterType(1, ScriptFunction.class); 291 final int[] reorder = new int[type.parameterCount()]; 292 reorder[0] = 1; 293 assert reorder[1] == 0; 294 for (int i = 2; i < reorder.length; ++i) { 295 reorder[i] = i; 296 } 297 return MethodHandles.permuteArguments(mh, newType, reorder); 298 } 299 300 /** 301 * Returns an invoker method handle for this function when invoked as a constructor. Note that the handle is safely 302 * composable in the sense that you can compose it with other handles using any combinators even if you can't affect 303 * call site invalidation. If this compiled function is non-optimistic, then it returns the same value as 304 * {@link #getConstructor()}. However, if the function is optimistic, then this handle will incur an overhead as it 305 * will add an intermediate internal call site that can relink itself when the function needs to regenerate its code 306 * to always point at the latest generated code version. 307 * @return a guaranteed composable constructor method handle for this function. 308 */ 309 MethodHandle createComposableConstructor() { 310 return createComposableInvoker(true); 311 } 312 313 boolean hasConstructor() { 314 return constructor != null; 315 } 316 317 MethodType type() { 318 return invoker.type(); 319 } 320 321 int weight() { 322 return weight(type()); 323 } 324 325 private static int weight(final MethodType type) { 326 if (isVarArgsType(type)) { 327 return Integer.MAX_VALUE; //if there is a varargs it should be the heavist and last fallback 328 } 329 330 int weight = Type.typeFor(type.returnType()).getWeight(); 331 for (int i = 0 ; i < type.parameterCount() ; i++) { 332 final Class<?> paramType = type.parameterType(i); 333 final int pweight = Type.typeFor(paramType).getWeight() * 2; //params are more important than call types as return values are always specialized 334 weight += pweight; 335 } 336 337 weight += type.parameterCount(); //more params outweigh few parameters 338 339 return weight; 340 } 341 342 static boolean isVarArgsType(final MethodType type) { 343 assert type.parameterCount() >= 1 : type; 344 return type.parameterType(type.parameterCount() - 1) == Object[].class; 345 } 346 347 static boolean moreGenericThan(final MethodType mt0, final MethodType mt1) { 348 return weight(mt0) > weight(mt1); 349 } 350 351 boolean betterThanFinal(final CompiledFunction other, final MethodType callSiteMethodType) { 352 // Prefer anything over nothing, as we can't compile new versions. 353 if (other == null) { 354 return true; 355 } 356 return betterThanFinal(this, other, callSiteMethodType); 357 } 358 359 private static boolean betterThanFinal(final CompiledFunction cf, final CompiledFunction other, final MethodType callSiteMethodType) { 360 final MethodType thisMethodType = cf.type(); 361 final MethodType otherMethodType = other.type(); 362 final int thisParamCount = getParamCount(thisMethodType); 363 final int otherParamCount = getParamCount(otherMethodType); 364 final int callSiteRawParamCount = getParamCount(callSiteMethodType); 365 final boolean csVarArg = callSiteRawParamCount == Integer.MAX_VALUE; 366 // Subtract 1 for callee for non-vararg call sites 367 final int callSiteParamCount = csVarArg ? callSiteRawParamCount : callSiteRawParamCount - 1; 368 369 // Prefer the function that discards less parameters 370 final int thisDiscardsParams = Math.max(callSiteParamCount - thisParamCount, 0); 371 final int otherDiscardsParams = Math.max(callSiteParamCount - otherParamCount, 0); 372 if(thisDiscardsParams < otherDiscardsParams) { 373 return true; 374 } 375 if(thisDiscardsParams > otherDiscardsParams) { 376 return false; 377 } 378 379 final boolean thisVarArg = thisParamCount == Integer.MAX_VALUE; 380 final boolean otherVarArg = otherParamCount == Integer.MAX_VALUE; 381 if(!(thisVarArg && otherVarArg && csVarArg)) { 382 // At least one of them isn't vararg 383 final Type[] thisType = toTypeWithoutCallee(thisMethodType, 0); // Never has callee 384 final Type[] otherType = toTypeWithoutCallee(otherMethodType, 0); // Never has callee 385 final Type[] callSiteType = toTypeWithoutCallee(callSiteMethodType, 1); // Always has callee 386 387 int narrowWeightDelta = 0; 388 int widenWeightDelta = 0; 389 final int minParamsCount = Math.min(Math.min(thisParamCount, otherParamCount), callSiteParamCount); 390 for(int i = 0; i < minParamsCount; ++i) { 391 final int callSiteParamWeight = getParamType(i, callSiteType, csVarArg).getWeight(); 392 // Delta is negative for narrowing, positive for widening 393 final int thisParamWeightDelta = getParamType(i, thisType, thisVarArg).getWeight() - callSiteParamWeight; 394 final int otherParamWeightDelta = getParamType(i, otherType, otherVarArg).getWeight() - callSiteParamWeight; 395 // Only count absolute values of narrowings 396 narrowWeightDelta += Math.max(-thisParamWeightDelta, 0) - Math.max(-otherParamWeightDelta, 0); 397 // Only count absolute values of widenings 398 widenWeightDelta += Math.max(thisParamWeightDelta, 0) - Math.max(otherParamWeightDelta, 0); 399 } 400 401 // If both functions accept more arguments than what is passed at the call site, account for ability 402 // to receive Undefined un-narrowed in the remaining arguments. 403 if(!thisVarArg) { 404 for(int i = callSiteParamCount; i < thisParamCount; ++i) { 405 narrowWeightDelta += Math.max(Type.OBJECT.getWeight() - thisType[i].getWeight(), 0); 406 } 407 } 408 if(!otherVarArg) { 409 for(int i = callSiteParamCount; i < otherParamCount; ++i) { 410 narrowWeightDelta -= Math.max(Type.OBJECT.getWeight() - otherType[i].getWeight(), 0); 411 } 412 } 413 414 // Prefer function that narrows less 415 if(narrowWeightDelta < 0) { 416 return true; 417 } 418 if(narrowWeightDelta > 0) { 419 return false; 420 } 421 422 // Prefer function that widens less 423 if(widenWeightDelta < 0) { 424 return true; 425 } 426 if(widenWeightDelta > 0) { 427 return false; 428 } 429 } 430 431 // Prefer the function that exactly matches the arity of the call site. 432 if(thisParamCount == callSiteParamCount && otherParamCount != callSiteParamCount) { 433 return true; 434 } 435 if(thisParamCount != callSiteParamCount && otherParamCount == callSiteParamCount) { 436 return false; 437 } 438 439 // Otherwise, neither function matches arity exactly. We also know that at this point, they both can receive 440 // more arguments than call site, otherwise we would've already chosen the one that discards less parameters. 441 // Note that variable arity methods are preferred, as they actually match the call site arity better, since they 442 // really have arbitrary arity. 443 if(thisVarArg) { 444 if(!otherVarArg) { 445 return true; // 446 } 447 } else if(otherVarArg) { 448 return false; 449 } 450 451 // Neither is variable arity; chose the one that has less extra parameters. 452 final int fnParamDelta = thisParamCount - otherParamCount; 453 if(fnParamDelta < 0) { 454 return true; 455 } 456 if(fnParamDelta > 0) { 457 return false; 458 } 459 460 final int callSiteRetWeight = Type.typeFor(callSiteMethodType.returnType()).getWeight(); 461 // Delta is negative for narrower return type, positive for wider return type 462 final int thisRetWeightDelta = Type.typeFor(thisMethodType.returnType()).getWeight() - callSiteRetWeight; 463 final int otherRetWeightDelta = Type.typeFor(otherMethodType.returnType()).getWeight() - callSiteRetWeight; 464 465 // Prefer function that returns a less wide return type 466 final int widenRetDelta = Math.max(thisRetWeightDelta, 0) - Math.max(otherRetWeightDelta, 0); 467 if(widenRetDelta < 0) { 468 return true; 469 } 470 if(widenRetDelta > 0) { 471 return false; 472 } 473 474 // Prefer function that returns a less narrow return type 475 final int narrowRetDelta = Math.max(-thisRetWeightDelta, 0) - Math.max(-otherRetWeightDelta, 0); 476 if(narrowRetDelta < 0) { 477 return true; 478 } 479 if(narrowRetDelta > 0) { 480 return false; 481 } 482 483 //if they are equal, pick the specialized one first 484 if (cf.isSpecialization() != other.isSpecialization()) { 485 return cf.isSpecialization(); //always pick the specialized version if we can 486 } 487 488 if (cf.isSpecialization() && other.isSpecialization()) { 489 return cf.getLinkLogicClass() != null; //pick link logic specialization above generic specializations 490 } 491 492 // Signatures are identical 493 throw new AssertionError(thisMethodType + " identically applicable to " + otherMethodType + " for " + callSiteMethodType); 494 } 495 496 private static Type[] toTypeWithoutCallee(final MethodType type, final int thisIndex) { 497 final int paramCount = type.parameterCount(); 498 final Type[] t = new Type[paramCount - thisIndex]; 499 for(int i = thisIndex; i < paramCount; ++i) { 500 t[i - thisIndex] = Type.typeFor(type.parameterType(i)); 501 } 502 return t; 503 } 504 505 private static Type getParamType(final int i, final Type[] paramTypes, final boolean isVarArg) { 506 final int fixParamCount = paramTypes.length - (isVarArg ? 1 : 0); 507 if(i < fixParamCount) { 508 return paramTypes[i]; 509 } 510 assert isVarArg; 511 return ((ArrayType)paramTypes[paramTypes.length - 1]).getElementType(); 512 } 513 514 boolean matchesCallSite(final MethodType other, final boolean pickVarArg) { 515 if (other.equals(this.callSiteType)) { 516 return true; 517 } 518 final MethodType type = type(); 519 final int fnParamCount = getParamCount(type); 520 final boolean isVarArg = fnParamCount == Integer.MAX_VALUE; 521 if (isVarArg) { 522 return pickVarArg; 523 } 524 525 final int csParamCount = getParamCount(other); 526 final boolean csIsVarArg = csParamCount == Integer.MAX_VALUE; 527 final int thisThisIndex = needsCallee() ? 1 : 0; // Index of "this" parameter in this function's type 528 529 final int fnParamCountNoCallee = fnParamCount - thisThisIndex; 530 final int minParams = Math.min(csParamCount - 1, fnParamCountNoCallee); // callSiteType always has callee, so subtract 1 531 // We must match all incoming parameters, including "this". "this" will usually be Object, but there 532 // are exceptions, e.g. when calling functions with primitive "this" in strict mode or through call/apply. 533 for(int i = 0; i < minParams; ++i) { 534 final Type fnType = Type.typeFor(type.parameterType(i + thisThisIndex)); 535 final Type csType = csIsVarArg ? Type.OBJECT : Type.typeFor(other.parameterType(i + 1)); 536 if(!fnType.isEquivalentTo(csType)) { 537 return false; 538 } 539 } 540 541 // Must match any undefined parameters to Object type. 542 for(int i = minParams; i < fnParamCountNoCallee; ++i) { 543 if(!Type.typeFor(type.parameterType(i + thisThisIndex)).isEquivalentTo(Type.OBJECT)) { 544 return false; 545 } 546 } 547 548 return true; 549 } 550 551 private static int getParamCount(final MethodType type) { 552 final int paramCount = type.parameterCount(); 553 return type.parameterType(paramCount - 1).isArray() ? Integer.MAX_VALUE : paramCount; 554 } 555 556 private boolean canBeDeoptimized() { 557 return optimismInfo != null; 558 } 559 560 private MethodHandle createComposableInvoker(final boolean isConstructor) { 561 final MethodHandle handle = getInvokerOrConstructor(isConstructor); 562 563 // If compiled function is not optimistic, it can't ever change its invoker/constructor, so just return them 564 // directly. 565 if(!canBeDeoptimized()) { 566 return handle; 567 } 568 569 // Otherwise, we need a new level of indirection; need to introduce a mutable call site that can relink itslef 570 // to the compiled function's changed target whenever the optimistic assumptions are invalidated. 571 final CallSite cs = new MutableCallSite(handle.type()); 572 relinkComposableInvoker(cs, this, isConstructor); 573 return cs.dynamicInvoker(); 574 } 575 576 private static class HandleAndAssumptions { 577 final MethodHandle handle; 578 final SwitchPoint assumptions; 579 580 HandleAndAssumptions(final MethodHandle handle, final SwitchPoint assumptions) { 581 this.handle = handle; 582 this.assumptions = assumptions; 583 } 584 585 GuardedInvocation createInvocation() { 586 return new GuardedInvocation(handle, assumptions); 587 } 588 } 589 590 /** 591 * Returns a pair of an invocation created with a passed-in supplier and a non-invalidated switch point for 592 * optimistic assumptions (or null for the switch point if the function can not be deoptimized). While the method 593 * makes a best effort to return a non-invalidated switch point (compensating for possible deoptimizing 594 * recompilation happening on another thread) it is still possible that by the time this method returns the 595 * switchpoint has been invalidated by a {@code RewriteException} triggered on another thread for this function. 596 * This is not a problem, though, as these switch points are always used to produce call sites that fall back to 597 * relinking when they are invalidated, and in this case the execution will end up here again. What this method 598 * basically does is minimize such busy-loop relinking while the function is being recompiled on a different thread. 599 * @param invocationSupplier the supplier that constructs the actual invocation method handle; should use the 600 * {@code CompiledFunction} method itself in some capacity. 601 * @return a tuple object containing the method handle as created by the supplier and an optimistic assumptions 602 * switch point that is guaranteed to not have been invalidated before the call to this method (or null if the 603 * function can't be further deoptimized). 604 */ 605 private synchronized HandleAndAssumptions getValidOptimisticInvocation(final Supplier<MethodHandle> invocationSupplier) { 606 for(;;) { 607 final MethodHandle handle = invocationSupplier.get(); 608 final SwitchPoint assumptions = canBeDeoptimized() ? optimismInfo.optimisticAssumptions : null; 609 if(assumptions != null && assumptions.hasBeenInvalidated()) { 610 // We can be in a situation where one thread is in the middle of a deoptimizing compilation when we hit 611 // this and thus, it has invalidated the old switch point, but hasn't created the new one yet. Note that 612 // the behavior of invalidating the old switch point before recompilation, and only creating the new one 613 // after recompilation is by design. If we didn't wait here for the recompilation to complete, we would 614 // be busy looping through the fallback path of the invalidated switch point, relinking the call site 615 // again with the same invalidated switch point, invoking the fallback, etc. stealing CPU cycles from 616 // the recompilation task we're dependent on. This can still happen if the switch point gets invalidated 617 // after we grabbed it here, in which case we'll indeed do one busy relink immediately. 618 try { 619 wait(); 620 } catch (final InterruptedException e) { 621 // Intentionally ignored. There's nothing meaningful we can do if we're interrupted 622 } 623 } else { 624 return new HandleAndAssumptions(handle, assumptions); 625 } 626 } 627 } 628 629 private static void relinkComposableInvoker(final CallSite cs, final CompiledFunction inv, final boolean constructor) { 630 final HandleAndAssumptions handleAndAssumptions = inv.getValidOptimisticInvocation(new Supplier<MethodHandle>() { 631 @Override 632 public MethodHandle get() { 633 return inv.getInvokerOrConstructor(constructor); 634 } 635 }); 636 final MethodHandle handle = handleAndAssumptions.handle; 637 final SwitchPoint assumptions = handleAndAssumptions.assumptions; 638 final MethodHandle target; 639 if(assumptions == null) { 640 target = handle; 641 } else { 642 final MethodHandle relink = MethodHandles.insertArguments(RELINK_COMPOSABLE_INVOKER, 0, cs, inv, constructor); 643 target = assumptions.guardWithTest(handle, MethodHandles.foldArguments(cs.dynamicInvoker(), relink)); 644 } 645 cs.setTarget(target.asType(cs.type())); 646 } 647 648 private MethodHandle getInvokerOrConstructor(final boolean selectCtor) { 649 return selectCtor ? getConstructor() : createInvokerForPessimisticCaller(); 650 } 651 652 /** 653 * Returns a guarded invocation for this function when not invoked as a constructor. The guarded invocation has no 654 * guard but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a 655 * final guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 656 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 657 * continue to use the switch point. If that is not possible, use {@link #createComposableInvoker()} instead. 658 * @return a guarded invocation for an ordinary (non-constructor) invocation of this function. 659 */ 660 GuardedInvocation createFunctionInvocation(final Class<?> callSiteReturnType, final int callerProgramPoint) { 661 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 662 @Override 663 public MethodHandle get() { 664 return createInvoker(callSiteReturnType, callerProgramPoint); 665 } 666 }).createInvocation(); 667 } 668 669 /** 670 * Returns a guarded invocation for this function when invoked as a constructor. The guarded invocation has no guard 671 * but it potentially has an optimistic assumptions switch point. As such, it will probably not be used as a final 672 * guarded invocation, but rather as a holder for an invocation handle and switch point to be decomposed and 673 * reassembled into a different final invocation by the user of this method. Any recompositions should take care to 674 * continue to use the switch point. If that is not possible, use {@link #createComposableConstructor()} instead. 675 * @return a guarded invocation for invocation of this function as a constructor. 676 */ 677 GuardedInvocation createConstructorInvocation() { 678 return getValidOptimisticInvocation(new Supplier<MethodHandle>() { 679 @Override 680 public MethodHandle get() { 681 return getConstructor(); 682 } 683 }).createInvocation(); 684 } 685 686 private MethodHandle createInvoker(final Class<?> callSiteReturnType, final int callerProgramPoint) { 687 final boolean isOptimistic = canBeDeoptimized(); 688 MethodHandle handleRewriteException = isOptimistic ? createRewriteExceptionHandler() : null; 689 690 MethodHandle inv = invoker; 691 if(isValid(callerProgramPoint)) { 692 inv = OptimisticReturnFilters.filterOptimisticReturnValue(inv, callSiteReturnType, callerProgramPoint); 693 inv = changeReturnType(inv, callSiteReturnType); 694 if(callSiteReturnType.isPrimitive() && handleRewriteException != null) { 695 // because handleRewriteException always returns Object 696 handleRewriteException = OptimisticReturnFilters.filterOptimisticReturnValue(handleRewriteException, 697 callSiteReturnType, callerProgramPoint); 698 } 699 } else if(isOptimistic) { 700 // Required so that rewrite exception has the same return type. It'd be okay to do it even if we weren't 701 // optimistic, but it isn't necessary as the linker upstream will eventually convert the return type. 702 inv = changeReturnType(inv, callSiteReturnType); 703 } 704 705 if(isOptimistic) { 706 assert handleRewriteException != null; 707 final MethodHandle typedHandleRewriteException = changeReturnType(handleRewriteException, inv.type().returnType()); 708 return MH.catchException(inv, RewriteException.class, typedHandleRewriteException); 709 } 710 return inv; 711 } 712 713 private MethodHandle createRewriteExceptionHandler() { 714 return MH.foldArguments(RESTOF_INVOKER, MH.insertArguments(HANDLE_REWRITE_EXCEPTION, 0, this, optimismInfo)); 715 } 716 717 private static MethodHandle changeReturnType(final MethodHandle mh, final Class<?> newReturnType) { 718 return Bootstrap.getLinkerServices().asType(mh, mh.type().changeReturnType(newReturnType)); 719 } 720 721 @SuppressWarnings("unused") 722 private static MethodHandle handleRewriteException(final CompiledFunction function, final OptimismInfo oldOptimismInfo, final RewriteException re) { 723 return function.handleRewriteException(oldOptimismInfo, re); 724 } 725 726 /** 727 * Debug function for printing out all invalidated program points and their 728 * invalidation mapping to next type 729 * @param ipp 730 * @return string describing the ipp map 731 */ 732 private static List<String> toStringInvalidations(final Map<Integer, Type> ipp) { 733 if (ipp == null) { 734 return Collections.emptyList(); 735 } 736 737 final List<String> list = new ArrayList<>(); 738 739 for (final Iterator<Map.Entry<Integer, Type>> iter = ipp.entrySet().iterator(); iter.hasNext(); ) { 740 final Map.Entry<Integer, Type> entry = iter.next(); 741 final char bct = entry.getValue().getBytecodeStackType(); 742 final String type; 743 744 switch (entry.getValue().getBytecodeStackType()) { 745 case 'A': 746 type = "object"; 747 break; 748 case 'I': 749 type = "int"; 750 break; 751 case 'J': 752 type = "long"; 753 break; 754 case 'D': 755 type = "double"; 756 break; 757 default: 758 type = String.valueOf(bct); 759 break; 760 } 761 762 final StringBuilder sb = new StringBuilder(); 763 sb.append('['). 764 append("program point: "). 765 append(entry.getKey()). 766 append(" -> "). 767 append(type). 768 append(']'); 769 770 list.add(sb.toString()); 771 } 772 773 return list; 774 } 775 776 private void logRecompile(final String reason, final FunctionNode fn, final MethodType type, final Map<Integer, Type> ipp) { 777 if (log.isEnabled()) { 778 log.info(reason, DebugLogger.quote(fn.getName()), " signature: ", type); 779 log.indent(); 780 for (final String str : toStringInvalidations(ipp)) { 781 log.fine(str); 782 } 783 log.unindent(); 784 } 785 } 786 787 /** 788 * Handles a {@link RewriteException} raised during the execution of this function by recompiling (if needed) the 789 * function with an optimistic assumption invalidated at the program point indicated by the exception, and then 790 * executing a rest-of method to complete the execution with the deoptimized version. 791 * @param oldOptInfo the optimism info of this function. We must store it explicitly as a bound argument in the 792 * method handle, otherwise it could be null for handling a rewrite exception in an outer invocation of a recursive 793 * function when recursive invocations of the function have completely deoptimized it. 794 * @param re the rewrite exception that was raised 795 * @return the method handle for the rest-of method, for folding composition. 796 */ 797 private synchronized MethodHandle handleRewriteException(final OptimismInfo oldOptInfo, final RewriteException re) { 798 if (log.isEnabled()) { 799 log.info( 800 new RecompilationEvent( 801 Level.INFO, 802 re, 803 re.getReturnValueNonDestructive()), 804 "caught RewriteException ", 805 re.getMessageShort()); 806 log.indent(); 807 } 808 809 final MethodType type = type(); 810 811 // Compiler needs a call site type as its input, which always has a callee parameter, so we must add it if 812 // this function doesn't have a callee parameter. 813 final MethodType ct = type.parameterType(0) == ScriptFunction.class ? 814 type : 815 type.insertParameterTypes(0, ScriptFunction.class); 816 final OptimismInfo currentOptInfo = optimismInfo; 817 final boolean shouldRecompile = currentOptInfo != null && currentOptInfo.requestRecompile(re); 818 819 // Effective optimism info, for subsequent use. We'll normally try to use the current (latest) one, but if it 820 // isn't available, we'll use the old one bound into the call site. 821 final OptimismInfo effectiveOptInfo = currentOptInfo != null ? currentOptInfo : oldOptInfo; 822 FunctionNode fn = effectiveOptInfo.reparse(); 823 final boolean serialized = effectiveOptInfo.isSerialized(); 824 final Compiler compiler = effectiveOptInfo.getCompiler(fn, ct, re); //set to non rest-of 825 826 if (!shouldRecompile) { 827 // It didn't necessarily recompile, e.g. for an outer invocation of a recursive function if we already 828 // recompiled a deoptimized version for an inner invocation. 829 // We still need to do the rest of from the beginning 830 logRecompile("Rest-of compilation [STANDALONE] ", fn, ct, effectiveOptInfo.invalidatedProgramPoints); 831 return restOfHandle(effectiveOptInfo, compiler.compile(fn, serialized ? CompilationPhases.COMPILE_SERIALIZED_RESTOF : CompilationPhases.COMPILE_ALL_RESTOF), currentOptInfo != null); 832 } 833 834 logRecompile("Deoptimizing recompilation (up to bytecode) ", fn, ct, effectiveOptInfo.invalidatedProgramPoints); 835 fn = compiler.compile(fn, serialized ? CompilationPhases.RECOMPILE_SERIALIZED_UPTO_BYTECODE : CompilationPhases.COMPILE_UPTO_BYTECODE); 836 log.fine("Reusable IR generated"); 837 838 // compile the rest of the function, and install it 839 log.info("Generating and installing bytecode from reusable IR..."); 840 logRecompile("Rest-of compilation [CODE PIPELINE REUSE] ", fn, ct, effectiveOptInfo.invalidatedProgramPoints); 841 final FunctionNode normalFn = compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL); 842 843 if (effectiveOptInfo.data.usePersistentCodeCache()) { 844 final RecompilableScriptFunctionData data = effectiveOptInfo.data; 845 final int functionNodeId = data.getFunctionNodeId(); 846 final TypeMap typeMap = data.typeMap(ct); 847 final Type[] paramTypes = typeMap == null ? null : typeMap.getParameterTypes(functionNodeId); 848 final String cacheKey = CodeStore.getCacheKey(functionNodeId, paramTypes); 849 compiler.persistClassInfo(cacheKey, normalFn); 850 } 851 852 final boolean canBeDeoptimized = normalFn.canBeDeoptimized(); 853 854 if (log.isEnabled()) { 855 log.unindent(); 856 log.info("Done."); 857 858 log.info("Recompiled '", fn.getName(), "' (", Debug.id(this), ") ", canBeDeoptimized ? "can still be deoptimized." : " is completely deoptimized."); 859 log.finest("Looking up invoker..."); 860 } 861 862 final MethodHandle newInvoker = effectiveOptInfo.data.lookup(fn); 863 invoker = newInvoker.asType(type.changeReturnType(newInvoker.type().returnType())); 864 constructor = null; // Will be regenerated when needed 865 866 log.info("Done: ", invoker); 867 final MethodHandle restOf = restOfHandle(effectiveOptInfo, compiler.compile(fn, CompilationPhases.GENERATE_BYTECODE_AND_INSTALL_RESTOF), canBeDeoptimized); 868 869 // Note that we only adjust the switch point after we set the invoker/constructor. This is important. 870 if (canBeDeoptimized) { 871 effectiveOptInfo.newOptimisticAssumptions(); // Otherwise, set a new switch point. 872 } else { 873 optimismInfo = null; // If we got to a point where we no longer have optimistic assumptions, let the optimism info go. 874 } 875 notifyAll(); 876 877 return restOf; 878 } 879 880 private MethodHandle restOfHandle(final OptimismInfo info, final FunctionNode restOfFunction, final boolean canBeDeoptimized) { 881 assert info != null; 882 assert restOfFunction.getCompileUnit().getUnitClassName().contains("restOf"); 883 final MethodHandle restOf = 884 changeReturnType( 885 info.data.lookupCodeMethod( 886 restOfFunction.getCompileUnit().getCode(), 887 MH.type(restOfFunction.getReturnType().getTypeClass(), 888 RewriteException.class)), 889 Object.class); 890 891 if (!canBeDeoptimized) { 892 return restOf; 893 } 894 895 // If rest-of is itself optimistic, we must make sure that we can repeat a deoptimization if it, too hits an exception. 896 return MH.catchException(restOf, RewriteException.class, createRewriteExceptionHandler()); 897 898 } 899 900 private static class OptimismInfo { 901 // TODO: this is pointing to its owning ScriptFunctionData. Re-evaluate if that's okay. 902 private final RecompilableScriptFunctionData data; 903 private final Map<Integer, Type> invalidatedProgramPoints; 904 private SwitchPoint optimisticAssumptions; 905 private final DebugLogger log; 906 907 OptimismInfo(final RecompilableScriptFunctionData data, final Map<Integer, Type> invalidatedProgramPoints) { 908 this.data = data; 909 this.log = data.getLogger(); 910 this.invalidatedProgramPoints = invalidatedProgramPoints == null ? new TreeMap<>() : invalidatedProgramPoints; 911 newOptimisticAssumptions(); 912 } 913 914 private void newOptimisticAssumptions() { 915 optimisticAssumptions = new SwitchPoint(); 916 } 917 918 boolean requestRecompile(final RewriteException e) { 919 final Type retType = e.getReturnType(); 920 final Type previousFailedType = invalidatedProgramPoints.put(e.getProgramPoint(), retType); 921 922 if (previousFailedType != null && !previousFailedType.narrowerThan(retType)) { 923 final StackTraceElement[] stack = e.getStackTrace(); 924 final String functionId = stack.length == 0 ? 925 data.getName() : 926 stack[0].getClassName() + "." + stack[0].getMethodName(); 927 928 log.info("RewriteException for an already invalidated program point ", e.getProgramPoint(), " in ", functionId, ". This is okay for a recursive function invocation, but a bug otherwise."); 929 930 return false; 931 } 932 933 SwitchPoint.invalidateAll(new SwitchPoint[] { optimisticAssumptions }); 934 935 return true; 936 } 937 938 Compiler getCompiler(final FunctionNode fn, final MethodType actualCallSiteType, final RewriteException e) { 939 return data.getCompiler(fn, actualCallSiteType, e.getRuntimeScope(), invalidatedProgramPoints, getEntryPoints(e)); 940 } 941 942 private static int[] getEntryPoints(final RewriteException e) { 943 final int[] prevEntryPoints = e.getPreviousContinuationEntryPoints(); 944 final int[] entryPoints; 945 if (prevEntryPoints == null) { 946 entryPoints = new int[1]; 947 } else { 948 final int l = prevEntryPoints.length; 949 entryPoints = new int[l + 1]; 950 System.arraycopy(prevEntryPoints, 0, entryPoints, 1, l); 951 } 952 entryPoints[0] = e.getProgramPoint(); 953 return entryPoints; 954 } 955 956 FunctionNode reparse() { 957 return data.reparse(); 958 } 959 960 boolean isSerialized() { 961 return data.isSerialized(); 962 } 963 } 964 965 @SuppressWarnings("unused") 966 private static Object newFilter(final Object result, final Object allocation) { 967 return (result instanceof ScriptObject || !JSType.isPrimitive(result))? result : allocation; 968 } 969 970 private static MethodHandle findOwnMH(final String name, final Class<?> rtype, final Class<?>... types) { 971 return MH.findStatic(MethodHandles.lookup(), CompiledFunction.class, name, MH.type(rtype, types)); 972 } 973} 974