CodeGenerator.java revision 1136:42f7a7a8f34d
1/* 2 * Copyright (c) 2010, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package jdk.nashorn.internal.codegen; 27 28import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.PRIVATE; 29import static jdk.nashorn.internal.codegen.ClassEmitter.Flag.STATIC; 30import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS; 31import static jdk.nashorn.internal.codegen.CompilerConstants.CALLEE; 32import static jdk.nashorn.internal.codegen.CompilerConstants.CREATE_PROGRAM_FUNCTION; 33import static jdk.nashorn.internal.codegen.CompilerConstants.GET_MAP; 34import static jdk.nashorn.internal.codegen.CompilerConstants.GET_STRING; 35import static jdk.nashorn.internal.codegen.CompilerConstants.QUICK_PREFIX; 36import static jdk.nashorn.internal.codegen.CompilerConstants.REGEX_PREFIX; 37import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE; 38import static jdk.nashorn.internal.codegen.CompilerConstants.SPLIT_PREFIX; 39import static jdk.nashorn.internal.codegen.CompilerConstants.THIS; 40import static jdk.nashorn.internal.codegen.CompilerConstants.VARARGS; 41import static jdk.nashorn.internal.codegen.CompilerConstants.constructorNoLookup; 42import static jdk.nashorn.internal.codegen.CompilerConstants.interfaceCallNoLookup; 43import static jdk.nashorn.internal.codegen.CompilerConstants.methodDescriptor; 44import static jdk.nashorn.internal.codegen.CompilerConstants.staticCallNoLookup; 45import static jdk.nashorn.internal.codegen.CompilerConstants.typeDescriptor; 46import static jdk.nashorn.internal.codegen.CompilerConstants.virtualCallNoLookup; 47import static jdk.nashorn.internal.codegen.ObjectClassGenerator.OBJECT_FIELDS_ONLY; 48import static jdk.nashorn.internal.ir.Symbol.HAS_SLOT; 49import static jdk.nashorn.internal.ir.Symbol.IS_INTERNAL; 50import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.INVALID_PROGRAM_POINT; 51import static jdk.nashorn.internal.runtime.UnwarrantedOptimismException.isValid; 52import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_APPLY_TO_CALL; 53import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_DECLARE; 54import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_FAST_SCOPE; 55import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_OPTIMISTIC; 56import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_PROGRAM_POINT_SHIFT; 57import static jdk.nashorn.internal.runtime.linker.NashornCallSiteDescriptor.CALLSITE_SCOPE; 58 59import java.io.PrintWriter; 60import java.util.ArrayDeque; 61import java.util.ArrayList; 62import java.util.Arrays; 63import java.util.BitSet; 64import java.util.Collection; 65import java.util.Collections; 66import java.util.Deque; 67import java.util.EnumSet; 68import java.util.HashMap; 69import java.util.HashSet; 70import java.util.Iterator; 71import java.util.LinkedList; 72import java.util.List; 73import java.util.Map; 74import java.util.Set; 75import java.util.TreeMap; 76import java.util.function.Supplier; 77import jdk.nashorn.internal.AssertsEnabled; 78import jdk.nashorn.internal.IntDeque; 79import jdk.nashorn.internal.codegen.ClassEmitter.Flag; 80import jdk.nashorn.internal.codegen.CompilerConstants.Call; 81import jdk.nashorn.internal.codegen.types.ArrayType; 82import jdk.nashorn.internal.codegen.types.Type; 83import jdk.nashorn.internal.ir.AccessNode; 84import jdk.nashorn.internal.ir.BaseNode; 85import jdk.nashorn.internal.ir.BinaryNode; 86import jdk.nashorn.internal.ir.Block; 87import jdk.nashorn.internal.ir.BlockStatement; 88import jdk.nashorn.internal.ir.BreakNode; 89import jdk.nashorn.internal.ir.BreakableNode; 90import jdk.nashorn.internal.ir.CallNode; 91import jdk.nashorn.internal.ir.CaseNode; 92import jdk.nashorn.internal.ir.CatchNode; 93import jdk.nashorn.internal.ir.ContinueNode; 94import jdk.nashorn.internal.ir.EmptyNode; 95import jdk.nashorn.internal.ir.Expression; 96import jdk.nashorn.internal.ir.ExpressionStatement; 97import jdk.nashorn.internal.ir.ForNode; 98import jdk.nashorn.internal.ir.FunctionNode; 99import jdk.nashorn.internal.ir.FunctionNode.CompilationState; 100import jdk.nashorn.internal.ir.GetSplitState; 101import jdk.nashorn.internal.ir.IdentNode; 102import jdk.nashorn.internal.ir.IfNode; 103import jdk.nashorn.internal.ir.IndexNode; 104import jdk.nashorn.internal.ir.JoinPredecessorExpression; 105import jdk.nashorn.internal.ir.JumpStatement; 106import jdk.nashorn.internal.ir.LabelNode; 107import jdk.nashorn.internal.ir.LexicalContext; 108import jdk.nashorn.internal.ir.LexicalContextNode; 109import jdk.nashorn.internal.ir.LiteralNode; 110import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode; 111import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode.ArrayUnit; 112import jdk.nashorn.internal.ir.LiteralNode.PrimitiveLiteralNode; 113import jdk.nashorn.internal.ir.LocalVariableConversion; 114import jdk.nashorn.internal.ir.LoopNode; 115import jdk.nashorn.internal.ir.Node; 116import jdk.nashorn.internal.ir.ObjectNode; 117import jdk.nashorn.internal.ir.Optimistic; 118import jdk.nashorn.internal.ir.PropertyNode; 119import jdk.nashorn.internal.ir.ReturnNode; 120import jdk.nashorn.internal.ir.RuntimeNode; 121import jdk.nashorn.internal.ir.RuntimeNode.Request; 122import jdk.nashorn.internal.ir.SetSplitState; 123import jdk.nashorn.internal.ir.SplitReturn; 124import jdk.nashorn.internal.ir.Statement; 125import jdk.nashorn.internal.ir.SwitchNode; 126import jdk.nashorn.internal.ir.Symbol; 127import jdk.nashorn.internal.ir.TernaryNode; 128import jdk.nashorn.internal.ir.ThrowNode; 129import jdk.nashorn.internal.ir.TryNode; 130import jdk.nashorn.internal.ir.UnaryNode; 131import jdk.nashorn.internal.ir.VarNode; 132import jdk.nashorn.internal.ir.WhileNode; 133import jdk.nashorn.internal.ir.WithNode; 134import jdk.nashorn.internal.ir.visitor.NodeOperatorVisitor; 135import jdk.nashorn.internal.ir.visitor.NodeVisitor; 136import jdk.nashorn.internal.objects.Global; 137import jdk.nashorn.internal.objects.ScriptFunctionImpl; 138import jdk.nashorn.internal.parser.Lexer.RegexToken; 139import jdk.nashorn.internal.parser.TokenType; 140import jdk.nashorn.internal.runtime.Context; 141import jdk.nashorn.internal.runtime.Debug; 142import jdk.nashorn.internal.runtime.ECMAException; 143import jdk.nashorn.internal.runtime.JSType; 144import jdk.nashorn.internal.runtime.OptimisticReturnFilters; 145import jdk.nashorn.internal.runtime.PropertyMap; 146import jdk.nashorn.internal.runtime.RecompilableScriptFunctionData; 147import jdk.nashorn.internal.runtime.RewriteException; 148import jdk.nashorn.internal.runtime.Scope; 149import jdk.nashorn.internal.runtime.ScriptEnvironment; 150import jdk.nashorn.internal.runtime.ScriptFunction; 151import jdk.nashorn.internal.runtime.ScriptObject; 152import jdk.nashorn.internal.runtime.ScriptRuntime; 153import jdk.nashorn.internal.runtime.Source; 154import jdk.nashorn.internal.runtime.Undefined; 155import jdk.nashorn.internal.runtime.UnwarrantedOptimismException; 156import jdk.nashorn.internal.runtime.arrays.ArrayData; 157import jdk.nashorn.internal.runtime.linker.LinkerCallSite; 158import jdk.nashorn.internal.runtime.logging.DebugLogger; 159import jdk.nashorn.internal.runtime.logging.Loggable; 160import jdk.nashorn.internal.runtime.logging.Logger; 161import jdk.nashorn.internal.runtime.options.Options; 162 163/** 164 * This is the lowest tier of the code generator. It takes lowered ASTs emitted 165 * from Lower and emits Java byte code. The byte code emission logic is broken 166 * out into MethodEmitter. MethodEmitter works internally with a type stack, and 167 * keeps track of the contents of the byte code stack. This way we avoid a large 168 * number of special cases on the form 169 * <pre> 170 * if (type == INT) { 171 * visitInsn(ILOAD, slot); 172 * } else if (type == DOUBLE) { 173 * visitInsn(DOUBLE, slot); 174 * } 175 * </pre> 176 * This quickly became apparent when the code generator was generalized to work 177 * with all types, and not just numbers or objects. 178 * <p> 179 * The CodeGenerator visits nodes only once, tags them as resolved and emits 180 * bytecode for them. 181 */ 182@Logger(name="codegen") 183final class CodeGenerator extends NodeOperatorVisitor<CodeGeneratorLexicalContext> implements Loggable { 184 185 private static final Type SCOPE_TYPE = Type.typeFor(ScriptObject.class); 186 187 private static final String GLOBAL_OBJECT = Type.getInternalName(Global.class); 188 189 private static final String SCRIPTFUNCTION_IMPL_NAME = Type.getInternalName(ScriptFunctionImpl.class); 190 private static final Type SCRIPTFUNCTION_IMPL_TYPE = Type.typeFor(ScriptFunction.class); 191 192 private static final Call CREATE_REWRITE_EXCEPTION = CompilerConstants.staticCallNoLookup(RewriteException.class, 193 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class); 194 private static final Call CREATE_REWRITE_EXCEPTION_REST_OF = CompilerConstants.staticCallNoLookup(RewriteException.class, 195 "create", RewriteException.class, UnwarrantedOptimismException.class, Object[].class, String[].class, int[].class); 196 197 private static final Call ENSURE_INT = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 198 "ensureInt", int.class, Object.class, int.class); 199 private static final Call ENSURE_LONG = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 200 "ensureLong", long.class, Object.class, int.class); 201 private static final Call ENSURE_NUMBER = CompilerConstants.staticCallNoLookup(OptimisticReturnFilters.class, 202 "ensureNumber", double.class, Object.class, int.class); 203 204 private static final Class<?> ITERATOR_CLASS = Iterator.class; 205 static { 206 assert ITERATOR_CLASS == CompilerConstants.ITERATOR_PREFIX.type(); 207 } 208 private static final Type ITERATOR_TYPE = Type.typeFor(ITERATOR_CLASS); 209 private static final Type EXCEPTION_TYPE = Type.typeFor(CompilerConstants.EXCEPTION_PREFIX.type()); 210 211 private static final Integer INT_ZERO = Integer.valueOf(0); 212 213 /** Constant data & installation. The only reason the compiler keeps this is because it is assigned 214 * by reflection in class installation */ 215 private final Compiler compiler; 216 217 /** Is the current code submitted by 'eval' call? */ 218 private final boolean evalCode; 219 220 /** Call site flags given to the code generator to be used for all generated call sites */ 221 private final int callSiteFlags; 222 223 /** How many regexp fields have been emitted */ 224 private int regexFieldCount; 225 226 /** Line number for last statement. If we encounter a new line number, line number bytecode information 227 * needs to be generated */ 228 private int lastLineNumber = -1; 229 230 /** When should we stop caching regexp expressions in fields to limit bytecode size? */ 231 private static final int MAX_REGEX_FIELDS = 2 * 1024; 232 233 /** Current method emitter */ 234 private MethodEmitter method; 235 236 /** Current compile unit */ 237 private CompileUnit unit; 238 239 private final DebugLogger log; 240 241 /** From what size should we use spill instead of fields for JavaScript objects? */ 242 private static final int OBJECT_SPILL_THRESHOLD = Options.getIntProperty("nashorn.spill.threshold", 256); 243 244 private final Set<String> emittedMethods = new HashSet<>(); 245 246 // Function Id -> ContinuationInfo. Used by compilation of rest-of function only. 247 private final Map<Integer, ContinuationInfo> fnIdToContinuationInfo = new HashMap<>(); 248 249 private final Deque<Label> scopeEntryLabels = new ArrayDeque<>(); 250 251 private static final Label METHOD_BOUNDARY = new Label(""); 252 private final Deque<Label> catchLabels = new ArrayDeque<>(); 253 // Number of live locals on entry to (and thus also break from) labeled blocks. 254 private final IntDeque labeledBlockBreakLiveLocals = new IntDeque(); 255 256 //is this a rest of compilation 257 private final int[] continuationEntryPoints; 258 259 /** 260 * Constructor. 261 * 262 * @param compiler 263 */ 264 CodeGenerator(final Compiler compiler, final int[] continuationEntryPoints) { 265 super(new CodeGeneratorLexicalContext()); 266 this.compiler = compiler; 267 this.evalCode = compiler.getSource().isEvalCode(); 268 this.continuationEntryPoints = continuationEntryPoints; 269 this.callSiteFlags = compiler.getScriptEnvironment()._callsite_flags; 270 this.log = initLogger(compiler.getContext()); 271 } 272 273 @Override 274 public DebugLogger getLogger() { 275 return log; 276 } 277 278 @Override 279 public DebugLogger initLogger(final Context context) { 280 return context.getLogger(this.getClass()); 281 } 282 283 /** 284 * Gets the call site flags, adding the strict flag if the current function 285 * being generated is in strict mode 286 * 287 * @return the correct flags for a call site in the current function 288 */ 289 int getCallSiteFlags() { 290 return lc.getCurrentFunction().getCallSiteFlags() | callSiteFlags; 291 } 292 293 /** 294 * Are we generating code for 'eval' code? 295 * @return true if currently compiled code is 'eval' code. 296 */ 297 boolean isEvalCode() { 298 return evalCode; 299 } 300 301 /** 302 * Load an identity node 303 * 304 * @param identNode an identity node to load 305 * @return the method generator used 306 */ 307 private MethodEmitter loadIdent(final IdentNode identNode, final TypeBounds resultBounds) { 308 checkTemporalDeadZone(identNode); 309 final Symbol symbol = identNode.getSymbol(); 310 311 if (!symbol.isScope()) { 312 final Type type = identNode.getType(); 313 if(type == Type.UNDEFINED) { 314 return method.loadUndefined(resultBounds.widest); 315 } 316 317 assert symbol.hasSlot() || symbol.isParam(); 318 return method.load(identNode); 319 } 320 321 assert identNode.getSymbol().isScope() : identNode + " is not in scope!"; 322 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 323 if (isFastScope(symbol)) { 324 // Only generate shared scope getter for fast-scope symbols so we know we can dial in correct scope. 325 if (symbol.getUseCount() > SharedScopeCall.FAST_SCOPE_GET_THRESHOLD && !isOptimisticOrRestOf()) { 326 method.loadCompilerConstant(SCOPE); 327 // As shared scope vars are only used in non-optimistic compilation, we switch from using TypeBounds to 328 // just a single definitive type, resultBounds.widest. 329 loadSharedScopeVar(resultBounds.widest, symbol, flags); 330 } else { 331 new LoadFastScopeVar(identNode, resultBounds, flags).emit(); 332 } 333 } else { 334 //slow scope load, we have no proto depth 335 new LoadScopeVar(identNode, resultBounds, flags).emit(); 336 } 337 338 return method; 339 } 340 341 // Any access to LET and CONST variables before their declaration must throw ReferenceError. 342 // This is called the temporal dead zone (TDZ). See https://gist.github.com/rwaldron/f0807a758aa03bcdd58a 343 private void checkTemporalDeadZone(final IdentNode identNode) { 344 if (identNode.isDead()) { 345 method.load(identNode.getSymbol().getName()); 346 method.invoke(ScriptRuntime.THROW_REFERENCE_ERROR); 347 } 348 } 349 350 private boolean isRestOf() { 351 return continuationEntryPoints != null; 352 } 353 354 private boolean isOptimisticOrRestOf() { 355 return useOptimisticTypes() || isRestOf(); 356 } 357 358 private boolean isCurrentContinuationEntryPoint(final int programPoint) { 359 return isRestOf() && getCurrentContinuationEntryPoint() == programPoint; 360 } 361 362 private int[] getContinuationEntryPoints() { 363 return isRestOf() ? continuationEntryPoints : null; 364 } 365 366 private int getCurrentContinuationEntryPoint() { 367 return isRestOf() ? continuationEntryPoints[0] : INVALID_PROGRAM_POINT; 368 } 369 370 private boolean isContinuationEntryPoint(final int programPoint) { 371 if (isRestOf()) { 372 assert continuationEntryPoints != null; 373 for (final int cep : continuationEntryPoints) { 374 if (cep == programPoint) { 375 return true; 376 } 377 } 378 } 379 return false; 380 } 381 382 /** 383 * Check if this symbol can be accessed directly with a putfield or getfield or dynamic load 384 * 385 * @param symbol symbol to check for fast scope 386 * @return true if fast scope 387 */ 388 private boolean isFastScope(final Symbol symbol) { 389 if (!symbol.isScope()) { 390 return false; 391 } 392 393 if (!lc.inDynamicScope()) { 394 // If there's no with or eval in context, and the symbol is marked as scoped, it is fast scoped. Such a 395 // symbol must either be global, or its defining block must need scope. 396 assert symbol.isGlobal() || lc.getDefiningBlock(symbol).needsScope() : symbol.getName(); 397 return true; 398 } 399 400 if (symbol.isGlobal()) { 401 // Shortcut: if there's a with or eval in context, globals can't be fast scoped 402 return false; 403 } 404 405 // Otherwise, check if there's a dynamic scope between use of the symbol and its definition 406 final String name = symbol.getName(); 407 boolean previousWasBlock = false; 408 for (final Iterator<LexicalContextNode> it = lc.getAllNodes(); it.hasNext();) { 409 final LexicalContextNode node = it.next(); 410 if (node instanceof Block) { 411 // If this block defines the symbol, then we can fast scope the symbol. 412 final Block block = (Block)node; 413 if (block.getExistingSymbol(name) == symbol) { 414 assert block.needsScope(); 415 return true; 416 } 417 previousWasBlock = true; 418 } else { 419 if (node instanceof WithNode && previousWasBlock || node instanceof FunctionNode && ((FunctionNode)node).needsDynamicScope()) { 420 // If we hit a scope that can have symbols introduced into it at run time before finding the defining 421 // block, the symbol can't be fast scoped. A WithNode only counts if we've immediately seen a block 422 // before - its block. Otherwise, we are currently processing the WithNode's expression, and that's 423 // obviously not subjected to introducing new symbols. 424 return false; 425 } 426 previousWasBlock = false; 427 } 428 } 429 // Should've found the symbol defined in a block 430 throw new AssertionError(); 431 } 432 433 private MethodEmitter loadSharedScopeVar(final Type valueType, final Symbol symbol, final int flags) { 434 assert !isOptimisticOrRestOf(); 435 if (isFastScope(symbol)) { 436 method.load(getScopeProtoDepth(lc.getCurrentBlock(), symbol)); 437 } else { 438 method.load(-1); 439 } 440 return lc.getScopeGet(unit, symbol, valueType, flags | CALLSITE_FAST_SCOPE).generateInvoke(method); 441 } 442 443 private class LoadScopeVar extends OptimisticOperation { 444 final IdentNode identNode; 445 private final int flags; 446 447 LoadScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) { 448 super(identNode, resultBounds); 449 this.identNode = identNode; 450 this.flags = flags; 451 } 452 453 @Override 454 void loadStack() { 455 method.loadCompilerConstant(SCOPE); 456 getProto(); 457 } 458 459 void getProto() { 460 //empty 461 } 462 463 @Override 464 void consumeStack() { 465 // If this is either __FILE__, __DIR__, or __LINE__ then load the property initially as Object as we'd convert 466 // it anyway for replaceLocationPropertyPlaceholder. 467 if(identNode.isCompileTimePropertyName()) { 468 method.dynamicGet(Type.OBJECT, identNode.getSymbol().getName(), flags, identNode.isFunction()); 469 replaceCompileTimeProperty(); 470 } else { 471 dynamicGet(identNode.getSymbol().getName(), flags, identNode.isFunction()); 472 } 473 } 474 } 475 476 private class LoadFastScopeVar extends LoadScopeVar { 477 LoadFastScopeVar(final IdentNode identNode, final TypeBounds resultBounds, final int flags) { 478 super(identNode, resultBounds, flags | CALLSITE_FAST_SCOPE); 479 } 480 481 @Override 482 void getProto() { 483 loadFastScopeProto(identNode.getSymbol(), false); 484 } 485 } 486 487 private MethodEmitter storeFastScopeVar(final Symbol symbol, final int flags) { 488 loadFastScopeProto(symbol, true); 489 method.dynamicSet(symbol.getName(), flags | CALLSITE_FAST_SCOPE); 490 return method; 491 } 492 493 private int getScopeProtoDepth(final Block startingBlock, final Symbol symbol) { 494 //walk up the chain from starting block and when we bump into the current function boundary, add the external 495 //information. 496 final FunctionNode fn = lc.getCurrentFunction(); 497 final int externalDepth = compiler.getScriptFunctionData(fn.getId()).getExternalSymbolDepth(symbol.getName()); 498 499 //count the number of scopes from this place to the start of the function 500 501 final int internalDepth = FindScopeDepths.findInternalDepth(lc, fn, startingBlock, symbol); 502 final int scopesToStart = FindScopeDepths.findScopesToStart(lc, fn, startingBlock); 503 int depth = 0; 504 if (internalDepth == -1) { 505 depth = scopesToStart + externalDepth; 506 } else { 507 assert internalDepth <= scopesToStart; 508 depth = internalDepth; 509 } 510 511 return depth; 512 } 513 514 private void loadFastScopeProto(final Symbol symbol, final boolean swap) { 515 final int depth = getScopeProtoDepth(lc.getCurrentBlock(), symbol); 516 assert depth != -1 : "Couldn't find scope depth for symbol " + symbol.getName() + " in " + lc.getCurrentFunction(); 517 if (depth > 0) { 518 if (swap) { 519 method.swap(); 520 } 521 for (int i = 0; i < depth; i++) { 522 method.invoke(ScriptObject.GET_PROTO); 523 } 524 if (swap) { 525 method.swap(); 526 } 527 } 528 } 529 530 /** 531 * Generate code that loads this node to the stack, not constraining its type 532 * 533 * @param expr node to load 534 * 535 * @return the method emitter used 536 */ 537 private MethodEmitter loadExpressionUnbounded(final Expression expr) { 538 return loadExpression(expr, TypeBounds.UNBOUNDED); 539 } 540 541 private MethodEmitter loadExpressionAsObject(final Expression expr) { 542 return loadExpression(expr, TypeBounds.OBJECT); 543 } 544 545 MethodEmitter loadExpressionAsBoolean(final Expression expr) { 546 return loadExpression(expr, TypeBounds.BOOLEAN); 547 } 548 549 // Test whether conversion from source to target involves a call of ES 9.1 ToPrimitive 550 // with possible side effects from calling an object's toString or valueOf methods. 551 private static boolean noToPrimitiveConversion(final Type source, final Type target) { 552 // Object to boolean conversion does not cause ToPrimitive call 553 return source.isJSPrimitive() || !target.isJSPrimitive() || target.isBoolean(); 554 } 555 556 MethodEmitter loadBinaryOperands(final BinaryNode binaryNode) { 557 return loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(binaryNode.getWidestOperandType()), false, false); 558 } 559 560 private MethodEmitter loadBinaryOperands(final Expression lhs, final Expression rhs, final TypeBounds explicitOperandBounds, final boolean baseAlreadyOnStack, final boolean forceConversionSeparation) { 561 // ECMAScript 5.1 specification (sections 11.5-11.11 and 11.13) prescribes that when evaluating a binary 562 // expression "LEFT op RIGHT", the order of operations must be: LOAD LEFT, LOAD RIGHT, CONVERT LEFT, CONVERT 563 // RIGHT, EXECUTE OP. Unfortunately, doing it in this order defeats potential optimizations that arise when we 564 // can combine a LOAD with a CONVERT operation (e.g. use a dynamic getter with the conversion target type as its 565 // return value). What we do here is reorder LOAD RIGHT and CONVERT LEFT when possible; it is possible only when 566 // we can prove that executing CONVERT LEFT can't have a side effect that changes the value of LOAD RIGHT. 567 // Basically, if we know that either LEFT already is a primitive value, or does not have to be converted to 568 // a primitive value, or RIGHT is an expression that loads without side effects, then we can do the 569 // reordering and collapse LOAD/CONVERT into a single operation; otherwise we need to do the more costly 570 // separate operations to preserve specification semantics. 571 572 // Operands' load type should not be narrower than the narrowest of the individual operand types, nor narrower 573 // than the lower explicit bound, but it should also not be wider than 574 final Type lhsType = undefinedToNumber(lhs.getType()); 575 final Type rhsType = undefinedToNumber(rhs.getType()); 576 final Type narrowestOperandType = Type.narrowest(Type.widest(lhsType, rhsType), explicitOperandBounds.widest); 577 final TypeBounds operandBounds = explicitOperandBounds.notNarrowerThan(narrowestOperandType); 578 if (noToPrimitiveConversion(lhsType, explicitOperandBounds.widest) || rhs.isLocal()) { 579 // Can reorder. We might still need to separate conversion, but at least we can do it with reordering 580 if (forceConversionSeparation) { 581 // Can reorder, but can't move conversion into the operand as the operation depends on operands 582 // exact types for its overflow guarantees. E.g. with {L}{%I}expr1 {L}* {L}{%I}expr2 we are not allowed 583 // to merge {L}{%I} into {%L}, as that can cause subsequent overflows; test for JDK-8058610 contains 584 // concrete cases where this could happen. 585 final TypeBounds safeConvertBounds = TypeBounds.UNBOUNDED.notNarrowerThan(narrowestOperandType); 586 loadExpression(lhs, safeConvertBounds, baseAlreadyOnStack); 587 method.convert(operandBounds.within(method.peekType())); 588 loadExpression(rhs, safeConvertBounds, false); 589 method.convert(operandBounds.within(method.peekType())); 590 } else { 591 // Can reorder and move conversion into the operand. Combine load and convert into single operations. 592 loadExpression(lhs, operandBounds, baseAlreadyOnStack); 593 loadExpression(rhs, operandBounds, false); 594 } 595 } else { 596 // Can't reorder. Load and convert separately. 597 final TypeBounds safeConvertBounds = TypeBounds.UNBOUNDED.notNarrowerThan(narrowestOperandType); 598 loadExpression(lhs, safeConvertBounds, baseAlreadyOnStack); 599 final Type lhsLoadedType = method.peekType(); 600 loadExpression(rhs, safeConvertBounds, false); 601 final Type convertedLhsType = operandBounds.within(method.peekType()); 602 if (convertedLhsType != lhsLoadedType) { 603 // Do it conditionally, so that if conversion is a no-op we don't introduce a SWAP, SWAP. 604 method.swap().convert(convertedLhsType).swap(); 605 } 606 method.convert(operandBounds.within(method.peekType())); 607 } 608 assert Type.generic(method.peekType()) == operandBounds.narrowest; 609 assert Type.generic(method.peekType(1)) == operandBounds.narrowest; 610 611 return method; 612 } 613 614 private static final Type undefinedToNumber(final Type type) { 615 return type == Type.UNDEFINED ? Type.NUMBER : type; 616 } 617 618 private static final class TypeBounds { 619 final Type narrowest; 620 final Type widest; 621 622 static final TypeBounds UNBOUNDED = new TypeBounds(Type.UNKNOWN, Type.OBJECT); 623 static final TypeBounds INT = exact(Type.INT); 624 static final TypeBounds OBJECT = exact(Type.OBJECT); 625 static final TypeBounds BOOLEAN = exact(Type.BOOLEAN); 626 627 static TypeBounds exact(final Type type) { 628 return new TypeBounds(type, type); 629 } 630 631 TypeBounds(final Type narrowest, final Type widest) { 632 assert widest != null && widest != Type.UNDEFINED && widest != Type.UNKNOWN : widest; 633 assert narrowest != null && narrowest != Type.UNDEFINED : narrowest; 634 assert !narrowest.widerThan(widest) : narrowest + " wider than " + widest; 635 assert !widest.narrowerThan(narrowest); 636 this.narrowest = Type.generic(narrowest); 637 this.widest = Type.generic(widest); 638 } 639 640 TypeBounds notNarrowerThan(final Type type) { 641 return maybeNew(Type.narrowest(Type.widest(narrowest, type), widest), widest); 642 } 643 644 TypeBounds notWiderThan(final Type type) { 645 return maybeNew(Type.narrowest(narrowest, type), Type.narrowest(widest, type)); 646 } 647 648 boolean canBeNarrowerThan(final Type type) { 649 return narrowest.narrowerThan(type); 650 } 651 652 TypeBounds maybeNew(final Type newNarrowest, final Type newWidest) { 653 if(newNarrowest == narrowest && newWidest == widest) { 654 return this; 655 } 656 return new TypeBounds(newNarrowest, newWidest); 657 } 658 659 TypeBounds booleanToInt() { 660 return maybeNew(CodeGenerator.booleanToInt(narrowest), CodeGenerator.booleanToInt(widest)); 661 } 662 663 TypeBounds objectToNumber() { 664 return maybeNew(CodeGenerator.objectToNumber(narrowest), CodeGenerator.objectToNumber(widest)); 665 } 666 667 Type within(final Type type) { 668 if(type.narrowerThan(narrowest)) { 669 return narrowest; 670 } 671 if(type.widerThan(widest)) { 672 return widest; 673 } 674 return type; 675 } 676 677 @Override 678 public String toString() { 679 return "[" + narrowest + ", " + widest + "]"; 680 } 681 } 682 683 private static Type booleanToInt(final Type t) { 684 return t == Type.BOOLEAN ? Type.INT : t; 685 } 686 687 private static Type objectToNumber(final Type t) { 688 return t.isObject() ? Type.NUMBER : t; 689 } 690 691 MethodEmitter loadExpressionAsType(final Expression expr, final Type type) { 692 if(type == Type.BOOLEAN) { 693 return loadExpressionAsBoolean(expr); 694 } else if(type == Type.UNDEFINED) { 695 assert expr.getType() == Type.UNDEFINED; 696 return loadExpressionAsObject(expr); 697 } 698 // having no upper bound preserves semantics of optimistic operations in the expression (by not having them 699 // converted early) and then applies explicit conversion afterwards. 700 return loadExpression(expr, TypeBounds.UNBOUNDED.notNarrowerThan(type)).convert(type); 701 } 702 703 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds) { 704 return loadExpression(expr, resultBounds, false); 705 } 706 707 /** 708 * Emits code for evaluating an expression and leaving its value on top of the stack, narrowing or widening it if 709 * necessary. 710 * @param expr the expression to load 711 * @param resultBounds the incoming type bounds. The value on the top of the stack is guaranteed to not be of narrower 712 * type than the narrowest bound, or wider type than the widest bound after it is loaded. 713 * @param baseAlreadyOnStack true if the base of an access or index node is already on the stack. Used to avoid 714 * double evaluation of bases in self-assignment expressions to access and index nodes. {@code Type.OBJECT} is used 715 * to indicate the widest possible type. 716 * @return the method emitter 717 */ 718 private MethodEmitter loadExpression(final Expression expr, final TypeBounds resultBounds, final boolean baseAlreadyOnStack) { 719 720 /* 721 * The load may be of type IdentNode, e.g. "x", AccessNode, e.g. "x.y" 722 * or IndexNode e.g. "x[y]". Both AccessNodes and IndexNodes are 723 * BaseNodes and the logic for loading the base object is reused 724 */ 725 final CodeGenerator codegen = this; 726 727 final Node currentDiscard = codegen.lc.getCurrentDiscard(); 728 expr.accept(new NodeOperatorVisitor<LexicalContext>(new LexicalContext()) { 729 @Override 730 public boolean enterIdentNode(final IdentNode identNode) { 731 loadIdent(identNode, resultBounds); 732 return false; 733 } 734 735 @Override 736 public boolean enterAccessNode(final AccessNode accessNode) { 737 new OptimisticOperation(accessNode, resultBounds) { 738 @Override 739 void loadStack() { 740 if (!baseAlreadyOnStack) { 741 loadExpressionAsObject(accessNode.getBase()); 742 } 743 assert method.peekType().isObject(); 744 } 745 @Override 746 void consumeStack() { 747 final int flags = getCallSiteFlags(); 748 dynamicGet(accessNode.getProperty(), flags, accessNode.isFunction()); 749 } 750 }.emit(baseAlreadyOnStack ? 1 : 0); 751 return false; 752 } 753 754 @Override 755 public boolean enterIndexNode(final IndexNode indexNode) { 756 new OptimisticOperation(indexNode, resultBounds) { 757 @Override 758 void loadStack() { 759 if (!baseAlreadyOnStack) { 760 loadExpressionAsObject(indexNode.getBase()); 761 loadExpressionUnbounded(indexNode.getIndex()); 762 } 763 } 764 @Override 765 void consumeStack() { 766 final int flags = getCallSiteFlags(); 767 dynamicGetIndex(flags, indexNode.isFunction()); 768 } 769 }.emit(baseAlreadyOnStack ? 2 : 0); 770 return false; 771 } 772 773 @Override 774 public boolean enterFunctionNode(final FunctionNode functionNode) { 775 // function nodes will always leave a constructed function object on stack, no need to load the symbol 776 // separately as in enterDefault() 777 lc.pop(functionNode); 778 functionNode.accept(codegen); 779 // NOTE: functionNode.accept() will produce a different FunctionNode that we discard. This incidentally 780 // doesn't cause problems as we're never touching FunctionNode again after it's visited here - codegen 781 // is the last element in the compilation pipeline, the AST it produces is not used externally. So, we 782 // re-push the original functionNode. 783 lc.push(functionNode); 784 return false; 785 } 786 787 @Override 788 public boolean enterASSIGN(final BinaryNode binaryNode) { 789 loadASSIGN(binaryNode); 790 return false; 791 } 792 793 @Override 794 public boolean enterASSIGN_ADD(final BinaryNode binaryNode) { 795 loadASSIGN_ADD(binaryNode); 796 return false; 797 } 798 799 @Override 800 public boolean enterASSIGN_BIT_AND(final BinaryNode binaryNode) { 801 loadASSIGN_BIT_AND(binaryNode); 802 return false; 803 } 804 805 @Override 806 public boolean enterASSIGN_BIT_OR(final BinaryNode binaryNode) { 807 loadASSIGN_BIT_OR(binaryNode); 808 return false; 809 } 810 811 @Override 812 public boolean enterASSIGN_BIT_XOR(final BinaryNode binaryNode) { 813 loadASSIGN_BIT_XOR(binaryNode); 814 return false; 815 } 816 817 @Override 818 public boolean enterASSIGN_DIV(final BinaryNode binaryNode) { 819 loadASSIGN_DIV(binaryNode); 820 return false; 821 } 822 823 @Override 824 public boolean enterASSIGN_MOD(final BinaryNode binaryNode) { 825 loadASSIGN_MOD(binaryNode); 826 return false; 827 } 828 829 @Override 830 public boolean enterASSIGN_MUL(final BinaryNode binaryNode) { 831 loadASSIGN_MUL(binaryNode); 832 return false; 833 } 834 835 @Override 836 public boolean enterASSIGN_SAR(final BinaryNode binaryNode) { 837 loadASSIGN_SAR(binaryNode); 838 return false; 839 } 840 841 @Override 842 public boolean enterASSIGN_SHL(final BinaryNode binaryNode) { 843 loadASSIGN_SHL(binaryNode); 844 return false; 845 } 846 847 @Override 848 public boolean enterASSIGN_SHR(final BinaryNode binaryNode) { 849 loadASSIGN_SHR(binaryNode); 850 return false; 851 } 852 853 @Override 854 public boolean enterASSIGN_SUB(final BinaryNode binaryNode) { 855 loadASSIGN_SUB(binaryNode); 856 return false; 857 } 858 859 @Override 860 public boolean enterCallNode(final CallNode callNode) { 861 return loadCallNode(callNode, resultBounds); 862 } 863 864 @Override 865 public boolean enterLiteralNode(final LiteralNode<?> literalNode) { 866 loadLiteral(literalNode, resultBounds); 867 return false; 868 } 869 870 @Override 871 public boolean enterTernaryNode(final TernaryNode ternaryNode) { 872 loadTernaryNode(ternaryNode, resultBounds); 873 return false; 874 } 875 876 @Override 877 public boolean enterADD(final BinaryNode binaryNode) { 878 loadADD(binaryNode, resultBounds); 879 return false; 880 } 881 882 @Override 883 public boolean enterSUB(final UnaryNode unaryNode) { 884 loadSUB(unaryNode, resultBounds); 885 return false; 886 } 887 888 @Override 889 public boolean enterSUB(final BinaryNode binaryNode) { 890 loadSUB(binaryNode, resultBounds); 891 return false; 892 } 893 894 @Override 895 public boolean enterMUL(final BinaryNode binaryNode) { 896 loadMUL(binaryNode, resultBounds); 897 return false; 898 } 899 900 @Override 901 public boolean enterDIV(final BinaryNode binaryNode) { 902 loadDIV(binaryNode, resultBounds); 903 return false; 904 } 905 906 @Override 907 public boolean enterMOD(final BinaryNode binaryNode) { 908 loadMOD(binaryNode, resultBounds); 909 return false; 910 } 911 912 @Override 913 public boolean enterSAR(final BinaryNode binaryNode) { 914 loadSAR(binaryNode); 915 return false; 916 } 917 918 @Override 919 public boolean enterSHL(final BinaryNode binaryNode) { 920 loadSHL(binaryNode); 921 return false; 922 } 923 924 @Override 925 public boolean enterSHR(final BinaryNode binaryNode) { 926 loadSHR(binaryNode); 927 return false; 928 } 929 930 @Override 931 public boolean enterCOMMALEFT(final BinaryNode binaryNode) { 932 loadCOMMALEFT(binaryNode, resultBounds); 933 return false; 934 } 935 936 @Override 937 public boolean enterCOMMARIGHT(final BinaryNode binaryNode) { 938 loadCOMMARIGHT(binaryNode, resultBounds); 939 return false; 940 } 941 942 @Override 943 public boolean enterAND(final BinaryNode binaryNode) { 944 loadAND_OR(binaryNode, resultBounds, true); 945 return false; 946 } 947 948 @Override 949 public boolean enterOR(final BinaryNode binaryNode) { 950 loadAND_OR(binaryNode, resultBounds, false); 951 return false; 952 } 953 954 @Override 955 public boolean enterNOT(final UnaryNode unaryNode) { 956 loadNOT(unaryNode); 957 return false; 958 } 959 960 @Override 961 public boolean enterADD(final UnaryNode unaryNode) { 962 loadADD(unaryNode, resultBounds); 963 return false; 964 } 965 966 @Override 967 public boolean enterBIT_NOT(final UnaryNode unaryNode) { 968 loadBIT_NOT(unaryNode); 969 return false; 970 } 971 972 @Override 973 public boolean enterBIT_AND(final BinaryNode binaryNode) { 974 loadBIT_AND(binaryNode); 975 return false; 976 } 977 978 @Override 979 public boolean enterBIT_OR(final BinaryNode binaryNode) { 980 loadBIT_OR(binaryNode); 981 return false; 982 } 983 984 @Override 985 public boolean enterBIT_XOR(final BinaryNode binaryNode) { 986 loadBIT_XOR(binaryNode); 987 return false; 988 } 989 990 @Override 991 public boolean enterVOID(final UnaryNode unaryNode) { 992 loadVOID(unaryNode, resultBounds); 993 return false; 994 } 995 996 @Override 997 public boolean enterEQ(final BinaryNode binaryNode) { 998 loadCmp(binaryNode, Condition.EQ); 999 return false; 1000 } 1001 1002 @Override 1003 public boolean enterEQ_STRICT(final BinaryNode binaryNode) { 1004 loadCmp(binaryNode, Condition.EQ); 1005 return false; 1006 } 1007 1008 @Override 1009 public boolean enterGE(final BinaryNode binaryNode) { 1010 loadCmp(binaryNode, Condition.GE); 1011 return false; 1012 } 1013 1014 @Override 1015 public boolean enterGT(final BinaryNode binaryNode) { 1016 loadCmp(binaryNode, Condition.GT); 1017 return false; 1018 } 1019 1020 @Override 1021 public boolean enterLE(final BinaryNode binaryNode) { 1022 loadCmp(binaryNode, Condition.LE); 1023 return false; 1024 } 1025 1026 @Override 1027 public boolean enterLT(final BinaryNode binaryNode) { 1028 loadCmp(binaryNode, Condition.LT); 1029 return false; 1030 } 1031 1032 @Override 1033 public boolean enterNE(final BinaryNode binaryNode) { 1034 loadCmp(binaryNode, Condition.NE); 1035 return false; 1036 } 1037 1038 @Override 1039 public boolean enterNE_STRICT(final BinaryNode binaryNode) { 1040 loadCmp(binaryNode, Condition.NE); 1041 return false; 1042 } 1043 1044 @Override 1045 public boolean enterObjectNode(final ObjectNode objectNode) { 1046 loadObjectNode(objectNode); 1047 return false; 1048 } 1049 1050 @Override 1051 public boolean enterRuntimeNode(final RuntimeNode runtimeNode) { 1052 loadRuntimeNode(runtimeNode); 1053 return false; 1054 } 1055 1056 @Override 1057 public boolean enterNEW(final UnaryNode unaryNode) { 1058 loadNEW(unaryNode); 1059 return false; 1060 } 1061 1062 @Override 1063 public boolean enterDECINC(final UnaryNode unaryNode) { 1064 loadDECINC(unaryNode); 1065 return false; 1066 } 1067 1068 @Override 1069 public boolean enterJoinPredecessorExpression(final JoinPredecessorExpression joinExpr) { 1070 loadExpression(joinExpr.getExpression(), resultBounds); 1071 return false; 1072 } 1073 1074 @Override 1075 public boolean enterGetSplitState(final GetSplitState getSplitState) { 1076 method.loadScope(); 1077 method.invoke(Scope.GET_SPLIT_STATE); 1078 return false; 1079 } 1080 1081 @Override 1082 public boolean enterDefault(final Node otherNode) { 1083 // Must have handled all expressions that can legally be encountered. 1084 throw new AssertionError(otherNode.getClass().getName()); 1085 } 1086 }); 1087 if(currentDiscard != expr) { 1088 coerceStackTop(resultBounds); 1089 } 1090 return method; 1091 } 1092 1093 private MethodEmitter coerceStackTop(final TypeBounds typeBounds) { 1094 return method.convert(typeBounds.within(method.peekType())); 1095 } 1096 1097 /** 1098 * Closes any still open entries for this block's local variables in the bytecode local variable table. 1099 * 1100 * @param block block containing symbols. 1101 */ 1102 private void closeBlockVariables(final Block block) { 1103 for (final Symbol symbol : block.getSymbols()) { 1104 if (symbol.isBytecodeLocal()) { 1105 method.closeLocalVariable(symbol, block.getBreakLabel()); 1106 } 1107 } 1108 } 1109 1110 @Override 1111 public boolean enterBlock(final Block block) { 1112 method.label(block.getEntryLabel()); 1113 if(!method.isReachable()) { 1114 return false; 1115 } 1116 if(lc.isFunctionBody() && emittedMethods.contains(lc.getCurrentFunction().getName())) { 1117 return false; 1118 } 1119 initLocals(block); 1120 1121 assert lc.getUsedSlotCount() == method.getFirstTemp(); 1122 return true; 1123 } 1124 1125 private boolean useOptimisticTypes() { 1126 return !lc.inSplitNode() && compiler.useOptimisticTypes(); 1127 } 1128 1129 @Override 1130 public Node leaveBlock(final Block block) { 1131 popBlockScope(block); 1132 method.beforeJoinPoint(block); 1133 1134 closeBlockVariables(block); 1135 lc.releaseSlots(); 1136 assert !method.isReachable() || (lc.isFunctionBody() ? 0 : lc.getUsedSlotCount()) == method.getFirstTemp() : 1137 "reachable="+method.isReachable() + 1138 " isFunctionBody=" + lc.isFunctionBody() + 1139 " usedSlotCount=" + lc.getUsedSlotCount() + 1140 " firstTemp=" + method.getFirstTemp(); 1141 1142 return block; 1143 } 1144 1145 private void popBlockScope(final Block block) { 1146 final Label breakLabel = block.getBreakLabel(); 1147 1148 if(!block.needsScope() || lc.isFunctionBody()) { 1149 emitBlockBreakLabel(breakLabel); 1150 return; 1151 } 1152 1153 final Label beginTryLabel = scopeEntryLabels.pop(); 1154 final Label recoveryLabel = new Label("block_popscope_catch"); 1155 emitBlockBreakLabel(breakLabel); 1156 final boolean bodyCanThrow = breakLabel.isAfter(beginTryLabel); 1157 if(bodyCanThrow) { 1158 method._try(beginTryLabel, breakLabel, recoveryLabel); 1159 } 1160 1161 Label afterCatchLabel = null; 1162 1163 if(method.isReachable()) { 1164 popScope(); 1165 if(bodyCanThrow) { 1166 afterCatchLabel = new Label("block_after_catch"); 1167 method._goto(afterCatchLabel); 1168 } 1169 } 1170 1171 if(bodyCanThrow) { 1172 assert !method.isReachable(); 1173 method._catch(recoveryLabel); 1174 popScopeException(); 1175 method.athrow(); 1176 } 1177 if(afterCatchLabel != null) { 1178 method.label(afterCatchLabel); 1179 } 1180 } 1181 1182 private void emitBlockBreakLabel(final Label breakLabel) { 1183 // TODO: this is totally backwards. Block should not be breakable, LabelNode should be breakable. 1184 final LabelNode labelNode = lc.getCurrentBlockLabelNode(); 1185 if(labelNode != null) { 1186 // Only have conversions if we're reachable 1187 assert labelNode.getLocalVariableConversion() == null || method.isReachable(); 1188 method.beforeJoinPoint(labelNode); 1189 method.breakLabel(breakLabel, labeledBlockBreakLiveLocals.pop()); 1190 } else { 1191 method.label(breakLabel); 1192 } 1193 } 1194 1195 private void popScope() { 1196 popScopes(1); 1197 } 1198 1199 /** 1200 * Pop scope as part of an exception handler. Similar to {@code popScope()} but also takes care of adjusting the 1201 * number of scopes that needs to be popped in case a rest-of continuation handler encounters an exception while 1202 * performing a ToPrimitive conversion. 1203 */ 1204 private void popScopeException() { 1205 popScope(); 1206 final ContinuationInfo ci = getContinuationInfo(); 1207 if(ci != null) { 1208 final Label catchLabel = ci.catchLabel; 1209 if(catchLabel != METHOD_BOUNDARY && catchLabel == catchLabels.peek()) { 1210 ++ci.exceptionScopePops; 1211 } 1212 } 1213 } 1214 1215 private void popScopesUntil(final LexicalContextNode until) { 1216 popScopes(lc.getScopeNestingLevelTo(until)); 1217 } 1218 1219 private void popScopes(final int count) { 1220 if(count == 0) { 1221 return; 1222 } 1223 assert count > 0; // together with count == 0 check, asserts nonnegative count 1224 if (!method.hasScope()) { 1225 // We can sometimes invoke this method even if the method has no slot for the scope object. Typical example: 1226 // for(;;) { with({}) { break; } }. WithNode normally creates a scope, but if it uses no identifiers and 1227 // nothing else forces creation of a scope in the method, we just won't have the :scope local variable. 1228 return; 1229 } 1230 method.loadCompilerConstant(SCOPE); 1231 for(int i = 0; i < count; ++i) { 1232 method.invoke(ScriptObject.GET_PROTO); 1233 } 1234 method.storeCompilerConstant(SCOPE); 1235 } 1236 1237 @Override 1238 public boolean enterBreakNode(final BreakNode breakNode) { 1239 return enterJumpStatement(breakNode); 1240 } 1241 1242 private boolean enterJumpStatement(final JumpStatement jump) { 1243 if(!method.isReachable()) { 1244 return false; 1245 } 1246 enterStatement(jump); 1247 1248 method.beforeJoinPoint(jump); 1249 final BreakableNode target = jump.getTarget(lc); 1250 popScopesUntil(target); 1251 final Label targetLabel = jump.getTargetLabel(target); 1252 targetLabel.markAsBreakTarget(); 1253 method._goto(targetLabel); 1254 1255 return false; 1256 } 1257 1258 private int loadArgs(final List<Expression> args) { 1259 final int argCount = args.size(); 1260 // arg have already been converted to objects here. 1261 if (argCount > LinkerCallSite.ARGLIMIT) { 1262 loadArgsArray(args); 1263 return 1; 1264 } 1265 1266 for (final Expression arg : args) { 1267 assert arg != null; 1268 loadExpressionUnbounded(arg); 1269 } 1270 return argCount; 1271 } 1272 1273 private boolean loadCallNode(final CallNode callNode, final TypeBounds resultBounds) { 1274 lineNumber(callNode.getLineNumber()); 1275 1276 final List<Expression> args = callNode.getArgs(); 1277 final Expression function = callNode.getFunction(); 1278 final Block currentBlock = lc.getCurrentBlock(); 1279 final CodeGeneratorLexicalContext codegenLexicalContext = lc; 1280 1281 function.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 1282 1283 private MethodEmitter sharedScopeCall(final IdentNode identNode, final int flags) { 1284 final Symbol symbol = identNode.getSymbol(); 1285 final boolean isFastScope = isFastScope(symbol); 1286 final int scopeCallFlags = flags | (isFastScope ? CALLSITE_FAST_SCOPE : 0); 1287 new OptimisticOperation(callNode, resultBounds) { 1288 @Override 1289 void loadStack() { 1290 method.loadCompilerConstant(SCOPE); 1291 if (isFastScope) { 1292 method.load(getScopeProtoDepth(currentBlock, symbol)); 1293 } else { 1294 method.load(-1); // Bypass fast-scope code in shared callsite 1295 } 1296 loadArgs(args); 1297 } 1298 @Override 1299 void consumeStack() { 1300 final Type[] paramTypes = method.getTypesFromStack(args.size()); 1301 // We have trouble finding e.g. in Type.typeFor(asm.Type) because it can't see the Context class 1302 // loader, so we need to weaken reference signatures to Object. 1303 for(int i = 0; i < paramTypes.length; ++i) { 1304 paramTypes[i] = Type.generic(paramTypes[i]); 1305 } 1306 // As shared scope calls are only used in non-optimistic compilation, we switch from using 1307 // TypeBounds to just a single definitive type, resultBounds.widest. 1308 final SharedScopeCall scopeCall = codegenLexicalContext.getScopeCall(unit, symbol, 1309 identNode.getType(), resultBounds.widest, paramTypes, scopeCallFlags); 1310 scopeCall.generateInvoke(method); 1311 } 1312 }.emit(); 1313 return method; 1314 } 1315 1316 private void scopeCall(final IdentNode ident, final int flags) { 1317 new OptimisticOperation(callNode, resultBounds) { 1318 int argsCount; 1319 @Override 1320 void loadStack() { 1321 loadExpressionAsObject(ident); // foo() makes no sense if foo == 3 1322 // ScriptFunction will see CALLSITE_SCOPE and will bind scope accordingly. 1323 method.loadUndefined(Type.OBJECT); //the 'this' 1324 argsCount = loadArgs(args); 1325 } 1326 @Override 1327 void consumeStack() { 1328 dynamicCall(2 + argsCount, flags); 1329 } 1330 }.emit(); 1331 } 1332 1333 private void evalCall(final IdentNode ident, final int flags) { 1334 final Label invoke_direct_eval = new Label("invoke_direct_eval"); 1335 final Label is_not_eval = new Label("is_not_eval"); 1336 final Label eval_done = new Label("eval_done"); 1337 1338 new OptimisticOperation(callNode, resultBounds) { 1339 int argsCount; 1340 @Override 1341 void loadStack() { 1342 /** 1343 * We want to load 'eval' to check if it is indeed global builtin eval. 1344 * If this eval call is inside a 'with' statement, dyn:getMethod|getProp|getElem 1345 * would be generated if ident is a "isFunction". But, that would result in a 1346 * bound function from WithObject. We don't want that as bound function as that 1347 * won't be detected as builtin eval. So, we make ident as "not a function" which 1348 * results in "dyn:getProp|getElem|getMethod" being generated and so WithObject 1349 * would return unbounded eval function. 1350 * 1351 * Example: 1352 * 1353 * var global = this; 1354 * function func() { 1355 * with({ eval: global.eval) { eval("var x = 10;") } 1356 * } 1357 */ 1358 loadExpressionAsObject(ident.setIsNotFunction()); // Type.OBJECT as foo() makes no sense if foo == 3 1359 globalIsEval(); 1360 method.ifeq(is_not_eval); 1361 1362 // Load up self (scope). 1363 method.loadCompilerConstant(SCOPE); 1364 final List<Expression> evalArgs = callNode.getEvalArgs().getArgs(); 1365 // load evaluated code 1366 loadExpressionAsObject(evalArgs.get(0)); 1367 // load second and subsequent args for side-effect 1368 final int numArgs = evalArgs.size(); 1369 for (int i = 1; i < numArgs; i++) { 1370 loadAndDiscard(evalArgs.get(i)); 1371 } 1372 method._goto(invoke_direct_eval); 1373 1374 method.label(is_not_eval); 1375 // load this time but with dyn:getMethod|getProp|getElem 1376 loadExpressionAsObject(ident); // Type.OBJECT as foo() makes no sense if foo == 3 1377 // This is some scope 'eval' or global eval replaced by user 1378 // but not the built-in ECMAScript 'eval' function call 1379 method.loadNull(); 1380 argsCount = loadArgs(callNode.getArgs()); 1381 } 1382 1383 @Override 1384 void consumeStack() { 1385 // Ordinary call 1386 dynamicCall(2 + argsCount, flags); 1387 method._goto(eval_done); 1388 1389 method.label(invoke_direct_eval); 1390 // Special/extra 'eval' arguments. These can be loaded late (in consumeStack) as we know none of 1391 // them can ever be optimistic. 1392 method.loadCompilerConstant(THIS); 1393 method.load(callNode.getEvalArgs().getLocation()); 1394 method.load(CodeGenerator.this.lc.getCurrentFunction().isStrict()); 1395 // direct call to Global.directEval 1396 globalDirectEval(); 1397 convertOptimisticReturnValue(); 1398 coerceStackTop(resultBounds); 1399 } 1400 }.emit(); 1401 1402 method.label(eval_done); 1403 } 1404 1405 @Override 1406 public boolean enterIdentNode(final IdentNode node) { 1407 final Symbol symbol = node.getSymbol(); 1408 1409 if (symbol.isScope()) { 1410 final int flags = getCallSiteFlags() | CALLSITE_SCOPE; 1411 final int useCount = symbol.getUseCount(); 1412 1413 // Threshold for generating shared scope callsite is lower for fast scope symbols because we know 1414 // we can dial in the correct scope. However, we also need to enable it for non-fast scopes to 1415 // support huge scripts like mandreel.js. 1416 if (callNode.isEval()) { 1417 evalCall(node, flags); 1418 } else if (useCount <= SharedScopeCall.FAST_SCOPE_CALL_THRESHOLD 1419 || !isFastScope(symbol) && useCount <= SharedScopeCall.SLOW_SCOPE_CALL_THRESHOLD 1420 || CodeGenerator.this.lc.inDynamicScope() 1421 || isOptimisticOrRestOf()) { 1422 scopeCall(node, flags); 1423 } else { 1424 sharedScopeCall(node, flags); 1425 } 1426 assert method.peekType().equals(resultBounds.within(callNode.getType())) : method.peekType() + " != " + resultBounds + "(" + callNode.getType() + ")"; 1427 } else { 1428 enterDefault(node); 1429 } 1430 1431 return false; 1432 } 1433 1434 @Override 1435 public boolean enterAccessNode(final AccessNode node) { 1436 //check if this is an apply to call node. only real applies, that haven't been 1437 //shadowed from their way to the global scope counts 1438 1439 //call nodes have program points. 1440 1441 final int flags = getCallSiteFlags() | (callNode.isApplyToCall() ? CALLSITE_APPLY_TO_CALL : 0); 1442 1443 new OptimisticOperation(callNode, resultBounds) { 1444 int argCount; 1445 @Override 1446 void loadStack() { 1447 loadExpressionAsObject(node.getBase()); 1448 method.dup(); 1449 // NOTE: not using a nested OptimisticOperation on this dynamicGet, as we expect to get back 1450 // a callable object. Nobody in their right mind would optimistically type this call site. 1451 assert !node.isOptimistic(); 1452 method.dynamicGet(node.getType(), node.getProperty(), flags, true); 1453 method.swap(); 1454 argCount = loadArgs(args); 1455 } 1456 @Override 1457 void consumeStack() { 1458 dynamicCall(2 + argCount, flags); 1459 } 1460 }.emit(); 1461 1462 return false; 1463 } 1464 1465 @Override 1466 public boolean enterFunctionNode(final FunctionNode origCallee) { 1467 new OptimisticOperation(callNode, resultBounds) { 1468 FunctionNode callee; 1469 int argsCount; 1470 @Override 1471 void loadStack() { 1472 callee = (FunctionNode)origCallee.accept(CodeGenerator.this); 1473 if (callee.isStrict()) { // "this" is undefined 1474 method.loadUndefined(Type.OBJECT); 1475 } else { // get global from scope (which is the self) 1476 globalInstance(); 1477 } 1478 argsCount = loadArgs(args); 1479 } 1480 1481 @Override 1482 void consumeStack() { 1483 final int flags = getCallSiteFlags(); 1484 //assert callNodeType.equals(callee.getReturnType()) : callNodeType + " != " + callee.getReturnType(); 1485 dynamicCall(2 + argsCount, flags); 1486 } 1487 }.emit(); 1488 return false; 1489 } 1490 1491 @Override 1492 public boolean enterIndexNode(final IndexNode node) { 1493 new OptimisticOperation(callNode, resultBounds) { 1494 int argsCount; 1495 @Override 1496 void loadStack() { 1497 loadExpressionAsObject(node.getBase()); 1498 method.dup(); 1499 final Type indexType = node.getIndex().getType(); 1500 if (indexType.isObject() || indexType.isBoolean()) { 1501 loadExpressionAsObject(node.getIndex()); //TODO boolean 1502 } else { 1503 loadExpressionUnbounded(node.getIndex()); 1504 } 1505 // NOTE: not using a nested OptimisticOperation on this dynamicGetIndex, as we expect to get 1506 // back a callable object. Nobody in their right mind would optimistically type this call site. 1507 assert !node.isOptimistic(); 1508 method.dynamicGetIndex(node.getType(), getCallSiteFlags(), true); 1509 method.swap(); 1510 argsCount = loadArgs(args); 1511 } 1512 @Override 1513 void consumeStack() { 1514 final int flags = getCallSiteFlags(); 1515 dynamicCall(2 + argsCount, flags); 1516 } 1517 }.emit(); 1518 return false; 1519 } 1520 1521 @Override 1522 protected boolean enterDefault(final Node node) { 1523 new OptimisticOperation(callNode, resultBounds) { 1524 int argsCount; 1525 @Override 1526 void loadStack() { 1527 // Load up function. 1528 loadExpressionAsObject(function); //TODO, e.g. booleans can be used as functions 1529 method.loadUndefined(Type.OBJECT); // ScriptFunction will figure out the correct this when it sees CALLSITE_SCOPE 1530 argsCount = loadArgs(args); 1531 } 1532 @Override 1533 void consumeStack() { 1534 final int flags = getCallSiteFlags() | CALLSITE_SCOPE; 1535 dynamicCall(2 + argsCount, flags); 1536 } 1537 }.emit(); 1538 return false; 1539 } 1540 }); 1541 1542 return false; 1543 } 1544 1545 /** 1546 * Returns the flags with optimistic flag and program point removed. 1547 * @param flags the flags that need optimism stripped from them. 1548 * @return flags without optimism 1549 */ 1550 static int nonOptimisticFlags(final int flags) { 1551 return flags & ~(CALLSITE_OPTIMISTIC | -1 << CALLSITE_PROGRAM_POINT_SHIFT); 1552 } 1553 1554 @Override 1555 public boolean enterContinueNode(final ContinueNode continueNode) { 1556 return enterJumpStatement(continueNode); 1557 } 1558 1559 @Override 1560 public boolean enterEmptyNode(final EmptyNode emptyNode) { 1561 if(!method.isReachable()) { 1562 return false; 1563 } 1564 enterStatement(emptyNode); 1565 1566 return false; 1567 } 1568 1569 @Override 1570 public boolean enterExpressionStatement(final ExpressionStatement expressionStatement) { 1571 if(!method.isReachable()) { 1572 return false; 1573 } 1574 enterStatement(expressionStatement); 1575 1576 loadAndDiscard(expressionStatement.getExpression()); 1577 assert method.getStackSize() == 0; 1578 1579 return false; 1580 } 1581 1582 @Override 1583 public boolean enterBlockStatement(final BlockStatement blockStatement) { 1584 if(!method.isReachable()) { 1585 return false; 1586 } 1587 enterStatement(blockStatement); 1588 1589 blockStatement.getBlock().accept(this); 1590 1591 return false; 1592 } 1593 1594 @Override 1595 public boolean enterForNode(final ForNode forNode) { 1596 if(!method.isReachable()) { 1597 return false; 1598 } 1599 enterStatement(forNode); 1600 if (forNode.isForIn()) { 1601 enterForIn(forNode); 1602 } else { 1603 final Expression init = forNode.getInit(); 1604 if (init != null) { 1605 loadAndDiscard(init); 1606 } 1607 enterForOrWhile(forNode, forNode.getModify()); 1608 } 1609 1610 return false; 1611 } 1612 1613 private void enterForIn(final ForNode forNode) { 1614 loadExpression(forNode.getModify(), TypeBounds.OBJECT); 1615 method.invoke(forNode.isForEach() ? ScriptRuntime.TO_VALUE_ITERATOR : ScriptRuntime.TO_PROPERTY_ITERATOR); 1616 final Symbol iterSymbol = forNode.getIterator(); 1617 final int iterSlot = iterSymbol.getSlot(Type.OBJECT); 1618 method.store(iterSymbol, ITERATOR_TYPE); 1619 1620 method.beforeJoinPoint(forNode); 1621 1622 final Label continueLabel = forNode.getContinueLabel(); 1623 final Label breakLabel = forNode.getBreakLabel(); 1624 1625 method.label(continueLabel); 1626 method.load(ITERATOR_TYPE, iterSlot); 1627 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "hasNext", boolean.class)); 1628 final JoinPredecessorExpression test = forNode.getTest(); 1629 final Block body = forNode.getBody(); 1630 if(LocalVariableConversion.hasLiveConversion(test)) { 1631 final Label afterConversion = new Label("for_in_after_test_conv"); 1632 method.ifne(afterConversion); 1633 method.beforeJoinPoint(test); 1634 method._goto(breakLabel); 1635 method.label(afterConversion); 1636 } else { 1637 method.ifeq(breakLabel); 1638 } 1639 1640 new Store<Expression>(forNode.getInit()) { 1641 @Override 1642 protected void storeNonDiscard() { 1643 // This expression is neither part of a discard, nor needs to be left on the stack after it was 1644 // stored, so we override storeNonDiscard to be a no-op. 1645 } 1646 1647 @Override 1648 protected void evaluate() { 1649 new OptimisticOperation((Optimistic)forNode.getInit(), TypeBounds.UNBOUNDED) { 1650 @Override 1651 void loadStack() { 1652 method.load(ITERATOR_TYPE, iterSlot); 1653 } 1654 1655 @Override 1656 void consumeStack() { 1657 method.invoke(interfaceCallNoLookup(ITERATOR_CLASS, "next", Object.class)); 1658 convertOptimisticReturnValue(); 1659 } 1660 }.emit(); 1661 } 1662 }.store(); 1663 body.accept(this); 1664 1665 if(method.isReachable()) { 1666 method._goto(continueLabel); 1667 } 1668 method.label(breakLabel); 1669 } 1670 1671 /** 1672 * Initialize the slots in a frame to undefined. 1673 * 1674 * @param block block with local vars. 1675 */ 1676 private void initLocals(final Block block) { 1677 lc.onEnterBlock(block); 1678 1679 final boolean isFunctionBody = lc.isFunctionBody(); 1680 final FunctionNode function = lc.getCurrentFunction(); 1681 if (isFunctionBody) { 1682 initializeMethodParameters(function); 1683 if(!function.isVarArg()) { 1684 expandParameterSlots(function); 1685 } 1686 if (method.hasScope()) { 1687 if (function.needsParentScope()) { 1688 method.loadCompilerConstant(CALLEE); 1689 method.invoke(ScriptFunction.GET_SCOPE); 1690 } else { 1691 assert function.hasScopeBlock(); 1692 method.loadNull(); 1693 } 1694 method.storeCompilerConstant(SCOPE); 1695 } 1696 if (function.needsArguments()) { 1697 initArguments(function); 1698 } 1699 } 1700 1701 /* 1702 * Determine if block needs scope, if not, just do initSymbols for this block. 1703 */ 1704 if (block.needsScope()) { 1705 /* 1706 * Determine if function is varargs and consequently variables have to 1707 * be in the scope. 1708 */ 1709 final boolean varsInScope = function.allVarsInScope(); 1710 1711 // TODO for LET we can do better: if *block* does not contain any eval/with, we don't need its vars in scope. 1712 1713 final boolean hasArguments = function.needsArguments(); 1714 final List<MapTuple<Symbol>> tuples = new ArrayList<>(); 1715 final Iterator<IdentNode> paramIter = function.getParameters().iterator(); 1716 for (final Symbol symbol : block.getSymbols()) { 1717 if (symbol.isInternal() || symbol.isThis()) { 1718 continue; 1719 } 1720 1721 if (symbol.isVar()) { 1722 assert !varsInScope || symbol.isScope(); 1723 if (varsInScope || symbol.isScope()) { 1724 assert symbol.isScope() : "scope for " + symbol + " should have been set in Lower already " + function.getName(); 1725 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already" + function.getName(); 1726 1727 //this tuple will not be put fielded, as it has no value, just a symbol 1728 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, null)); 1729 } else { 1730 assert symbol.hasSlot() || symbol.slotCount() == 0 : symbol + " should have a slot only, no scope"; 1731 } 1732 } else if (symbol.isParam() && (varsInScope || hasArguments || symbol.isScope())) { 1733 assert symbol.isScope() : "scope for " + symbol + " should have been set in AssignSymbols already " + function.getName() + " varsInScope="+varsInScope+" hasArguments="+hasArguments+" symbol.isScope()=" + symbol.isScope(); 1734 assert !(hasArguments && symbol.hasSlot()) : "slot for " + symbol + " should have been removed in Lower already " + function.getName(); 1735 1736 final Type paramType; 1737 final Symbol paramSymbol; 1738 1739 if (hasArguments) { 1740 assert !symbol.hasSlot() : "slot for " + symbol + " should have been removed in Lower already "; 1741 paramSymbol = null; 1742 paramType = null; 1743 } else { 1744 paramSymbol = symbol; 1745 // NOTE: We're relying on the fact here that Block.symbols is a LinkedHashMap, hence it will 1746 // return symbols in the order they were defined, and parameters are defined in the same order 1747 // they appear in the function. That's why we can have a single pass over the parameter list 1748 // with an iterator, always just scanning forward for the next parameter that matches the symbol 1749 // name. 1750 for(;;) { 1751 final IdentNode nextParam = paramIter.next(); 1752 if(nextParam.getName().equals(symbol.getName())) { 1753 paramType = nextParam.getType(); 1754 break; 1755 } 1756 } 1757 } 1758 1759 tuples.add(new MapTuple<Symbol>(symbol.getName(), symbol, paramType, paramSymbol) { 1760 //this symbol will be put fielded, we can't initialize it as undefined with a known type 1761 @Override 1762 public Class<?> getValueType() { 1763 if (OBJECT_FIELDS_ONLY || value == null || paramType == null) { 1764 return Object.class; 1765 } 1766 return paramType.isBoolean() ? Object.class : paramType.getTypeClass(); 1767 } 1768 }); 1769 } 1770 } 1771 1772 /* 1773 * Create a new object based on the symbols and values, generate 1774 * bootstrap code for object 1775 */ 1776 new FieldObjectCreator<Symbol>(this, tuples, true, hasArguments) { 1777 @Override 1778 protected void loadValue(final Symbol value, final Type type) { 1779 method.load(value, type); 1780 } 1781 }.makeObject(method); 1782 // program function: merge scope into global 1783 if (isFunctionBody && function.isProgram()) { 1784 method.invoke(ScriptRuntime.MERGE_SCOPE); 1785 } 1786 1787 method.storeCompilerConstant(SCOPE); 1788 if(!isFunctionBody) { 1789 // Function body doesn't need a try/catch to restore scope, as it'd be a dead store anyway. Allowing it 1790 // actually causes issues with UnwarrantedOptimismException handlers as ASM will sort this handler to 1791 // the top of the exception handler table, so it'll be triggered instead of the UOE handlers. 1792 final Label scopeEntryLabel = new Label("scope_entry"); 1793 scopeEntryLabels.push(scopeEntryLabel); 1794 method.label(scopeEntryLabel); 1795 } 1796 } else if (isFunctionBody && function.isVarArg()) { 1797 // Since we don't have a scope, parameters didn't get assigned array indices by the FieldObjectCreator, so 1798 // we need to assign them separately here. 1799 int nextParam = 0; 1800 for (final IdentNode param : function.getParameters()) { 1801 param.getSymbol().setFieldIndex(nextParam++); 1802 } 1803 } 1804 1805 // Debugging: print symbols? @see --print-symbols flag 1806 printSymbols(block, function, (isFunctionBody ? "Function " : "Block in ") + (function.getIdent() == null ? "<anonymous>" : function.getIdent().getName())); 1807 } 1808 1809 /** 1810 * Incoming method parameters are always declared on method entry; declare them in the local variable table. 1811 * @param function function for which code is being generated. 1812 */ 1813 private void initializeMethodParameters(final FunctionNode function) { 1814 final Label functionStart = new Label("fn_start"); 1815 method.label(functionStart); 1816 int nextSlot = 0; 1817 if(function.needsCallee()) { 1818 initializeInternalFunctionParameter(CALLEE, function, functionStart, nextSlot++); 1819 } 1820 initializeInternalFunctionParameter(THIS, function, functionStart, nextSlot++); 1821 if(function.isVarArg()) { 1822 initializeInternalFunctionParameter(VARARGS, function, functionStart, nextSlot++); 1823 } else { 1824 for(final IdentNode param: function.getParameters()) { 1825 final Symbol symbol = param.getSymbol(); 1826 if(symbol.isBytecodeLocal()) { 1827 method.initializeMethodParameter(symbol, param.getType(), functionStart); 1828 } 1829 } 1830 } 1831 } 1832 1833 private void initializeInternalFunctionParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) { 1834 final Symbol symbol = initializeInternalFunctionOrSplitParameter(cc, fn, functionStart, slot); 1835 // Internal function params (:callee, this, and :varargs) are never expanded to multiple slots 1836 assert symbol.getFirstSlot() == slot; 1837 } 1838 1839 private Symbol initializeInternalFunctionOrSplitParameter(final CompilerConstants cc, final FunctionNode fn, final Label functionStart, final int slot) { 1840 final Symbol symbol = fn.getBody().getExistingSymbol(cc.symbolName()); 1841 final Type type = Type.typeFor(cc.type()); 1842 method.initializeMethodParameter(symbol, type, functionStart); 1843 method.onLocalStore(type, slot); 1844 return symbol; 1845 } 1846 1847 /** 1848 * Parameters come into the method packed into local variable slots next to each other. Nashorn on the other hand 1849 * can use 1-6 slots for a local variable depending on all the types it needs to store. When this method is invoked, 1850 * the symbols are already allocated such wider slots, but the values are still in tightly packed incoming slots, 1851 * and we need to spread them into their new locations. 1852 * @param function the function for which parameter-spreading code needs to be emitted 1853 */ 1854 private void expandParameterSlots(final FunctionNode function) { 1855 final List<IdentNode> parameters = function.getParameters(); 1856 // Calculate the total number of incoming parameter slots 1857 int currentIncomingSlot = function.needsCallee() ? 2 : 1; 1858 for(final IdentNode parameter: parameters) { 1859 currentIncomingSlot += parameter.getType().getSlots(); 1860 } 1861 // Starting from last parameter going backwards, move the parameter values into their new slots. 1862 for(int i = parameters.size(); i-- > 0;) { 1863 final IdentNode parameter = parameters.get(i); 1864 final Type parameterType = parameter.getType(); 1865 final int typeWidth = parameterType.getSlots(); 1866 currentIncomingSlot -= typeWidth; 1867 final Symbol symbol = parameter.getSymbol(); 1868 final int slotCount = symbol.slotCount(); 1869 assert slotCount > 0; 1870 // Scoped parameters must not hold more than one value 1871 assert symbol.isBytecodeLocal() || slotCount == typeWidth; 1872 1873 // Mark it as having its value stored into it by the method invocation. 1874 method.onLocalStore(parameterType, currentIncomingSlot); 1875 if(currentIncomingSlot != symbol.getSlot(parameterType)) { 1876 method.load(parameterType, currentIncomingSlot); 1877 method.store(symbol, parameterType); 1878 } 1879 } 1880 } 1881 1882 private void initArguments(final FunctionNode function) { 1883 method.loadCompilerConstant(VARARGS); 1884 if (function.needsCallee()) { 1885 method.loadCompilerConstant(CALLEE); 1886 } else { 1887 // If function is strict mode, "arguments.callee" is not populated, so we don't necessarily need the 1888 // caller. 1889 assert function.isStrict(); 1890 method.loadNull(); 1891 } 1892 method.load(function.getParameters().size()); 1893 globalAllocateArguments(); 1894 method.storeCompilerConstant(ARGUMENTS); 1895 } 1896 1897 private boolean skipFunction(final FunctionNode functionNode) { 1898 final ScriptEnvironment env = compiler.getScriptEnvironment(); 1899 final boolean lazy = env._lazy_compilation; 1900 final boolean onDemand = compiler.isOnDemandCompilation(); 1901 1902 // If this is on-demand or lazy compilation, don't compile a nested (not topmost) function. 1903 if((onDemand || lazy) && lc.getOutermostFunction() != functionNode) { 1904 return true; 1905 } 1906 1907 // If lazy compiling with optimistic types, don't compile the program eagerly either. It will soon be 1908 // invalidated anyway. In presence of a class cache, this further means that an obsoleted program version 1909 // lingers around. Also, currently loading previously persisted optimistic types information only works if 1910 // we're on-demand compiling a function, so with this strategy the :program method can also have the warmup 1911 // benefit of using previously persisted types. 1912 // 1913 // NOTE that this means the first compiled class will effectively just have a :createProgramFunction method, and 1914 // the RecompilableScriptFunctionData (RSFD) object in its constants array. It won't even have the :program 1915 // method. This is by design. It does mean that we're wasting one compiler execution (and we could minimize this 1916 // by just running it up to scope depth calculation, which creates the RSFDs and then this limited codegen). 1917 // We could emit an initial separate compile unit with the initial version of :program in it to better utilize 1918 // the compilation pipeline, but that would need more invasive changes, as currently the assumption that 1919 // :program is emitted into the first compilation unit of the function lives in many places. 1920 return !onDemand && lazy && env._optimistic_types && functionNode.isProgram(); 1921 } 1922 1923 @Override 1924 public boolean enterFunctionNode(final FunctionNode functionNode) { 1925 final int fnId = functionNode.getId(); 1926 1927 if (skipFunction(functionNode)) { 1928 // In case we are not generating code for the function, we must create or retrieve the function object and 1929 // load it on the stack here. 1930 newFunctionObject(functionNode, false); 1931 return false; 1932 } 1933 1934 final String fnName = functionNode.getName(); 1935 1936 // NOTE: we only emit the method for a function with the given name once. We can have multiple functions with 1937 // the same name as a result of inlining finally blocks. However, in the future -- with type specialization, 1938 // notably -- we might need to check for both name *and* signature. Of course, even that might not be 1939 // sufficient; the function might have a code dependency on the type of the variables in its enclosing scopes, 1940 // and the type of such a variable can be different in catch and finally blocks. So, in the future we will have 1941 // to decide to either generate a unique method for each inlined copy of the function, maybe figure out its 1942 // exact type closure and deduplicate based on that, or just decide that functions in finally blocks aren't 1943 // worth it, and generate one method with most generic type closure. 1944 if (!emittedMethods.contains(fnName)) { 1945 log.info("=== BEGIN ", fnName); 1946 1947 assert functionNode.getCompileUnit() != null : "no compile unit for " + fnName + " " + Debug.id(functionNode); 1948 unit = lc.pushCompileUnit(functionNode.getCompileUnit()); 1949 assert lc.hasCompileUnits(); 1950 1951 final ClassEmitter classEmitter = unit.getClassEmitter(); 1952 pushMethodEmitter(isRestOf() ? classEmitter.restOfMethod(functionNode) : classEmitter.method(functionNode)); 1953 method.setPreventUndefinedLoad(); 1954 if(useOptimisticTypes()) { 1955 lc.pushUnwarrantedOptimismHandlers(); 1956 } 1957 1958 // new method - reset last line number 1959 lastLineNumber = -1; 1960 1961 method.begin(); 1962 1963 if (isRestOf()) { 1964 final ContinuationInfo ci = new ContinuationInfo(); 1965 fnIdToContinuationInfo.put(fnId, ci); 1966 method.gotoLoopStart(ci.getHandlerLabel()); 1967 } 1968 } 1969 1970 return true; 1971 } 1972 1973 private void pushMethodEmitter(final MethodEmitter newMethod) { 1974 method = lc.pushMethodEmitter(newMethod); 1975 catchLabels.push(METHOD_BOUNDARY); 1976 } 1977 1978 private void popMethodEmitter() { 1979 method = lc.popMethodEmitter(method); 1980 assert catchLabels.peek() == METHOD_BOUNDARY; 1981 catchLabels.pop(); 1982 } 1983 1984 @Override 1985 public Node leaveFunctionNode(final FunctionNode functionNode) { 1986 try { 1987 final boolean markOptimistic; 1988 if (emittedMethods.add(functionNode.getName())) { 1989 markOptimistic = generateUnwarrantedOptimismExceptionHandlers(functionNode); 1990 generateContinuationHandler(); 1991 method.end(); // wrap up this method 1992 unit = lc.popCompileUnit(functionNode.getCompileUnit()); 1993 popMethodEmitter(); 1994 log.info("=== END ", functionNode.getName()); 1995 } else { 1996 markOptimistic = false; 1997 } 1998 1999 FunctionNode newFunctionNode = functionNode.setState(lc, CompilationState.BYTECODE_GENERATED); 2000 if (markOptimistic) { 2001 newFunctionNode = newFunctionNode.setFlag(lc, FunctionNode.IS_DEOPTIMIZABLE); 2002 } 2003 2004 newFunctionObject(newFunctionNode, true); 2005 return newFunctionNode; 2006 } catch (final Throwable t) { 2007 Context.printStackTrace(t); 2008 final VerifyError e = new VerifyError("Code generation bug in \"" + functionNode.getName() + "\": likely stack misaligned: " + t + " " + functionNode.getSource().getName()); 2009 e.initCause(t); 2010 throw e; 2011 } 2012 } 2013 2014 @Override 2015 public boolean enterIfNode(final IfNode ifNode) { 2016 if(!method.isReachable()) { 2017 return false; 2018 } 2019 enterStatement(ifNode); 2020 2021 final Expression test = ifNode.getTest(); 2022 final Block pass = ifNode.getPass(); 2023 final Block fail = ifNode.getFail(); 2024 2025 if (Expression.isAlwaysTrue(test)) { 2026 loadAndDiscard(test); 2027 pass.accept(this); 2028 return false; 2029 } else if (Expression.isAlwaysFalse(test)) { 2030 loadAndDiscard(test); 2031 if (fail != null) { 2032 fail.accept(this); 2033 } 2034 return false; 2035 } 2036 2037 final boolean hasFailConversion = LocalVariableConversion.hasLiveConversion(ifNode); 2038 2039 final Label failLabel = new Label("if_fail"); 2040 final Label afterLabel = (fail == null && !hasFailConversion) ? null : new Label("if_done"); 2041 2042 emitBranch(test, failLabel, false); 2043 2044 pass.accept(this); 2045 if(method.isReachable() && afterLabel != null) { 2046 method._goto(afterLabel); //don't fallthru to fail block 2047 } 2048 method.label(failLabel); 2049 2050 if (fail != null) { 2051 fail.accept(this); 2052 } else if(hasFailConversion) { 2053 method.beforeJoinPoint(ifNode); 2054 } 2055 2056 if(afterLabel != null && afterLabel.isReachable()) { 2057 method.label(afterLabel); 2058 } 2059 2060 return false; 2061 } 2062 2063 private void emitBranch(final Expression test, final Label label, final boolean jumpWhenTrue) { 2064 new BranchOptimizer(this, method).execute(test, label, jumpWhenTrue); 2065 } 2066 2067 private void enterStatement(final Statement statement) { 2068 lineNumber(statement); 2069 } 2070 2071 private void lineNumber(final Statement statement) { 2072 lineNumber(statement.getLineNumber()); 2073 } 2074 2075 private void lineNumber(final int lineNumber) { 2076 if (lineNumber != lastLineNumber && lineNumber != Node.NO_LINE_NUMBER) { 2077 method.lineNumber(lineNumber); 2078 lastLineNumber = lineNumber; 2079 } 2080 } 2081 2082 int getLastLineNumber() { 2083 return lastLineNumber; 2084 } 2085 2086 /** 2087 * Load a list of nodes as an array of a specific type 2088 * The array will contain the visited nodes. 2089 * 2090 * @param arrayLiteralNode the array of contents 2091 * @param arrayType the type of the array, e.g. ARRAY_NUMBER or ARRAY_OBJECT 2092 * 2093 * @return the method generator that was used 2094 */ 2095 private MethodEmitter loadArray(final ArrayLiteralNode arrayLiteralNode, final ArrayType arrayType) { 2096 assert arrayType == Type.INT_ARRAY || arrayType == Type.LONG_ARRAY || arrayType == Type.NUMBER_ARRAY || arrayType == Type.OBJECT_ARRAY; 2097 2098 final Expression[] nodes = arrayLiteralNode.getValue(); 2099 final Object presets = arrayLiteralNode.getPresets(); 2100 final int[] postsets = arrayLiteralNode.getPostsets(); 2101 final Class<?> type = arrayType.getTypeClass(); 2102 final List<ArrayUnit> units = arrayLiteralNode.getUnits(); 2103 2104 loadConstant(presets); 2105 2106 final Type elementType = arrayType.getElementType(); 2107 2108 if (units != null) { 2109 final MethodEmitter savedMethod = method; 2110 final FunctionNode currentFunction = lc.getCurrentFunction(); 2111 2112 for (final ArrayUnit arrayUnit : units) { 2113 unit = lc.pushCompileUnit(arrayUnit.getCompileUnit()); 2114 2115 final String className = unit.getUnitClassName(); 2116 assert unit != null; 2117 final String name = currentFunction.uniqueName(SPLIT_PREFIX.symbolName()); 2118 final String signature = methodDescriptor(type, ScriptFunction.class, Object.class, ScriptObject.class, type); 2119 2120 pushMethodEmitter(unit.getClassEmitter().method(EnumSet.of(Flag.PUBLIC, Flag.STATIC), name, signature)); 2121 2122 method.setFunctionNode(currentFunction); 2123 method.begin(); 2124 2125 defineCommonSplitMethodParameters(); 2126 defineSplitMethodParameter(CompilerConstants.SPLIT_ARRAY_ARG.slot(), arrayType); 2127 2128 // NOTE: when this is no longer needed, SplitIntoFunctions will no longer have to add IS_SPLIT 2129 // to synthetic functions, and FunctionNode.needsCallee() will no longer need to test for isSplit(). 2130 final int arraySlot = fixScopeSlot(currentFunction, 3); 2131 2132 lc.enterSplitNode(); 2133 2134 for (int i = arrayUnit.getLo(); i < arrayUnit.getHi(); i++) { 2135 method.load(arrayType, arraySlot); 2136 storeElement(nodes, elementType, postsets[i]); 2137 } 2138 2139 method.load(arrayType, arraySlot); 2140 method._return(); 2141 lc.exitSplitNode(); 2142 method.end(); 2143 lc.releaseSlots(); 2144 popMethodEmitter(); 2145 2146 assert method == savedMethod; 2147 method.loadCompilerConstant(CALLEE); 2148 method.swap(); 2149 method.loadCompilerConstant(THIS); 2150 method.swap(); 2151 method.loadCompilerConstant(SCOPE); 2152 method.swap(); 2153 method.invokestatic(className, name, signature); 2154 2155 unit = lc.popCompileUnit(unit); 2156 } 2157 2158 return method; 2159 } 2160 2161 if(postsets.length > 0) { 2162 final int arraySlot = method.getUsedSlotsWithLiveTemporaries(); 2163 method.storeTemp(arrayType, arraySlot); 2164 for (final int postset : postsets) { 2165 method.load(arrayType, arraySlot); 2166 storeElement(nodes, elementType, postset); 2167 } 2168 method.load(arrayType, arraySlot); 2169 } 2170 return method; 2171 } 2172 2173 private void storeElement(final Expression[] nodes, final Type elementType, final int index) { 2174 method.load(index); 2175 2176 final Expression element = nodes[index]; 2177 2178 if (element == null) { 2179 method.loadEmpty(elementType); 2180 } else { 2181 loadExpressionAsType(element, elementType); 2182 } 2183 2184 method.arraystore(); 2185 } 2186 2187 private MethodEmitter loadArgsArray(final List<Expression> args) { 2188 final Object[] array = new Object[args.size()]; 2189 loadConstant(array); 2190 2191 for (int i = 0; i < args.size(); i++) { 2192 method.dup(); 2193 method.load(i); 2194 loadExpression(args.get(i), TypeBounds.OBJECT); // variable arity methods always take objects 2195 method.arraystore(); 2196 } 2197 2198 return method; 2199 } 2200 2201 /** 2202 * Load a constant from the constant array. This is only public to be callable from the objects 2203 * subpackage. Do not call directly. 2204 * 2205 * @param string string to load 2206 */ 2207 void loadConstant(final String string) { 2208 final String unitClassName = unit.getUnitClassName(); 2209 final ClassEmitter classEmitter = unit.getClassEmitter(); 2210 final int index = compiler.getConstantData().add(string); 2211 2212 method.load(index); 2213 method.invokestatic(unitClassName, GET_STRING.symbolName(), methodDescriptor(String.class, int.class)); 2214 classEmitter.needGetConstantMethod(String.class); 2215 } 2216 2217 /** 2218 * Load a constant from the constant array. This is only public to be callable from the objects 2219 * subpackage. Do not call directly. 2220 * 2221 * @param object object to load 2222 */ 2223 void loadConstant(final Object object) { 2224 loadConstant(object, unit, method); 2225 } 2226 2227 private void loadConstant(final Object object, final CompileUnit compileUnit, final MethodEmitter methodEmitter) { 2228 final String unitClassName = compileUnit.getUnitClassName(); 2229 final ClassEmitter classEmitter = compileUnit.getClassEmitter(); 2230 final int index = compiler.getConstantData().add(object); 2231 final Class<?> cls = object.getClass(); 2232 2233 if (cls == PropertyMap.class) { 2234 methodEmitter.load(index); 2235 methodEmitter.invokestatic(unitClassName, GET_MAP.symbolName(), methodDescriptor(PropertyMap.class, int.class)); 2236 classEmitter.needGetConstantMethod(PropertyMap.class); 2237 } else if (cls.isArray()) { 2238 methodEmitter.load(index); 2239 final String methodName = ClassEmitter.getArrayMethodName(cls); 2240 methodEmitter.invokestatic(unitClassName, methodName, methodDescriptor(cls, int.class)); 2241 classEmitter.needGetConstantMethod(cls); 2242 } else { 2243 methodEmitter.loadConstants().load(index).arrayload(); 2244 if (object instanceof ArrayData) { 2245 // avoid cast to non-public ArrayData subclass 2246 methodEmitter.checkcast(ArrayData.class); 2247 methodEmitter.invoke(virtualCallNoLookup(ArrayData.class, "copy", ArrayData.class)); 2248 } else if (cls != Object.class) { 2249 methodEmitter.checkcast(cls); 2250 } 2251 } 2252 } 2253 2254 // literal values 2255 private void loadLiteral(final LiteralNode<?> node, final TypeBounds resultBounds) { 2256 final Object value = node.getValue(); 2257 2258 if (value == null) { 2259 method.loadNull(); 2260 } else if (value instanceof Undefined) { 2261 method.loadUndefined(resultBounds.within(Type.OBJECT)); 2262 } else if (value instanceof String) { 2263 final String string = (String)value; 2264 2265 if (string.length() > MethodEmitter.LARGE_STRING_THRESHOLD / 3) { // 3 == max bytes per encoded char 2266 loadConstant(string); 2267 } else { 2268 method.load(string); 2269 } 2270 } else if (value instanceof RegexToken) { 2271 loadRegex((RegexToken)value); 2272 } else if (value instanceof Boolean) { 2273 method.load((Boolean)value); 2274 } else if (value instanceof Integer) { 2275 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2276 method.load((Integer)value); 2277 method.convert(Type.OBJECT); 2278 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) { 2279 method.load(((Integer)value).doubleValue()); 2280 } else if(!resultBounds.canBeNarrowerThan(Type.LONG)) { 2281 method.load(((Integer)value).longValue()); 2282 } else { 2283 method.load((Integer)value); 2284 } 2285 } else if (value instanceof Long) { 2286 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2287 method.load((Long)value); 2288 method.convert(Type.OBJECT); 2289 } else if(!resultBounds.canBeNarrowerThan(Type.NUMBER)) { 2290 method.load(((Long)value).doubleValue()); 2291 } else { 2292 method.load((Long)value); 2293 } 2294 } else if (value instanceof Double) { 2295 if(!resultBounds.canBeNarrowerThan(Type.OBJECT)) { 2296 method.load((Double)value); 2297 method.convert(Type.OBJECT); 2298 } else { 2299 method.load((Double)value); 2300 } 2301 } else if (node instanceof ArrayLiteralNode) { 2302 final ArrayLiteralNode arrayLiteral = (ArrayLiteralNode)node; 2303 final ArrayType atype = arrayLiteral.getArrayType(); 2304 loadArray(arrayLiteral, atype); 2305 globalAllocateArray(atype); 2306 } else { 2307 throw new UnsupportedOperationException("Unknown literal for " + node.getClass() + " " + value.getClass() + " " + value); 2308 } 2309 } 2310 2311 private MethodEmitter loadRegexToken(final RegexToken value) { 2312 method.load(value.getExpression()); 2313 method.load(value.getOptions()); 2314 return globalNewRegExp(); 2315 } 2316 2317 private MethodEmitter loadRegex(final RegexToken regexToken) { 2318 if (regexFieldCount > MAX_REGEX_FIELDS) { 2319 return loadRegexToken(regexToken); 2320 } 2321 // emit field 2322 final String regexName = lc.getCurrentFunction().uniqueName(REGEX_PREFIX.symbolName()); 2323 final ClassEmitter classEmitter = unit.getClassEmitter(); 2324 2325 classEmitter.field(EnumSet.of(PRIVATE, STATIC), regexName, Object.class); 2326 regexFieldCount++; 2327 2328 // get field, if null create new regex, finally clone regex object 2329 method.getStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class)); 2330 method.dup(); 2331 final Label cachedLabel = new Label("cached"); 2332 method.ifnonnull(cachedLabel); 2333 2334 method.pop(); 2335 loadRegexToken(regexToken); 2336 method.dup(); 2337 method.putStatic(unit.getUnitClassName(), regexName, typeDescriptor(Object.class)); 2338 2339 method.label(cachedLabel); 2340 globalRegExpCopy(); 2341 2342 return method; 2343 } 2344 2345 /** 2346 * Check if a property value contains a particular program point 2347 * @param value value 2348 * @param pp program point 2349 * @return true if it's there. 2350 */ 2351 private static boolean propertyValueContains(final Expression value, final int pp) { 2352 return new Supplier<Boolean>() { 2353 boolean contains; 2354 2355 @Override 2356 public Boolean get() { 2357 value.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 2358 @Override 2359 public boolean enterFunctionNode(final FunctionNode functionNode) { 2360 return false; 2361 } 2362 2363 @Override 2364 public boolean enterObjectNode(final ObjectNode objectNode) { 2365 return false; 2366 } 2367 2368 @Override 2369 public boolean enterDefault(final Node node) { 2370 if (contains) { 2371 return false; 2372 } 2373 if (node instanceof Optimistic && ((Optimistic)node).getProgramPoint() == pp) { 2374 contains = true; 2375 return false; 2376 } 2377 return true; 2378 } 2379 }); 2380 2381 return contains; 2382 } 2383 }.get(); 2384 } 2385 2386 private void loadObjectNode(final ObjectNode objectNode) { 2387 final List<PropertyNode> elements = objectNode.getElements(); 2388 2389 final List<MapTuple<Expression>> tuples = new ArrayList<>(); 2390 final List<PropertyNode> gettersSetters = new ArrayList<>(); 2391 final int ccp = getCurrentContinuationEntryPoint(); 2392 2393 Expression protoNode = null; 2394 boolean restOfProperty = false; 2395 2396 for (final PropertyNode propertyNode : elements) { 2397 final Expression value = propertyNode.getValue(); 2398 final String key = propertyNode.getKeyName(); 2399 // Just use a pseudo-symbol. We just need something non null; use the name and zero flags. 2400 final Symbol symbol = value == null ? null : new Symbol(key, 0); 2401 2402 if (value == null) { 2403 gettersSetters.add(propertyNode); 2404 } else if (propertyNode.getKey() instanceof IdentNode && 2405 key.equals(ScriptObject.PROTO_PROPERTY_NAME)) { 2406 // ES6 draft compliant __proto__ inside object literal 2407 // Identifier key and name is __proto__ 2408 protoNode = value; 2409 continue; 2410 } 2411 2412 restOfProperty |= 2413 value != null && 2414 isValid(ccp) && 2415 propertyValueContains(value, ccp); 2416 2417 //for literals, a value of null means object type, i.e. the value null or getter setter function 2418 //(I think) 2419 final Class<?> valueType = (OBJECT_FIELDS_ONLY || value == null || value.getType().isBoolean()) ? Object.class : value.getType().getTypeClass(); 2420 tuples.add(new MapTuple<Expression>(key, symbol, Type.typeFor(valueType), value) { 2421 @Override 2422 public Class<?> getValueType() { 2423 return type.getTypeClass(); 2424 } 2425 }); 2426 } 2427 2428 final ObjectCreator<?> oc; 2429 if (elements.size() > OBJECT_SPILL_THRESHOLD) { 2430 oc = new SpillObjectCreator(this, tuples); 2431 } else { 2432 oc = new FieldObjectCreator<Expression>(this, tuples) { 2433 @Override 2434 protected void loadValue(final Expression node, final Type type) { 2435 loadExpressionAsType(node, type); 2436 }}; 2437 } 2438 oc.makeObject(method); 2439 2440 //if this is a rest of method and our continuation point was found as one of the values 2441 //in the properties above, we need to reset the map to oc.getMap() in the continuation 2442 //handler 2443 if (restOfProperty) { 2444 final ContinuationInfo ci = getContinuationInfo(); 2445 // Can be set at most once for a single rest-of method 2446 assert ci.getObjectLiteralMap() == null; 2447 ci.setObjectLiteralMap(oc.getMap()); 2448 ci.setObjectLiteralStackDepth(method.getStackSize()); 2449 } 2450 2451 method.dup(); 2452 if (protoNode != null) { 2453 loadExpressionAsObject(protoNode); 2454 // take care of { __proto__: 34 } or some such! 2455 method.convert(Type.OBJECT); 2456 method.invoke(ScriptObject.SET_PROTO_FROM_LITERAL); 2457 } else { 2458 method.invoke(ScriptObject.SET_GLOBAL_OBJECT_PROTO); 2459 } 2460 2461 for (final PropertyNode propertyNode : gettersSetters) { 2462 final FunctionNode getter = propertyNode.getGetter(); 2463 final FunctionNode setter = propertyNode.getSetter(); 2464 2465 assert getter != null || setter != null; 2466 2467 method.dup().loadKey(propertyNode.getKey()); 2468 if (getter == null) { 2469 method.loadNull(); 2470 } else { 2471 getter.accept(this); 2472 } 2473 2474 if (setter == null) { 2475 method.loadNull(); 2476 } else { 2477 setter.accept(this); 2478 } 2479 2480 method.invoke(ScriptObject.SET_USER_ACCESSORS); 2481 } 2482 } 2483 2484 @Override 2485 public boolean enterReturnNode(final ReturnNode returnNode) { 2486 if(!method.isReachable()) { 2487 return false; 2488 } 2489 enterStatement(returnNode); 2490 2491 method.registerReturn(); 2492 2493 final Type returnType = lc.getCurrentFunction().getReturnType(); 2494 2495 final Expression expression = returnNode.getExpression(); 2496 if (expression != null) { 2497 loadExpressionUnbounded(expression); 2498 } else { 2499 method.loadUndefined(returnType); 2500 } 2501 2502 method._return(returnType); 2503 2504 return false; 2505 } 2506 2507 private boolean undefinedCheck(final RuntimeNode runtimeNode, final List<Expression> args) { 2508 final Request request = runtimeNode.getRequest(); 2509 2510 if (!Request.isUndefinedCheck(request)) { 2511 return false; 2512 } 2513 2514 final Expression lhs = args.get(0); 2515 final Expression rhs = args.get(1); 2516 2517 final Symbol lhsSymbol = lhs instanceof IdentNode ? ((IdentNode)lhs).getSymbol() : null; 2518 final Symbol rhsSymbol = rhs instanceof IdentNode ? ((IdentNode)rhs).getSymbol() : null; 2519 // One must be a "undefined" identifier, otherwise we can't get here 2520 assert lhsSymbol != null || rhsSymbol != null; 2521 2522 final Symbol undefinedSymbol; 2523 if (isUndefinedSymbol(lhsSymbol)) { 2524 undefinedSymbol = lhsSymbol; 2525 } else { 2526 assert isUndefinedSymbol(rhsSymbol); 2527 undefinedSymbol = rhsSymbol; 2528 } 2529 2530 assert undefinedSymbol != null; //remove warning 2531 if (!undefinedSymbol.isScope()) { 2532 return false; //disallow undefined as local var or parameter 2533 } 2534 2535 if (lhsSymbol == undefinedSymbol && lhs.getType().isPrimitive()) { 2536 //we load the undefined first. never mind, because this will deoptimize anyway 2537 return false; 2538 } 2539 2540 if(isDeoptimizedExpression(lhs)) { 2541 // This is actually related to "lhs.getType().isPrimitive()" above: any expression being deoptimized in 2542 // the current chain of rest-of compilations used to have a type narrower than Object (so it was primitive). 2543 // We must not perform undefined check specialization for them, as then we'd violate the basic rule of 2544 // "Thou shalt not alter the stack shape between a deoptimized method and any of its (transitive) rest-ofs." 2545 return false; 2546 } 2547 2548 //make sure that undefined has not been overridden or scoped as a local var 2549 //between us and global 2550 if (!compiler.isGlobalSymbol(lc.getCurrentFunction(), "undefined")) { 2551 return false; 2552 } 2553 2554 final boolean isUndefinedCheck = request == Request.IS_UNDEFINED; 2555 final Expression expr = undefinedSymbol == lhsSymbol ? rhs : lhs; 2556 if (expr.getType().isPrimitive()) { 2557 loadAndDiscard(expr); //throw away lhs, but it still needs to be evaluated for side effects, even if not in scope, as it can be optimistic 2558 method.load(!isUndefinedCheck); 2559 } else { 2560 final Label checkTrue = new Label("ud_check_true"); 2561 final Label end = new Label("end"); 2562 loadExpressionAsObject(expr); 2563 method.loadUndefined(Type.OBJECT); 2564 method.if_acmpeq(checkTrue); 2565 method.load(!isUndefinedCheck); 2566 method._goto(end); 2567 method.label(checkTrue); 2568 method.load(isUndefinedCheck); 2569 method.label(end); 2570 } 2571 2572 return true; 2573 } 2574 2575 private static boolean isUndefinedSymbol(final Symbol symbol) { 2576 return symbol != null && "undefined".equals(symbol.getName()); 2577 } 2578 2579 private static boolean isNullLiteral(final Node node) { 2580 return node instanceof LiteralNode<?> && ((LiteralNode<?>) node).isNull(); 2581 } 2582 2583 private boolean nullCheck(final RuntimeNode runtimeNode, final List<Expression> args) { 2584 final Request request = runtimeNode.getRequest(); 2585 2586 if (!Request.isEQ(request) && !Request.isNE(request)) { 2587 return false; 2588 } 2589 2590 assert args.size() == 2 : "EQ or NE or TYPEOF need two args"; 2591 2592 Expression lhs = args.get(0); 2593 Expression rhs = args.get(1); 2594 2595 if (isNullLiteral(lhs)) { 2596 final Expression tmp = lhs; 2597 lhs = rhs; 2598 rhs = tmp; 2599 } 2600 2601 if (!isNullLiteral(rhs)) { 2602 return false; 2603 } 2604 2605 if (!lhs.getType().isObject()) { 2606 return false; 2607 } 2608 2609 if(isDeoptimizedExpression(lhs)) { 2610 // This is actually related to "!lhs.getType().isObject()" above: any expression being deoptimized in 2611 // the current chain of rest-of compilations used to have a type narrower than Object. We must not 2612 // perform null check specialization for them, as then we'd no longer be loading aconst_null on stack 2613 // and thus violate the basic rule of "Thou shalt not alter the stack shape between a deoptimized 2614 // method and any of its (transitive) rest-ofs." 2615 // NOTE also that if we had a representation for well-known constants (e.g. null, 0, 1, -1, etc.) in 2616 // Label$Stack.localLoads then this wouldn't be an issue, as we would never (somewhat ridiculously) 2617 // allocate a temporary local to hold the result of aconst_null before attempting an optimistic 2618 // operation. 2619 return false; 2620 } 2621 2622 // this is a null literal check, so if there is implicit coercion 2623 // involved like {D}x=null, we will fail - this is very rare 2624 final Label trueLabel = new Label("trueLabel"); 2625 final Label falseLabel = new Label("falseLabel"); 2626 final Label endLabel = new Label("end"); 2627 2628 loadExpressionUnbounded(lhs); //lhs 2629 final Label popLabel; 2630 if (!Request.isStrict(request)) { 2631 method.dup(); //lhs lhs 2632 popLabel = new Label("pop"); 2633 } else { 2634 popLabel = null; 2635 } 2636 2637 if (Request.isEQ(request)) { 2638 method.ifnull(!Request.isStrict(request) ? popLabel : trueLabel); 2639 if (!Request.isStrict(request)) { 2640 method.loadUndefined(Type.OBJECT); 2641 method.if_acmpeq(trueLabel); 2642 } 2643 method.label(falseLabel); 2644 method.load(false); 2645 method._goto(endLabel); 2646 if (!Request.isStrict(request)) { 2647 method.label(popLabel); 2648 method.pop(); 2649 } 2650 method.label(trueLabel); 2651 method.load(true); 2652 method.label(endLabel); 2653 } else if (Request.isNE(request)) { 2654 method.ifnull(!Request.isStrict(request) ? popLabel : falseLabel); 2655 if (!Request.isStrict(request)) { 2656 method.loadUndefined(Type.OBJECT); 2657 method.if_acmpeq(falseLabel); 2658 } 2659 method.label(trueLabel); 2660 method.load(true); 2661 method._goto(endLabel); 2662 if (!Request.isStrict(request)) { 2663 method.label(popLabel); 2664 method.pop(); 2665 } 2666 method.label(falseLabel); 2667 method.load(false); 2668 method.label(endLabel); 2669 } 2670 2671 assert runtimeNode.getType().isBoolean(); 2672 method.convert(runtimeNode.getType()); 2673 2674 return true; 2675 } 2676 2677 /** 2678 * Was this expression or any of its subexpressions deoptimized in the current recompilation chain of rest-of methods? 2679 * @param rootExpr the expression being tested 2680 * @return true if the expression or any of its subexpressions was deoptimized in the current recompilation chain. 2681 */ 2682 private boolean isDeoptimizedExpression(final Expression rootExpr) { 2683 if(!isRestOf()) { 2684 return false; 2685 } 2686 return new Supplier<Boolean>() { 2687 boolean contains; 2688 @Override 2689 public Boolean get() { 2690 rootExpr.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 2691 @Override 2692 public boolean enterFunctionNode(final FunctionNode functionNode) { 2693 return false; 2694 } 2695 @Override 2696 public boolean enterDefault(final Node node) { 2697 if(!contains && node instanceof Optimistic) { 2698 final int pp = ((Optimistic)node).getProgramPoint(); 2699 contains = isValid(pp) && isContinuationEntryPoint(pp); 2700 } 2701 return !contains; 2702 } 2703 }); 2704 return contains; 2705 } 2706 }.get(); 2707 } 2708 2709 private void loadRuntimeNode(final RuntimeNode runtimeNode) { 2710 final List<Expression> args = new ArrayList<>(runtimeNode.getArgs()); 2711 if (nullCheck(runtimeNode, args)) { 2712 return; 2713 } else if(undefinedCheck(runtimeNode, args)) { 2714 return; 2715 } 2716 // Revert a false undefined check to a strict equality check 2717 final RuntimeNode newRuntimeNode; 2718 final Request request = runtimeNode.getRequest(); 2719 if (Request.isUndefinedCheck(request)) { 2720 newRuntimeNode = runtimeNode.setRequest(request == Request.IS_UNDEFINED ? Request.EQ_STRICT : Request.NE_STRICT); 2721 } else { 2722 newRuntimeNode = runtimeNode; 2723 } 2724 2725 new OptimisticOperation(newRuntimeNode, TypeBounds.UNBOUNDED) { 2726 @Override 2727 void loadStack() { 2728 for (final Expression arg : args) { 2729 loadExpression(arg, TypeBounds.OBJECT); 2730 } 2731 } 2732 @Override 2733 void consumeStack() { 2734 method.invokestatic( 2735 CompilerConstants.className(ScriptRuntime.class), 2736 newRuntimeNode.getRequest().toString(), 2737 new FunctionSignature( 2738 false, 2739 false, 2740 newRuntimeNode.getType(), 2741 args.size()).toString()); 2742 } 2743 }.emit(); 2744 2745 method.convert(newRuntimeNode.getType()); 2746 } 2747 2748 private void defineCommonSplitMethodParameters() { 2749 defineSplitMethodParameter(0, CALLEE); 2750 defineSplitMethodParameter(1, THIS); 2751 defineSplitMethodParameter(2, SCOPE); 2752 } 2753 2754 private void defineSplitMethodParameter(final int slot, final CompilerConstants cc) { 2755 defineSplitMethodParameter(slot, Type.typeFor(cc.type())); 2756 } 2757 2758 private void defineSplitMethodParameter(final int slot, final Type type) { 2759 method.defineBlockLocalVariable(slot, slot + type.getSlots()); 2760 method.onLocalStore(type, slot); 2761 } 2762 2763 private int fixScopeSlot(final FunctionNode functionNode, final int extraSlot) { 2764 // TODO hack to move the scope to the expected slot (needed because split methods reuse the same slots as the root method) 2765 final int actualScopeSlot = functionNode.compilerConstant(SCOPE).getSlot(SCOPE_TYPE); 2766 final int defaultScopeSlot = SCOPE.slot(); 2767 int newExtraSlot = extraSlot; 2768 if (actualScopeSlot != defaultScopeSlot) { 2769 if (actualScopeSlot == extraSlot) { 2770 newExtraSlot = extraSlot + 1; 2771 method.defineBlockLocalVariable(newExtraSlot, newExtraSlot + 1); 2772 method.load(Type.OBJECT, extraSlot); 2773 method.storeHidden(Type.OBJECT, newExtraSlot); 2774 } else { 2775 method.defineBlockLocalVariable(actualScopeSlot, actualScopeSlot + 1); 2776 } 2777 method.load(SCOPE_TYPE, defaultScopeSlot); 2778 method.storeCompilerConstant(SCOPE); 2779 } 2780 return newExtraSlot; 2781 } 2782 2783 @Override 2784 public boolean enterSplitReturn(final SplitReturn splitReturn) { 2785 if (method.isReachable()) { 2786 method.loadUndefined(lc.getCurrentFunction().getReturnType())._return(); 2787 } 2788 return false; 2789 } 2790 2791 @Override 2792 public boolean enterSetSplitState(final SetSplitState setSplitState) { 2793 if (method.isReachable()) { 2794 method.setSplitState(setSplitState.getState()); 2795 } 2796 return false; 2797 } 2798 2799 @Override 2800 public boolean enterSwitchNode(final SwitchNode switchNode) { 2801 if(!method.isReachable()) { 2802 return false; 2803 } 2804 enterStatement(switchNode); 2805 2806 final Expression expression = switchNode.getExpression(); 2807 final List<CaseNode> cases = switchNode.getCases(); 2808 2809 if (cases.isEmpty()) { 2810 // still evaluate expression for side-effects. 2811 loadAndDiscard(expression); 2812 return false; 2813 } 2814 2815 final CaseNode defaultCase = switchNode.getDefaultCase(); 2816 final Label breakLabel = switchNode.getBreakLabel(); 2817 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries(); 2818 2819 if (defaultCase != null && cases.size() == 1) { 2820 // default case only 2821 assert cases.get(0) == defaultCase; 2822 loadAndDiscard(expression); 2823 defaultCase.getBody().accept(this); 2824 method.breakLabel(breakLabel, liveLocalsOnBreak); 2825 return false; 2826 } 2827 2828 // NOTE: it can still change in the tableswitch/lookupswitch case if there's no default case 2829 // but we need to add a synthetic default case for local variable conversions 2830 Label defaultLabel = defaultCase != null ? defaultCase.getEntry() : breakLabel; 2831 final boolean hasSkipConversion = LocalVariableConversion.hasLiveConversion(switchNode); 2832 2833 if (switchNode.isUniqueInteger()) { 2834 // Tree for sorting values. 2835 final TreeMap<Integer, Label> tree = new TreeMap<>(); 2836 2837 // Build up sorted tree. 2838 for (final CaseNode caseNode : cases) { 2839 final Node test = caseNode.getTest(); 2840 2841 if (test != null) { 2842 final Integer value = (Integer)((LiteralNode<?>)test).getValue(); 2843 final Label entry = caseNode.getEntry(); 2844 2845 // Take first duplicate. 2846 if (!tree.containsKey(value)) { 2847 tree.put(value, entry); 2848 } 2849 } 2850 } 2851 2852 // Copy values and labels to arrays. 2853 final int size = tree.size(); 2854 final Integer[] values = tree.keySet().toArray(new Integer[size]); 2855 final Label[] labels = tree.values().toArray(new Label[size]); 2856 2857 // Discern low, high and range. 2858 final int lo = values[0]; 2859 final int hi = values[size - 1]; 2860 final long range = (long)hi - (long)lo + 1; 2861 2862 // Find an unused value for default. 2863 int deflt = Integer.MIN_VALUE; 2864 for (final int value : values) { 2865 if (deflt == value) { 2866 deflt++; 2867 } else if (deflt < value) { 2868 break; 2869 } 2870 } 2871 2872 // Load switch expression. 2873 loadExpressionUnbounded(expression); 2874 final Type type = expression.getType(); 2875 2876 // If expression not int see if we can convert, if not use deflt to trigger default. 2877 if (!type.isInteger()) { 2878 method.load(deflt); 2879 final Class<?> exprClass = type.getTypeClass(); 2880 method.invoke(staticCallNoLookup(ScriptRuntime.class, "switchTagAsInt", int.class, exprClass.isPrimitive()? exprClass : Object.class, int.class)); 2881 } 2882 2883 if(hasSkipConversion) { 2884 assert defaultLabel == breakLabel; 2885 defaultLabel = new Label("switch_skip"); 2886 } 2887 // TABLESWITCH needs (range + 3) 32-bit values; LOOKUPSWITCH needs ((size * 2) + 2). Choose the one with 2888 // smaller representation, favor TABLESWITCH when they're equal size. 2889 if (range + 1 <= (size * 2) && range <= Integer.MAX_VALUE) { 2890 final Label[] table = new Label[(int)range]; 2891 Arrays.fill(table, defaultLabel); 2892 for (int i = 0; i < size; i++) { 2893 final int value = values[i]; 2894 table[value - lo] = labels[i]; 2895 } 2896 2897 method.tableswitch(lo, hi, defaultLabel, table); 2898 } else { 2899 final int[] ints = new int[size]; 2900 for (int i = 0; i < size; i++) { 2901 ints[i] = values[i]; 2902 } 2903 2904 method.lookupswitch(defaultLabel, ints, labels); 2905 } 2906 // This is a synthetic "default case" used in absence of actual default case, created if we need to apply 2907 // local variable conversions if neither case is taken. 2908 if(hasSkipConversion) { 2909 method.label(defaultLabel); 2910 method.beforeJoinPoint(switchNode); 2911 method._goto(breakLabel); 2912 } 2913 } else { 2914 final Symbol tagSymbol = switchNode.getTag(); 2915 // TODO: we could have non-object tag 2916 final int tagSlot = tagSymbol.getSlot(Type.OBJECT); 2917 loadExpressionAsObject(expression); 2918 method.store(tagSymbol, Type.OBJECT); 2919 2920 for (final CaseNode caseNode : cases) { 2921 final Expression test = caseNode.getTest(); 2922 2923 if (test != null) { 2924 method.load(Type.OBJECT, tagSlot); 2925 loadExpressionAsObject(test); 2926 method.invoke(ScriptRuntime.EQ_STRICT); 2927 method.ifne(caseNode.getEntry()); 2928 } 2929 } 2930 2931 if (defaultCase != null) { 2932 method._goto(defaultLabel); 2933 } else { 2934 method.beforeJoinPoint(switchNode); 2935 method._goto(breakLabel); 2936 } 2937 } 2938 2939 // First case is only reachable through jump 2940 assert !method.isReachable(); 2941 2942 for (final CaseNode caseNode : cases) { 2943 final Label fallThroughLabel; 2944 if(caseNode.getLocalVariableConversion() != null && method.isReachable()) { 2945 fallThroughLabel = new Label("fallthrough"); 2946 method._goto(fallThroughLabel); 2947 } else { 2948 fallThroughLabel = null; 2949 } 2950 method.label(caseNode.getEntry()); 2951 method.beforeJoinPoint(caseNode); 2952 if(fallThroughLabel != null) { 2953 method.label(fallThroughLabel); 2954 } 2955 caseNode.getBody().accept(this); 2956 } 2957 2958 method.breakLabel(breakLabel, liveLocalsOnBreak); 2959 2960 return false; 2961 } 2962 2963 @Override 2964 public boolean enterThrowNode(final ThrowNode throwNode) { 2965 if(!method.isReachable()) { 2966 return false; 2967 } 2968 enterStatement(throwNode); 2969 2970 if (throwNode.isSyntheticRethrow()) { 2971 method.beforeJoinPoint(throwNode); 2972 2973 //do not wrap whatever this is in an ecma exception, just rethrow it 2974 final IdentNode exceptionExpr = (IdentNode)throwNode.getExpression(); 2975 final Symbol exceptionSymbol = exceptionExpr.getSymbol(); 2976 method.load(exceptionSymbol, EXCEPTION_TYPE); 2977 method.checkcast(EXCEPTION_TYPE.getTypeClass()); 2978 method.athrow(); 2979 return false; 2980 } 2981 2982 final Source source = getCurrentSource(); 2983 final Expression expression = throwNode.getExpression(); 2984 final int position = throwNode.position(); 2985 final int line = throwNode.getLineNumber(); 2986 final int column = source.getColumn(position); 2987 2988 // NOTE: we first evaluate the expression, and only after it was evaluated do we create the new ECMAException 2989 // object and then somewhat cumbersomely move it beneath the evaluated expression on the stack. The reason for 2990 // this is that if expression is optimistic (or contains an optimistic subexpression), we'd potentially access 2991 // the not-yet-<init>ialized object on the stack from the UnwarrantedOptimismException handler, and bytecode 2992 // verifier forbids that. 2993 loadExpressionAsObject(expression); 2994 2995 method.load(source.getName()); 2996 method.load(line); 2997 method.load(column); 2998 method.invoke(ECMAException.CREATE); 2999 3000 method.beforeJoinPoint(throwNode); 3001 method.athrow(); 3002 3003 return false; 3004 } 3005 3006 private Source getCurrentSource() { 3007 return lc.getCurrentFunction().getSource(); 3008 } 3009 3010 @Override 3011 public boolean enterTryNode(final TryNode tryNode) { 3012 if(!method.isReachable()) { 3013 return false; 3014 } 3015 enterStatement(tryNode); 3016 3017 final Block body = tryNode.getBody(); 3018 final List<Block> catchBlocks = tryNode.getCatchBlocks(); 3019 final Symbol vmException = tryNode.getException(); 3020 final Label entry = new Label("try"); 3021 final Label recovery = new Label("catch"); 3022 final Label exit = new Label("end_try"); 3023 final Label skip = new Label("skip"); 3024 3025 method.canThrow(recovery); 3026 // Effect any conversions that might be observed at the entry of the catch node before entering the try node. 3027 // This is because even the first instruction in the try block must be presumed to be able to transfer control 3028 // to the catch block. Note that this doesn't kill the original values; in this regard it works a lot like 3029 // conversions of assignments within the try block. 3030 method.beforeTry(tryNode, recovery); 3031 method.label(entry); 3032 catchLabels.push(recovery); 3033 try { 3034 body.accept(this); 3035 } finally { 3036 assert catchLabels.peek() == recovery; 3037 catchLabels.pop(); 3038 } 3039 3040 method.label(exit); 3041 final boolean bodyCanThrow = exit.isAfter(entry); 3042 if(!bodyCanThrow) { 3043 // The body can't throw an exception; don't even bother emitting the catch handlers, they're all dead code. 3044 return false; 3045 } 3046 3047 method._try(entry, exit, recovery, Throwable.class); 3048 3049 if (method.isReachable()) { 3050 method._goto(skip); 3051 } 3052 method._catch(recovery); 3053 method.store(vmException, EXCEPTION_TYPE); 3054 3055 final int catchBlockCount = catchBlocks.size(); 3056 final Label afterCatch = new Label("after_catch"); 3057 for (int i = 0; i < catchBlockCount; i++) { 3058 assert method.isReachable(); 3059 final Block catchBlock = catchBlocks.get(i); 3060 3061 // Because of the peculiarities of the flow control, we need to use an explicit push/enterBlock/leaveBlock 3062 // here. 3063 lc.push(catchBlock); 3064 enterBlock(catchBlock); 3065 3066 final CatchNode catchNode = (CatchNode)catchBlocks.get(i).getStatements().get(0); 3067 final IdentNode exception = catchNode.getException(); 3068 final Expression exceptionCondition = catchNode.getExceptionCondition(); 3069 final Block catchBody = catchNode.getBody(); 3070 3071 new Store<IdentNode>(exception) { 3072 @Override 3073 protected void storeNonDiscard() { 3074 // This expression is neither part of a discard, nor needs to be left on the stack after it was 3075 // stored, so we override storeNonDiscard to be a no-op. 3076 } 3077 3078 @Override 3079 protected void evaluate() { 3080 if (catchNode.isSyntheticRethrow()) { 3081 method.load(vmException, EXCEPTION_TYPE); 3082 return; 3083 } 3084 /* 3085 * If caught object is an instance of ECMAException, then 3086 * bind obj.thrown to the script catch var. Or else bind the 3087 * caught object itself to the script catch var. 3088 */ 3089 final Label notEcmaException = new Label("no_ecma_exception"); 3090 method.load(vmException, EXCEPTION_TYPE).dup()._instanceof(ECMAException.class).ifeq(notEcmaException); 3091 method.checkcast(ECMAException.class); //TODO is this necessary? 3092 method.getField(ECMAException.THROWN); 3093 method.label(notEcmaException); 3094 } 3095 }.store(); 3096 3097 final boolean isConditionalCatch = exceptionCondition != null; 3098 final Label nextCatch; 3099 if (isConditionalCatch) { 3100 loadExpressionAsBoolean(exceptionCondition); 3101 nextCatch = new Label("next_catch"); 3102 nextCatch.markAsBreakTarget(); 3103 method.ifeq(nextCatch); 3104 } else { 3105 nextCatch = null; 3106 } 3107 3108 catchBody.accept(this); 3109 leaveBlock(catchBlock); 3110 lc.pop(catchBlock); 3111 if(method.isReachable()) { 3112 method._goto(afterCatch); 3113 } 3114 if(nextCatch != null) { 3115 method.breakLabel(nextCatch, lc.getUsedSlotCount()); 3116 } 3117 } 3118 3119 assert !method.isReachable(); 3120 // afterCatch could be the same as skip, except that we need to establish that the vmException is dead. 3121 method.label(afterCatch); 3122 if(method.isReachable()) { 3123 method.markDeadLocalVariable(vmException); 3124 } 3125 method.label(skip); 3126 3127 // Finally body is always inlined elsewhere so it doesn't need to be emitted 3128 return false; 3129 } 3130 3131 @Override 3132 public boolean enterVarNode(final VarNode varNode) { 3133 if(!method.isReachable()) { 3134 return false; 3135 } 3136 final Expression init = varNode.getInit(); 3137 final IdentNode identNode = varNode.getName(); 3138 final Symbol identSymbol = identNode.getSymbol(); 3139 assert identSymbol != null : "variable node " + varNode + " requires a name with a symbol"; 3140 final boolean needsScope = identSymbol.isScope(); 3141 3142 if (init == null) { 3143 if (needsScope && varNode.isBlockScoped()) { 3144 // block scoped variables need a DECLARE flag to signal end of temporal dead zone (TDZ) 3145 method.loadCompilerConstant(SCOPE); 3146 method.loadUndefined(Type.OBJECT); 3147 final int flags = CALLSITE_SCOPE | getCallSiteFlags() | (varNode.isBlockScoped() ? CALLSITE_DECLARE : 0); 3148 assert isFastScope(identSymbol); 3149 storeFastScopeVar(identSymbol, flags); 3150 } 3151 return false; 3152 } 3153 3154 enterStatement(varNode); 3155 assert method != null; 3156 3157 if (needsScope) { 3158 method.loadCompilerConstant(SCOPE); 3159 } 3160 3161 if (needsScope) { 3162 loadExpressionUnbounded(init); 3163 // block scoped variables need a DECLARE flag to signal end of temporal dead zone (TDZ) 3164 final int flags = CALLSITE_SCOPE | getCallSiteFlags() | (varNode.isBlockScoped() ? CALLSITE_DECLARE : 0); 3165 if (isFastScope(identSymbol)) { 3166 storeFastScopeVar(identSymbol, flags); 3167 } else { 3168 method.dynamicSet(identNode.getName(), flags); 3169 } 3170 } else { 3171 final Type identType = identNode.getType(); 3172 if(identType == Type.UNDEFINED) { 3173 // The initializer is either itself undefined (explicit assignment of undefined to undefined), 3174 // or the left hand side is a dead variable. 3175 assert init.getType() == Type.UNDEFINED || identNode.getSymbol().slotCount() == 0; 3176 loadAndDiscard(init); 3177 return false; 3178 } 3179 loadExpressionAsType(init, identType); 3180 storeIdentWithCatchConversion(identNode, identType); 3181 } 3182 3183 return false; 3184 } 3185 3186 private void storeIdentWithCatchConversion(final IdentNode identNode, final Type type) { 3187 // Assignments happening in try/catch blocks need to ensure that they also store a possibly wider typed value 3188 // that will be live at the exit from the try block 3189 final LocalVariableConversion conversion = identNode.getLocalVariableConversion(); 3190 final Symbol symbol = identNode.getSymbol(); 3191 if(conversion != null && conversion.isLive()) { 3192 assert symbol == conversion.getSymbol(); 3193 assert symbol.isBytecodeLocal(); 3194 // Only a single conversion from the target type to the join type is expected. 3195 assert conversion.getNext() == null; 3196 assert conversion.getFrom() == type; 3197 // We must propagate potential type change to the catch block 3198 final Label catchLabel = catchLabels.peek(); 3199 assert catchLabel != METHOD_BOUNDARY; // ident conversion only exists in try blocks 3200 assert catchLabel.isReachable(); 3201 final Type joinType = conversion.getTo(); 3202 final Label.Stack catchStack = catchLabel.getStack(); 3203 final int joinSlot = symbol.getSlot(joinType); 3204 // With nested try/catch blocks (incl. synthetic ones for finally), we can have a supposed conversion for 3205 // the exception symbol in the nested catch, but it isn't live in the outer catch block, so prevent doing 3206 // conversions for it. E.g. in "try { try { ... } catch(e) { e = 1; } } catch(e2) { ... }", we must not 3207 // introduce an I->O conversion on "e = 1" assignment as "e" is not live in "catch(e2)". 3208 if(catchStack.getUsedSlotsWithLiveTemporaries() > joinSlot) { 3209 method.dup(); 3210 method.convert(joinType); 3211 method.store(symbol, joinType); 3212 catchLabel.getStack().onLocalStore(joinType, joinSlot, true); 3213 method.canThrow(catchLabel); 3214 // Store but keep the previous store live too. 3215 method.store(symbol, type, false); 3216 return; 3217 } 3218 } 3219 3220 method.store(symbol, type, true); 3221 } 3222 3223 @Override 3224 public boolean enterWhileNode(final WhileNode whileNode) { 3225 if(!method.isReachable()) { 3226 return false; 3227 } 3228 if(whileNode.isDoWhile()) { 3229 enterDoWhile(whileNode); 3230 } else { 3231 enterStatement(whileNode); 3232 enterForOrWhile(whileNode, null); 3233 } 3234 return false; 3235 } 3236 3237 private void enterForOrWhile(final LoopNode loopNode, final JoinPredecessorExpression modify) { 3238 // NOTE: the usual pattern for compiling test-first loops is "GOTO test; body; test; IFNE body". We use the less 3239 // conventional "test; IFEQ break; body; GOTO test; break;". It has one extra unconditional GOTO in each repeat 3240 // of the loop, but it's not a problem for modern JIT compilers. We do this because our local variable type 3241 // tracking is unfortunately not really prepared for out-of-order execution, e.g. compiling the following 3242 // contrived but legal JavaScript code snippet would fail because the test changes the type of "i" from object 3243 // to double: var i = {valueOf: function() { return 1} }; while(--i >= 0) { ... } 3244 // Instead of adding more complexity to the local variable type tracking, we instead choose to emit this 3245 // different code shape. 3246 final int liveLocalsOnBreak = method.getUsedSlotsWithLiveTemporaries(); 3247 final JoinPredecessorExpression test = loopNode.getTest(); 3248 if(Expression.isAlwaysFalse(test)) { 3249 loadAndDiscard(test); 3250 return; 3251 } 3252 3253 method.beforeJoinPoint(loopNode); 3254 3255 final Label continueLabel = loopNode.getContinueLabel(); 3256 final Label repeatLabel = modify != null ? new Label("for_repeat") : continueLabel; 3257 method.label(repeatLabel); 3258 final int liveLocalsOnContinue = method.getUsedSlotsWithLiveTemporaries(); 3259 3260 final Block body = loopNode.getBody(); 3261 final Label breakLabel = loopNode.getBreakLabel(); 3262 final boolean testHasLiveConversion = test != null && LocalVariableConversion.hasLiveConversion(test); 3263 3264 if(Expression.isAlwaysTrue(test)) { 3265 if(test != null) { 3266 loadAndDiscard(test); 3267 if(testHasLiveConversion) { 3268 method.beforeJoinPoint(test); 3269 } 3270 } 3271 } else if (test != null) { 3272 if (testHasLiveConversion) { 3273 emitBranch(test.getExpression(), body.getEntryLabel(), true); 3274 method.beforeJoinPoint(test); 3275 method._goto(breakLabel); 3276 } else { 3277 emitBranch(test.getExpression(), breakLabel, false); 3278 } 3279 } 3280 3281 body.accept(this); 3282 if(repeatLabel != continueLabel) { 3283 emitContinueLabel(continueLabel, liveLocalsOnContinue); 3284 } 3285 3286 if (loopNode.hasPerIterationScope() && lc.getParentBlock().needsScope()) { 3287 // ES6 for loops with LET init need a new scope for each iteration. We just create a shallow copy here. 3288 method.loadCompilerConstant(SCOPE); 3289 method.invoke(virtualCallNoLookup(ScriptObject.class, "copy", ScriptObject.class)); 3290 method.storeCompilerConstant(SCOPE); 3291 } 3292 3293 if(method.isReachable()) { 3294 if(modify != null) { 3295 lineNumber(loopNode); 3296 loadAndDiscard(modify); 3297 method.beforeJoinPoint(modify); 3298 } 3299 method._goto(repeatLabel); 3300 } 3301 3302 method.breakLabel(breakLabel, liveLocalsOnBreak); 3303 } 3304 3305 private void emitContinueLabel(final Label continueLabel, final int liveLocals) { 3306 final boolean reachable = method.isReachable(); 3307 method.breakLabel(continueLabel, liveLocals); 3308 // If we reach here only through a continue statement (e.g. body does not exit normally) then the 3309 // continueLabel can have extra non-temp symbols (e.g. exception from a try/catch contained in the body). We 3310 // must make sure those are thrown away. 3311 if(!reachable) { 3312 method.undefineLocalVariables(lc.getUsedSlotCount(), false); 3313 } 3314 } 3315 3316 private void enterDoWhile(final WhileNode whileNode) { 3317 final int liveLocalsOnContinueOrBreak = method.getUsedSlotsWithLiveTemporaries(); 3318 method.beforeJoinPoint(whileNode); 3319 3320 final Block body = whileNode.getBody(); 3321 body.accept(this); 3322 3323 emitContinueLabel(whileNode.getContinueLabel(), liveLocalsOnContinueOrBreak); 3324 if(method.isReachable()) { 3325 lineNumber(whileNode); 3326 final JoinPredecessorExpression test = whileNode.getTest(); 3327 final Label bodyEntryLabel = body.getEntryLabel(); 3328 final boolean testHasLiveConversion = LocalVariableConversion.hasLiveConversion(test); 3329 if(Expression.isAlwaysFalse(test)) { 3330 loadAndDiscard(test); 3331 if(testHasLiveConversion) { 3332 method.beforeJoinPoint(test); 3333 } 3334 } else if(testHasLiveConversion) { 3335 // If we have conversions after the test in do-while, they need to be effected on both branches. 3336 final Label beforeExit = new Label("do_while_preexit"); 3337 emitBranch(test.getExpression(), beforeExit, false); 3338 method.beforeJoinPoint(test); 3339 method._goto(bodyEntryLabel); 3340 method.label(beforeExit); 3341 method.beforeJoinPoint(test); 3342 } else { 3343 emitBranch(test.getExpression(), bodyEntryLabel, true); 3344 } 3345 } 3346 method.breakLabel(whileNode.getBreakLabel(), liveLocalsOnContinueOrBreak); 3347 } 3348 3349 3350 @Override 3351 public boolean enterWithNode(final WithNode withNode) { 3352 if(!method.isReachable()) { 3353 return false; 3354 } 3355 enterStatement(withNode); 3356 final Expression expression = withNode.getExpression(); 3357 final Block body = withNode.getBody(); 3358 3359 // It is possible to have a "pathological" case where the with block does not reference *any* identifiers. It's 3360 // pointless, but legal. In that case, if nothing else in the method forced the assignment of a slot to the 3361 // scope object, its' possible that it won't have a slot assigned. In this case we'll only evaluate expression 3362 // for its side effect and visit the body, and not bother opening and closing a WithObject. 3363 final boolean hasScope = method.hasScope(); 3364 3365 if (hasScope) { 3366 method.loadCompilerConstant(SCOPE); 3367 } 3368 3369 loadExpressionAsObject(expression); 3370 3371 final Label tryLabel; 3372 if (hasScope) { 3373 // Construct a WithObject if we have a scope 3374 method.invoke(ScriptRuntime.OPEN_WITH); 3375 method.storeCompilerConstant(SCOPE); 3376 tryLabel = new Label("with_try"); 3377 method.label(tryLabel); 3378 } else { 3379 // We just loaded the expression for its side effect and to check 3380 // for null or undefined value. 3381 globalCheckObjectCoercible(); 3382 tryLabel = null; 3383 } 3384 3385 // Always process body 3386 body.accept(this); 3387 3388 if (hasScope) { 3389 // Ensure we always close the WithObject 3390 final Label endLabel = new Label("with_end"); 3391 final Label catchLabel = new Label("with_catch"); 3392 final Label exitLabel = new Label("with_exit"); 3393 3394 method.label(endLabel); 3395 // Somewhat conservatively presume that if the body is not empty, it can throw an exception. In any case, 3396 // we must prevent trying to emit a try-catch for empty range, as it causes a verification error. 3397 final boolean bodyCanThrow = endLabel.isAfter(tryLabel); 3398 if(bodyCanThrow) { 3399 method._try(tryLabel, endLabel, catchLabel); 3400 } 3401 3402 final boolean reachable = method.isReachable(); 3403 if(reachable) { 3404 popScope(); 3405 if(bodyCanThrow) { 3406 method._goto(exitLabel); 3407 } 3408 } 3409 3410 if(bodyCanThrow) { 3411 method._catch(catchLabel); 3412 popScopeException(); 3413 method.athrow(); 3414 if(reachable) { 3415 method.label(exitLabel); 3416 } 3417 } 3418 } 3419 return false; 3420 } 3421 3422 private void loadADD(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3423 loadExpression(unaryNode.getExpression(), resultBounds.booleanToInt().notWiderThan(Type.NUMBER)); 3424 if(method.peekType() == Type.BOOLEAN) { 3425 // It's a no-op in bytecode, but we must make sure it is treated as an int for purposes of type signatures 3426 method.convert(Type.INT); 3427 } 3428 } 3429 3430 private void loadBIT_NOT(final UnaryNode unaryNode) { 3431 loadExpression(unaryNode.getExpression(), TypeBounds.INT).load(-1).xor(); 3432 } 3433 3434 private void loadDECINC(final UnaryNode unaryNode) { 3435 final Expression operand = unaryNode.getExpression(); 3436 final Type type = unaryNode.getType(); 3437 final TypeBounds typeBounds = new TypeBounds(type, Type.NUMBER); 3438 final TokenType tokenType = unaryNode.tokenType(); 3439 final boolean isPostfix = tokenType == TokenType.DECPOSTFIX || tokenType == TokenType.INCPOSTFIX; 3440 final boolean isIncrement = tokenType == TokenType.INCPREFIX || tokenType == TokenType.INCPOSTFIX; 3441 3442 assert !type.isObject(); 3443 3444 new SelfModifyingStore<UnaryNode>(unaryNode, operand) { 3445 3446 private void loadRhs() { 3447 loadExpression(operand, typeBounds, true); 3448 } 3449 3450 @Override 3451 protected void evaluate() { 3452 if(isPostfix) { 3453 loadRhs(); 3454 } else { 3455 new OptimisticOperation(unaryNode, typeBounds) { 3456 @Override 3457 void loadStack() { 3458 loadRhs(); 3459 loadMinusOne(); 3460 } 3461 @Override 3462 void consumeStack() { 3463 doDecInc(getProgramPoint()); 3464 } 3465 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(operand)); 3466 } 3467 } 3468 3469 @Override 3470 protected void storeNonDiscard() { 3471 super.storeNonDiscard(); 3472 if (isPostfix) { 3473 new OptimisticOperation(unaryNode, typeBounds) { 3474 @Override 3475 void loadStack() { 3476 loadMinusOne(); 3477 } 3478 @Override 3479 void consumeStack() { 3480 doDecInc(getProgramPoint()); 3481 } 3482 }.emit(1); // 1 for non-incremented result on the top of the stack pushed in evaluate() 3483 } 3484 } 3485 3486 private void loadMinusOne() { 3487 if (type.isInteger()) { 3488 method.load(isIncrement ? 1 : -1); 3489 } else if (type.isLong()) { 3490 method.load(isIncrement ? 1L : -1L); 3491 } else { 3492 method.load(isIncrement ? 1.0 : -1.0); 3493 } 3494 } 3495 3496 private void doDecInc(final int programPoint) { 3497 method.add(programPoint); 3498 } 3499 }.store(); 3500 } 3501 3502 private static int getOptimisticIgnoreCountForSelfModifyingExpression(final Expression target) { 3503 return target instanceof AccessNode ? 1 : target instanceof IndexNode ? 2 : 0; 3504 } 3505 3506 private void loadAndDiscard(final Expression expr) { 3507 // TODO: move checks for discarding to actual expression load code (e.g. as we do with void). That way we might 3508 // be able to eliminate even more checks. 3509 if(expr instanceof PrimitiveLiteralNode | isLocalVariable(expr)) { 3510 assert lc.getCurrentDiscard() != expr; 3511 // Don't bother evaluating expressions without side effects. Typical usage is "void 0" for reliably generating 3512 // undefined. 3513 return; 3514 } 3515 3516 lc.pushDiscard(expr); 3517 loadExpression(expr, TypeBounds.UNBOUNDED); 3518 if (lc.getCurrentDiscard() == expr) { 3519 assert !expr.isAssignment(); 3520 // NOTE: if we had a way to load with type void, we could avoid popping 3521 method.pop(); 3522 lc.popDiscard(); 3523 } 3524 } 3525 3526 private void loadNEW(final UnaryNode unaryNode) { 3527 final CallNode callNode = (CallNode)unaryNode.getExpression(); 3528 final List<Expression> args = callNode.getArgs(); 3529 3530 // Load function reference. 3531 loadExpressionAsObject(callNode.getFunction()); // must detect type error 3532 3533 method.dynamicNew(1 + loadArgs(args), getCallSiteFlags()); 3534 } 3535 3536 private void loadNOT(final UnaryNode unaryNode) { 3537 final Expression expr = unaryNode.getExpression(); 3538 if(expr instanceof UnaryNode && expr.isTokenType(TokenType.NOT)) { 3539 // !!x is idiomatic boolean cast in JavaScript 3540 loadExpressionAsBoolean(((UnaryNode)expr).getExpression()); 3541 } else { 3542 final Label trueLabel = new Label("true"); 3543 final Label afterLabel = new Label("after"); 3544 3545 emitBranch(expr, trueLabel, true); 3546 method.load(true); 3547 method._goto(afterLabel); 3548 method.label(trueLabel); 3549 method.load(false); 3550 method.label(afterLabel); 3551 } 3552 } 3553 3554 private void loadSUB(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3555 final Type type = unaryNode.getType(); 3556 assert type.isNumeric(); 3557 final TypeBounds numericBounds = resultBounds.booleanToInt(); 3558 new OptimisticOperation(unaryNode, numericBounds) { 3559 @Override 3560 void loadStack() { 3561 final Expression expr = unaryNode.getExpression(); 3562 loadExpression(expr, numericBounds.notWiderThan(Type.NUMBER)); 3563 } 3564 @Override 3565 void consumeStack() { 3566 // Must do an explicit conversion to the operation's type when it's double so that we correctly handle 3567 // negation of an int 0 to a double -0. With this, we get the correct negation of a local variable after 3568 // it deoptimized, e.g. "iload_2; i2d; dneg". Without this, we get "iload_2; ineg; i2d". 3569 if(type.isNumber()) { 3570 method.convert(type); 3571 } 3572 method.neg(getProgramPoint()); 3573 } 3574 }.emit(); 3575 } 3576 3577 public void loadVOID(final UnaryNode unaryNode, final TypeBounds resultBounds) { 3578 loadAndDiscard(unaryNode.getExpression()); 3579 if(lc.getCurrentDiscard() == unaryNode) { 3580 lc.popDiscard(); 3581 } else { 3582 method.loadUndefined(resultBounds.widest); 3583 } 3584 } 3585 3586 public void loadADD(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3587 new OptimisticOperation(binaryNode, resultBounds) { 3588 @Override 3589 void loadStack() { 3590 final TypeBounds operandBounds; 3591 final boolean isOptimistic = isValid(getProgramPoint()); 3592 boolean forceConversionSeparation = false; 3593 if(isOptimistic) { 3594 operandBounds = new TypeBounds(binaryNode.getType(), Type.OBJECT); 3595 } else { 3596 // Non-optimistic, non-FP +. Allow it to overflow. 3597 final Type widestOperationType = binaryNode.getWidestOperationType(); 3598 operandBounds = new TypeBounds(Type.narrowest(binaryNode.getWidestOperandType(), resultBounds.widest), widestOperationType); 3599 forceConversionSeparation = widestOperationType.narrowerThan(resultBounds.widest); 3600 } 3601 loadBinaryOperands(binaryNode.lhs(), binaryNode.rhs(), operandBounds, false, forceConversionSeparation); 3602 } 3603 3604 @Override 3605 void consumeStack() { 3606 method.add(getProgramPoint()); 3607 } 3608 }.emit(); 3609 } 3610 3611 private void loadAND_OR(final BinaryNode binaryNode, final TypeBounds resultBounds, final boolean isAnd) { 3612 final Type narrowestOperandType = Type.widestReturnType(binaryNode.lhs().getType(), binaryNode.rhs().getType()); 3613 3614 final Label skip = new Label("skip"); 3615 if(narrowestOperandType == Type.BOOLEAN) { 3616 // optimize all-boolean logical expressions 3617 final Label onTrue = new Label("andor_true"); 3618 emitBranch(binaryNode, onTrue, true); 3619 method.load(false); 3620 method._goto(skip); 3621 method.label(onTrue); 3622 method.load(true); 3623 method.label(skip); 3624 return; 3625 } 3626 3627 final TypeBounds outBounds = resultBounds.notNarrowerThan(narrowestOperandType); 3628 final JoinPredecessorExpression lhs = (JoinPredecessorExpression)binaryNode.lhs(); 3629 final boolean lhsConvert = LocalVariableConversion.hasLiveConversion(lhs); 3630 final Label evalRhs = lhsConvert ? new Label("eval_rhs") : null; 3631 3632 loadExpression(lhs, outBounds).dup().convert(Type.BOOLEAN); 3633 if (isAnd) { 3634 if(lhsConvert) { 3635 method.ifne(evalRhs); 3636 } else { 3637 method.ifeq(skip); 3638 } 3639 } else if(lhsConvert) { 3640 method.ifeq(evalRhs); 3641 } else { 3642 method.ifne(skip); 3643 } 3644 3645 if(lhsConvert) { 3646 method.beforeJoinPoint(lhs); 3647 method._goto(skip); 3648 method.label(evalRhs); 3649 } 3650 3651 method.pop(); 3652 final JoinPredecessorExpression rhs = (JoinPredecessorExpression)binaryNode.rhs(); 3653 loadExpression(rhs, outBounds); 3654 method.beforeJoinPoint(rhs); 3655 method.label(skip); 3656 } 3657 3658 private static boolean isLocalVariable(final Expression lhs) { 3659 return lhs instanceof IdentNode && isLocalVariable((IdentNode)lhs); 3660 } 3661 3662 private static boolean isLocalVariable(final IdentNode lhs) { 3663 return lhs.getSymbol().isBytecodeLocal(); 3664 } 3665 3666 // NOTE: does not use resultBounds as the assignment is driven by the type of the RHS 3667 private void loadASSIGN(final BinaryNode binaryNode) { 3668 final Expression lhs = binaryNode.lhs(); 3669 final Expression rhs = binaryNode.rhs(); 3670 3671 final Type rhsType = rhs.getType(); 3672 // Detect dead assignments 3673 if(lhs instanceof IdentNode) { 3674 final Symbol symbol = ((IdentNode)lhs).getSymbol(); 3675 if(!symbol.isScope() && !symbol.hasSlotFor(rhsType) && lc.getCurrentDiscard() == binaryNode) { 3676 loadAndDiscard(rhs); 3677 lc.popDiscard(); 3678 method.markDeadLocalVariable(symbol); 3679 return; 3680 } 3681 } 3682 3683 new Store<BinaryNode>(binaryNode, lhs) { 3684 @Override 3685 protected void evaluate() { 3686 // NOTE: we're loading with "at least as wide as" so optimistic operations on the right hand side 3687 // remain optimistic, and then explicitly convert to the required type if needed. 3688 loadExpressionAsType(rhs, rhsType); 3689 } 3690 }.store(); 3691 } 3692 3693 /** 3694 * Binary self-assignment that can be optimistic: +=, -=, *=, and /=. 3695 */ 3696 private abstract class BinaryOptimisticSelfAssignment extends SelfModifyingStore<BinaryNode> { 3697 3698 /** 3699 * Constructor 3700 * 3701 * @param node the assign op node 3702 */ 3703 BinaryOptimisticSelfAssignment(final BinaryNode node) { 3704 super(node, node.lhs()); 3705 } 3706 3707 protected abstract void op(OptimisticOperation oo); 3708 3709 @Override 3710 protected void evaluate() { 3711 final Expression lhs = assignNode.lhs(); 3712 final Expression rhs = assignNode.rhs(); 3713 final Type widestOperationType = assignNode.getWidestOperationType(); 3714 final TypeBounds bounds = new TypeBounds(assignNode.getType(), widestOperationType); 3715 new OptimisticOperation(assignNode, bounds) { 3716 @Override 3717 void loadStack() { 3718 final boolean forceConversionSeparation; 3719 if (isValid(getProgramPoint()) || widestOperationType == Type.NUMBER) { 3720 forceConversionSeparation = false; 3721 } else { 3722 final Type operandType = Type.widest(booleanToInt(objectToNumber(lhs.getType())), booleanToInt(objectToNumber(rhs.getType()))); 3723 forceConversionSeparation = operandType.narrowerThan(widestOperationType); 3724 } 3725 loadBinaryOperands(lhs, rhs, bounds, true, forceConversionSeparation); 3726 } 3727 @Override 3728 void consumeStack() { 3729 op(this); 3730 } 3731 }.emit(getOptimisticIgnoreCountForSelfModifyingExpression(lhs)); 3732 method.convert(assignNode.getType()); 3733 } 3734 } 3735 3736 /** 3737 * Non-optimistic binary self-assignment operation. Basically, everything except +=, -=, *=, and /=. 3738 */ 3739 private abstract class BinarySelfAssignment extends SelfModifyingStore<BinaryNode> { 3740 BinarySelfAssignment(final BinaryNode node) { 3741 super(node, node.lhs()); 3742 } 3743 3744 protected abstract void op(); 3745 3746 @Override 3747 protected void evaluate() { 3748 loadBinaryOperands(assignNode.lhs(), assignNode.rhs(), TypeBounds.UNBOUNDED.notWiderThan(assignNode.getWidestOperandType()), true, false); 3749 op(); 3750 } 3751 } 3752 3753 private void loadASSIGN_ADD(final BinaryNode binaryNode) { 3754 new BinaryOptimisticSelfAssignment(binaryNode) { 3755 @Override 3756 protected void op(final OptimisticOperation oo) { 3757 assert !(binaryNode.getType().isObject() && oo.isOptimistic); 3758 method.add(oo.getProgramPoint()); 3759 } 3760 }.store(); 3761 } 3762 3763 private void loadASSIGN_BIT_AND(final BinaryNode binaryNode) { 3764 new BinarySelfAssignment(binaryNode) { 3765 @Override 3766 protected void op() { 3767 method.and(); 3768 } 3769 }.store(); 3770 } 3771 3772 private void loadASSIGN_BIT_OR(final BinaryNode binaryNode) { 3773 new BinarySelfAssignment(binaryNode) { 3774 @Override 3775 protected void op() { 3776 method.or(); 3777 } 3778 }.store(); 3779 } 3780 3781 private void loadASSIGN_BIT_XOR(final BinaryNode binaryNode) { 3782 new BinarySelfAssignment(binaryNode) { 3783 @Override 3784 protected void op() { 3785 method.xor(); 3786 } 3787 }.store(); 3788 } 3789 3790 private void loadASSIGN_DIV(final BinaryNode binaryNode) { 3791 new BinaryOptimisticSelfAssignment(binaryNode) { 3792 @Override 3793 protected void op(final OptimisticOperation oo) { 3794 method.div(oo.getProgramPoint()); 3795 } 3796 }.store(); 3797 } 3798 3799 private void loadASSIGN_MOD(final BinaryNode binaryNode) { 3800 new BinaryOptimisticSelfAssignment(binaryNode) { 3801 @Override 3802 protected void op(final OptimisticOperation oo) { 3803 method.rem(oo.getProgramPoint()); 3804 } 3805 }.store(); 3806 } 3807 3808 private void loadASSIGN_MUL(final BinaryNode binaryNode) { 3809 new BinaryOptimisticSelfAssignment(binaryNode) { 3810 @Override 3811 protected void op(final OptimisticOperation oo) { 3812 method.mul(oo.getProgramPoint()); 3813 } 3814 }.store(); 3815 } 3816 3817 private void loadASSIGN_SAR(final BinaryNode binaryNode) { 3818 new BinarySelfAssignment(binaryNode) { 3819 @Override 3820 protected void op() { 3821 method.sar(); 3822 } 3823 }.store(); 3824 } 3825 3826 private void loadASSIGN_SHL(final BinaryNode binaryNode) { 3827 new BinarySelfAssignment(binaryNode) { 3828 @Override 3829 protected void op() { 3830 method.shl(); 3831 } 3832 }.store(); 3833 } 3834 3835 private void loadASSIGN_SHR(final BinaryNode binaryNode) { 3836 new BinarySelfAssignment(binaryNode) { 3837 @Override 3838 protected void op() { 3839 doSHR(); 3840 } 3841 3842 }.store(); 3843 } 3844 3845 private void doSHR() { 3846 // TODO: make SHR optimistic 3847 method.shr(); 3848 toUint(); 3849 } 3850 3851 private void toUint() { 3852 JSType.TO_UINT32_I.invoke(method); 3853 } 3854 3855 private void loadASSIGN_SUB(final BinaryNode binaryNode) { 3856 new BinaryOptimisticSelfAssignment(binaryNode) { 3857 @Override 3858 protected void op(final OptimisticOperation oo) { 3859 method.sub(oo.getProgramPoint()); 3860 } 3861 }.store(); 3862 } 3863 3864 /** 3865 * Helper class for binary arithmetic ops 3866 */ 3867 private abstract class BinaryArith { 3868 protected abstract void op(int programPoint); 3869 3870 protected void evaluate(final BinaryNode node, final TypeBounds resultBounds) { 3871 final TypeBounds numericBounds = resultBounds.booleanToInt().objectToNumber(); 3872 new OptimisticOperation(node, numericBounds) { 3873 @Override 3874 void loadStack() { 3875 final TypeBounds operandBounds; 3876 boolean forceConversionSeparation = false; 3877 if(numericBounds.narrowest == Type.NUMBER) { 3878 // Result should be double always. Propagate it into the operands so we don't have lots of I2D 3879 // and L2D after operand evaluation. 3880 assert numericBounds.widest == Type.NUMBER; 3881 operandBounds = numericBounds; 3882 } else { 3883 final boolean isOptimistic = isValid(getProgramPoint()); 3884 if(isOptimistic || node.isTokenType(TokenType.DIV) || node.isTokenType(TokenType.MOD)) { 3885 operandBounds = new TypeBounds(node.getType(), Type.NUMBER); 3886 } else { 3887 // Non-optimistic, non-FP subtraction or multiplication. Allow them to overflow. 3888 operandBounds = new TypeBounds(Type.narrowest(node.getWidestOperandType(), 3889 numericBounds.widest), Type.NUMBER); 3890 forceConversionSeparation = node.getWidestOperationType().narrowerThan(numericBounds.widest); 3891 } 3892 } 3893 loadBinaryOperands(node.lhs(), node.rhs(), operandBounds, false, forceConversionSeparation); 3894 } 3895 3896 @Override 3897 void consumeStack() { 3898 op(getProgramPoint()); 3899 } 3900 }.emit(); 3901 } 3902 } 3903 3904 private void loadBIT_AND(final BinaryNode binaryNode) { 3905 loadBinaryOperands(binaryNode); 3906 method.and(); 3907 } 3908 3909 private void loadBIT_OR(final BinaryNode binaryNode) { 3910 // Optimize x|0 to (int)x 3911 if (isRhsZero(binaryNode)) { 3912 loadExpressionAsType(binaryNode.lhs(), Type.INT); 3913 } else { 3914 loadBinaryOperands(binaryNode); 3915 method.or(); 3916 } 3917 } 3918 3919 private static boolean isRhsZero(final BinaryNode binaryNode) { 3920 final Expression rhs = binaryNode.rhs(); 3921 return rhs instanceof LiteralNode && INT_ZERO.equals(((LiteralNode<?>)rhs).getValue()); 3922 } 3923 3924 private void loadBIT_XOR(final BinaryNode binaryNode) { 3925 loadBinaryOperands(binaryNode); 3926 method.xor(); 3927 } 3928 3929 private void loadCOMMARIGHT(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3930 loadAndDiscard(binaryNode.lhs()); 3931 loadExpression(binaryNode.rhs(), resultBounds); 3932 } 3933 3934 private void loadCOMMALEFT(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3935 loadExpression(binaryNode.lhs(), resultBounds); 3936 loadAndDiscard(binaryNode.rhs()); 3937 } 3938 3939 private void loadDIV(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3940 new BinaryArith() { 3941 @Override 3942 protected void op(final int programPoint) { 3943 method.div(programPoint); 3944 } 3945 }.evaluate(binaryNode, resultBounds); 3946 } 3947 3948 private void loadCmp(final BinaryNode binaryNode, final Condition cond) { 3949 assert comparisonOperandsArePrimitive(binaryNode) : binaryNode; 3950 loadBinaryOperands(binaryNode); 3951 3952 final Label trueLabel = new Label("trueLabel"); 3953 final Label afterLabel = new Label("skip"); 3954 3955 method.conditionalJump(cond, trueLabel); 3956 3957 method.load(Boolean.FALSE); 3958 method._goto(afterLabel); 3959 method.label(trueLabel); 3960 method.load(Boolean.TRUE); 3961 method.label(afterLabel); 3962 } 3963 3964 private static boolean comparisonOperandsArePrimitive(final BinaryNode binaryNode) { 3965 final Type widest = Type.widest(binaryNode.lhs().getType(), binaryNode.rhs().getType()); 3966 return widest.isNumeric() || widest.isBoolean(); 3967 } 3968 3969 private void loadMOD(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3970 new BinaryArith() { 3971 @Override 3972 protected void op(final int programPoint) { 3973 method.rem(programPoint); 3974 } 3975 }.evaluate(binaryNode, resultBounds); 3976 } 3977 3978 private void loadMUL(final BinaryNode binaryNode, final TypeBounds resultBounds) { 3979 new BinaryArith() { 3980 @Override 3981 protected void op(final int programPoint) { 3982 method.mul(programPoint); 3983 } 3984 }.evaluate(binaryNode, resultBounds); 3985 } 3986 3987 private void loadSAR(final BinaryNode binaryNode) { 3988 loadBinaryOperands(binaryNode); 3989 method.sar(); 3990 } 3991 3992 private void loadSHL(final BinaryNode binaryNode) { 3993 loadBinaryOperands(binaryNode); 3994 method.shl(); 3995 } 3996 3997 private void loadSHR(final BinaryNode binaryNode) { 3998 // Optimize x >>> 0 to (uint)x 3999 if (isRhsZero(binaryNode)) { 4000 loadExpressionAsType(binaryNode.lhs(), Type.INT); 4001 toUint(); 4002 } else { 4003 loadBinaryOperands(binaryNode); 4004 doSHR(); 4005 } 4006 } 4007 4008 private void loadSUB(final BinaryNode binaryNode, final TypeBounds resultBounds) { 4009 new BinaryArith() { 4010 @Override 4011 protected void op(final int programPoint) { 4012 method.sub(programPoint); 4013 } 4014 }.evaluate(binaryNode, resultBounds); 4015 } 4016 4017 @Override 4018 public boolean enterLabelNode(final LabelNode labelNode) { 4019 labeledBlockBreakLiveLocals.push(lc.getUsedSlotCount()); 4020 return true; 4021 } 4022 4023 @Override 4024 protected boolean enterDefault(final Node node) { 4025 throw new AssertionError("Code generator entered node of type " + node.getClass().getName()); 4026 } 4027 4028 private void loadTernaryNode(final TernaryNode ternaryNode, final TypeBounds resultBounds) { 4029 final Expression test = ternaryNode.getTest(); 4030 final JoinPredecessorExpression trueExpr = ternaryNode.getTrueExpression(); 4031 final JoinPredecessorExpression falseExpr = ternaryNode.getFalseExpression(); 4032 4033 final Label falseLabel = new Label("ternary_false"); 4034 final Label exitLabel = new Label("ternary_exit"); 4035 4036 final Type outNarrowest = Type.narrowest(resultBounds.widest, Type.generic(Type.widestReturnType(trueExpr.getType(), falseExpr.getType()))); 4037 final TypeBounds outBounds = resultBounds.notNarrowerThan(outNarrowest); 4038 4039 emitBranch(test, falseLabel, false); 4040 4041 loadExpression(trueExpr.getExpression(), outBounds); 4042 assert Type.generic(method.peekType()) == outBounds.narrowest; 4043 method.beforeJoinPoint(trueExpr); 4044 method._goto(exitLabel); 4045 method.label(falseLabel); 4046 loadExpression(falseExpr.getExpression(), outBounds); 4047 assert Type.generic(method.peekType()) == outBounds.narrowest; 4048 method.beforeJoinPoint(falseExpr); 4049 method.label(exitLabel); 4050 } 4051 4052 /** 4053 * Generate all shared scope calls generated during codegen. 4054 */ 4055 void generateScopeCalls() { 4056 for (final SharedScopeCall scopeAccess : lc.getScopeCalls()) { 4057 scopeAccess.generateScopeCall(); 4058 } 4059 } 4060 4061 /** 4062 * Debug code used to print symbols 4063 * 4064 * @param block the block we are in 4065 * @param function the function we are in 4066 * @param ident identifier for block or function where applicable 4067 */ 4068 private void printSymbols(final Block block, final FunctionNode function, final String ident) { 4069 if (compiler.getScriptEnvironment()._print_symbols || function.getFlag(FunctionNode.IS_PRINT_SYMBOLS)) { 4070 final PrintWriter out = compiler.getScriptEnvironment().getErr(); 4071 out.println("[BLOCK in '" + ident + "']"); 4072 if (!block.printSymbols(out)) { 4073 out.println("<no symbols>"); 4074 } 4075 out.println(); 4076 } 4077 } 4078 4079 4080 /** 4081 * The difference between a store and a self modifying store is that 4082 * the latter may load part of the target on the stack, e.g. the base 4083 * of an AccessNode or the base and index of an IndexNode. These are used 4084 * both as target and as an extra source. Previously it was problematic 4085 * for self modifying stores if the target/lhs didn't belong to one 4086 * of three trivial categories: IdentNode, AcessNodes, IndexNodes. In that 4087 * case it was evaluated and tagged as "resolved", which meant at the second 4088 * time the lhs of this store was read (e.g. in a = a (second) + b for a += b, 4089 * it would be evaluated to a nop in the scope and cause stack underflow 4090 * 4091 * see NASHORN-703 4092 * 4093 * @param <T> 4094 */ 4095 private abstract class SelfModifyingStore<T extends Expression> extends Store<T> { 4096 protected SelfModifyingStore(final T assignNode, final Expression target) { 4097 super(assignNode, target); 4098 } 4099 4100 @Override 4101 protected boolean isSelfModifying() { 4102 return true; 4103 } 4104 } 4105 4106 /** 4107 * Helper class to generate stores 4108 */ 4109 private abstract class Store<T extends Expression> { 4110 4111 /** An assignment node, e.g. x += y */ 4112 protected final T assignNode; 4113 4114 /** The target node to store to, e.g. x */ 4115 private final Expression target; 4116 4117 /** How deep on the stack do the arguments go if this generates an indy call */ 4118 private int depth; 4119 4120 /** If we have too many arguments, we need temporary storage, this is stored in 'quick' */ 4121 private IdentNode quick; 4122 4123 /** 4124 * Constructor 4125 * 4126 * @param assignNode the node representing the whole assignment 4127 * @param target the target node of the assignment (destination) 4128 */ 4129 protected Store(final T assignNode, final Expression target) { 4130 this.assignNode = assignNode; 4131 this.target = target; 4132 } 4133 4134 /** 4135 * Constructor 4136 * 4137 * @param assignNode the node representing the whole assignment 4138 */ 4139 protected Store(final T assignNode) { 4140 this(assignNode, assignNode); 4141 } 4142 4143 /** 4144 * Is this a self modifying store operation, e.g. *= or ++ 4145 * @return true if self modifying store 4146 */ 4147 protected boolean isSelfModifying() { 4148 return false; 4149 } 4150 4151 private void prologue() { 4152 /** 4153 * This loads the parts of the target, e.g base and index. they are kept 4154 * on the stack throughout the store and used at the end to execute it 4155 */ 4156 4157 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 4158 @Override 4159 public boolean enterIdentNode(final IdentNode node) { 4160 if (node.getSymbol().isScope()) { 4161 method.loadCompilerConstant(SCOPE); 4162 depth += Type.SCOPE.getSlots(); 4163 assert depth == 1; 4164 } 4165 return false; 4166 } 4167 4168 private void enterBaseNode() { 4169 assert target instanceof BaseNode : "error - base node " + target + " must be instanceof BaseNode"; 4170 final BaseNode baseNode = (BaseNode)target; 4171 final Expression base = baseNode.getBase(); 4172 4173 loadExpressionAsObject(base); 4174 depth += Type.OBJECT.getSlots(); 4175 assert depth == 1; 4176 4177 if (isSelfModifying()) { 4178 method.dup(); 4179 } 4180 } 4181 4182 @Override 4183 public boolean enterAccessNode(final AccessNode node) { 4184 enterBaseNode(); 4185 return false; 4186 } 4187 4188 @Override 4189 public boolean enterIndexNode(final IndexNode node) { 4190 enterBaseNode(); 4191 4192 final Expression index = node.getIndex(); 4193 if (!index.getType().isNumeric()) { 4194 // could be boolean here as well 4195 loadExpressionAsObject(index); 4196 } else { 4197 loadExpressionUnbounded(index); 4198 } 4199 depth += index.getType().getSlots(); 4200 4201 if (isSelfModifying()) { 4202 //convert "base base index" to "base index base index" 4203 method.dup(1); 4204 } 4205 4206 return false; 4207 } 4208 4209 }); 4210 } 4211 4212 /** 4213 * Generates an extra local variable, always using the same slot, one that is available after the end of the 4214 * frame. 4215 * 4216 * @param type the type of the variable 4217 * 4218 * @return the quick variable 4219 */ 4220 private IdentNode quickLocalVariable(final Type type) { 4221 final String name = lc.getCurrentFunction().uniqueName(QUICK_PREFIX.symbolName()); 4222 final Symbol symbol = new Symbol(name, IS_INTERNAL | HAS_SLOT); 4223 symbol.setHasSlotFor(type); 4224 symbol.setFirstSlot(lc.quickSlot(type)); 4225 4226 final IdentNode quickIdent = IdentNode.createInternalIdentifier(symbol).setType(type); 4227 4228 return quickIdent; 4229 } 4230 4231 // store the result that "lives on" after the op, e.g. "i" in i++ postfix. 4232 protected void storeNonDiscard() { 4233 if (lc.getCurrentDiscard() == assignNode) { 4234 assert assignNode.isAssignment(); 4235 lc.popDiscard(); 4236 return; 4237 } 4238 4239 if (method.dup(depth) == null) { 4240 method.dup(); 4241 final Type quickType = method.peekType(); 4242 this.quick = quickLocalVariable(quickType); 4243 final Symbol quickSymbol = quick.getSymbol(); 4244 method.storeTemp(quickType, quickSymbol.getFirstSlot()); 4245 } 4246 } 4247 4248 private void epilogue() { 4249 /** 4250 * Take the original target args from the stack and use them 4251 * together with the value to be stored to emit the store code 4252 * 4253 * The case that targetSymbol is in scope (!hasSlot) and we actually 4254 * need to do a conversion on non-equivalent types exists, but is 4255 * very rare. See for example test/script/basic/access-specializer.js 4256 */ 4257 target.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 4258 @Override 4259 protected boolean enterDefault(final Node node) { 4260 throw new AssertionError("Unexpected node " + node + " in store epilogue"); 4261 } 4262 4263 @Override 4264 public boolean enterIdentNode(final IdentNode node) { 4265 final Symbol symbol = node.getSymbol(); 4266 assert symbol != null; 4267 if (symbol.isScope()) { 4268 final int flags = CALLSITE_SCOPE | getCallSiteFlags(); 4269 if (isFastScope(symbol)) { 4270 storeFastScopeVar(symbol, flags); 4271 } else { 4272 method.dynamicSet(node.getName(), flags); 4273 } 4274 } else { 4275 final Type storeType = assignNode.getType(); 4276 if (symbol.hasSlotFor(storeType)) { 4277 // Only emit a convert for a store known to be live; converts for dead stores can 4278 // give us an unnecessary ClassCastException. 4279 method.convert(storeType); 4280 } 4281 storeIdentWithCatchConversion(node, storeType); 4282 } 4283 return false; 4284 4285 } 4286 4287 @Override 4288 public boolean enterAccessNode(final AccessNode node) { 4289 method.dynamicSet(node.getProperty(), getCallSiteFlags()); 4290 return false; 4291 } 4292 4293 @Override 4294 public boolean enterIndexNode(final IndexNode node) { 4295 method.dynamicSetIndex(getCallSiteFlags()); 4296 return false; 4297 } 4298 }); 4299 4300 4301 // whatever is on the stack now is the final answer 4302 } 4303 4304 protected abstract void evaluate(); 4305 4306 void store() { 4307 if (target instanceof IdentNode) { 4308 checkTemporalDeadZone((IdentNode)target); 4309 } 4310 prologue(); 4311 evaluate(); // leaves an operation of whatever the operationType was on the stack 4312 storeNonDiscard(); 4313 epilogue(); 4314 if (quick != null) { 4315 method.load(quick); 4316 } 4317 } 4318 } 4319 4320 private void newFunctionObject(final FunctionNode functionNode, final boolean addInitializer) { 4321 assert lc.peek() == functionNode; 4322 4323 final RecompilableScriptFunctionData data = compiler.getScriptFunctionData(functionNode.getId()); 4324 4325 if (functionNode.isProgram() && !compiler.isOnDemandCompilation()) { 4326 final CompileUnit fnUnit = functionNode.getCompileUnit(); 4327 final MethodEmitter createFunction = fnUnit.getClassEmitter().method( 4328 EnumSet.of(Flag.PUBLIC, Flag.STATIC), CREATE_PROGRAM_FUNCTION.symbolName(), 4329 ScriptFunction.class, ScriptObject.class); 4330 createFunction.begin(); 4331 createFunction._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup(); 4332 loadConstant(data, fnUnit, createFunction); 4333 createFunction.load(SCOPE_TYPE, 0); 4334 createFunction.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class)); 4335 createFunction._return(); 4336 createFunction.end(); 4337 } 4338 4339 if (addInitializer && !compiler.isOnDemandCompilation()) { 4340 compiler.addFunctionInitializer(data, functionNode); 4341 } 4342 4343 // We don't emit a ScriptFunction on stack for the outermost compiled function (as there's no code being 4344 // generated in its outer context that'd need it as a callee). 4345 if (lc.getOutermostFunction() == functionNode) { 4346 return; 4347 } 4348 4349 method._new(SCRIPTFUNCTION_IMPL_NAME, SCRIPTFUNCTION_IMPL_TYPE).dup(); 4350 loadConstant(data); 4351 4352 if (functionNode.needsParentScope()) { 4353 method.loadCompilerConstant(SCOPE); 4354 } else { 4355 method.loadNull(); 4356 } 4357 method.invoke(constructorNoLookup(SCRIPTFUNCTION_IMPL_NAME, RecompilableScriptFunctionData.class, ScriptObject.class)); 4358 } 4359 4360 // calls on Global class. 4361 private MethodEmitter globalInstance() { 4362 return method.invokestatic(GLOBAL_OBJECT, "instance", "()L" + GLOBAL_OBJECT + ';'); 4363 } 4364 4365 private MethodEmitter globalAllocateArguments() { 4366 return method.invokestatic(GLOBAL_OBJECT, "allocateArguments", methodDescriptor(ScriptObject.class, Object[].class, Object.class, int.class)); 4367 } 4368 4369 private MethodEmitter globalNewRegExp() { 4370 return method.invokestatic(GLOBAL_OBJECT, "newRegExp", methodDescriptor(Object.class, String.class, String.class)); 4371 } 4372 4373 private MethodEmitter globalRegExpCopy() { 4374 return method.invokestatic(GLOBAL_OBJECT, "regExpCopy", methodDescriptor(Object.class, Object.class)); 4375 } 4376 4377 private MethodEmitter globalAllocateArray(final ArrayType type) { 4378 //make sure the native array is treated as an array type 4379 return method.invokestatic(GLOBAL_OBJECT, "allocate", "(" + type.getDescriptor() + ")Ljdk/nashorn/internal/objects/NativeArray;"); 4380 } 4381 4382 private MethodEmitter globalIsEval() { 4383 return method.invokestatic(GLOBAL_OBJECT, "isEval", methodDescriptor(boolean.class, Object.class)); 4384 } 4385 4386 private MethodEmitter globalReplaceLocationPropertyPlaceholder() { 4387 return method.invokestatic(GLOBAL_OBJECT, "replaceLocationPropertyPlaceholder", methodDescriptor(Object.class, Object.class, Object.class)); 4388 } 4389 4390 private MethodEmitter globalCheckObjectCoercible() { 4391 return method.invokestatic(GLOBAL_OBJECT, "checkObjectCoercible", methodDescriptor(void.class, Object.class)); 4392 } 4393 4394 private MethodEmitter globalDirectEval() { 4395 return method.invokestatic(GLOBAL_OBJECT, "directEval", 4396 methodDescriptor(Object.class, Object.class, Object.class, Object.class, Object.class, boolean.class)); 4397 } 4398 4399 private abstract class OptimisticOperation { 4400 private final boolean isOptimistic; 4401 // expression and optimistic are the same reference 4402 private final Expression expression; 4403 private final Optimistic optimistic; 4404 private final TypeBounds resultBounds; 4405 4406 OptimisticOperation(final Optimistic optimistic, final TypeBounds resultBounds) { 4407 this.optimistic = optimistic; 4408 this.expression = (Expression)optimistic; 4409 this.resultBounds = resultBounds; 4410 this.isOptimistic = isOptimistic(optimistic) && useOptimisticTypes() && 4411 // Operation is only effectively optimistic if its type, after being coerced into the result bounds 4412 // is narrower than the upper bound. 4413 resultBounds.within(Type.generic(((Expression)optimistic).getType())).narrowerThan(resultBounds.widest); 4414 } 4415 4416 MethodEmitter emit() { 4417 return emit(0); 4418 } 4419 4420 MethodEmitter emit(final int ignoredArgCount) { 4421 final int programPoint = optimistic.getProgramPoint(); 4422 final boolean optimisticOrContinuation = isOptimistic || isContinuationEntryPoint(programPoint); 4423 final boolean currentContinuationEntryPoint = isCurrentContinuationEntryPoint(programPoint); 4424 final int stackSizeOnEntry = method.getStackSize() - ignoredArgCount; 4425 4426 // First store the values on the stack opportunistically into local variables. Doing it before loadStack() 4427 // allows us to not have to pop/load any arguments that are pushed onto it by loadStack() in the second 4428 // storeStack(). 4429 storeStack(ignoredArgCount, optimisticOrContinuation); 4430 4431 // Now, load the stack 4432 loadStack(); 4433 4434 // Now store the values on the stack ultimately into local variables. In vast majority of cases, this is 4435 // (aside from creating the local types map) a no-op, as the first opportunistic stack store will already 4436 // store all variables. However, there can be operations in the loadStack() that invalidate some of the 4437 // stack stores, e.g. in "x[i] = x[++i]", "++i" will invalidate the already stored value for "i". In such 4438 // unfortunate cases this second storeStack() will restore the invariant that everything on the stack is 4439 // stored into a local variable, although at the cost of doing a store/load on the loaded arguments as well. 4440 final int liveLocalsCount = storeStack(method.getStackSize() - stackSizeOnEntry, optimisticOrContinuation); 4441 assert optimisticOrContinuation == (liveLocalsCount != -1); 4442 4443 final Label beginTry; 4444 final Label catchLabel; 4445 final Label afterConsumeStack = isOptimistic || currentContinuationEntryPoint ? new Label("after_consume_stack") : null; 4446 if(isOptimistic) { 4447 beginTry = new Label("try_optimistic"); 4448 final String catchLabelName = (afterConsumeStack == null ? "" : afterConsumeStack.toString()) + "_handler"; 4449 catchLabel = new Label(catchLabelName); 4450 method.label(beginTry); 4451 } else { 4452 beginTry = catchLabel = null; 4453 } 4454 4455 consumeStack(); 4456 4457 if(isOptimistic) { 4458 method._try(beginTry, afterConsumeStack, catchLabel, UnwarrantedOptimismException.class); 4459 } 4460 4461 if(isOptimistic || currentContinuationEntryPoint) { 4462 method.label(afterConsumeStack); 4463 4464 final int[] localLoads = method.getLocalLoadsOnStack(0, stackSizeOnEntry); 4465 assert everyStackValueIsLocalLoad(localLoads) : Arrays.toString(localLoads) + ", " + stackSizeOnEntry + ", " + ignoredArgCount; 4466 final List<Type> localTypesList = method.getLocalVariableTypes(); 4467 final int usedLocals = method.getUsedSlotsWithLiveTemporaries(); 4468 final List<Type> localTypes = method.getWidestLiveLocals(localTypesList.subList(0, usedLocals)); 4469 assert everyLocalLoadIsValid(localLoads, usedLocals) : Arrays.toString(localLoads) + " ~ " + localTypes; 4470 4471 if(isOptimistic) { 4472 addUnwarrantedOptimismHandlerLabel(localTypes, catchLabel); 4473 } 4474 if(currentContinuationEntryPoint) { 4475 final ContinuationInfo ci = getContinuationInfo(); 4476 assert ci != null : "no continuation info found for " + lc.getCurrentFunction(); 4477 assert !ci.hasTargetLabel(); // No duplicate program points 4478 ci.setTargetLabel(afterConsumeStack); 4479 ci.getHandlerLabel().markAsOptimisticContinuationHandlerFor(afterConsumeStack); 4480 // Can't rely on targetLabel.stack.localVariableTypes.length, as it can be higher due to effectively 4481 // dead local variables. 4482 ci.lvarCount = localTypes.size(); 4483 ci.setStackStoreSpec(localLoads); 4484 ci.setStackTypes(Arrays.copyOf(method.getTypesFromStack(method.getStackSize()), stackSizeOnEntry)); 4485 assert ci.getStackStoreSpec().length == ci.getStackTypes().length; 4486 ci.setReturnValueType(method.peekType()); 4487 ci.lineNumber = getLastLineNumber(); 4488 ci.catchLabel = catchLabels.peek(); 4489 } 4490 } 4491 return method; 4492 } 4493 4494 /** 4495 * Stores the current contents of the stack into local variables so they are not lost before invoking something that 4496 * can result in an {@code UnwarantedOptimizationException}. 4497 * @param ignoreArgCount the number of topmost arguments on stack to ignore when deciding on the shape of the catch 4498 * block. Those are used in the situations when we could not place the call to {@code storeStack} early enough 4499 * (before emitting code for pushing the arguments that the optimistic call will pop). This is admittedly a 4500 * deficiency in the design of the code generator when it deals with self-assignments and we should probably look 4501 * into fixing it. 4502 * @return types of the significant local variables after the stack was stored (types for local variables used 4503 * for temporary storage of ignored arguments are not returned). 4504 * @param optimisticOrContinuation if false, this method should not execute 4505 * a label for a catch block for the {@code UnwarantedOptimizationException}, suitable for capturing the 4506 * currently live local variables, tailored to their types. 4507 */ 4508 private int storeStack(final int ignoreArgCount, final boolean optimisticOrContinuation) { 4509 if(!optimisticOrContinuation) { 4510 return -1; // NOTE: correct value to return is lc.getUsedSlotCount(), but it wouldn't be used anyway 4511 } 4512 4513 final int stackSize = method.getStackSize(); 4514 final Type[] stackTypes = method.getTypesFromStack(stackSize); 4515 final int[] localLoadsOnStack = method.getLocalLoadsOnStack(0, stackSize); 4516 final int usedSlots = method.getUsedSlotsWithLiveTemporaries(); 4517 4518 final int firstIgnored = stackSize - ignoreArgCount; 4519 // Find the first value on the stack (from the bottom) that is not a load from a local variable. 4520 int firstNonLoad = 0; 4521 while(firstNonLoad < firstIgnored && localLoadsOnStack[firstNonLoad] != Label.Stack.NON_LOAD) { 4522 firstNonLoad++; 4523 } 4524 4525 // Only do the store/load if first non-load is not an ignored argument. Otherwise, do nothing and return 4526 // the number of used slots as the number of live local variables. 4527 if(firstNonLoad >= firstIgnored) { 4528 return usedSlots; 4529 } 4530 4531 // Find the number of new temporary local variables that we need; it's the number of values on the stack that 4532 // are not direct loads of existing local variables. 4533 int tempSlotsNeeded = 0; 4534 for(int i = firstNonLoad; i < stackSize; ++i) { 4535 if(localLoadsOnStack[i] == Label.Stack.NON_LOAD) { 4536 tempSlotsNeeded += stackTypes[i].getSlots(); 4537 } 4538 } 4539 4540 // Ensure all values on the stack that weren't directly loaded from a local variable are stored in a local 4541 // variable. We're starting from highest local variable index, so that in case ignoreArgCount > 0 the ignored 4542 // ones end up at the end of the local variable table. 4543 int lastTempSlot = usedSlots + tempSlotsNeeded; 4544 int ignoreSlotCount = 0; 4545 for(int i = stackSize; i -- > firstNonLoad;) { 4546 final int loadSlot = localLoadsOnStack[i]; 4547 if(loadSlot == Label.Stack.NON_LOAD) { 4548 final Type type = stackTypes[i]; 4549 final int slots = type.getSlots(); 4550 lastTempSlot -= slots; 4551 if(i >= firstIgnored) { 4552 ignoreSlotCount += slots; 4553 } 4554 method.storeTemp(type, lastTempSlot); 4555 } else { 4556 method.pop(); 4557 } 4558 } 4559 assert lastTempSlot == usedSlots; // used all temporary locals 4560 4561 final List<Type> localTypesList = method.getLocalVariableTypes(); 4562 4563 // Load values back on stack. 4564 for(int i = firstNonLoad; i < stackSize; ++i) { 4565 final int loadSlot = localLoadsOnStack[i]; 4566 final Type stackType = stackTypes[i]; 4567 final boolean isLoad = loadSlot != Label.Stack.NON_LOAD; 4568 final int lvarSlot = isLoad ? loadSlot : lastTempSlot; 4569 final Type lvarType = localTypesList.get(lvarSlot); 4570 method.load(lvarType, lvarSlot); 4571 if(isLoad) { 4572 // Conversion operators (I2L etc.) preserve "load"-ness of the value despite the fact that, in the 4573 // strict sense they are creating a derived value from the loaded value. This special behavior of 4574 // on-stack conversion operators is necessary to accommodate for differences in local variable types 4575 // after deoptimization; having a conversion operator throw away "load"-ness would create different 4576 // local variable table shapes between optimism-failed code and its deoptimized rest-of method). 4577 // After we load the value back, we need to redo the conversion to the stack type if stack type is 4578 // different. 4579 // NOTE: this would only strictly be necessary for widening conversions (I2L, L2D, I2D), and not for 4580 // narrowing ones (L2I, D2L, D2I) as only widening conversions are the ones that can get eliminated 4581 // in a deoptimized method, as their original input argument got widened. Maybe experiment with 4582 // throwing away "load"-ness for narrowing conversions in MethodEmitter.convert()? 4583 method.convert(stackType); 4584 } else { 4585 // temporary stores never needs a convert, as their type is always the same as the stack type. 4586 assert lvarType == stackType; 4587 lastTempSlot += lvarType.getSlots(); 4588 } 4589 } 4590 // used all temporaries 4591 assert lastTempSlot == usedSlots + tempSlotsNeeded; 4592 4593 return lastTempSlot - ignoreSlotCount; 4594 } 4595 4596 private void addUnwarrantedOptimismHandlerLabel(final List<Type> localTypes, final Label label) { 4597 final String lvarTypesDescriptor = getLvarTypesDescriptor(localTypes); 4598 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.getUnwarrantedOptimismHandlers(); 4599 Collection<Label> labels = unwarrantedOptimismHandlers.get(lvarTypesDescriptor); 4600 if(labels == null) { 4601 labels = new LinkedList<>(); 4602 unwarrantedOptimismHandlers.put(lvarTypesDescriptor, labels); 4603 } 4604 method.markLabelAsOptimisticCatchHandler(label, localTypes.size()); 4605 labels.add(label); 4606 } 4607 4608 abstract void loadStack(); 4609 4610 // Make sure that whatever indy call site you emit from this method uses {@code getCallSiteFlagsOptimistic(node)} 4611 // or otherwise ensure optimistic flag is correctly set in the call site, otherwise it doesn't make much sense 4612 // to use OptimisticExpression for emitting it. 4613 abstract void consumeStack(); 4614 4615 /** 4616 * Emits the correct dynamic getter code. Normally just delegates to method emitter, except when the target 4617 * expression is optimistic, and the desired type is narrower than the optimistic type. In that case, it'll emit a 4618 * dynamic getter with its original optimistic type, and explicitly insert a narrowing conversion. This way we can 4619 * preserve the optimism of the values even if they're subsequently immediately coerced into a narrower type. This 4620 * is beneficial because in this case we can still presume that since the original getter was optimistic, the 4621 * conversion has no side effects. 4622 * @param name the name of the property being get 4623 * @param flags call site flags 4624 * @param isMethod whether we're preferrably retrieving a function 4625 * @return the current method emitter 4626 */ 4627 MethodEmitter dynamicGet(final String name, final int flags, final boolean isMethod) { 4628 if(isOptimistic) { 4629 return method.dynamicGet(getOptimisticCoercedType(), name, getOptimisticFlags(flags), isMethod); 4630 } 4631 return method.dynamicGet(resultBounds.within(expression.getType()), name, nonOptimisticFlags(flags), isMethod); 4632 } 4633 4634 MethodEmitter dynamicGetIndex(final int flags, final boolean isMethod) { 4635 if(isOptimistic) { 4636 return method.dynamicGetIndex(getOptimisticCoercedType(), getOptimisticFlags(flags), isMethod); 4637 } 4638 return method.dynamicGetIndex(resultBounds.within(expression.getType()), nonOptimisticFlags(flags), isMethod); 4639 } 4640 4641 MethodEmitter dynamicCall(final int argCount, final int flags) { 4642 if (isOptimistic) { 4643 return method.dynamicCall(getOptimisticCoercedType(), argCount, getOptimisticFlags(flags)); 4644 } 4645 return method.dynamicCall(resultBounds.within(expression.getType()), argCount, nonOptimisticFlags(flags)); 4646 } 4647 4648 int getOptimisticFlags(final int flags) { 4649 return flags | CALLSITE_OPTIMISTIC | (optimistic.getProgramPoint() << CALLSITE_PROGRAM_POINT_SHIFT); //encode program point in high bits 4650 } 4651 4652 int getProgramPoint() { 4653 return isOptimistic ? optimistic.getProgramPoint() : INVALID_PROGRAM_POINT; 4654 } 4655 4656 void convertOptimisticReturnValue() { 4657 if (isOptimistic) { 4658 final Type optimisticType = getOptimisticCoercedType(); 4659 if(!optimisticType.isObject()) { 4660 method.load(optimistic.getProgramPoint()); 4661 if(optimisticType.isInteger()) { 4662 method.invoke(ENSURE_INT); 4663 } else if(optimisticType.isLong()) { 4664 method.invoke(ENSURE_LONG); 4665 } else if(optimisticType.isNumber()) { 4666 method.invoke(ENSURE_NUMBER); 4667 } else { 4668 throw new AssertionError(optimisticType); 4669 } 4670 } 4671 } 4672 } 4673 4674 void replaceCompileTimeProperty() { 4675 final IdentNode identNode = (IdentNode)expression; 4676 final String name = identNode.getSymbol().getName(); 4677 if (CompilerConstants.__FILE__.name().equals(name)) { 4678 replaceCompileTimeProperty(getCurrentSource().getName()); 4679 } else if (CompilerConstants.__DIR__.name().equals(name)) { 4680 replaceCompileTimeProperty(getCurrentSource().getBase()); 4681 } else if (CompilerConstants.__LINE__.name().equals(name)) { 4682 replaceCompileTimeProperty(getCurrentSource().getLine(identNode.position())); 4683 } 4684 } 4685 4686 /** 4687 * When an ident with name __FILE__, __DIR__, or __LINE__ is loaded, we'll try to look it up as any other 4688 * identifier. However, if it gets all the way up to the Global object, it will send back a special value that 4689 * represents a placeholder for these compile-time location properties. This method will generate code that loads 4690 * the value of the compile-time location property and then invokes a method in Global that will replace the 4691 * placeholder with the value. Effectively, if the symbol for these properties is defined anywhere in the lexical 4692 * scope, they take precedence, but if they aren't, then they resolve to the compile-time location property. 4693 * @param propertyValue the actual value of the property 4694 */ 4695 private void replaceCompileTimeProperty(final Object propertyValue) { 4696 assert method.peekType().isObject(); 4697 if(propertyValue instanceof String || propertyValue == null) { 4698 method.load((String)propertyValue); 4699 } else if(propertyValue instanceof Integer) { 4700 method.load(((Integer)propertyValue).intValue()); 4701 method.convert(Type.OBJECT); 4702 } else { 4703 throw new AssertionError(); 4704 } 4705 globalReplaceLocationPropertyPlaceholder(); 4706 convertOptimisticReturnValue(); 4707 } 4708 4709 /** 4710 * Returns the type that should be used as the return type of the dynamic invocation that is emitted as the code 4711 * for the current optimistic operation. If the type bounds is exact boolean or narrower than the expression's 4712 * optimistic type, then the optimistic type is returned, otherwise the coercing type. Effectively, this method 4713 * allows for moving the coercion into the optimistic type when it won't adversely affect the optimistic 4714 * evaluation semantics, and for preserving the optimistic type and doing a separate coercion when it would 4715 * affect it. 4716 * @return 4717 */ 4718 private Type getOptimisticCoercedType() { 4719 final Type optimisticType = expression.getType(); 4720 assert resultBounds.widest.widerThan(optimisticType); 4721 final Type narrowest = resultBounds.narrowest; 4722 4723 if(narrowest.isBoolean() || narrowest.narrowerThan(optimisticType)) { 4724 assert !optimisticType.isObject(); 4725 return optimisticType; 4726 } 4727 assert !narrowest.isObject(); 4728 return narrowest; 4729 } 4730 } 4731 4732 private static boolean isOptimistic(final Optimistic optimistic) { 4733 if(!optimistic.canBeOptimistic()) { 4734 return false; 4735 } 4736 final Expression expr = (Expression)optimistic; 4737 return expr.getType().narrowerThan(expr.getWidestOperationType()); 4738 } 4739 4740 private static boolean everyLocalLoadIsValid(final int[] loads, final int localCount) { 4741 for (final int load : loads) { 4742 if(load < 0 || load >= localCount) { 4743 return false; 4744 } 4745 } 4746 return true; 4747 } 4748 4749 private static boolean everyStackValueIsLocalLoad(final int[] loads) { 4750 for (final int load : loads) { 4751 if(load == Label.Stack.NON_LOAD) { 4752 return false; 4753 } 4754 } 4755 return true; 4756 } 4757 4758 private String getLvarTypesDescriptor(final List<Type> localVarTypes) { 4759 final int count = localVarTypes.size(); 4760 final StringBuilder desc = new StringBuilder(count); 4761 for(int i = 0; i < count;) { 4762 i += appendType(desc, localVarTypes.get(i)); 4763 } 4764 return method.markSymbolBoundariesInLvarTypesDescriptor(desc.toString()); 4765 } 4766 4767 private static int appendType(final StringBuilder b, final Type t) { 4768 b.append(t.getBytecodeStackType()); 4769 return t.getSlots(); 4770 } 4771 4772 private static int countSymbolsInLvarTypeDescriptor(final String lvarTypeDescriptor) { 4773 int count = 0; 4774 for(int i = 0; i < lvarTypeDescriptor.length(); ++i) { 4775 if(Character.isUpperCase(lvarTypeDescriptor.charAt(i))) { 4776 ++count; 4777 } 4778 } 4779 return count; 4780 4781 } 4782 /** 4783 * Generates all the required {@code UnwarrantedOptimismException} handlers for the current function. The employed 4784 * strategy strives to maximize code reuse. Every handler constructs an array to hold the local variables, then 4785 * fills in some trailing part of the local variables (those for which it has a unique suffix in the descriptor), 4786 * then jumps to a handler for a prefix that's shared with other handlers. A handler that fills up locals up to 4787 * position 0 will not jump to a prefix handler (as it has no prefix), but instead end with constructing and 4788 * throwing a {@code RewriteException}. Since we lexicographically sort the entries, we only need to check every 4789 * entry to its immediately preceding one for longest matching prefix. 4790 * @return true if there is at least one exception handler 4791 */ 4792 private boolean generateUnwarrantedOptimismExceptionHandlers(final FunctionNode fn) { 4793 if(!useOptimisticTypes()) { 4794 return false; 4795 } 4796 4797 // Take the mapping of lvarSpecs -> labels, and turn them into a descending lexicographically sorted list of 4798 // handler specifications. 4799 final Map<String, Collection<Label>> unwarrantedOptimismHandlers = lc.popUnwarrantedOptimismHandlers(); 4800 if(unwarrantedOptimismHandlers.isEmpty()) { 4801 return false; 4802 } 4803 4804 method.lineNumber(0); 4805 4806 final List<OptimismExceptionHandlerSpec> handlerSpecs = new ArrayList<>(unwarrantedOptimismHandlers.size() * 4/3); 4807 for(final String spec: unwarrantedOptimismHandlers.keySet()) { 4808 handlerSpecs.add(new OptimismExceptionHandlerSpec(spec, true)); 4809 } 4810 Collections.sort(handlerSpecs, Collections.reverseOrder()); 4811 4812 // Map of local variable specifications to labels for populating the array for that local variable spec. 4813 final Map<String, Label> delegationLabels = new HashMap<>(); 4814 4815 // Do everything in a single pass over the handlerSpecs list. Note that the list can actually grow as we're 4816 // passing through it as we might add new prefix handlers into it, so can't hoist size() outside of the loop. 4817 for(int handlerIndex = 0; handlerIndex < handlerSpecs.size(); ++handlerIndex) { 4818 final OptimismExceptionHandlerSpec spec = handlerSpecs.get(handlerIndex); 4819 final String lvarSpec = spec.lvarSpec; 4820 if(spec.catchTarget) { 4821 assert !method.isReachable(); 4822 // Start a catch block and assign the labels for this lvarSpec with it. 4823 method._catch(unwarrantedOptimismHandlers.get(lvarSpec)); 4824 // This spec is a catch target, so emit array creation code. The length of the array is the number of 4825 // symbols - the number of uppercase characters. 4826 method.load(countSymbolsInLvarTypeDescriptor(lvarSpec)); 4827 method.newarray(Type.OBJECT_ARRAY); 4828 } 4829 if(spec.delegationTarget) { 4830 // If another handler can delegate to this handler as its prefix, then put a jump target here for the 4831 // shared code (after the array creation code, which is never shared). 4832 method.label(delegationLabels.get(lvarSpec)); // label must exist 4833 } 4834 4835 final boolean lastHandler = handlerIndex == handlerSpecs.size() - 1; 4836 4837 int lvarIndex; 4838 final int firstArrayIndex; 4839 final int firstLvarIndex; 4840 Label delegationLabel; 4841 final String commonLvarSpec; 4842 if(lastHandler) { 4843 // Last handler block, doesn't delegate to anything. 4844 lvarIndex = 0; 4845 firstLvarIndex = 0; 4846 firstArrayIndex = 0; 4847 delegationLabel = null; 4848 commonLvarSpec = null; 4849 } else { 4850 // Not yet the last handler block, will definitely delegate to another handler; let's figure out which 4851 // one. It can be an already declared handler further down the list, or it might need to declare a new 4852 // prefix handler. 4853 4854 // Since we're lexicographically ordered, the common prefix handler is defined by the common prefix of 4855 // this handler and the next handler on the list. 4856 final int nextHandlerIndex = handlerIndex + 1; 4857 final String nextLvarSpec = handlerSpecs.get(nextHandlerIndex).lvarSpec; 4858 commonLvarSpec = commonPrefix(lvarSpec, nextLvarSpec); 4859 // We don't chop symbols in half 4860 assert Character.isUpperCase(commonLvarSpec.charAt(commonLvarSpec.length() - 1)); 4861 4862 // Let's find if we already have a declaration for such handler, or we need to insert it. 4863 { 4864 boolean addNewHandler = true; 4865 int commonHandlerIndex = nextHandlerIndex; 4866 for(; commonHandlerIndex < handlerSpecs.size(); ++commonHandlerIndex) { 4867 final OptimismExceptionHandlerSpec forwardHandlerSpec = handlerSpecs.get(commonHandlerIndex); 4868 final String forwardLvarSpec = forwardHandlerSpec.lvarSpec; 4869 if(forwardLvarSpec.equals(commonLvarSpec)) { 4870 // We already have a handler for the common prefix. 4871 addNewHandler = false; 4872 // Make sure we mark it as a delegation target. 4873 forwardHandlerSpec.delegationTarget = true; 4874 break; 4875 } else if(!forwardLvarSpec.startsWith(commonLvarSpec)) { 4876 break; 4877 } 4878 } 4879 if(addNewHandler) { 4880 // We need to insert a common prefix handler. Note handlers created with catchTarget == false 4881 // will automatically have delegationTarget == true (because that's the only reason for their 4882 // existence). 4883 handlerSpecs.add(commonHandlerIndex, new OptimismExceptionHandlerSpec(commonLvarSpec, false)); 4884 } 4885 } 4886 4887 firstArrayIndex = countSymbolsInLvarTypeDescriptor(commonLvarSpec); 4888 lvarIndex = 0; 4889 for(int j = 0; j < commonLvarSpec.length(); ++j) { 4890 lvarIndex += CodeGeneratorLexicalContext.getTypeForSlotDescriptor(commonLvarSpec.charAt(j)).getSlots(); 4891 } 4892 firstLvarIndex = lvarIndex; 4893 4894 // Create a delegation label if not already present 4895 delegationLabel = delegationLabels.get(commonLvarSpec); 4896 if(delegationLabel == null) { 4897 // uo_pa == "unwarranted optimism, populate array" 4898 delegationLabel = new Label("uo_pa_" + commonLvarSpec); 4899 delegationLabels.put(commonLvarSpec, delegationLabel); 4900 } 4901 } 4902 4903 // Load local variables handled by this handler on stack 4904 int args = 0; 4905 boolean symbolHadValue = false; 4906 for(int typeIndex = commonLvarSpec == null ? 0 : commonLvarSpec.length(); typeIndex < lvarSpec.length(); ++typeIndex) { 4907 final char typeDesc = lvarSpec.charAt(typeIndex); 4908 final Type lvarType = CodeGeneratorLexicalContext.getTypeForSlotDescriptor(typeDesc); 4909 if (!lvarType.isUnknown()) { 4910 method.load(lvarType, lvarIndex); 4911 symbolHadValue = true; 4912 args++; 4913 } else if(typeDesc == 'U' && !symbolHadValue) { 4914 // Symbol boundary with undefined last value. Check if all previous values for this symbol were also 4915 // undefined; if so, emit one explicit Undefined. This serves to ensure that we're emiting exactly 4916 // one value for every symbol that uses local slots. While we could in theory ignore symbols that 4917 // are undefined (in other words, dead) at the point where this exception was thrown, unfortunately 4918 // we can't do it in practice. The reason for this is that currently our liveness analysis is 4919 // coarse (it can determine whether a symbol has not been read with a particular type anywhere in 4920 // the function being compiled, but that's it), and a symbol being promoted to Object due to a 4921 // deoptimization will suddenly show up as "live for Object type", and previously dead U->O 4922 // conversions on loop entries will suddenly become alive in the deoptimized method which will then 4923 // expect a value for that slot in its continuation handler. If we had precise liveness analysis, we 4924 // could go back to excluding known dead symbols from the payload of the RewriteException. 4925 if(method.peekType() == Type.UNDEFINED) { 4926 method.dup(); 4927 } else { 4928 method.loadUndefined(Type.OBJECT); 4929 } 4930 args++; 4931 } 4932 if(Character.isUpperCase(typeDesc)) { 4933 // Reached symbol boundary; reset flag for the next symbol. 4934 symbolHadValue = false; 4935 } 4936 lvarIndex += lvarType.getSlots(); 4937 } 4938 assert args > 0; 4939 // Delegate actual storing into array to an array populator utility method. 4940 //on the stack: 4941 // object array to be populated 4942 // start index 4943 // a lot of types 4944 method.dynamicArrayPopulatorCall(args + 1, firstArrayIndex); 4945 if(delegationLabel != null) { 4946 // We cascade to a prefix handler to fill out the rest of the local variables and throw the 4947 // RewriteException. 4948 assert !lastHandler; 4949 assert commonLvarSpec != null; 4950 // Must undefine the local variables that we have already processed for the sake of correct join on the 4951 // delegate label 4952 method.undefineLocalVariables(firstLvarIndex, true); 4953 final OptimismExceptionHandlerSpec nextSpec = handlerSpecs.get(handlerIndex + 1); 4954 // If the delegate immediately follows, and it's not a catch target (so it doesn't have array setup 4955 // code) don't bother emitting a jump, as we'd just jump to the next instruction. 4956 if(!nextSpec.lvarSpec.equals(commonLvarSpec) || nextSpec.catchTarget) { 4957 method._goto(delegationLabel); 4958 } 4959 } else { 4960 assert lastHandler; 4961 // Nothing to delegate to, so this handler must create and throw the RewriteException. 4962 // At this point we have the UnwarrantedOptimismException and the Object[] with local variables on 4963 // stack. We need to create a RewriteException, push two references to it below the constructor 4964 // arguments, invoke the constructor, and throw the exception. 4965 loadConstant(getByteCodeSymbolNames(fn)); 4966 if (isRestOf()) { 4967 loadConstant(getContinuationEntryPoints()); 4968 method.invoke(CREATE_REWRITE_EXCEPTION_REST_OF); 4969 } else { 4970 method.invoke(CREATE_REWRITE_EXCEPTION); 4971 } 4972 method.athrow(); 4973 } 4974 } 4975 return true; 4976 } 4977 4978 private static String[] getByteCodeSymbolNames(final FunctionNode fn) { 4979 // Only names of local variables on the function level are captured. This information is used to reduce 4980 // deoptimizations, so as much as we can capture will help. We rely on the fact that function wide variables are 4981 // all live all the time, so the array passed to rewrite exception contains one element for every slotted symbol 4982 // here. 4983 final List<String> names = new ArrayList<>(); 4984 for (final Symbol symbol: fn.getBody().getSymbols()) { 4985 if (symbol.hasSlot()) { 4986 if (symbol.isScope()) { 4987 // slot + scope can only be true for parameters 4988 assert symbol.isParam(); 4989 names.add(null); 4990 } else { 4991 names.add(symbol.getName()); 4992 } 4993 } 4994 } 4995 return names.toArray(new String[names.size()]); 4996 } 4997 4998 private static String commonPrefix(final String s1, final String s2) { 4999 final int l1 = s1.length(); 5000 final int l = Math.min(l1, s2.length()); 5001 int lms = -1; // last matching symbol 5002 for(int i = 0; i < l; ++i) { 5003 final char c1 = s1.charAt(i); 5004 if(c1 != s2.charAt(i)) { 5005 return s1.substring(0, lms + 1); 5006 } else if(Character.isUpperCase(c1)) { 5007 lms = i; 5008 } 5009 } 5010 return l == l1 ? s1 : s2; 5011 } 5012 5013 private static class OptimismExceptionHandlerSpec implements Comparable<OptimismExceptionHandlerSpec> { 5014 private final String lvarSpec; 5015 private final boolean catchTarget; 5016 private boolean delegationTarget; 5017 5018 OptimismExceptionHandlerSpec(final String lvarSpec, final boolean catchTarget) { 5019 this.lvarSpec = lvarSpec; 5020 this.catchTarget = catchTarget; 5021 if(!catchTarget) { 5022 delegationTarget = true; 5023 } 5024 } 5025 5026 @Override 5027 public int compareTo(final OptimismExceptionHandlerSpec o) { 5028 return lvarSpec.compareTo(o.lvarSpec); 5029 } 5030 5031 @Override 5032 public String toString() { 5033 final StringBuilder b = new StringBuilder(64).append("[HandlerSpec ").append(lvarSpec); 5034 if(catchTarget) { 5035 b.append(", catchTarget"); 5036 } 5037 if(delegationTarget) { 5038 b.append(", delegationTarget"); 5039 } 5040 return b.append("]").toString(); 5041 } 5042 } 5043 5044 private static class ContinuationInfo { 5045 private final Label handlerLabel; 5046 private Label targetLabel; // Label for the target instruction. 5047 int lvarCount; 5048 // Indices of local variables that need to be loaded on the stack when this node completes 5049 private int[] stackStoreSpec; 5050 // Types of values loaded on the stack 5051 private Type[] stackTypes; 5052 // If non-null, this node should perform the requisite type conversion 5053 private Type returnValueType; 5054 // If we are in the middle of an object literal initialization, we need to update the map 5055 private PropertyMap objectLiteralMap; 5056 // Object literal stack depth for object literal - not necessarly top if property is a tree 5057 private int objectLiteralStackDepth = -1; 5058 // The line number at the continuation point 5059 private int lineNumber; 5060 // The active catch label, in case the continuation point is in a try/catch block 5061 private Label catchLabel; 5062 // The number of scopes that need to be popped before control is transferred to the catch label. 5063 private int exceptionScopePops; 5064 5065 ContinuationInfo() { 5066 this.handlerLabel = new Label("continuation_handler"); 5067 } 5068 5069 Label getHandlerLabel() { 5070 return handlerLabel; 5071 } 5072 5073 boolean hasTargetLabel() { 5074 return targetLabel != null; 5075 } 5076 5077 Label getTargetLabel() { 5078 return targetLabel; 5079 } 5080 5081 void setTargetLabel(final Label targetLabel) { 5082 this.targetLabel = targetLabel; 5083 } 5084 5085 int[] getStackStoreSpec() { 5086 return stackStoreSpec.clone(); 5087 } 5088 5089 void setStackStoreSpec(final int[] stackStoreSpec) { 5090 this.stackStoreSpec = stackStoreSpec; 5091 } 5092 5093 Type[] getStackTypes() { 5094 return stackTypes.clone(); 5095 } 5096 5097 void setStackTypes(final Type[] stackTypes) { 5098 this.stackTypes = stackTypes; 5099 } 5100 5101 Type getReturnValueType() { 5102 return returnValueType; 5103 } 5104 5105 void setReturnValueType(final Type returnValueType) { 5106 this.returnValueType = returnValueType; 5107 } 5108 5109 int getObjectLiteralStackDepth() { 5110 return objectLiteralStackDepth; 5111 } 5112 5113 void setObjectLiteralStackDepth(final int objectLiteralStackDepth) { 5114 this.objectLiteralStackDepth = objectLiteralStackDepth; 5115 } 5116 5117 PropertyMap getObjectLiteralMap() { 5118 return objectLiteralMap; 5119 } 5120 5121 void setObjectLiteralMap(final PropertyMap objectLiteralMap) { 5122 this.objectLiteralMap = objectLiteralMap; 5123 } 5124 5125 @Override 5126 public String toString() { 5127 return "[localVariableTypes=" + targetLabel.getStack().getLocalVariableTypesCopy() + ", stackStoreSpec=" + 5128 Arrays.toString(stackStoreSpec) + ", returnValueType=" + returnValueType + "]"; 5129 } 5130 } 5131 5132 private ContinuationInfo getContinuationInfo() { 5133 return fnIdToContinuationInfo.get(lc.getCurrentFunction().getId()); 5134 } 5135 5136 private void generateContinuationHandler() { 5137 if (!isRestOf()) { 5138 return; 5139 } 5140 5141 final ContinuationInfo ci = getContinuationInfo(); 5142 method.label(ci.getHandlerLabel()); 5143 5144 // There should never be an exception thrown from the continuation handler, but in case there is (meaning, 5145 // Nashorn has a bug), then line number 0 will be an indication of where it came from (line numbers are Uint16). 5146 method.lineNumber(0); 5147 5148 final Label.Stack stack = ci.getTargetLabel().getStack(); 5149 final List<Type> lvarTypes = stack.getLocalVariableTypesCopy(); 5150 final BitSet symbolBoundary = stack.getSymbolBoundaryCopy(); 5151 final int lvarCount = ci.lvarCount; 5152 5153 final Type rewriteExceptionType = Type.typeFor(RewriteException.class); 5154 // Store the RewriteException into an unused local variable slot. 5155 method.load(rewriteExceptionType, 0); 5156 method.storeTemp(rewriteExceptionType, lvarCount); 5157 // Get local variable array 5158 method.load(rewriteExceptionType, 0); 5159 method.invoke(RewriteException.GET_BYTECODE_SLOTS); 5160 // Store local variables. Note that deoptimization might introduce new value types for existing local variables, 5161 // so we must use both liveLocals and symbolBoundary, as in some cases (when the continuation is inside of a try 5162 // block) we need to store the incoming value into multiple slots. The optimism exception handlers will have 5163 // exactly one array element for every symbol that uses bytecode storage. If in the originating method the value 5164 // was undefined, there will be an explicit Undefined value in the array. 5165 int arrayIndex = 0; 5166 for(int lvarIndex = 0; lvarIndex < lvarCount;) { 5167 final Type lvarType = lvarTypes.get(lvarIndex); 5168 if(!lvarType.isUnknown()) { 5169 method.dup(); 5170 method.load(arrayIndex).arrayload(); 5171 final Class<?> typeClass = lvarType.getTypeClass(); 5172 // Deoptimization in array initializers can cause arrays to undergo component type widening 5173 if(typeClass == long[].class) { 5174 method.load(rewriteExceptionType, lvarCount); 5175 method.invoke(RewriteException.TO_LONG_ARRAY); 5176 } else if(typeClass == double[].class) { 5177 method.load(rewriteExceptionType, lvarCount); 5178 method.invoke(RewriteException.TO_DOUBLE_ARRAY); 5179 } else if(typeClass == Object[].class) { 5180 method.load(rewriteExceptionType, lvarCount); 5181 method.invoke(RewriteException.TO_OBJECT_ARRAY); 5182 } else { 5183 if(!(typeClass.isPrimitive() || typeClass == Object.class)) { 5184 // NOTE: this can only happen with dead stores. E.g. for the program "1; []; f();" in which the 5185 // call to f() will deoptimize the call site, but it'll expect :return to have the type 5186 // NativeArray. However, in the more optimal version, :return's only live type is int, therefore 5187 // "{O}:return = []" is a dead store, and the variable will be sent into the continuation as 5188 // Undefined, however NativeArray can't hold Undefined instance. 5189 method.loadType(Type.getInternalName(typeClass)); 5190 method.invoke(RewriteException.INSTANCE_OR_NULL); 5191 } 5192 method.convert(lvarType); 5193 } 5194 method.storeHidden(lvarType, lvarIndex, false); 5195 } 5196 final int nextLvarIndex = lvarIndex + lvarType.getSlots(); 5197 if(symbolBoundary.get(nextLvarIndex - 1)) { 5198 ++arrayIndex; 5199 } 5200 lvarIndex = nextLvarIndex; 5201 } 5202 if (AssertsEnabled.assertsEnabled()) { 5203 method.load(arrayIndex); 5204 method.invoke(RewriteException.ASSERT_ARRAY_LENGTH); 5205 } else { 5206 method.pop(); 5207 } 5208 5209 final int[] stackStoreSpec = ci.getStackStoreSpec(); 5210 final Type[] stackTypes = ci.getStackTypes(); 5211 final boolean isStackEmpty = stackStoreSpec.length == 0; 5212 boolean replacedObjectLiteralMap = false; 5213 if(!isStackEmpty) { 5214 // Load arguments on the stack 5215 final int objectLiteralStackDepth = ci.getObjectLiteralStackDepth(); 5216 for(int i = 0; i < stackStoreSpec.length; ++i) { 5217 final int slot = stackStoreSpec[i]; 5218 method.load(lvarTypes.get(slot), slot); 5219 method.convert(stackTypes[i]); 5220 // stack: s0=object literal being initialized 5221 // change map of s0 so that the property we are initilizing when we failed 5222 // is now ci.returnValueType 5223 if (i == objectLiteralStackDepth) { 5224 method.dup(); 5225 assert ci.getObjectLiteralMap() != null; 5226 assert ScriptObject.class.isAssignableFrom(method.peekType().getTypeClass()) : method.peekType().getTypeClass() + " is not a script object"; 5227 loadConstant(ci.getObjectLiteralMap()); 5228 method.invoke(ScriptObject.SET_MAP); 5229 replacedObjectLiteralMap = true; 5230 } 5231 } 5232 } 5233 // Must have emitted the code for replacing the map of an object literal if we have a set object literal stack depth 5234 assert ci.getObjectLiteralStackDepth() == -1 || replacedObjectLiteralMap; 5235 // Load RewriteException back. 5236 method.load(rewriteExceptionType, lvarCount); 5237 // Get rid of the stored reference 5238 method.loadNull(); 5239 method.storeHidden(Type.OBJECT, lvarCount); 5240 // Mark it dead 5241 method.markDeadSlots(lvarCount, Type.OBJECT.getSlots()); 5242 5243 // Load return value on the stack 5244 method.invoke(RewriteException.GET_RETURN_VALUE); 5245 5246 final Type returnValueType = ci.getReturnValueType(); 5247 5248 // Set up an exception handler for primitive type conversion of return value if needed 5249 boolean needsCatch = false; 5250 final Label targetCatchLabel = ci.catchLabel; 5251 Label _try = null; 5252 if(returnValueType.isPrimitive()) { 5253 // If the conversion throws an exception, we want to report the line number of the continuation point. 5254 method.lineNumber(ci.lineNumber); 5255 5256 if(targetCatchLabel != METHOD_BOUNDARY) { 5257 _try = new Label(""); 5258 method.label(_try); 5259 needsCatch = true; 5260 } 5261 } 5262 5263 // Convert return value 5264 method.convert(returnValueType); 5265 5266 final int scopePopCount = needsCatch ? ci.exceptionScopePops : 0; 5267 5268 // Declare a try/catch for the conversion. If no scopes need to be popped until the target catch block, just 5269 // jump into it. Otherwise, we'll need to create a scope-popping catch block below. 5270 final Label catchLabel = scopePopCount > 0 ? new Label("") : targetCatchLabel; 5271 if(needsCatch) { 5272 final Label _end_try = new Label(""); 5273 method.label(_end_try); 5274 method._try(_try, _end_try, catchLabel); 5275 } 5276 5277 // Jump to continuation point 5278 method._goto(ci.getTargetLabel()); 5279 5280 // Make a scope-popping exception delegate if needed 5281 if(catchLabel != targetCatchLabel) { 5282 method.lineNumber(0); 5283 assert scopePopCount > 0; 5284 method._catch(catchLabel); 5285 popScopes(scopePopCount); 5286 method.uncheckedGoto(targetCatchLabel); 5287 } 5288 } 5289} 5290