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 26 package jdk.nashorn.internal.codegen; 27 28 import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS; 29 import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS_VAR; 30 import static jdk.nashorn.internal.codegen.CompilerConstants.CALLEE; 31 import static jdk.nashorn.internal.codegen.CompilerConstants.EXCEPTION_PREFIX; 32 import static jdk.nashorn.internal.codegen.CompilerConstants.ITERATOR_PREFIX; 33 import static jdk.nashorn.internal.codegen.CompilerConstants.RETURN; 34 import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE; 35 import static jdk.nashorn.internal.codegen.CompilerConstants.SWITCH_TAG_PREFIX; 36 import static jdk.nashorn.internal.codegen.CompilerConstants.THIS; 37 import static jdk.nashorn.internal.codegen.CompilerConstants.VARARGS; 38 import static jdk.nashorn.internal.ir.Symbol.HAS_OBJECT_VALUE; 39 import static jdk.nashorn.internal.ir.Symbol.IS_CONST; 40 import static jdk.nashorn.internal.ir.Symbol.IS_FUNCTION_SELF; 41 import static jdk.nashorn.internal.ir.Symbol.IS_GLOBAL; 42 import static jdk.nashorn.internal.ir.Symbol.IS_INTERNAL; 43 import static jdk.nashorn.internal.ir.Symbol.IS_LET; 44 import static jdk.nashorn.internal.ir.Symbol.IS_PARAM; 45 import static jdk.nashorn.internal.ir.Symbol.IS_PROGRAM_LEVEL; 46 import static jdk.nashorn.internal.ir.Symbol.IS_SCOPE; 47 import static jdk.nashorn.internal.ir.Symbol.IS_THIS; 48 import static jdk.nashorn.internal.ir.Symbol.IS_VAR; 49 import static jdk.nashorn.internal.ir.Symbol.KINDMASK; 50 51 import java.util.ArrayDeque; 52 import java.util.ArrayList; 53 import java.util.Deque; 54 import java.util.HashMap; 55 import java.util.HashSet; 56 import java.util.Iterator; 57 import java.util.List; 58 import java.util.ListIterator; 59 import java.util.Map; 60 import java.util.Set; 61 import jdk.nashorn.internal.ir.AccessNode; 62 import jdk.nashorn.internal.ir.BaseNode; 63 import jdk.nashorn.internal.ir.BinaryNode; 64 import jdk.nashorn.internal.ir.Block; 65 import jdk.nashorn.internal.ir.CatchNode; 66 import jdk.nashorn.internal.ir.Expression; 67 import jdk.nashorn.internal.ir.ForNode; 68 import jdk.nashorn.internal.ir.FunctionNode; 69 import jdk.nashorn.internal.ir.IdentNode; 70 import jdk.nashorn.internal.ir.IndexNode; 71 import jdk.nashorn.internal.ir.LexicalContextNode; 72 import jdk.nashorn.internal.ir.LiteralNode; 73 import jdk.nashorn.internal.ir.Node; 74 import jdk.nashorn.internal.ir.RuntimeNode; 75 import jdk.nashorn.internal.ir.RuntimeNode.Request; 76 import jdk.nashorn.internal.ir.Splittable; 77 import jdk.nashorn.internal.ir.Statement; 78 import jdk.nashorn.internal.ir.SwitchNode; 79 import jdk.nashorn.internal.ir.Symbol; 80 import jdk.nashorn.internal.ir.TryNode; 81 import jdk.nashorn.internal.ir.UnaryNode; 82 import jdk.nashorn.internal.ir.VarNode; 83 import jdk.nashorn.internal.ir.WithNode; 84 import jdk.nashorn.internal.ir.visitor.SimpleNodeVisitor; 85 import jdk.nashorn.internal.parser.TokenType; 86 import jdk.nashorn.internal.runtime.Context; 87 import jdk.nashorn.internal.runtime.ECMAErrors; 88 import jdk.nashorn.internal.runtime.ErrorManager; 89 import jdk.nashorn.internal.runtime.JSErrorType; 90 import jdk.nashorn.internal.runtime.ParserException; 91 import jdk.nashorn.internal.runtime.Source; 92 import jdk.nashorn.internal.runtime.logging.DebugLogger; 93 import jdk.nashorn.internal.runtime.logging.Loggable; 94 import jdk.nashorn.internal.runtime.logging.Logger; 95 96 /** 97 * This visitor assigns symbols to identifiers denoting variables. It does few more minor calculations that are only 98 * possible after symbols have been assigned; such is the transformation of "delete" and "typeof" operators into runtime 99 * nodes and counting of number of properties assigned to "this" in constructor functions. This visitor is also notable 100 * for what it doesn't do, most significantly it does no type calculations as in JavaScript variables can change types 101 * during runtime and as such symbols don't have types. Calculation of expression types is performed by a separate 102 * visitor. 103 */ 104 @Logger(name="symbols") 105 final class AssignSymbols extends SimpleNodeVisitor implements Loggable { 106 private final DebugLogger log; 107 private final boolean debug; 108 109 private static boolean isParamOrVar(final IdentNode identNode) { 110 final Symbol symbol = identNode.getSymbol(); 111 return symbol.isParam() || symbol.isVar(); 112 } 113 114 private static String name(final Node node) { 115 final String cn = node.getClass().getName(); 116 final int lastDot = cn.lastIndexOf('.'); 117 if (lastDot == -1) { 118 return cn; 119 } 120 return cn.substring(lastDot + 1); 121 } 122 123 /** 124 * Checks if various symbols that were provisionally marked as needing a slot ended up unused, and marks them as not 125 * needing a slot after all. 126 * @param functionNode the function node 127 * @return the passed in node, for easy chaining 128 */ 129 private static FunctionNode removeUnusedSlots(final FunctionNode functionNode) { 130 if (!functionNode.needsCallee()) { 131 functionNode.compilerConstant(CALLEE).setNeedsSlot(false); 132 } 133 if (!(functionNode.hasScopeBlock() || functionNode.needsParentScope())) { 134 functionNode.compilerConstant(SCOPE).setNeedsSlot(false); 135 } 136 // Named function expressions that end up not referencing themselves won't need a local slot for the self symbol. 137 if(functionNode.isNamedFunctionExpression() && !functionNode.usesSelfSymbol()) { 138 final Symbol selfSymbol = functionNode.getBody().getExistingSymbol(functionNode.getIdent().getName()); 139 if(selfSymbol != null && selfSymbol.isFunctionSelf()) { 140 selfSymbol.setNeedsSlot(false); 141 selfSymbol.clearFlag(Symbol.IS_VAR); 142 } 143 } 144 return functionNode; 145 } 146 147 private final Deque<Set<String>> thisProperties = new ArrayDeque<>(); 148 private final Map<String, Symbol> globalSymbols = new HashMap<>(); //reuse the same global symbol 149 private final Compiler compiler; 150 private final boolean isOnDemand; 151 152 public AssignSymbols(final Compiler compiler) { 153 this.compiler = compiler; 154 this.log = initLogger(compiler.getContext()); 155 this.debug = log.isEnabled(); 156 this.isOnDemand = compiler.isOnDemandCompilation(); 157 } 158 159 @Override 160 public DebugLogger getLogger() { 161 return log; 162 } 163 164 @Override 165 public DebugLogger initLogger(final Context context) { 166 return context.getLogger(this.getClass()); 167 } 168 169 /** 170 * Define symbols for all variable declarations at the top of the function scope. This way we can get around 171 * problems like 172 * 173 * while (true) { 174 * break; 175 * if (true) { 176 * var s; 177 * } 178 * } 179 * 180 * to an arbitrary nesting depth. 181 * 182 * see NASHORN-73 183 * 184 * @param functionNode the FunctionNode we are entering 185 * @param body the body of the FunctionNode we are entering 186 */ 187 private void acceptDeclarations(final FunctionNode functionNode, final Block body) { 188 // This visitor will assign symbol to all declared variables. 189 body.accept(new SimpleNodeVisitor() { 190 @Override 191 protected boolean enterDefault(final Node node) { 192 // Don't bother visiting expressions; var is a statement, it can't be inside an expression. 193 // This will also prevent visiting nested functions (as FunctionNode is an expression). 194 return !(node instanceof Expression); 195 } 196 197 @Override 198 public Node leaveVarNode(final VarNode varNode) { 199 final IdentNode ident = varNode.getName(); 200 final boolean blockScoped = varNode.isBlockScoped(); 201 if (blockScoped && lc.inUnprotectedSwitchContext()) { 202 throwUnprotectedSwitchError(varNode); 203 } 204 final Block block = blockScoped ? lc.getCurrentBlock() : body; 205 final Symbol symbol = defineSymbol(block, ident.getName(), ident, varNode.getSymbolFlags()); 206 if (varNode.isFunctionDeclaration()) { 207 symbol.setIsFunctionDeclaration(); 208 } 209 return varNode.setName(ident.setSymbol(symbol)); 210 } 211 }); 212 } 213 214 private IdentNode compilerConstantIdentifier(final CompilerConstants cc) { 215 return createImplicitIdentifier(cc.symbolName()).setSymbol(lc.getCurrentFunction().compilerConstant(cc)); 216 } 217 218 /** 219 * Creates an ident node for an implicit identifier within the function (one not declared in the script source 220 * code). These identifiers are defined with function's token and finish. 221 * @param name the name of the identifier 222 * @return an ident node representing the implicit identifier. 223 */ 224 private IdentNode createImplicitIdentifier(final String name) { 225 final FunctionNode fn = lc.getCurrentFunction(); 226 return new IdentNode(fn.getToken(), fn.getFinish(), name); 227 } 228 229 private Symbol createSymbol(final String name, final int flags) { 230 if ((flags & Symbol.KINDMASK) == IS_GLOBAL) { 231 //reuse global symbols so they can be hashed 232 Symbol global = globalSymbols.get(name); 233 if (global == null) { 234 global = new Symbol(name, flags); 235 globalSymbols.put(name, global); 236 } 237 return global; 238 } 239 return new Symbol(name, flags); 240 } 241 242 /** 243 * Creates a synthetic initializer for a variable (a var statement that doesn't occur in the source code). Typically 244 * used to create assignment of {@code :callee} to the function name symbol in self-referential function 245 * expressions as well as for assignment of {@code :arguments} to {@code arguments}. 246 * 247 * @param name the ident node identifying the variable to initialize 248 * @param initConstant the compiler constant it is initialized to 249 * @param fn the function node the assignment is for 250 * @return a var node with the appropriate assignment 251 */ 252 private VarNode createSyntheticInitializer(final IdentNode name, final CompilerConstants initConstant, final FunctionNode fn) { 253 final IdentNode init = compilerConstantIdentifier(initConstant); 254 assert init.getSymbol() != null && init.getSymbol().isBytecodeLocal(); 255 256 final VarNode synthVar = new VarNode(fn.getLineNumber(), fn.getToken(), fn.getFinish(), name, init); 257 258 final Symbol nameSymbol = fn.getBody().getExistingSymbol(name.getName()); 259 assert nameSymbol != null; 260 261 return (VarNode)synthVar.setName(name.setSymbol(nameSymbol)).accept(this); 262 } 263 264 private FunctionNode createSyntheticInitializers(final FunctionNode functionNode) { 265 final List<VarNode> syntheticInitializers = new ArrayList<>(2); 266 267 // Must visit the new var nodes in the context of the body. We could also just set the new statements into the 268 // block and then revisit the entire block, but that seems to be too much double work. 269 final Block body = functionNode.getBody(); 270 lc.push(body); 271 try { 272 if (functionNode.usesSelfSymbol()) { 273 // "var fn = :callee" 274 syntheticInitializers.add(createSyntheticInitializer(functionNode.getIdent(), CALLEE, functionNode)); 275 } 276 277 if (functionNode.needsArguments()) { 278 // "var arguments = :arguments" 279 syntheticInitializers.add(createSyntheticInitializer(createImplicitIdentifier(ARGUMENTS_VAR.symbolName()), 280 ARGUMENTS, functionNode)); 281 } 282 283 if (syntheticInitializers.isEmpty()) { 284 return functionNode; 285 } 286 287 for(final ListIterator<VarNode> it = syntheticInitializers.listIterator(); it.hasNext();) { 288 it.set((VarNode)it.next().accept(this)); 289 } 290 } finally { 291 lc.pop(body); 292 } 293 294 final List<Statement> stmts = body.getStatements(); 295 final List<Statement> newStatements = new ArrayList<>(stmts.size() + syntheticInitializers.size()); 296 newStatements.addAll(syntheticInitializers); 297 newStatements.addAll(stmts); 298 return functionNode.setBody(lc, body.setStatements(lc, newStatements)); 299 } 300 301 /** 302 * Defines a new symbol in the given block. 303 * 304 * @param block the block in which to define the symbol 305 * @param name name of symbol. 306 * @param origin origin node 307 * @param symbolFlags Symbol flags. 308 * 309 * @return Symbol for given name or null for redefinition. 310 */ 311 private Symbol defineSymbol(final Block block, final String name, final Node origin, final int symbolFlags) { 312 int flags = symbolFlags; 313 final boolean isBlockScope = (flags & IS_LET) != 0 || (flags & IS_CONST) != 0; 314 final boolean isGlobal = (flags & KINDMASK) == IS_GLOBAL; 315 316 Symbol symbol; 317 final FunctionNode function; 318 if (isBlockScope) { 319 // block scoped variables always live in current block, no need to look for existing symbols in parent blocks. 320 symbol = block.getExistingSymbol(name); 321 function = lc.getCurrentFunction(); 322 } else { 323 symbol = findSymbol(block, name); 324 function = lc.getFunction(block); 325 } 326 327 // Global variables are implicitly always scope variables too. 328 if (isGlobal) { 329 flags |= IS_SCOPE; 330 } 331 332 if (lc.getCurrentFunction().isProgram()) { 333 flags |= IS_PROGRAM_LEVEL; 334 } 335 336 final boolean isParam = (flags & KINDMASK) == IS_PARAM; 337 final boolean isVar = (flags & KINDMASK) == IS_VAR; 338 339 if (symbol != null) { 340 // Symbol was already defined. Check if it needs to be redefined. 341 if (isParam) { 342 if (!isLocal(function, symbol)) { 343 // Not defined in this function. Create a new definition. 344 symbol = null; 345 } else if (symbol.isParam()) { 346 // Duplicate parameter. Null return will force an error. 347 throwParserException(ECMAErrors.getMessage("syntax.error.duplicate.parameter", name), origin); 348 } 349 } else if (isVar) { 350 if (isBlockScope) { 351 // Check redeclaration in same block 352 if (symbol.hasBeenDeclared()) { 353 throwParserException(ECMAErrors.getMessage("syntax.error.redeclare.variable", name), origin); 354 } else { 355 symbol.setHasBeenDeclared(); 356 // Set scope flag on top-level block scoped symbols 357 if (function.isProgram() && function.getBody() == block) { 358 symbol.setIsScope(); 359 } 360 } 361 } else if ((flags & IS_INTERNAL) != 0) { 362 // Always create a new definition. 363 symbol = null; 364 } else { 365 // Found LET or CONST in parent scope of same function - s SyntaxError 366 if (symbol.isBlockScoped() && isLocal(lc.getCurrentFunction(), symbol)) { 367 throwParserException(ECMAErrors.getMessage("syntax.error.redeclare.variable", name), origin); 368 } 369 // Not defined in this function. Create a new definition. 370 if (!isLocal(function, symbol) || symbol.less(IS_VAR)) { 371 symbol = null; 372 } 373 } 374 } 375 } 376 377 if (symbol == null) { 378 // If not found, then create a new one. 379 final Block symbolBlock; 380 381 // Determine where to create it. 382 if (isVar && ((flags & IS_INTERNAL) != 0 || isBlockScope)) { 383 symbolBlock = block; //internal vars are always defined in the block closest to them 384 } else if (isGlobal) { 385 symbolBlock = lc.getOutermostFunction().getBody(); 386 } else { 387 symbolBlock = lc.getFunctionBody(function); 388 } 389 390 // Create and add to appropriate block. 391 symbol = createSymbol(name, flags); 392 symbolBlock.putSymbol(symbol); 393 394 if ((flags & IS_SCOPE) == 0) { 395 // Initial assumption; symbol can lose its slot later 396 symbol.setNeedsSlot(true); 397 } 398 } else if (symbol.less(flags)) { 399 symbol.setFlags(flags); 400 } 401 402 return symbol; 403 } 404 405 private <T extends Node> T end(final T node) { 406 return end(node, true); 407 } 408 409 private <T extends Node> T end(final T node, final boolean printNode) { 410 if (debug) { 411 final StringBuilder sb = new StringBuilder(); 412 413 sb.append("[LEAVE "). 414 append(name(node)). 415 append("] "). 416 append(printNode ? node.toString() : ""). 417 append(" in '"). 418 append(lc.getCurrentFunction().getName()). 419 append('\''); 420 421 if (node instanceof IdentNode) { 422 final Symbol symbol = ((IdentNode)node).getSymbol(); 423 if (symbol == null) { 424 sb.append(" <NO SYMBOL>"); 425 } else { 426 sb.append(" <symbol=").append(symbol).append('>'); 427 } 428 } 429 430 log.unindent(); 431 log.info(sb); 432 } 433 434 return node; 435 } 436 437 @Override 438 public boolean enterBlock(final Block block) { 439 start(block); 440 441 if (lc.isFunctionBody()) { 442 assert !block.hasSymbols(); 443 final FunctionNode fn = lc.getCurrentFunction(); 444 if (isUnparsedFunction(fn)) { 445 // It's a skipped nested function. Just mark the symbols being used by it as being in use. 446 for(final String name: compiler.getScriptFunctionData(fn.getId()).getExternalSymbolNames()) { 447 nameIsUsed(name, null); 448 } 449 // Don't bother descending into it, it must be empty anyway. 450 assert block.getStatements().isEmpty(); 451 return false; 452 } 453 454 enterFunctionBody(); 455 } 456 457 return true; 458 } 459 460 private boolean isUnparsedFunction(final FunctionNode fn) { 461 return isOnDemand && fn != lc.getOutermostFunction(); 462 } 463 464 @Override 465 public boolean enterCatchNode(final CatchNode catchNode) { 466 final IdentNode exception = catchNode.getExceptionIdentifier(); 467 final Block block = lc.getCurrentBlock(); 468 469 start(catchNode); 470 471 // define block-local exception variable 472 final String exname = exception.getName(); 473 // If the name of the exception starts with ":e", this is a synthetic catch block, likely a catch-all. Its 474 // symbol is naturally internal, and should be treated as such. 475 final boolean isInternal = exname.startsWith(EXCEPTION_PREFIX.symbolName()); 476 // IS_LET flag is required to make sure symbol is not visible outside catch block. However, we need to 477 // clear the IS_LET flag after creation to allow redefinition of symbol inside the catch block. 478 final Symbol symbol = defineSymbol(block, exname, catchNode, IS_VAR | IS_LET | (isInternal ? IS_INTERNAL : 0) | HAS_OBJECT_VALUE); 479 symbol.clearFlag(IS_LET); 480 481 return true; 482 } 483 484 private void enterFunctionBody() { 485 final FunctionNode functionNode = lc.getCurrentFunction(); 486 final Block body = lc.getCurrentBlock(); 487 488 initFunctionWideVariables(functionNode, body); 489 acceptDeclarations(functionNode, body); 490 defineFunctionSelfSymbol(functionNode, body); 491 } 492 493 private void defineFunctionSelfSymbol(final FunctionNode functionNode, final Block body) { 494 // Function self-symbol is only declared as a local variable for named function expressions. Declared functions 495 // don't need it as they are local variables in their declaring scope. 496 if (!functionNode.isNamedFunctionExpression()) { 497 return; 498 } 499 500 final String name = functionNode.getIdent().getName(); 501 assert name != null; // As it's a named function expression. 502 503 if (body.getExistingSymbol(name) != null) { 504 // Body already has a declaration for the name. It's either a parameter "function x(x)" or a 505 // top-level variable "function x() { ... var x; ... }". 506 return; 507 } 508 509 defineSymbol(body, name, functionNode, IS_VAR | IS_FUNCTION_SELF | HAS_OBJECT_VALUE); 510 if(functionNode.allVarsInScope()) { // basically, has deep eval 511 // We must conservatively presume that eval'd code can dynamically use the function symbol. 512 lc.setFlag(functionNode, FunctionNode.USES_SELF_SYMBOL); 513 } 514 } 515 516 @Override 517 public boolean enterFunctionNode(final FunctionNode functionNode) { 518 start(functionNode, false); 519 520 thisProperties.push(new HashSet<String>()); 521 522 // Every function has a body, even the ones skipped on reparse (they have an empty one). We're 523 // asserting this as even for those, enterBlock() must be invoked to correctly process symbols that 524 // are used in them. 525 assert functionNode.getBody() != null; 526 527 return true; 528 } 529 530 @Override 531 public boolean enterVarNode(final VarNode varNode) { 532 start(varNode); 533 // Normally, a symbol assigned in a var statement is not live for its RHS. Since we also represent function 534 // declarations as VarNodes, they are exception to the rule, as they need to have the symbol visible to the 535 // body of the declared function for self-reference. 536 if (varNode.isFunctionDeclaration()) { 537 defineVarIdent(varNode); 538 } 539 return true; 540 } 541 542 @Override 543 public Node leaveVarNode(final VarNode varNode) { 544 if (!varNode.isFunctionDeclaration()) { 545 defineVarIdent(varNode); 546 } 547 return super.leaveVarNode(varNode); 548 } 549 550 private void defineVarIdent(final VarNode varNode) { 551 final IdentNode ident = varNode.getName(); 552 final int flags; 553 if (!varNode.isBlockScoped() && lc.getCurrentFunction().isProgram()) { 554 flags = IS_SCOPE; 555 } else { 556 flags = 0; 557 } 558 defineSymbol(lc.getCurrentBlock(), ident.getName(), ident, varNode.getSymbolFlags() | flags); 559 } 560 561 private Symbol exceptionSymbol() { 562 return newObjectInternal(EXCEPTION_PREFIX); 563 } 564 565 /** 566 * This has to run before fix assignment types, store any type specializations for 567 * parameters, then turn them into objects for the generic version of this method. 568 * 569 * @param functionNode functionNode 570 */ 571 private FunctionNode finalizeParameters(final FunctionNode functionNode) { 572 final List<IdentNode> newParams = new ArrayList<>(); 573 final boolean isVarArg = functionNode.isVarArg(); 574 575 final Block body = functionNode.getBody(); 576 for (final IdentNode param : functionNode.getParameters()) { 577 final Symbol paramSymbol = body.getExistingSymbol(param.getName()); 578 assert paramSymbol != null; 579 assert paramSymbol.isParam() : paramSymbol + " " + paramSymbol.getFlags(); 580 newParams.add(param.setSymbol(paramSymbol)); 581 582 // parameters should not be slots for a function that uses variable arity signature 583 if (isVarArg) { 584 paramSymbol.setNeedsSlot(false); 585 } 586 } 587 588 return functionNode.setParameters(lc, newParams); 589 } 590 591 /** 592 * Search for symbol in the lexical context starting from the given block. 593 * @param name Symbol name. 594 * @return Found symbol or null if not found. 595 */ 596 private Symbol findSymbol(final Block block, final String name) { 597 for (final Iterator<Block> blocks = lc.getBlocks(block); blocks.hasNext();) { 598 final Symbol symbol = blocks.next().getExistingSymbol(name); 599 if (symbol != null) { 600 return symbol; 601 } 602 } 603 return null; 604 } 605 606 /** 607 * Marks the current function as one using any global symbol. The function and all its parent functions will all be 608 * marked as needing parent scope. 609 * @see FunctionNode#needsParentScope() 610 */ 611 private void functionUsesGlobalSymbol() { 612 for (final Iterator<FunctionNode> fns = lc.getFunctions(); fns.hasNext();) { 613 lc.setFlag(fns.next(), FunctionNode.USES_ANCESTOR_SCOPE); 614 } 615 } 616 617 /** 618 * Marks the current function as one using a scoped symbol. The block defining the symbol will be marked as needing 619 * its own scope to hold the variable. If the symbol is defined outside of the current function, it and all 620 * functions up to (but not including) the function containing the defining block will be marked as needing parent 621 * function scope. 622 * @see FunctionNode#needsParentScope() 623 */ 624 private void functionUsesScopeSymbol(final Symbol symbol) { 625 final String name = symbol.getName(); 626 for (final Iterator<LexicalContextNode> contextNodeIter = lc.getAllNodes(); contextNodeIter.hasNext(); ) { 627 final LexicalContextNode node = contextNodeIter.next(); 628 if (node instanceof Block) { 629 final Block block = (Block)node; 630 if (block.getExistingSymbol(name) != null) { 631 assert lc.contains(block); 632 lc.setBlockNeedsScope(block); 633 break; 634 } 635 } else if (node instanceof FunctionNode) { 636 lc.setFlag(node, FunctionNode.USES_ANCESTOR_SCOPE); 637 } 638 } 639 } 640 641 /** 642 * Declares that the current function is using the symbol. 643 * @param symbol the symbol used by the current function. 644 */ 645 private void functionUsesSymbol(final Symbol symbol) { 646 assert symbol != null; 647 if (symbol.isScope()) { 648 if (symbol.isGlobal()) { 649 functionUsesGlobalSymbol(); 650 } else { 651 functionUsesScopeSymbol(symbol); 652 } 653 } else { 654 assert !symbol.isGlobal(); // Every global is also scope 655 } 656 } 657 658 private void initCompileConstant(final CompilerConstants cc, final Block block, final int flags) { 659 defineSymbol(block, cc.symbolName(), null, flags).setNeedsSlot(true); 660 } 661 662 private void initFunctionWideVariables(final FunctionNode functionNode, final Block body) { 663 initCompileConstant(CALLEE, body, IS_PARAM | IS_INTERNAL | HAS_OBJECT_VALUE); 664 initCompileConstant(THIS, body, IS_PARAM | IS_THIS | HAS_OBJECT_VALUE); 665 666 if (functionNode.isVarArg()) { 667 initCompileConstant(VARARGS, body, IS_PARAM | IS_INTERNAL | HAS_OBJECT_VALUE); 668 if (functionNode.needsArguments()) { 669 initCompileConstant(ARGUMENTS, body, IS_VAR | IS_INTERNAL | HAS_OBJECT_VALUE); 670 defineSymbol(body, ARGUMENTS_VAR.symbolName(), null, IS_VAR | HAS_OBJECT_VALUE); 671 } 672 } 673 674 initParameters(functionNode, body); 675 initCompileConstant(SCOPE, body, IS_VAR | IS_INTERNAL | HAS_OBJECT_VALUE); 676 initCompileConstant(RETURN, body, IS_VAR | IS_INTERNAL); 677 } 678 679 /** 680 * Initialize parameters for function node. 681 * @param functionNode the function node 682 */ 683 private void initParameters(final FunctionNode functionNode, final Block body) { 684 final boolean isVarArg = functionNode.isVarArg(); 685 final boolean scopeParams = functionNode.allVarsInScope() || isVarArg; 686 for (final IdentNode param : functionNode.getParameters()) { 687 final Symbol symbol = defineSymbol(body, param.getName(), param, IS_PARAM); 688 if(scopeParams) { 689 // NOTE: this "set is scope" is a poor substitute for clear expression of where the symbol is stored. 690 // It will force creation of scopes where they would otherwise not necessarily be needed (functions 691 // using arguments object and other variable arity functions). Tracked by JDK-8038942. 692 symbol.setIsScope(); 693 assert symbol.hasSlot(); 694 if(isVarArg) { 695 symbol.setNeedsSlot(false); 696 } 697 } 698 } 699 } 700 701 /** 702 * Is the symbol local to (that is, defined in) the specified function? 703 * @param function the function 704 * @param symbol the symbol 705 * @return true if the symbol is defined in the specified function 706 */ 707 private boolean isLocal(final FunctionNode function, final Symbol symbol) { 708 final FunctionNode definingFn = lc.getDefiningFunction(symbol); 709 assert definingFn != null; 710 return definingFn == function; 711 } 712 713 @Override 714 public Node leaveBinaryNode(final BinaryNode binaryNode) { 715 if (binaryNode.isTokenType(TokenType.ASSIGN)) { 716 return leaveASSIGN(binaryNode); 717 } 718 return super.leaveBinaryNode(binaryNode); 719 } 720 721 private Node leaveASSIGN(final BinaryNode binaryNode) { 722 // If we're assigning a property of the this object ("this.foo = ..."), record it. 723 final Expression lhs = binaryNode.lhs(); 724 if (lhs instanceof AccessNode) { 725 final AccessNode accessNode = (AccessNode) lhs; 726 final Expression base = accessNode.getBase(); 727 if (base instanceof IdentNode) { 728 final Symbol symbol = ((IdentNode)base).getSymbol(); 729 if(symbol.isThis()) { 730 thisProperties.peek().add(accessNode.getProperty()); 731 } 732 } 733 } 734 return binaryNode; 735 } 736 737 @Override 738 public Node leaveUnaryNode(final UnaryNode unaryNode) { 739 if (unaryNode.tokenType() == TokenType.TYPEOF) { 740 return leaveTYPEOF(unaryNode); 741 } else { 742 return super.leaveUnaryNode(unaryNode); 743 } 744 } 745 746 @Override 747 public Node leaveForNode(final ForNode forNode) { 748 if (forNode.isForInOrOf()) { 749 return forNode.setIterator(lc, newObjectInternal(ITERATOR_PREFIX)); //NASHORN-73 750 } 751 752 return end(forNode); 753 } 754 755 @Override 756 public Node leaveFunctionNode(final FunctionNode functionNode) { 757 final FunctionNode finalizedFunction; 758 if (isUnparsedFunction(functionNode)) { 759 finalizedFunction = functionNode; 760 } else { 761 finalizedFunction = 762 markProgramBlock( 763 removeUnusedSlots( 764 createSyntheticInitializers( 765 finalizeParameters( 766 lc.applyTopFlags(functionNode)))) 767 .setThisProperties(lc, thisProperties.pop().size())); 768 } 769 return finalizedFunction; 770 } 771 772 @Override 773 public Node leaveIdentNode(final IdentNode identNode) { 774 if (identNode.isPropertyName()) { 775 return identNode; 776 } 777 778 final Symbol symbol = nameIsUsed(identNode.getName(), identNode); 779 780 if (!identNode.isInitializedHere()) { 781 symbol.increaseUseCount(); 782 } 783 784 IdentNode newIdentNode = identNode.setSymbol(symbol); 785 786 // If a block-scoped var is used before its declaration mark it as dead. 787 // We can only statically detect this for local vars, cross-function symbols require runtime checks. 788 if (symbol.isBlockScoped() && !symbol.hasBeenDeclared() && !identNode.isDeclaredHere() && isLocal(lc.getCurrentFunction(), symbol)) { 789 newIdentNode = newIdentNode.markDead(); 790 } 791 792 return end(newIdentNode); 793 } 794 795 private Symbol nameIsUsed(final String name, final IdentNode origin) { 796 final Block block = lc.getCurrentBlock(); 797 798 Symbol symbol = findSymbol(block, name); 799 800 //If an existing symbol with the name is found, use that otherwise, declare a new one 801 if (symbol != null) { 802 log.info("Existing symbol = ", symbol); 803 if (symbol.isFunctionSelf()) { 804 final FunctionNode functionNode = lc.getDefiningFunction(symbol); 805 assert functionNode != null; 806 assert lc.getFunctionBody(functionNode).getExistingSymbol(CALLEE.symbolName()) != null; 807 lc.setFlag(functionNode, FunctionNode.USES_SELF_SYMBOL); 808 } 809 810 // if symbol is non-local or we're in a with block, we need to put symbol in scope (if it isn't already) 811 maybeForceScope(symbol); 812 } else { 813 log.info("No symbol exists. Declare as global: ", name); 814 symbol = defineSymbol(block, name, origin, IS_GLOBAL | IS_SCOPE); 815 } 816 817 functionUsesSymbol(symbol); 818 return symbol; 819 } 820 821 @Override 822 public Node leaveSwitchNode(final SwitchNode switchNode) { 823 // We only need a symbol for the tag if it's not an integer switch node 824 if(!switchNode.isUniqueInteger()) { 825 return switchNode.setTag(lc, newObjectInternal(SWITCH_TAG_PREFIX)); 826 } 827 return switchNode; 828 } 829 830 @Override 831 public Node leaveTryNode(final TryNode tryNode) { 832 assert tryNode.getFinallyBody() == null; 833 834 end(tryNode); 835 836 return tryNode.setException(lc, exceptionSymbol()); 837 } 838 839 private Node leaveTYPEOF(final UnaryNode unaryNode) { 840 final Expression rhs = unaryNode.getExpression(); 841 842 final List<Expression> args = new ArrayList<>(); 843 if (rhs instanceof IdentNode && !isParamOrVar((IdentNode)rhs)) { 844 args.add(compilerConstantIdentifier(SCOPE)); 845 args.add(LiteralNode.newInstance(rhs, ((IdentNode)rhs).getName())); //null 846 } else { 847 args.add(rhs); 848 args.add(LiteralNode.newInstance(unaryNode)); //null, do not reuse token of identifier rhs, it can be e.g. 'this' 849 } 850 851 final Node runtimeNode = new RuntimeNode(unaryNode, Request.TYPEOF, args); 852 853 end(unaryNode); 854 855 return runtimeNode; 856 } 857 858 private FunctionNode markProgramBlock(final FunctionNode functionNode) { 859 if (isOnDemand || !functionNode.isProgram()) { 860 return functionNode; 861 } 862 863 return functionNode.setBody(lc, functionNode.getBody().setFlag(lc, Block.IS_GLOBAL_SCOPE)); 864 } 865 866 /** 867 * If the symbol isn't already a scope symbol, but it needs to be (see {@link #symbolNeedsToBeScope(Symbol)}, it is 868 * promoted to a scope symbol and its block marked as needing a scope. 869 * @param symbol the symbol that might be scoped 870 */ 871 private void maybeForceScope(final Symbol symbol) { 872 if (!symbol.isScope() && symbolNeedsToBeScope(symbol)) { 873 Symbol.setSymbolIsScope(lc, symbol); 874 } 875 } 876 877 private Symbol newInternal(final CompilerConstants cc, final int flags) { 878 return defineSymbol(lc.getCurrentBlock(), lc.getCurrentFunction().uniqueName(cc.symbolName()), null, IS_VAR | IS_INTERNAL | flags); //NASHORN-73 879 } 880 881 private Symbol newObjectInternal(final CompilerConstants cc) { 882 return newInternal(cc, HAS_OBJECT_VALUE); 883 } 884 885 private boolean start(final Node node) { 886 return start(node, true); 887 } 888 889 private boolean start(final Node node, final boolean printNode) { 890 if (debug) { 891 final StringBuilder sb = new StringBuilder(); 892 893 sb.append("[ENTER "). 894 append(name(node)). 895 append("] "). 896 append(printNode ? node.toString() : ""). 897 append(" in '"). 898 append(lc.getCurrentFunction().getName()). 899 append("'"); 900 log.info(sb); 901 log.indent(); 902 } 903 904 return true; 905 } 906 907 /** 908 * Determines if the symbol has to be a scope symbol. In general terms, it has to be a scope symbol if it can only 909 * be reached from the current block by traversing a function node, a split node, or a with node. 910 * @param symbol the symbol checked for needing to be a scope symbol 911 * @return true if the symbol has to be a scope symbol. 912 */ 913 private boolean symbolNeedsToBeScope(final Symbol symbol) { 914 if (symbol.isThis() || symbol.isInternal()) { 915 return false; 916 } 917 918 final FunctionNode func = lc.getCurrentFunction(); 919 if ( func.allVarsInScope() || (!symbol.isBlockScoped() && func.isProgram())) { 920 return true; 921 } 922 923 boolean previousWasBlock = false; 924 for (final Iterator<LexicalContextNode> it = lc.getAllNodes(); it.hasNext();) { 925 final LexicalContextNode node = it.next(); 926 if (node instanceof FunctionNode || isSplitLiteral(node)) { 927 // We reached the function boundary or a splitting boundary without seeing a definition for the symbol. 928 // It needs to be in scope. 929 return true; 930 } else if (node instanceof WithNode) { 931 if (previousWasBlock) { 932 // We reached a WithNode; the symbol must be scoped. Note that if the WithNode was not immediately 933 // preceded by a block, this means we're currently processing its expression, not its body, 934 // therefore it doesn't count. 935 return true; 936 } 937 previousWasBlock = false; 938 } else if (node instanceof Block) { 939 if (((Block)node).getExistingSymbol(symbol.getName()) == symbol) { 940 // We reached the block that defines the symbol without reaching either the function boundary, or a 941 // WithNode. The symbol need not be scoped. 942 return false; 943 } 944 previousWasBlock = true; 945 } else { 946 previousWasBlock = false; 947 } 948 } 949 throw new AssertionError(); 950 } 951 952 private static boolean isSplitLiteral(final LexicalContextNode expr) { 953 return expr instanceof Splittable && ((Splittable) expr).getSplitRanges() != null; 954 } 955 956 private void throwUnprotectedSwitchError(final VarNode varNode) { 957 // Block scoped declarations in switch statements without explicit blocks should be declared 958 // in a common block that contains all the case clauses. We cannot support this without a 959 // fundamental rewrite of how switch statements are handled (case nodes contain blocks and are 960 // directly contained by switch node). As a temporary solution we throw a reference error here. 961 final String msg = ECMAErrors.getMessage("syntax.error.unprotected.switch.declaration", varNode.isLet() ? "let" : "const"); 962 throwParserException(msg, varNode); 963 } 964 965 private void throwParserException(final String message, final Node origin) { 966 if (origin == null) { 967 throw new ParserException(message); 968 } 969 final Source source = compiler.getSource(); 970 final long token = origin.getToken(); 971 final int line = source.getLine(origin.getStart()); 972 final int column = source.getColumn(origin.getStart()); 973 final String formatted = ErrorManager.format(message, source, line, column, token); 974 throw new ParserException(JSErrorType.SYNTAX_ERROR, formatted, source, line, column, token); 975 } 976 }