AssignSymbols.java revision 1435:6e5080fdfaad
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.CompilerConstants.ARGUMENTS; 29import static jdk.nashorn.internal.codegen.CompilerConstants.ARGUMENTS_VAR; 30import static jdk.nashorn.internal.codegen.CompilerConstants.CALLEE; 31import static jdk.nashorn.internal.codegen.CompilerConstants.EXCEPTION_PREFIX; 32import static jdk.nashorn.internal.codegen.CompilerConstants.ITERATOR_PREFIX; 33import static jdk.nashorn.internal.codegen.CompilerConstants.RETURN; 34import static jdk.nashorn.internal.codegen.CompilerConstants.SCOPE; 35import static jdk.nashorn.internal.codegen.CompilerConstants.SWITCH_TAG_PREFIX; 36import static jdk.nashorn.internal.codegen.CompilerConstants.THIS; 37import static jdk.nashorn.internal.codegen.CompilerConstants.VARARGS; 38import static jdk.nashorn.internal.ir.Symbol.HAS_OBJECT_VALUE; 39import static jdk.nashorn.internal.ir.Symbol.IS_CONST; 40import static jdk.nashorn.internal.ir.Symbol.IS_FUNCTION_SELF; 41import static jdk.nashorn.internal.ir.Symbol.IS_GLOBAL; 42import static jdk.nashorn.internal.ir.Symbol.IS_INTERNAL; 43import static jdk.nashorn.internal.ir.Symbol.IS_LET; 44import static jdk.nashorn.internal.ir.Symbol.IS_PARAM; 45import static jdk.nashorn.internal.ir.Symbol.IS_PROGRAM_LEVEL; 46import static jdk.nashorn.internal.ir.Symbol.IS_SCOPE; 47import static jdk.nashorn.internal.ir.Symbol.IS_THIS; 48import static jdk.nashorn.internal.ir.Symbol.IS_VAR; 49import static jdk.nashorn.internal.ir.Symbol.KINDMASK; 50 51import java.util.ArrayDeque; 52import java.util.ArrayList; 53import java.util.Deque; 54import java.util.HashMap; 55import java.util.HashSet; 56import java.util.Iterator; 57import java.util.List; 58import java.util.ListIterator; 59import java.util.Map; 60import java.util.Set; 61import jdk.nashorn.internal.ir.AccessNode; 62import jdk.nashorn.internal.ir.BinaryNode; 63import jdk.nashorn.internal.ir.Block; 64import jdk.nashorn.internal.ir.CatchNode; 65import jdk.nashorn.internal.ir.Expression; 66import jdk.nashorn.internal.ir.ForNode; 67import jdk.nashorn.internal.ir.FunctionNode; 68import jdk.nashorn.internal.ir.IdentNode; 69import jdk.nashorn.internal.ir.IndexNode; 70import jdk.nashorn.internal.ir.LexicalContext; 71import jdk.nashorn.internal.ir.LexicalContextNode; 72import jdk.nashorn.internal.ir.LiteralNode; 73import jdk.nashorn.internal.ir.Node; 74import jdk.nashorn.internal.ir.RuntimeNode; 75import jdk.nashorn.internal.ir.RuntimeNode.Request; 76import jdk.nashorn.internal.ir.Splittable; 77import jdk.nashorn.internal.ir.Statement; 78import jdk.nashorn.internal.ir.SwitchNode; 79import jdk.nashorn.internal.ir.Symbol; 80import jdk.nashorn.internal.ir.TryNode; 81import jdk.nashorn.internal.ir.UnaryNode; 82import jdk.nashorn.internal.ir.VarNode; 83import jdk.nashorn.internal.ir.WithNode; 84import jdk.nashorn.internal.ir.visitor.NodeVisitor; 85import jdk.nashorn.internal.parser.TokenType; 86import jdk.nashorn.internal.runtime.Context; 87import jdk.nashorn.internal.runtime.ECMAErrors; 88import jdk.nashorn.internal.runtime.ErrorManager; 89import jdk.nashorn.internal.runtime.JSErrorType; 90import jdk.nashorn.internal.runtime.ParserException; 91import jdk.nashorn.internal.runtime.Source; 92import jdk.nashorn.internal.runtime.logging.DebugLogger; 93import jdk.nashorn.internal.runtime.logging.Loggable; 94import 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") 105final class AssignSymbols extends NodeVisitor<LexicalContext> 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 super(new LexicalContext()); 154 this.compiler = compiler; 155 this.log = initLogger(compiler.getContext()); 156 this.debug = log.isEnabled(); 157 this.isOnDemand = compiler.isOnDemandCompilation(); 158 } 159 160 @Override 161 public DebugLogger getLogger() { 162 return log; 163 } 164 165 @Override 166 public DebugLogger initLogger(final Context context) { 167 return context.getLogger(this.getClass()); 168 } 169 170 /** 171 * Define symbols for all variable declarations at the top of the function scope. This way we can get around 172 * problems like 173 * 174 * while (true) { 175 * break; 176 * if (true) { 177 * var s; 178 * } 179 * } 180 * 181 * to an arbitrary nesting depth. 182 * 183 * see NASHORN-73 184 * 185 * @param functionNode the FunctionNode we are entering 186 * @param body the body of the FunctionNode we are entering 187 */ 188 private void acceptDeclarations(final FunctionNode functionNode, final Block body) { 189 // This visitor will assign symbol to all declared variables. 190 body.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) { 191 @Override 192 protected boolean enterDefault(final Node node) { 193 // Don't bother visiting expressions; var is a statement, it can't be inside an expression. 194 // This will also prevent visiting nested functions (as FunctionNode is an expression). 195 return !(node instanceof Expression); 196 } 197 198 @Override 199 public Node leaveVarNode(final VarNode varNode) { 200 final IdentNode ident = varNode.getName(); 201 final boolean blockScoped = varNode.isBlockScoped(); 202 if (blockScoped && lc.inUnprotectedSwitchContext()) { 203 throwUnprotectedSwitchError(varNode); 204 } 205 final Block block = blockScoped ? lc.getCurrentBlock() : body; 206 final Symbol symbol = defineSymbol(block, ident.getName(), ident, varNode.getSymbolFlags()); 207 if (varNode.isFunctionDeclaration()) { 208 symbol.setIsFunctionDeclaration(); 209 } 210 return varNode.setName(ident.setSymbol(symbol)); 211 } 212 }); 213 } 214 215 private IdentNode compilerConstantIdentifier(final CompilerConstants cc) { 216 return createImplicitIdentifier(cc.symbolName()).setSymbol(lc.getCurrentFunction().compilerConstant(cc)); 217 } 218 219 /** 220 * Creates an ident node for an implicit identifier within the function (one not declared in the script source 221 * code). These identifiers are defined with function's token and finish. 222 * @param name the name of the identifier 223 * @return an ident node representing the implicit identifier. 224 */ 225 private IdentNode createImplicitIdentifier(final String name) { 226 final FunctionNode fn = lc.getCurrentFunction(); 227 return new IdentNode(fn.getToken(), fn.getFinish(), name); 228 } 229 230 private Symbol createSymbol(final String name, final int flags) { 231 if ((flags & Symbol.KINDMASK) == IS_GLOBAL) { 232 //reuse global symbols so they can be hashed 233 Symbol global = globalSymbols.get(name); 234 if (global == null) { 235 global = new Symbol(name, flags); 236 globalSymbols.put(name, global); 237 } 238 return global; 239 } 240 return new Symbol(name, flags); 241 } 242 243 /** 244 * Creates a synthetic initializer for a variable (a var statement that doesn't occur in the source code). Typically 245 * used to create assignment of {@code :callee} to the function name symbol in self-referential function 246 * expressions as well as for assignment of {@code :arguments} to {@code arguments}. 247 * 248 * @param name the ident node identifying the variable to initialize 249 * @param initConstant the compiler constant it is initialized to 250 * @param fn the function node the assignment is for 251 * @return a var node with the appropriate assignment 252 */ 253 private VarNode createSyntheticInitializer(final IdentNode name, final CompilerConstants initConstant, final FunctionNode fn) { 254 final IdentNode init = compilerConstantIdentifier(initConstant); 255 assert init.getSymbol() != null && init.getSymbol().isBytecodeLocal(); 256 257 final VarNode synthVar = new VarNode(fn.getLineNumber(), fn.getToken(), fn.getFinish(), name, init); 258 259 final Symbol nameSymbol = fn.getBody().getExistingSymbol(name.getName()); 260 assert nameSymbol != null; 261 262 return (VarNode)synthVar.setName(name.setSymbol(nameSymbol)).accept(this); 263 } 264 265 private FunctionNode createSyntheticInitializers(final FunctionNode functionNode) { 266 final List<VarNode> syntheticInitializers = new ArrayList<>(2); 267 268 // Must visit the new var nodes in the context of the body. We could also just set the new statements into the 269 // block and then revisit the entire block, but that seems to be too much double work. 270 final Block body = functionNode.getBody(); 271 lc.push(body); 272 try { 273 if (functionNode.usesSelfSymbol()) { 274 // "var fn = :callee" 275 syntheticInitializers.add(createSyntheticInitializer(functionNode.getIdent(), CALLEE, functionNode)); 276 } 277 278 if (functionNode.needsArguments()) { 279 // "var arguments = :arguments" 280 syntheticInitializers.add(createSyntheticInitializer(createImplicitIdentifier(ARGUMENTS_VAR.symbolName()), 281 ARGUMENTS, functionNode)); 282 } 283 284 if (syntheticInitializers.isEmpty()) { 285 return functionNode; 286 } 287 288 for(final ListIterator<VarNode> it = syntheticInitializers.listIterator(); it.hasNext();) { 289 it.set((VarNode)it.next().accept(this)); 290 } 291 } finally { 292 lc.pop(body); 293 } 294 295 final List<Statement> stmts = body.getStatements(); 296 final List<Statement> newStatements = new ArrayList<>(stmts.size() + syntheticInitializers.size()); 297 newStatements.addAll(syntheticInitializers); 298 newStatements.addAll(stmts); 299 return functionNode.setBody(lc, body.setStatements(lc, newStatements)); 300 } 301 302 /** 303 * Defines a new symbol in the given block. 304 * 305 * @param block the block in which to define the symbol 306 * @param name name of symbol. 307 * @param origin origin node 308 * @param symbolFlags Symbol flags. 309 * 310 * @return Symbol for given name or null for redefinition. 311 */ 312 private Symbol defineSymbol(final Block block, final String name, final Node origin, final int symbolFlags) { 313 int flags = symbolFlags; 314 final boolean isBlockScope = (flags & IS_LET) != 0 || (flags & IS_CONST) != 0; 315 final boolean isGlobal = (flags & KINDMASK) == IS_GLOBAL; 316 317 Symbol symbol; 318 final FunctionNode function; 319 if (isBlockScope) { 320 // block scoped variables always live in current block, no need to look for existing symbols in parent blocks. 321 symbol = block.getExistingSymbol(name); 322 function = lc.getCurrentFunction(); 323 } else { 324 symbol = findSymbol(block, name); 325 function = lc.getFunction(block); 326 } 327 328 // Global variables are implicitly always scope variables too. 329 if (isGlobal) { 330 flags |= IS_SCOPE; 331 } 332 333 if (lc.getCurrentFunction().isProgram()) { 334 flags |= IS_PROGRAM_LEVEL; 335 } 336 337 final boolean isParam = (flags & KINDMASK) == IS_PARAM; 338 final boolean isVar = (flags & KINDMASK) == IS_VAR; 339 340 if (symbol != null) { 341 // Symbol was already defined. Check if it needs to be redefined. 342 if (isParam) { 343 if (!isLocal(function, symbol)) { 344 // Not defined in this function. Create a new definition. 345 symbol = null; 346 } else if (symbol.isParam()) { 347 // Duplicate parameter. Null return will force an error. 348 throw new AssertionError("duplicate parameter"); 349 } 350 } else if (isVar) { 351 if (isBlockScope) { 352 // Check redeclaration in same block 353 if (symbol.hasBeenDeclared()) { 354 throwParserException(ECMAErrors.getMessage("syntax.error.redeclare.variable", name), origin); 355 } else { 356 symbol.setHasBeenDeclared(); 357 // Set scope flag on top-level block scoped symbols 358 if (function.isProgram() && function.getBody() == block) { 359 symbol.setIsScope(); 360 } 361 } 362 } else if ((flags & IS_INTERNAL) != 0) { 363 // Always create a new definition. 364 symbol = null; 365 } else { 366 // Found LET or CONST in parent scope of same function - s SyntaxError 367 if (symbol.isBlockScoped() && isLocal(lc.getCurrentFunction(), symbol)) { 368 throwParserException(ECMAErrors.getMessage("syntax.error.redeclare.variable", name), origin); 369 } 370 // Not defined in this function. Create a new definition. 371 if (!isLocal(function, symbol) || symbol.less(IS_VAR)) { 372 symbol = null; 373 } 374 } 375 } 376 } 377 378 if (symbol == null) { 379 // If not found, then create a new one. 380 final Block symbolBlock; 381 382 // Determine where to create it. 383 if (isVar && ((flags & IS_INTERNAL) != 0 || isBlockScope)) { 384 symbolBlock = block; //internal vars are always defined in the block closest to them 385 } else if (isGlobal) { 386 symbolBlock = lc.getOutermostFunction().getBody(); 387 } else { 388 symbolBlock = lc.getFunctionBody(function); 389 } 390 391 // Create and add to appropriate block. 392 symbol = createSymbol(name, flags); 393 symbolBlock.putSymbol(symbol); 394 395 if ((flags & IS_SCOPE) == 0) { 396 // Initial assumption; symbol can lose its slot later 397 symbol.setNeedsSlot(true); 398 } 399 } else if (symbol.less(flags)) { 400 symbol.setFlags(flags); 401 } 402 403 return symbol; 404 } 405 406 private <T extends Node> T end(final T node) { 407 return end(node, true); 408 } 409 410 private <T extends Node> T end(final T node, final boolean printNode) { 411 if (debug) { 412 final StringBuilder sb = new StringBuilder(); 413 414 sb.append("[LEAVE "). 415 append(name(node)). 416 append("] "). 417 append(printNode ? node.toString() : ""). 418 append(" in '"). 419 append(lc.getCurrentFunction().getName()). 420 append('\''); 421 422 if (node instanceof IdentNode) { 423 final Symbol symbol = ((IdentNode)node).getSymbol(); 424 if (symbol == null) { 425 sb.append(" <NO SYMBOL>"); 426 } else { 427 sb.append(" <symbol=").append(symbol).append('>'); 428 } 429 } 430 431 log.unindent(); 432 log.info(sb); 433 } 434 435 return node; 436 } 437 438 @Override 439 public boolean enterBlock(final Block block) { 440 start(block); 441 442 if (lc.isFunctionBody()) { 443 assert !block.hasSymbols(); 444 final FunctionNode fn = lc.getCurrentFunction(); 445 if (isUnparsedFunction(fn)) { 446 // It's a skipped nested function. Just mark the symbols being used by it as being in use. 447 for(final String name: compiler.getScriptFunctionData(fn.getId()).getExternalSymbolNames()) { 448 nameIsUsed(name, null); 449 } 450 // Don't bother descending into it, it must be empty anyway. 451 assert block.getStatements().isEmpty(); 452 return false; 453 } 454 455 enterFunctionBody(); 456 } 457 458 return true; 459 } 460 461 private boolean isUnparsedFunction(final FunctionNode fn) { 462 return isOnDemand && fn != lc.getOutermostFunction(); 463 } 464 465 @Override 466 public boolean enterCatchNode(final CatchNode catchNode) { 467 final IdentNode exception = catchNode.getException(); 468 final Block block = lc.getCurrentBlock(); 469 470 start(catchNode); 471 472 // define block-local exception variable 473 final String exname = exception.getName(); 474 // If the name of the exception starts with ":e", this is a synthetic catch block, likely a catch-all. Its 475 // symbol is naturally internal, and should be treated as such. 476 final boolean isInternal = exname.startsWith(EXCEPTION_PREFIX.symbolName()); 477 // IS_LET flag is required to make sure symbol is not visible outside catch block. However, we need to 478 // clear the IS_LET flag after creation to allow redefinition of symbol inside the catch block. 479 final Symbol symbol = defineSymbol(block, exname, catchNode, IS_VAR | IS_LET | (isInternal ? IS_INTERNAL : 0) | HAS_OBJECT_VALUE); 480 symbol.clearFlag(IS_LET); 481 482 return true; 483 } 484 485 private void enterFunctionBody() { 486 final FunctionNode functionNode = lc.getCurrentFunction(); 487 final Block body = lc.getCurrentBlock(); 488 489 initFunctionWideVariables(functionNode, body); 490 acceptDeclarations(functionNode, body); 491 defineFunctionSelfSymbol(functionNode, body); 492 } 493 494 private void defineFunctionSelfSymbol(final FunctionNode functionNode, final Block body) { 495 // Function self-symbol is only declared as a local variable for named function expressions. Declared functions 496 // don't need it as they are local variables in their declaring scope. 497 if (!functionNode.isNamedFunctionExpression()) { 498 return; 499 } 500 501 final String name = functionNode.getIdent().getName(); 502 assert name != null; // As it's a named function expression. 503 504 if (body.getExistingSymbol(name) != null) { 505 // Body already has a declaration for the name. It's either a parameter "function x(x)" or a 506 // top-level variable "function x() { ... var x; ... }". 507 return; 508 } 509 510 defineSymbol(body, name, functionNode, IS_VAR | IS_FUNCTION_SELF | HAS_OBJECT_VALUE); 511 if(functionNode.allVarsInScope()) { // basically, has deep eval 512 // We must conservatively presume that eval'd code can dynamically use the function symbol. 513 lc.setFlag(functionNode, FunctionNode.USES_SELF_SYMBOL); 514 } 515 } 516 517 @Override 518 public boolean enterFunctionNode(final FunctionNode functionNode) { 519 start(functionNode, false); 520 521 thisProperties.push(new HashSet<String>()); 522 523 // Every function has a body, even the ones skipped on reparse (they have an empty one). We're 524 // asserting this as even for those, enterBlock() must be invoked to correctly process symbols that 525 // are used in them. 526 assert functionNode.getBody() != null; 527 528 return true; 529 } 530 531 @Override 532 public boolean enterVarNode(final VarNode varNode) { 533 start(varNode); 534 // Normally, a symbol assigned in a var statement is not live for its RHS. Since we also represent function 535 // declarations as VarNodes, they are exception to the rule, as they need to have the symbol visible to the 536 // body of the declared function for self-reference. 537 if (varNode.isFunctionDeclaration()) { 538 defineVarIdent(varNode); 539 } 540 return true; 541 } 542 543 @Override 544 public Node leaveVarNode(final VarNode varNode) { 545 if (!varNode.isFunctionDeclaration()) { 546 defineVarIdent(varNode); 547 } 548 return super.leaveVarNode(varNode); 549 } 550 551 private void defineVarIdent(final VarNode varNode) { 552 final IdentNode ident = varNode.getName(); 553 final int flags; 554 if (!varNode.isBlockScoped() && lc.getCurrentFunction().isProgram()) { 555 flags = IS_SCOPE; 556 } else { 557 flags = 0; 558 } 559 defineSymbol(lc.getCurrentBlock(), ident.getName(), ident, varNode.getSymbolFlags() | flags); 560 } 561 562 private Symbol exceptionSymbol() { 563 return newObjectInternal(EXCEPTION_PREFIX); 564 } 565 566 /** 567 * This has to run before fix assignment types, store any type specializations for 568 * parameters, then turn them into objects for the generic version of this method. 569 * 570 * @param functionNode functionNode 571 */ 572 private FunctionNode finalizeParameters(final FunctionNode functionNode) { 573 final List<IdentNode> newParams = new ArrayList<>(); 574 final boolean isVarArg = functionNode.isVarArg(); 575 576 final Block body = functionNode.getBody(); 577 for (final IdentNode param : functionNode.getParameters()) { 578 final Symbol paramSymbol = body.getExistingSymbol(param.getName()); 579 assert paramSymbol != null; 580 assert paramSymbol.isParam() : paramSymbol + " " + paramSymbol.getFlags(); 581 newParams.add(param.setSymbol(paramSymbol)); 582 583 // parameters should not be slots for a function that uses variable arity signature 584 if (isVarArg) { 585 paramSymbol.setNeedsSlot(false); 586 } 587 } 588 589 return functionNode.setParameters(lc, newParams); 590 } 591 592 /** 593 * Search for symbol in the lexical context starting from the given block. 594 * @param name Symbol name. 595 * @return Found symbol or null if not found. 596 */ 597 private Symbol findSymbol(final Block block, final String name) { 598 for (final Iterator<Block> blocks = lc.getBlocks(block); blocks.hasNext();) { 599 final Symbol symbol = blocks.next().getExistingSymbol(name); 600 if (symbol != null) { 601 return symbol; 602 } 603 } 604 return null; 605 } 606 607 /** 608 * Marks the current function as one using any global symbol. The function and all its parent functions will all be 609 * marked as needing parent scope. 610 * @see FunctionNode#needsParentScope() 611 */ 612 private void functionUsesGlobalSymbol() { 613 for (final Iterator<FunctionNode> fns = lc.getFunctions(); fns.hasNext();) { 614 lc.setFlag(fns.next(), FunctionNode.USES_ANCESTOR_SCOPE); 615 } 616 } 617 618 /** 619 * Marks the current function as one using a scoped symbol. The block defining the symbol will be marked as needing 620 * its own scope to hold the variable. If the symbol is defined outside of the current function, it and all 621 * functions up to (but not including) the function containing the defining block will be marked as needing parent 622 * function scope. 623 * @see FunctionNode#needsParentScope() 624 */ 625 private void functionUsesScopeSymbol(final Symbol symbol) { 626 final String name = symbol.getName(); 627 for (final Iterator<LexicalContextNode> contextNodeIter = lc.getAllNodes(); contextNodeIter.hasNext(); ) { 628 final LexicalContextNode node = contextNodeIter.next(); 629 if (node instanceof Block) { 630 final Block block = (Block)node; 631 if (block.getExistingSymbol(name) != null) { 632 assert lc.contains(block); 633 lc.setBlockNeedsScope(block); 634 break; 635 } 636 } else if (node instanceof FunctionNode) { 637 lc.setFlag(node, FunctionNode.USES_ANCESTOR_SCOPE); 638 } 639 } 640 } 641 642 /** 643 * Declares that the current function is using the symbol. 644 * @param symbol the symbol used by the current function. 645 */ 646 private void functionUsesSymbol(final Symbol symbol) { 647 assert symbol != null; 648 if (symbol.isScope()) { 649 if (symbol.isGlobal()) { 650 functionUsesGlobalSymbol(); 651 } else { 652 functionUsesScopeSymbol(symbol); 653 } 654 } else { 655 assert !symbol.isGlobal(); // Every global is also scope 656 } 657 } 658 659 private void initCompileConstant(final CompilerConstants cc, final Block block, final int flags) { 660 defineSymbol(block, cc.symbolName(), null, flags).setNeedsSlot(true); 661 } 662 663 private void initFunctionWideVariables(final FunctionNode functionNode, final Block body) { 664 initCompileConstant(CALLEE, body, IS_PARAM | IS_INTERNAL | HAS_OBJECT_VALUE); 665 initCompileConstant(THIS, body, IS_PARAM | IS_THIS | HAS_OBJECT_VALUE); 666 667 if (functionNode.isVarArg()) { 668 initCompileConstant(VARARGS, body, IS_PARAM | IS_INTERNAL | HAS_OBJECT_VALUE); 669 if (functionNode.needsArguments()) { 670 initCompileConstant(ARGUMENTS, body, IS_VAR | IS_INTERNAL | HAS_OBJECT_VALUE); 671 defineSymbol(body, ARGUMENTS_VAR.symbolName(), null, IS_VAR | HAS_OBJECT_VALUE); 672 } 673 } 674 675 initParameters(functionNode, body); 676 initCompileConstant(SCOPE, body, IS_VAR | IS_INTERNAL | HAS_OBJECT_VALUE); 677 initCompileConstant(RETURN, body, IS_VAR | IS_INTERNAL); 678 } 679 680 /** 681 * Initialize parameters for function node. 682 * @param functionNode the function node 683 */ 684 private void initParameters(final FunctionNode functionNode, final Block body) { 685 final boolean isVarArg = functionNode.isVarArg(); 686 final boolean scopeParams = functionNode.allVarsInScope() || isVarArg; 687 for (final IdentNode param : functionNode.getParameters()) { 688 final Symbol symbol = defineSymbol(body, param.getName(), param, IS_PARAM); 689 if(scopeParams) { 690 // NOTE: this "set is scope" is a poor substitute for clear expression of where the symbol is stored. 691 // It will force creation of scopes where they would otherwise not necessarily be needed (functions 692 // using arguments object and other variable arity functions). Tracked by JDK-8038942. 693 symbol.setIsScope(); 694 assert symbol.hasSlot(); 695 if(isVarArg) { 696 symbol.setNeedsSlot(false); 697 } 698 } 699 } 700 } 701 702 /** 703 * Is the symbol local to (that is, defined in) the specified function? 704 * @param function the function 705 * @param symbol the symbol 706 * @return true if the symbol is defined in the specified function 707 */ 708 private boolean isLocal(final FunctionNode function, final Symbol symbol) { 709 final FunctionNode definingFn = lc.getDefiningFunction(symbol); 710 assert definingFn != null; 711 return definingFn == function; 712 } 713 714 @Override 715 public Node leaveBinaryNode(final BinaryNode binaryNode) { 716 if (binaryNode.isTokenType(TokenType.ASSIGN)) { 717 return leaveASSIGN(binaryNode); 718 } 719 return super.leaveBinaryNode(binaryNode); 720 } 721 722 private Node leaveASSIGN(final BinaryNode binaryNode) { 723 // If we're assigning a property of the this object ("this.foo = ..."), record it. 724 final Expression lhs = binaryNode.lhs(); 725 if (lhs instanceof AccessNode) { 726 final AccessNode accessNode = (AccessNode) lhs; 727 final Expression base = accessNode.getBase(); 728 if (base instanceof IdentNode) { 729 final Symbol symbol = ((IdentNode)base).getSymbol(); 730 if(symbol.isThis()) { 731 thisProperties.peek().add(accessNode.getProperty()); 732 } 733 } 734 } 735 return binaryNode; 736 } 737 738 @Override 739 public Node leaveUnaryNode(final UnaryNode unaryNode) { 740 switch (unaryNode.tokenType()) { 741 case DELETE: 742 return leaveDELETE(unaryNode); 743 case TYPEOF: 744 return leaveTYPEOF(unaryNode); 745 default: 746 return super.leaveUnaryNode(unaryNode); 747 } 748 } 749 750 private Node leaveDELETE(final UnaryNode unaryNode) { 751 final FunctionNode currentFunctionNode = lc.getCurrentFunction(); 752 final boolean strictMode = currentFunctionNode.isStrict(); 753 final Expression rhs = unaryNode.getExpression(); 754 final Expression strictFlagNode = (Expression)LiteralNode.newInstance(unaryNode, strictMode).accept(this); 755 756 Request request = Request.DELETE; 757 final List<Expression> args = new ArrayList<>(); 758 759 if (rhs instanceof IdentNode) { 760 final IdentNode ident = (IdentNode)rhs; 761 // If this is a declared variable or a function parameter, delete always fails (except for globals). 762 final String name = ident.getName(); 763 final Symbol symbol = ident.getSymbol(); 764 765 if (symbol.isThis()) { 766 // Can't delete "this", ignore and return true 767 return LiteralNode.newInstance(unaryNode, true); 768 } 769 final Expression literalNode = LiteralNode.newInstance(unaryNode, name); 770 final boolean failDelete = strictMode || (!symbol.isScope() && (symbol.isParam() || (symbol.isVar() && !symbol.isProgramLevel()))); 771 772 if (!failDelete) { 773 args.add(compilerConstantIdentifier(SCOPE)); 774 } 775 args.add(literalNode); 776 args.add(strictFlagNode); 777 778 if (failDelete) { 779 request = Request.FAIL_DELETE; 780 } else if ((symbol.isGlobal() && !symbol.isFunctionDeclaration()) || symbol.isProgramLevel()) { 781 request = Request.SLOW_DELETE; 782 } 783 } else if (rhs instanceof AccessNode) { 784 final Expression base = ((AccessNode)rhs).getBase(); 785 final String property = ((AccessNode)rhs).getProperty(); 786 787 args.add(base); 788 args.add(LiteralNode.newInstance(unaryNode, property)); 789 args.add(strictFlagNode); 790 791 } else if (rhs instanceof IndexNode) { 792 final IndexNode indexNode = (IndexNode)rhs; 793 final Expression base = indexNode.getBase(); 794 final Expression index = indexNode.getIndex(); 795 796 args.add(base); 797 args.add(index); 798 args.add(strictFlagNode); 799 800 } else { 801 return LiteralNode.newInstance(unaryNode, true); 802 } 803 return new RuntimeNode(unaryNode, request, args); 804 } 805 806 @Override 807 public Node leaveForNode(final ForNode forNode) { 808 if (forNode.isForIn()) { 809 return forNode.setIterator(lc, newObjectInternal(ITERATOR_PREFIX)); //NASHORN-73 810 } 811 812 return end(forNode); 813 } 814 815 @Override 816 public Node leaveFunctionNode(final FunctionNode functionNode) { 817 final FunctionNode finalizedFunction; 818 if (isUnparsedFunction(functionNode)) { 819 finalizedFunction = functionNode; 820 } else { 821 finalizedFunction = 822 markProgramBlock( 823 removeUnusedSlots( 824 createSyntheticInitializers( 825 finalizeParameters( 826 lc.applyTopFlags(functionNode)))) 827 .setThisProperties(lc, thisProperties.pop().size())); 828 } 829 return finalizedFunction; 830 } 831 832 @Override 833 public Node leaveIdentNode(final IdentNode identNode) { 834 if (identNode.isPropertyName()) { 835 return identNode; 836 } 837 838 final Symbol symbol = nameIsUsed(identNode.getName(), identNode); 839 840 if (!identNode.isInitializedHere()) { 841 symbol.increaseUseCount(); 842 } 843 844 IdentNode newIdentNode = identNode.setSymbol(symbol); 845 846 // If a block-scoped var is used before its declaration mark it as dead. 847 // We can only statically detect this for local vars, cross-function symbols require runtime checks. 848 if (symbol.isBlockScoped() && !symbol.hasBeenDeclared() && !identNode.isDeclaredHere() && isLocal(lc.getCurrentFunction(), symbol)) { 849 newIdentNode = newIdentNode.markDead(); 850 } 851 852 return end(newIdentNode); 853 } 854 855 private Symbol nameIsUsed(final String name, final IdentNode origin) { 856 final Block block = lc.getCurrentBlock(); 857 858 Symbol symbol = findSymbol(block, name); 859 860 //If an existing symbol with the name is found, use that otherwise, declare a new one 861 if (symbol != null) { 862 log.info("Existing symbol = ", symbol); 863 if (symbol.isFunctionSelf()) { 864 final FunctionNode functionNode = lc.getDefiningFunction(symbol); 865 assert functionNode != null; 866 assert lc.getFunctionBody(functionNode).getExistingSymbol(CALLEE.symbolName()) != null; 867 lc.setFlag(functionNode, FunctionNode.USES_SELF_SYMBOL); 868 } 869 870 // if symbol is non-local or we're in a with block, we need to put symbol in scope (if it isn't already) 871 maybeForceScope(symbol); 872 } else { 873 log.info("No symbol exists. Declare as global: ", name); 874 symbol = defineSymbol(block, name, origin, IS_GLOBAL | IS_SCOPE); 875 } 876 877 functionUsesSymbol(symbol); 878 return symbol; 879 } 880 881 @Override 882 public Node leaveSwitchNode(final SwitchNode switchNode) { 883 // We only need a symbol for the tag if it's not an integer switch node 884 if(!switchNode.isUniqueInteger()) { 885 return switchNode.setTag(lc, newObjectInternal(SWITCH_TAG_PREFIX)); 886 } 887 return switchNode; 888 } 889 890 @Override 891 public Node leaveTryNode(final TryNode tryNode) { 892 assert tryNode.getFinallyBody() == null; 893 894 end(tryNode); 895 896 return tryNode.setException(lc, exceptionSymbol()); 897 } 898 899 private Node leaveTYPEOF(final UnaryNode unaryNode) { 900 final Expression rhs = unaryNode.getExpression(); 901 902 final List<Expression> args = new ArrayList<>(); 903 if (rhs instanceof IdentNode && !isParamOrVar((IdentNode)rhs)) { 904 args.add(compilerConstantIdentifier(SCOPE)); 905 args.add(LiteralNode.newInstance(rhs, ((IdentNode)rhs).getName())); //null 906 } else { 907 args.add(rhs); 908 args.add(LiteralNode.newInstance(unaryNode)); //null, do not reuse token of identifier rhs, it can be e.g. 'this' 909 } 910 911 final Node runtimeNode = new RuntimeNode(unaryNode, Request.TYPEOF, args); 912 913 end(unaryNode); 914 915 return runtimeNode; 916 } 917 918 private FunctionNode markProgramBlock(final FunctionNode functionNode) { 919 if (isOnDemand || !functionNode.isProgram()) { 920 return functionNode; 921 } 922 923 return functionNode.setBody(lc, functionNode.getBody().setFlag(lc, Block.IS_GLOBAL_SCOPE)); 924 } 925 926 /** 927 * If the symbol isn't already a scope symbol, but it needs to be (see {@link #symbolNeedsToBeScope(Symbol)}, it is 928 * promoted to a scope symbol and its block marked as needing a scope. 929 * @param symbol the symbol that might be scoped 930 */ 931 private void maybeForceScope(final Symbol symbol) { 932 if (!symbol.isScope() && symbolNeedsToBeScope(symbol)) { 933 Symbol.setSymbolIsScope(lc, symbol); 934 } 935 } 936 937 private Symbol newInternal(final CompilerConstants cc, final int flags) { 938 return defineSymbol(lc.getCurrentBlock(), lc.getCurrentFunction().uniqueName(cc.symbolName()), null, IS_VAR | IS_INTERNAL | flags); //NASHORN-73 939 } 940 941 private Symbol newObjectInternal(final CompilerConstants cc) { 942 return newInternal(cc, HAS_OBJECT_VALUE); 943 } 944 945 private boolean start(final Node node) { 946 return start(node, true); 947 } 948 949 private boolean start(final Node node, final boolean printNode) { 950 if (debug) { 951 final StringBuilder sb = new StringBuilder(); 952 953 sb.append("[ENTER "). 954 append(name(node)). 955 append("] "). 956 append(printNode ? node.toString() : ""). 957 append(" in '"). 958 append(lc.getCurrentFunction().getName()). 959 append("'"); 960 log.info(sb); 961 log.indent(); 962 } 963 964 return true; 965 } 966 967 /** 968 * Determines if the symbol has to be a scope symbol. In general terms, it has to be a scope symbol if it can only 969 * be reached from the current block by traversing a function node, a split node, or a with node. 970 * @param symbol the symbol checked for needing to be a scope symbol 971 * @return true if the symbol has to be a scope symbol. 972 */ 973 private boolean symbolNeedsToBeScope(final Symbol symbol) { 974 if (symbol.isThis() || symbol.isInternal()) { 975 return false; 976 } 977 978 final FunctionNode func = lc.getCurrentFunction(); 979 if ( func.allVarsInScope() || (!symbol.isBlockScoped() && func.isProgram())) { 980 return true; 981 } 982 983 boolean previousWasBlock = false; 984 for (final Iterator<LexicalContextNode> it = lc.getAllNodes(); it.hasNext();) { 985 final LexicalContextNode node = it.next(); 986 if (node instanceof FunctionNode || isSplitLiteral(node)) { 987 // We reached the function boundary or a splitting boundary without seeing a definition for the symbol. 988 // It needs to be in scope. 989 return true; 990 } else if (node instanceof WithNode) { 991 if (previousWasBlock) { 992 // We reached a WithNode; the symbol must be scoped. Note that if the WithNode was not immediately 993 // preceded by a block, this means we're currently processing its expression, not its body, 994 // therefore it doesn't count. 995 return true; 996 } 997 previousWasBlock = false; 998 } else if (node instanceof Block) { 999 if (((Block)node).getExistingSymbol(symbol.getName()) == symbol) { 1000 // We reached the block that defines the symbol without reaching either the function boundary, or a 1001 // WithNode. The symbol need not be scoped. 1002 return false; 1003 } 1004 previousWasBlock = true; 1005 } else { 1006 previousWasBlock = false; 1007 } 1008 } 1009 throw new AssertionError(); 1010 } 1011 1012 private static boolean isSplitLiteral(final LexicalContextNode expr) { 1013 return expr instanceof Splittable && ((Splittable) expr).getSplitRanges() != null; 1014 } 1015 1016 private void throwUnprotectedSwitchError(final VarNode varNode) { 1017 // Block scoped declarations in switch statements without explicit blocks should be declared 1018 // in a common block that contains all the case clauses. We cannot support this without a 1019 // fundamental rewrite of how switch statements are handled (case nodes contain blocks and are 1020 // directly contained by switch node). As a temporary solution we throw a reference error here. 1021 final String msg = ECMAErrors.getMessage("syntax.error.unprotected.switch.declaration", varNode.isLet() ? "let" : "const"); 1022 throwParserException(msg, varNode); 1023 } 1024 1025 private void throwParserException(final String message, final Node origin) { 1026 if (origin == null) { 1027 throw new ParserException(message); 1028 } 1029 final Source source = compiler.getSource(); 1030 final long token = origin.getToken(); 1031 final int line = source.getLine(origin.getStart()); 1032 final int column = source.getColumn(origin.getStart()); 1033 final String formatted = ErrorManager.format(message, source, line, column, token); 1034 throw new ParserException(JSErrorType.SYNTAX_ERROR, formatted, source, line, column, token); 1035 } 1036} 1037