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.BinaryNode;
63 import jdk.nashorn.internal.ir.Block;
64 import jdk.nashorn.internal.ir.CatchNode;
65 import jdk.nashorn.internal.ir.Expression;
66 import jdk.nashorn.internal.ir.ForNode;
67 import jdk.nashorn.internal.ir.FunctionNode;
68 import jdk.nashorn.internal.ir.FunctionNode.CompilationState;
69 import jdk.nashorn.internal.ir.IdentNode;
70 import jdk.nashorn.internal.ir.IndexNode;
71 import jdk.nashorn.internal.ir.LexicalContext;
72 import jdk.nashorn.internal.ir.LexicalContextNode;
73 import jdk.nashorn.internal.ir.LiteralNode;
74 import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode;
75 import jdk.nashorn.internal.ir.LiteralNode.ArrayLiteralNode.ArrayUnit;
76 import jdk.nashorn.internal.ir.Node;
77 import jdk.nashorn.internal.ir.RuntimeNode;
78 import jdk.nashorn.internal.ir.RuntimeNode.Request;
79 import jdk.nashorn.internal.ir.Statement;
80 import jdk.nashorn.internal.ir.SwitchNode;
81 import jdk.nashorn.internal.ir.Symbol;
82 import jdk.nashorn.internal.ir.TryNode;
83 import jdk.nashorn.internal.ir.UnaryNode;
84 import jdk.nashorn.internal.ir.VarNode;
85 import jdk.nashorn.internal.ir.WithNode;
86 import jdk.nashorn.internal.ir.visitor.NodeVisitor;
87 import jdk.nashorn.internal.runtime.Context;
88 import jdk.nashorn.internal.runtime.ECMAErrors;
89 import jdk.nashorn.internal.runtime.ErrorManager;
90 import jdk.nashorn.internal.runtime.JSErrorType;
91 import jdk.nashorn.internal.runtime.ParserException;
92 import jdk.nashorn.internal.runtime.Source;
93 import jdk.nashorn.internal.runtime.logging.DebugLogger;
94 import jdk.nashorn.internal.runtime.logging.Loggable;
95 import jdk.nashorn.internal.runtime.logging.Logger;
96
97 /**
98 * This visitor assigns symbols to identifiers denoting variables. It does few more minor calculations that are only
99 * possible after symbols have been assigned; such is the transformation of "delete" and "typeof" operators into runtime
100 * nodes and counting of number of properties assigned to "this" in constructor functions. This visitor is also notable
101 * for what it doesn't do, most significantly it does no type calculations as in JavaScript variables can change types
102 * during runtime and as such symbols don't have types. Calculation of expression types is performed by a separate
103 * visitor.
104 */
105 @Logger(name="symbols")
106 final class AssignSymbols extends NodeVisitor<LexicalContext> implements Loggable {
107 private final DebugLogger log;
108 private final boolean debug;
109
110 private static boolean isParamOrVar(final IdentNode identNode) {
111 final Symbol symbol = identNode.getSymbol();
112 return symbol.isParam() || symbol.isVar();
113 }
114
115 private static String name(final Node node) {
116 final String cn = node.getClass().getName();
117 final int lastDot = cn.lastIndexOf('.');
118 if (lastDot == -1) {
119 return cn;
120 }
121 return cn.substring(lastDot + 1);
122 }
123
124 /**
125 * Checks if various symbols that were provisionally marked as needing a slot ended up unused, and marks them as not
126 * needing a slot after all.
127 * @param functionNode the function node
128 * @return the passed in node, for easy chaining
129 */
130 private static FunctionNode removeUnusedSlots(final FunctionNode functionNode) {
131 if (!functionNode.needsCallee()) {
132 functionNode.compilerConstant(CALLEE).setNeedsSlot(false);
133 }
134 if (!(functionNode.hasScopeBlock() || functionNode.needsParentScope())) {
135 functionNode.compilerConstant(SCOPE).setNeedsSlot(false);
136 }
137 // Named function expressions that end up not referencing themselves won't need a local slot for the self symbol.
138 if(!functionNode.isDeclared() && !functionNode.usesSelfSymbol() && !functionNode.isAnonymous()) {
139 final Symbol selfSymbol = functionNode.getBody().getExistingSymbol(functionNode.getIdent().getName());
140 if(selfSymbol != null) {
141 if(selfSymbol.isFunctionSelf()) {
142 selfSymbol.setNeedsSlot(false);
143 selfSymbol.clearFlag(Symbol.IS_VAR);
144 }
145 } else {
146 assert functionNode.isProgram();
147 }
148 }
149 return functionNode;
150 }
151
152 private final Deque<Set<String>> thisProperties = new ArrayDeque<>();
153 private final Map<String, Symbol> globalSymbols = new HashMap<>(); //reuse the same global symbol
154 private final Compiler compiler;
155
156 public AssignSymbols(final Compiler compiler) {
157 super(new LexicalContext());
158 this.compiler = compiler;
159 this.log = initLogger(compiler.getContext());
160 this.debug = log.isEnabled();
161 }
162
163 @Override
164 public DebugLogger getLogger() {
165 return log;
166 }
167
168 @Override
169 public DebugLogger initLogger(final Context context) {
170 return context.getLogger(this.getClass());
171 }
172
173 /**
174 * Define symbols for all variable declarations at the top of the function scope. This way we can get around
175 * problems like
176 *
177 * while (true) {
178 * break;
179 * if (true) {
180 * var s;
181 * }
182 * }
183 *
184 * to an arbitrary nesting depth.
185 *
186 * see NASHORN-73
187 *
188 * @param functionNode the FunctionNode we are entering
189 * @param body the body of the FunctionNode we are entering
190 */
191 private void acceptDeclarations(final FunctionNode functionNode, final Block body) {
192 // This visitor will assign symbol to all declared variables.
193 body.accept(new NodeVisitor<LexicalContext>(new LexicalContext()) {
194 @Override
195 protected boolean enterDefault(final Node node) {
196 // Don't bother visiting expressions; var is a statement, it can't be inside an expression.
197 // This will also prevent visiting nested functions (as FunctionNode is an expression).
198 return !(node instanceof Expression);
199 }
200
201 @Override
202 public Node leaveVarNode(final VarNode varNode) {
203 final IdentNode ident = varNode.getName();
204 final boolean blockScoped = varNode.isBlockScoped();
205 if (blockScoped && lc.inUnprotectedSwitchContext()) {
206 throwUnprotectedSwitchError(varNode);
207 }
208 final Block block = blockScoped ? lc.getCurrentBlock() : body;
209 final Symbol symbol = defineSymbol(block, ident.getName(), ident, varNode.getSymbolFlags());
210 if (varNode.isFunctionDeclaration()) {
211 symbol.setIsFunctionDeclaration();
212 }
213 return varNode.setName(ident.setSymbol(symbol));
214 }
215 });
216 }
217
218 private IdentNode compilerConstantIdentifier(final CompilerConstants cc) {
219 return createImplicitIdentifier(cc.symbolName()).setSymbol(lc.getCurrentFunction().compilerConstant(cc));
220 }
221
222 /**
223 * Creates an ident node for an implicit identifier within the function (one not declared in the script source
224 * code). These identifiers are defined with function's token and finish.
225 * @param name the name of the identifier
226 * @return an ident node representing the implicit identifier.
227 */
228 private IdentNode createImplicitIdentifier(final String name) {
229 final FunctionNode fn = lc.getCurrentFunction();
230 return new IdentNode(fn.getToken(), fn.getFinish(), name);
231 }
232
233 private Symbol createSymbol(final String name, final int flags) {
234 if ((flags & Symbol.KINDMASK) == IS_GLOBAL) {
235 //reuse global symbols so they can be hashed
236 Symbol global = globalSymbols.get(name);
237 if (global == null) {
238 global = new Symbol(name, flags);
239 globalSymbols.put(name, global);
240 }
241 return global;
242 }
243 return new Symbol(name, flags);
244 }
245
246 /**
247 * Creates a synthetic initializer for a variable (a var statement that doesn't occur in the source code). Typically
248 * used to create assignmnent of {@code :callee} to the function name symbol in self-referential function
249 * expressions as well as for assignment of {@code :arguments} to {@code arguments}.
250 *
251 * @param name the ident node identifying the variable to initialize
252 * @param initConstant the compiler constant it is initialized to
253 * @param fn the function node the assignment is for
254 * @return a var node with the appropriate assignment
255 */
256 private VarNode createSyntheticInitializer(final IdentNode name, final CompilerConstants initConstant, final FunctionNode fn) {
257 final IdentNode init = compilerConstantIdentifier(initConstant);
258 assert init.getSymbol() != null && init.getSymbol().isBytecodeLocal();
259
260 final VarNode synthVar = new VarNode(fn.getLineNumber(), fn.getToken(), fn.getFinish(), name, init);
261
262 final Symbol nameSymbol = fn.getBody().getExistingSymbol(name.getName());
263 assert nameSymbol != null;
264
265 return (VarNode)synthVar.setName(name.setSymbol(nameSymbol)).accept(this);
266 }
267
268 private FunctionNode createSyntheticInitializers(final FunctionNode functionNode) {
269 final List<VarNode> syntheticInitializers = new ArrayList<>(2);
270
271 // Must visit the new var nodes in the context of the body. We could also just set the new statements into the
272 // block and then revisit the entire block, but that seems to be too much double work.
273 final Block body = functionNode.getBody();
274 lc.push(body);
275 try {
276 if (functionNode.usesSelfSymbol()) {
277 // "var fn = :callee"
278 syntheticInitializers.add(createSyntheticInitializer(functionNode.getIdent(), CALLEE, functionNode));
279 }
280
281 if (functionNode.needsArguments()) {
282 // "var arguments = :arguments"
283 syntheticInitializers.add(createSyntheticInitializer(createImplicitIdentifier(ARGUMENTS_VAR.symbolName()),
284 ARGUMENTS, functionNode));
285 }
286
287 if (syntheticInitializers.isEmpty()) {
288 return functionNode;
289 }
290
291 for(final ListIterator<VarNode> it = syntheticInitializers.listIterator(); it.hasNext();) {
292 it.set((VarNode)it.next().accept(this));
293 }
294 } finally {
295 lc.pop(body);
296 }
297
298 final List<Statement> stmts = body.getStatements();
299 final List<Statement> newStatements = new ArrayList<>(stmts.size() + syntheticInitializers.size());
300 newStatements.addAll(syntheticInitializers);
301 newStatements.addAll(stmts);
302 return functionNode.setBody(lc, body.setStatements(lc, newStatements));
303 }
304
305 /**
306 * Defines a new symbol in the given block.
307 *
308 * @param block the block in which to define the symbol
309 * @param name name of symbol.
310 * @param origin origin node
311 * @param symbolFlags Symbol flags.
312 *
313 * @return Symbol for given name or null for redefinition.
314 */
315 private Symbol defineSymbol(final Block block, final String name, final Node origin, final int symbolFlags) {
316 int flags = symbolFlags;
317 final boolean isBlockScope = (flags & IS_LET) != 0 || (flags & IS_CONST) != 0;
318 final boolean isGlobal = (flags & KINDMASK) == IS_GLOBAL;
319
320 Symbol symbol;
321 final FunctionNode function;
322 if (isBlockScope) {
323 // block scoped variables always live in current block, no need to look for existing symbols in parent blocks.
324 symbol = block.getExistingSymbol(name);
325 function = lc.getCurrentFunction();
326 } else {
327 symbol = findSymbol(block, name);
328 function = lc.getFunction(block);
329 }
330
331 // Global variables are implicitly always scope variables too.
332 if (isGlobal) {
333 flags |= IS_SCOPE;
334 }
335
336 if (lc.getCurrentFunction().isProgram()) {
337 flags |= IS_PROGRAM_LEVEL;
338 }
339
340 final boolean isParam = (flags & KINDMASK) == IS_PARAM;
341 final boolean isVar = (flags & KINDMASK) == IS_VAR;
342
343 if (symbol != null) {
344 // Symbol was already defined. Check if it needs to be redefined.
345 if (isParam) {
346 if (!isLocal(function, symbol)) {
347 // Not defined in this function. Create a new definition.
348 symbol = null;
349 } else if (symbol.isParam()) {
350 // Duplicate parameter. Null return will force an error.
351 throw new AssertionError("duplicate parameter");
352 }
353 } else if (isVar) {
354 if (isBlockScope) {
355 // Check redeclaration in same block
356 if (symbol.hasBeenDeclared()) {
357 throwParserException(ECMAErrors.getMessage("syntax.error.redeclare.variable", name), origin);
358 } else {
359 symbol.setHasBeenDeclared();
360 // Set scope flag on top-level block scoped symbols
361 if (function.isProgram() && function.getBody() == block) {
362 symbol.setIsScope();
363 }
364 }
365 } else if ((flags & IS_INTERNAL) != 0) {
366 // Always create a new definition.
367 symbol = null;
368 } else {
369 // Found LET or CONST in parent scope of same function - s SyntaxError
370 if (symbol.isBlockScoped() && isLocal(lc.getCurrentFunction(), symbol)) {
371 throwParserException(ECMAErrors.getMessage("syntax.error.redeclare.variable", name), origin);
372 }
373 // Not defined in this function. Create a new definition.
374 if (!isLocal(function, symbol) || symbol.less(IS_VAR)) {
375 symbol = null;
376 }
377 }
378 }
379 }
380
381 if (symbol == null) {
382 // If not found, then create a new one.
383 final Block symbolBlock;
384
385 // Determine where to create it.
386 if (isVar && ((flags & IS_INTERNAL) != 0 || isBlockScope)) {
387 symbolBlock = block; //internal vars are always defined in the block closest to them
388 } else if (isGlobal) {
389 symbolBlock = lc.getOutermostFunction().getBody();
390 } else {
391 symbolBlock = lc.getFunctionBody(function);
392 }
393
394 // Create and add to appropriate block.
395 symbol = createSymbol(name, flags);
396 symbolBlock.putSymbol(lc, symbol);
397
398 if ((flags & IS_SCOPE) == 0) {
399 // Initial assumption; symbol can lose its slot later
400 symbol.setNeedsSlot(true);
401 }
402 } else if (symbol.less(flags)) {
403 symbol.setFlags(flags);
404 }
405
406 return symbol;
407 }
408
409 private <T extends Node> T end(final T node) {
410 return end(node, true);
411 }
412
413 private <T extends Node> T end(final T node, final boolean printNode) {
414 if (debug) {
415 final StringBuilder sb = new StringBuilder();
416
417 sb.append("[LEAVE ").
418 append(name(node)).
419 append("] ").
420 append(printNode ? node.toString() : "").
421 append(" in '").
422 append(lc.getCurrentFunction().getName()).
423 append('\'');
424
425 if (node instanceof IdentNode) {
426 final Symbol symbol = ((IdentNode)node).getSymbol();
427 if (symbol == null) {
428 sb.append(" <NO SYMBOL>");
429 } else {
430 sb.append(" <symbol=").append(symbol).append('>');
431 }
432 }
433
434 log.unindent();
435 log.info(sb);
436 }
437
438 return node;
439 }
440
441 @Override
442 public boolean enterBlock(final Block block) {
443 start(block);
444
445 if (lc.isFunctionBody()) {
446 block.clearSymbols();
447 final FunctionNode fn = lc.getCurrentFunction();
448 if (isUnparsedFunction(fn)) {
449 // It's a skipped nested function. Just mark the symbols being used by it as being in use.
450 for(final String name: compiler.getScriptFunctionData(fn.getId()).getExternalSymbolNames()) {
451 nameIsUsed(name, null);
452 }
453 // Don't bother descending into it, it must be empty anyway.
454 assert block.getStatements().isEmpty();
455 return false;
456 }
457
458 enterFunctionBody();
459 }
460
461 return true;
462 }
463
464 private boolean isUnparsedFunction(final FunctionNode fn) {
465 return compiler.isOnDemandCompilation() && fn != lc.getOutermostFunction();
466 }
467
468 @Override
469 public boolean enterCatchNode(final CatchNode catchNode) {
470 final IdentNode exception = catchNode.getException();
471 final Block block = lc.getCurrentBlock();
472
473 start(catchNode);
474
475 // define block-local exception variable
476 final String exname = exception.getName();
477 // If the name of the exception starts with ":e", this is a synthetic catch block, likely a catch-all. Its
478 // symbol is naturally internal, and should be treated as such.
479 final boolean isInternal = exname.startsWith(EXCEPTION_PREFIX.symbolName());
480 // IS_LET flag is required to make sure symbol is not visible outside catch block. However, we need to
481 // clear the IS_LET flag after creation to allow redefinition of symbol inside the catch block.
482 final Symbol symbol = defineSymbol(block, exname, catchNode, IS_VAR | IS_LET | (isInternal ? IS_INTERNAL : 0) | HAS_OBJECT_VALUE);
483 symbol.clearFlag(IS_LET);
484
485 return true;
486 }
487
488 private void enterFunctionBody() {
489 final FunctionNode functionNode = lc.getCurrentFunction();
490 final Block body = lc.getCurrentBlock();
491
492 initFunctionWideVariables(functionNode, body);
493
494 if (!functionNode.isProgram() && !functionNode.isDeclared() && !functionNode.isAnonymous()) {
495 // It's neither declared nor program - it's a function expression then; assign it a self-symbol unless it's
496 // anonymous.
497 final String name = functionNode.getIdent().getName();
498 assert name != null;
499 assert body.getExistingSymbol(name) == null;
500 defineSymbol(body, name, functionNode, IS_VAR | IS_FUNCTION_SELF | HAS_OBJECT_VALUE);
501 if(functionNode.allVarsInScope()) { // basically, has deep eval
502 lc.setFlag(functionNode, FunctionNode.USES_SELF_SYMBOL);
503 }
504 }
505
506 acceptDeclarations(functionNode, body);
507 }
508
509 @Override
510 public boolean enterFunctionNode(final FunctionNode functionNode) {
511 start(functionNode, false);
512
513 thisProperties.push(new HashSet<String>());
514
515 // Every function has a body, even the ones skipped on reparse (they have an empty one). We're
516 // asserting this as even for those, enterBlock() must be invoked to correctly process symbols that
517 // are used in them.
518 assert functionNode.getBody() != null;
519
520 return true;
521 }
522
523 @Override
524 public boolean enterVarNode(final VarNode varNode) {
525 start(varNode);
526 // Normally, a symbol assigned in a var statement is not live for its RHS. Since we also represent function
527 // declarations as VarNodes, they are exception to the rule, as they need to have the symbol visible to the
528 // body of the declared function for self-reference.
529 if (varNode.isFunctionDeclaration()) {
530 defineVarIdent(varNode);
531 }
532 return true;
533 }
534
535 @Override
536 public Node leaveVarNode(final VarNode varNode) {
537 if (!varNode.isFunctionDeclaration()) {
538 defineVarIdent(varNode);
539 }
540 return super.leaveVarNode(varNode);
541 }
542
543 private void defineVarIdent(final VarNode varNode) {
544 final IdentNode ident = varNode.getName();
545 final int flags;
546 if (varNode.isAnonymousFunctionDeclaration()) {
547 flags = IS_INTERNAL;
548 } else if (!varNode.isBlockScoped() && lc.getCurrentFunction().isProgram()) {
549 flags = IS_SCOPE;
550 } else {
551 flags = 0;
552 }
553 defineSymbol(lc.getCurrentBlock(), ident.getName(), ident, varNode.getSymbolFlags() | flags);
554 }
555
556 private Symbol exceptionSymbol() {
557 return newObjectInternal(EXCEPTION_PREFIX);
558 }
559
560 /**
561 * This has to run before fix assignment types, store any type specializations for
562 * parameters, then turn them into objects for the generic version of this method.
563 *
564 * @param functionNode functionNode
565 */
566 private FunctionNode finalizeParameters(final FunctionNode functionNode) {
567 final List<IdentNode> newParams = new ArrayList<>();
568 final boolean isVarArg = functionNode.isVarArg();
569
570 final Block body = functionNode.getBody();
571 for (final IdentNode param : functionNode.getParameters()) {
572 final Symbol paramSymbol = body.getExistingSymbol(param.getName());
573 assert paramSymbol != null;
574 assert paramSymbol.isParam() : paramSymbol + " " + paramSymbol.getFlags();
575 newParams.add(param.setSymbol(paramSymbol));
576
577 // parameters should not be slots for a function that uses variable arity signature
578 if (isVarArg) {
579 paramSymbol.setNeedsSlot(false);
580 }
581 }
582
583 return functionNode.setParameters(lc, newParams);
584 }
585
586 /**
587 * Search for symbol in the lexical context starting from the given block.
588 * @param name Symbol name.
589 * @return Found symbol or null if not found.
590 */
591 private Symbol findSymbol(final Block block, final String name) {
592 for (final Iterator<Block> blocks = lc.getBlocks(block); blocks.hasNext();) {
593 final Symbol symbol = blocks.next().getExistingSymbol(name);
594 if (symbol != null) {
595 return symbol;
596 }
597 }
598 return null;
599 }
600
601 /**
602 * Marks the current function as one using any global symbol. The function and all its parent functions will all be
603 * marked as needing parent scope.
604 * @see FunctionNode#needsParentScope()
605 */
606 private void functionUsesGlobalSymbol() {
607 for (final Iterator<FunctionNode> fns = lc.getFunctions(); fns.hasNext();) {
608 lc.setFlag(fns.next(), FunctionNode.USES_ANCESTOR_SCOPE);
609 }
610 }
611
612 /**
613 * Marks the current function as one using a scoped symbol. The block defining the symbol will be marked as needing
614 * its own scope to hold the variable. If the symbol is defined outside of the current function, it and all
615 * functions up to (but not including) the function containing the defining block will be marked as needing parent
616 * function scope.
617 * @see FunctionNode#needsParentScope()
618 */
619 private void functionUsesScopeSymbol(final Symbol symbol) {
620 final String name = symbol.getName();
621 for (final Iterator<LexicalContextNode> contextNodeIter = lc.getAllNodes(); contextNodeIter.hasNext(); ) {
622 final LexicalContextNode node = contextNodeIter.next();
623 if (node instanceof Block) {
624 final Block block = (Block)node;
625 if (block.getExistingSymbol(name) != null) {
626 assert lc.contains(block);
627 lc.setBlockNeedsScope(block);
628 break;
629 }
630 } else if (node instanceof FunctionNode) {
631 lc.setFlag(node, FunctionNode.USES_ANCESTOR_SCOPE);
632 }
633 }
634 }
635
636 /**
637 * Declares that the current function is using the symbol.
638 * @param symbol the symbol used by the current function.
639 */
640 private void functionUsesSymbol(final Symbol symbol) {
641 assert symbol != null;
642 if (symbol.isScope()) {
643 if (symbol.isGlobal()) {
644 functionUsesGlobalSymbol();
645 } else {
646 functionUsesScopeSymbol(symbol);
647 }
648 } else {
649 assert !symbol.isGlobal(); // Every global is also scope
650 }
651 }
652
653 private void initCompileConstant(final CompilerConstants cc, final Block block, final int flags) {
654 defineSymbol(block, cc.symbolName(), null, flags).setNeedsSlot(true);
655 }
656
657 private void initFunctionWideVariables(final FunctionNode functionNode, final Block body) {
658 initCompileConstant(CALLEE, body, IS_PARAM | IS_INTERNAL | HAS_OBJECT_VALUE);
659 initCompileConstant(THIS, body, IS_PARAM | IS_THIS | HAS_OBJECT_VALUE);
660
661 if (functionNode.isVarArg()) {
662 initCompileConstant(VARARGS, body, IS_PARAM | IS_INTERNAL | HAS_OBJECT_VALUE);
663 if (functionNode.needsArguments()) {
664 initCompileConstant(ARGUMENTS, body, IS_VAR | IS_INTERNAL | HAS_OBJECT_VALUE);
665 defineSymbol(body, ARGUMENTS_VAR.symbolName(), null, IS_VAR | HAS_OBJECT_VALUE);
666 }
667 }
668
669 initParameters(functionNode, body);
670 initCompileConstant(SCOPE, body, IS_VAR | IS_INTERNAL | HAS_OBJECT_VALUE);
671 initCompileConstant(RETURN, body, IS_VAR | IS_INTERNAL);
672 }
673
674 /**
675 * Initialize parameters for function node.
676 * @param functionNode the function node
677 */
678 private void initParameters(final FunctionNode functionNode, final Block body) {
679 final boolean isVarArg = functionNode.isVarArg();
680 final boolean scopeParams = functionNode.allVarsInScope() || isVarArg;
681 for (final IdentNode param : functionNode.getParameters()) {
682 final Symbol symbol = defineSymbol(body, param.getName(), param, IS_PARAM);
683 if(scopeParams) {
684 // NOTE: this "set is scope" is a poor substitute for clear expression of where the symbol is stored.
685 // It will force creation of scopes where they would otherwise not necessarily be needed (functions
686 // using arguments object and other variable arity functions). Tracked by JDK-8038942.
687 symbol.setIsScope();
688 assert symbol.hasSlot();
689 if(isVarArg) {
690 symbol.setNeedsSlot(false);
691 }
692 }
693 }
694 }
695
696 /**
697 * Is the symbol local to (that is, defined in) the specified function?
698 * @param function the function
699 * @param symbol the symbol
700 * @return true if the symbol is defined in the specified function
701 */
702 private boolean isLocal(final FunctionNode function, final Symbol symbol) {
703 final FunctionNode definingFn = lc.getDefiningFunction(symbol);
704 assert definingFn != null;
705 return definingFn == function;
706 }
707
708 @Override
709 public Node leaveBinaryNode(final BinaryNode binaryNode) {
710 switch (binaryNode.tokenType()) {
711 case ASSIGN:
712 return leaveASSIGN(binaryNode);
713 default:
714 return super.leaveBinaryNode(binaryNode);
715 }
716 }
717
718 private Node leaveASSIGN(final BinaryNode binaryNode) {
719 // If we're assigning a property of the this object ("this.foo = ..."), record it.
720 final Expression lhs = binaryNode.lhs();
721 if (lhs instanceof AccessNode) {
722 final AccessNode accessNode = (AccessNode) lhs;
723 final Expression base = accessNode.getBase();
724 if (base instanceof IdentNode) {
725 final Symbol symbol = ((IdentNode)base).getSymbol();
726 if(symbol.isThis()) {
727 thisProperties.peek().add(accessNode.getProperty());
728 }
729 }
730 }
731 return binaryNode;
732 }
733
734 @Override
735 public Node leaveUnaryNode(final UnaryNode unaryNode) {
736 switch (unaryNode.tokenType()) {
737 case DELETE:
738 return leaveDELETE(unaryNode);
739 case TYPEOF:
740 return leaveTYPEOF(unaryNode);
741 default:
742 return super.leaveUnaryNode(unaryNode);
743 }
744 }
745
746 @Override
747 public Node leaveBlock(final Block block) {
748 // It's not necessary to guard the marking of symbols as locals with this "if" condition for
749 // correctness, it's just an optimization -- runtime type calculation is not used when the compilation
750 // is not an on-demand optimistic compilation, so we can skip locals marking then.
751 if (compiler.useOptimisticTypes() && compiler.isOnDemandCompilation()) {
752 // OTOH, we must not declare symbols from nested functions to be locals. As we're doing on-demand
753 // compilation, and we're skipping parsing the function bodies for nested functions, this
754 // basically only means their parameters. It'd be enough to mistakenly declare to be a local a
755 // symbol in the outer function named the same as one of the parameters, though.
756 if (lc.getFunction(block) == lc.getOutermostFunction()) {
757 for (final Symbol symbol: block.getSymbols()) {
758 if (!symbol.isScope()) {
759 assert symbol.isVar() || symbol.isParam();
760 compiler.declareLocalSymbol(symbol.getName());
761 }
762 }
763 }
764 }
765 return block;
766 }
767
768 private Node leaveDELETE(final UnaryNode unaryNode) {
769 final FunctionNode currentFunctionNode = lc.getCurrentFunction();
770 final boolean strictMode = currentFunctionNode.isStrict();
771 final Expression rhs = unaryNode.getExpression();
772 final Expression strictFlagNode = (Expression)LiteralNode.newInstance(unaryNode, strictMode).accept(this);
773
774 Request request = Request.DELETE;
775 final List<Expression> args = new ArrayList<>();
776
777 if (rhs instanceof IdentNode) {
778 final IdentNode ident = (IdentNode)rhs;
779 // If this is a declared variable or a function parameter, delete always fails (except for globals).
780 final String name = ident.getName();
781 final Symbol symbol = ident.getSymbol();
782 final boolean failDelete = strictMode || (!symbol.isScope() && (symbol.isParam() || (symbol.isVar() && !symbol.isProgramLevel())));
783
784 if (failDelete && symbol.isThis()) {
785 return LiteralNode.newInstance(unaryNode, true).accept(this);
786 }
787 final Expression literalNode = (Expression)LiteralNode.newInstance(unaryNode, name).accept(this);
788
789 if (!failDelete) {
790 args.add(compilerConstantIdentifier(SCOPE));
791 }
792 args.add(literalNode);
793 args.add(strictFlagNode);
794
795 if (failDelete) {
796 request = Request.FAIL_DELETE;
797 }
798 } else if (rhs instanceof AccessNode) {
799 final Expression base = ((AccessNode)rhs).getBase();
800 final String property = ((AccessNode)rhs).getProperty();
801
802 args.add(base);
803 args.add((Expression)LiteralNode.newInstance(unaryNode, property).accept(this));
804 args.add(strictFlagNode);
805
806 } else if (rhs instanceof IndexNode) {
807 final IndexNode indexNode = (IndexNode)rhs;
808 final Expression base = indexNode.getBase();
809 final Expression index = indexNode.getIndex();
810
811 args.add(base);
812 args.add(index);
813 args.add(strictFlagNode);
814
815 } else {
816 return LiteralNode.newInstance(unaryNode, true).accept(this);
817 }
818 return new RuntimeNode(unaryNode, request, args).accept(this);
819 }
820
821 @Override
822 public Node leaveForNode(final ForNode forNode) {
823 if (forNode.isForIn()) {
824 forNode.setIterator(newObjectInternal(ITERATOR_PREFIX)); //NASHORN-73
825 }
826
827 return end(forNode);
828 }
829
830 @Override
831 public Node leaveFunctionNode(final FunctionNode functionNode) {
832 final FunctionNode finalizedFunction;
833 if (isUnparsedFunction(functionNode)) {
834 finalizedFunction = functionNode;
835 } else {
836 finalizedFunction =
837 markProgramBlock(
838 removeUnusedSlots(
839 createSyntheticInitializers(
840 finalizeParameters(
841 lc.applyTopFlags(functionNode))))
842 .setThisProperties(lc, thisProperties.pop().size()));
843 }
844 return finalizedFunction.setState(lc, CompilationState.SYMBOLS_ASSIGNED);
845 }
846
847 @Override
848 public Node leaveIdentNode(final IdentNode identNode) {
849 if (identNode.isPropertyName()) {
850 return identNode;
851 }
852
853 final Symbol symbol = nameIsUsed(identNode.getName(), identNode);
854
855 if (!identNode.isInitializedHere()) {
856 symbol.increaseUseCount();
857 }
858
859 IdentNode newIdentNode = identNode.setSymbol(symbol);
860
861 // If a block-scoped var is used before its declaration mark it as dead.
862 // We can only statically detect this for local vars, cross-function symbols require runtime checks.
863 if (symbol.isBlockScoped() && !symbol.hasBeenDeclared() && !identNode.isDeclaredHere() && isLocal(lc.getCurrentFunction(), symbol)) {
864 newIdentNode = newIdentNode.markDead();
865 }
866
867 return end(newIdentNode);
868 }
869
870 private Symbol nameIsUsed(final String name, final IdentNode origin) {
871 final Block block = lc.getCurrentBlock();
872
873 Symbol symbol = findSymbol(block, name);
874
875 //If an existing symbol with the name is found, use that otherwise, declare a new one
876 if (symbol != null) {
877 log.info("Existing symbol = ", symbol);
878 if (symbol.isFunctionSelf()) {
879 final FunctionNode functionNode = lc.getDefiningFunction(symbol);
880 assert functionNode != null;
881 assert lc.getFunctionBody(functionNode).getExistingSymbol(CALLEE.symbolName()) != null;
882 lc.setFlag(functionNode, FunctionNode.USES_SELF_SYMBOL);
883 }
884
885 // if symbol is non-local or we're in a with block, we need to put symbol in scope (if it isn't already)
886 maybeForceScope(symbol);
887 } else {
888 log.info("No symbol exists. Declare as global: ", name);
889 symbol = defineSymbol(block, name, origin, IS_GLOBAL | IS_SCOPE);
890 }
891
892 functionUsesSymbol(symbol);
893 return symbol;
894 }
895
896 @Override
897 public Node leaveSwitchNode(final SwitchNode switchNode) {
898 // We only need a symbol for the tag if it's not an integer switch node
899 if(!switchNode.isUniqueInteger()) {
900 switchNode.setTag(newObjectInternal(SWITCH_TAG_PREFIX));
901 }
902 return switchNode;
903 }
904
905 @Override
906 public Node leaveTryNode(final TryNode tryNode) {
907 tryNode.setException(exceptionSymbol());
908 assert tryNode.getFinallyBody() == null;
909
910 end(tryNode);
911
912 return tryNode;
913 }
914
915 private Node leaveTYPEOF(final UnaryNode unaryNode) {
916 final Expression rhs = unaryNode.getExpression();
917
918 final List<Expression> args = new ArrayList<>();
919 if (rhs instanceof IdentNode && !isParamOrVar((IdentNode)rhs)) {
920 args.add(compilerConstantIdentifier(SCOPE));
921 args.add((Expression)LiteralNode.newInstance(rhs, ((IdentNode)rhs).getName()).accept(this)); //null
922 } else {
923 args.add(rhs);
924 args.add((Expression)LiteralNode.newInstance(unaryNode).accept(this)); //null, do not reuse token of identifier rhs, it can be e.g. 'this'
925 }
926
927 final Node runtimeNode = new RuntimeNode(unaryNode, Request.TYPEOF, args).accept(this);
928
929 end(unaryNode);
930
931 return runtimeNode;
932 }
933
934 private FunctionNode markProgramBlock(final FunctionNode functionNode) {
935 if (compiler.isOnDemandCompilation() || !functionNode.isProgram()) {
936 return functionNode;
937 }
938
939 return functionNode.setBody(lc, functionNode.getBody().setFlag(lc, Block.IS_GLOBAL_SCOPE));
940 }
941
942 /**
943 * If the symbol isn't already a scope symbol, but it needs to be (see {@link #symbolNeedsToBeScope(Symbol)}, it is
944 * promoted to a scope symbol and its block marked as needing a scope.
945 * @param symbol the symbol that might be scoped
946 */
947 private void maybeForceScope(final Symbol symbol) {
948 if (!symbol.isScope() && symbolNeedsToBeScope(symbol)) {
949 Symbol.setSymbolIsScope(lc, symbol);
950 }
951 }
952
953 private Symbol newInternal(final CompilerConstants cc, final int flags) {
954 return defineSymbol(lc.getCurrentBlock(), lc.getCurrentFunction().uniqueName(cc.symbolName()), null, IS_VAR | IS_INTERNAL | flags); //NASHORN-73
955 }
956
957 private Symbol newObjectInternal(final CompilerConstants cc) {
958 return newInternal(cc, HAS_OBJECT_VALUE);
959 }
960
961 private boolean start(final Node node) {
962 return start(node, true);
963 }
964
965 private boolean start(final Node node, final boolean printNode) {
966 if (debug) {
967 final StringBuilder sb = new StringBuilder();
968
969 sb.append("[ENTER ").
970 append(name(node)).
971 append("] ").
972 append(printNode ? node.toString() : "").
973 append(" in '").
974 append(lc.getCurrentFunction().getName()).
975 append("'");
976 log.info(sb);
977 log.indent();
978 }
979
980 return true;
981 }
982
983 /**
984 * Determines if the symbol has to be a scope symbol. In general terms, it has to be a scope symbol if it can only
985 * be reached from the current block by traversing a function node, a split node, or a with node.
986 * @param symbol the symbol checked for needing to be a scope symbol
987 * @return true if the symbol has to be a scope symbol.
988 */
989 private boolean symbolNeedsToBeScope(final Symbol symbol) {
990 if (symbol.isThis() || symbol.isInternal()) {
991 return false;
992 }
993
994 final FunctionNode func = lc.getCurrentFunction();
995 if ( func.allVarsInScope() || (!symbol.isBlockScoped() && func.isProgram())) {
996 return true;
997 }
998
999 boolean previousWasBlock = false;
1000 for (final Iterator<LexicalContextNode> it = lc.getAllNodes(); it.hasNext();) {
1001 final LexicalContextNode node = it.next();
1002 if (node instanceof FunctionNode || isSplitArray(node)) {
1003 // We reached the function boundary or a splitting boundary without seeing a definition for the symbol.
1004 // It needs to be in scope.
1005 return true;
1006 } else if (node instanceof WithNode) {
1007 if (previousWasBlock) {
1008 // We reached a WithNode; the symbol must be scoped. Note that if the WithNode was not immediately
1009 // preceded by a block, this means we're currently processing its expression, not its body,
1010 // therefore it doesn't count.
1011 return true;
1012 }
1013 previousWasBlock = false;
1014 } else if (node instanceof Block) {
1015 if (((Block)node).getExistingSymbol(symbol.getName()) == symbol) {
1016 // We reached the block that defines the symbol without reaching either the function boundary, or a
1017 // WithNode. The symbol need not be scoped.
1018 return false;
1019 }
1020 previousWasBlock = true;
1021 } else {
1022 previousWasBlock = false;
1023 }
1024 }
1025 throw new AssertionError();
1026 }
1027
1028 private static boolean isSplitArray(final LexicalContextNode expr) {
1029 if(!(expr instanceof ArrayLiteralNode)) {
1030 return false;
1031 }
1032 final List<ArrayUnit> units = ((ArrayLiteralNode)expr).getUnits();
1033 return !(units == null || units.isEmpty());
1034 }
1035
1036 private void throwUnprotectedSwitchError(final VarNode varNode) {
1037 // Block scoped declarations in switch statements without explicit blocks should be declared
1038 // in a common block that contains all the case clauses. We cannot support this without a
1039 // fundamental rewrite of how switch statements are handled (case nodes contain blocks and are
1040 // directly contained by switch node). As a temporary solution we throw a reference error here.
1041 final String msg = ECMAErrors.getMessage("syntax.error.unprotected.switch.declaration", varNode.isLet() ? "let" : "const");
1042 throwParserException(msg, varNode);
1043 }
1044
1045 private void throwParserException(final String message, final Node origin) {
1046 if (origin == null) {
1047 throw new ParserException(message);
1048 }
1049 final Source source = compiler.getSource();
1050 final long token = origin.getToken();
1051 final int line = source.getLine(origin.getStart());
1052 final int column = source.getColumn(origin.getStart());
1053 final String formatted = ErrorManager.format(message, source, line, column, token);
1054 throw new ParserException(JSErrorType.SYNTAX_ERROR, formatted, source, line, column, token);
1055 }
1056 }