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.ir;
27
28 import java.io.PrintWriter;
29 import java.util.ArrayList;
30 import java.util.Arrays;
31 import java.util.Collections;
32 import java.util.Comparator;
33 import java.util.LinkedHashMap;
34 import java.util.List;
35 import java.util.Map;
36 import jdk.nashorn.internal.codegen.Label;
37 import jdk.nashorn.internal.ir.annotations.Immutable;
38 import jdk.nashorn.internal.ir.visitor.NodeVisitor;
39
40 /**
41 * IR representation for a list of statements.
42 */
43 @Immutable
44 public class Block extends Node implements BreakableNode, Terminal, Flags<Block> {
45 private static final long serialVersionUID = 1L;
46
47 /** List of statements */
48 protected final List<Statement> statements;
49
50 /** Symbol table - keys must be returned in the order they were put in. */
51 protected final Map<String, Symbol> symbols;
52
53 /** Entry label. */
54 private final Label entryLabel;
55
56 /** Break label. */
57 private final Label breakLabel;
58
59 /** Does the block/function need a new scope? Is this synthetic? */
60 protected final int flags;
61
62 /**
63 * @see JoinPredecessor
64 */
65 private final LocalVariableConversion conversion;
66
67 /** Flag indicating that this block needs scope */
68 public static final int NEEDS_SCOPE = 1 << 0;
69
70 /**
71 * Is this block tagged as terminal based on its contents
72 * (usually the last statement)
73 */
74 public static final int IS_TERMINAL = 1 << 2;
75
76 /**
77 * Is this block the eager global scope - i.e. the original program. This isn't true for the
78 * outermost level of recompiles
79 */
80 public static final int IS_GLOBAL_SCOPE = 1 << 3;
81
82 /**
83 * Is this block a synthetic one introduced by Parser?
84 */
85 public static final int IS_SYNTHETIC = 1 << 4;
86
87 /**
88 * Constructor
89 *
90 * @param token The first token of the block
91 * @param finish The index of the last character
92 * @param flags The flags of the block
93 * @param statements All statements in the block
94 */
95 public Block(final long token, final int finish, final int flags, final Statement... statements) {
96 super(token, finish);
97
98 this.statements = Arrays.asList(statements);
99 this.symbols = new LinkedHashMap<>();
100 this.entryLabel = new Label("block_entry");
101 this.breakLabel = new Label("block_break");
102 final int len = statements.length;
103 final int terminalFlags = len > 0 && statements[len - 1].hasTerminalFlags() ? IS_TERMINAL : 0;
104 this.flags = terminalFlags | flags;
105 this.conversion = null;
106 }
107
108 /**
109 * Constructs a new block
110 *
111 * @param token The first token of the block
112 * @param finish The index of the last character
113 * @param statements All statements in the block
114 */
115 public Block(final long token, final int finish, final Statement...statements){
116 this(token, finish, IS_SYNTHETIC, statements);
117 }
118
119 /**
120 * Constructs a new block
121 *
122 * @param token The first token of the block
123 * @param finish The index of the last character
124 * @param statements All statements in the block
125 */
126 public Block(final long token, final int finish, final List<Statement> statements){
127 this(token, finish, IS_SYNTHETIC, statements);
128 }
129
130 /**
131 * Constructor
132 *
133 * @param token The first token of the block
134 * @param finish The index of the last character
135 * @param flags The flags of the block
136 * @param statements All statements in the block
137 */
138 public Block(final long token, final int finish, final int flags, final List<Statement> statements) {
139 this(token, finish, flags, statements.toArray(new Statement[statements.size()]));
140 }
141
142 private Block(final Block block, final int finish, final List<Statement> statements, final int flags, final Map<String, Symbol> symbols, final LocalVariableConversion conversion) {
143 super(block, finish);
144 this.statements = statements;
145 this.flags = flags;
146 this.symbols = new LinkedHashMap<>(symbols); //todo - symbols have no dependencies on any IR node and can as far as we understand it be shallow copied now
147 this.entryLabel = new Label(block.entryLabel);
148 this.breakLabel = new Label(block.breakLabel);
149 this.conversion = conversion;
150 }
151
152 /**
153 * Is this block the outermost eager global scope - i.e. the primordial program?
154 * Used for global anchor point for scope depth computation for recompilation code
155 * @return true if outermost eager global scope
156 */
157 public boolean isGlobalScope() {
158 return getFlag(IS_GLOBAL_SCOPE);
159 }
160
161 /**
162 * Clear the symbols in the block.
163 * TODO: make this immutable.
164 */
165 public void clearSymbols() {
166 symbols.clear();
167 }
168
169 @Override
170 public Node ensureUniqueLabels(final LexicalContext lc) {
171 return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags, symbols, conversion));
172 }
173
174 /**
175 * Assist in IR navigation.
176 *
177 * @param visitor IR navigating visitor.
178 * @return new or same node
179 */
180 @Override
181 public Node accept(final LexicalContext lc, final NodeVisitor<? extends LexicalContext> visitor) {
182 if (visitor.enterBlock(this)) {
183 return visitor.leaveBlock(setStatements(lc, Node.accept(visitor, statements)));
184 }
185
186 return this;
187 }
188
189 /**
190 * Get a copy of the list for all the symbols defined in this block
191 * @return symbol iterator
192 */
193 public List<Symbol> getSymbols() {
194 return Collections.unmodifiableList(new ArrayList<>(symbols.values()));
195 }
196
197 /**
198 * Retrieves an existing symbol defined in the current block.
199 * @param name the name of the symbol
200 * @return an existing symbol with the specified name defined in the current block, or null if this block doesn't
201 * define a symbol with this name.T
202 */
203 public Symbol getExistingSymbol(final String name) {
204 return symbols.get(name);
205 }
206
207 /**
208 * Test if this block represents a <tt>catch</tt> block in a <tt>try</tt> statement.
209 * This is used by the Splitter as catch blocks are not be subject to splitting.
210 *
211 * @return true if this block represents a catch block in a try statement.
212 */
213 public boolean isCatchBlock() {
214 return statements.size() == 1 && statements.get(0) instanceof CatchNode;
215 }
216
217 @Override
218 public void toString(final StringBuilder sb, final boolean printType) {
219 for (final Node statement : statements) {
220 statement.toString(sb, printType);
221 sb.append(';');
222 }
223 }
224
225 /**
226 * Print symbols in block in alphabetical order, sorted on name
227 * Used for debugging, see the --print-symbols flag
228 *
229 * @param stream print writer to output symbols to
230 *
231 * @return true if symbols were found
232 */
233 public boolean printSymbols(final PrintWriter stream) {
234 final List<Symbol> values = new ArrayList<>(symbols.values());
235
236 Collections.sort(values, new Comparator<Symbol>() {
237 @Override
238 public int compare(final Symbol s0, final Symbol s1) {
239 return s0.getName().compareTo(s1.getName());
240 }
241 });
242
243 for (final Symbol symbol : values) {
244 symbol.print(stream);
245 }
246
247 return !values.isEmpty();
248 }
249
250 /**
251 * Tag block as terminal or non terminal
252 * @param lc lexical context
253 * @param isTerminal is block terminal
254 * @return same block, or new if flag changed
255 */
256 public Block setIsTerminal(final LexicalContext lc, final boolean isTerminal) {
257 return isTerminal ? setFlag(lc, IS_TERMINAL) : clearFlag(lc, IS_TERMINAL);
258 }
259
260 @Override
261 public int getFlags() {
262 return flags;
263 }
264
265 /**
266 * Is this a terminal block, i.e. does it end control flow like ending with a throw or return?
267 *
268 * @return true if this node statement is terminal
269 */
270 @Override
271 public boolean isTerminal() {
272 return getFlag(IS_TERMINAL);
273 }
274
275 /**
276 * Get the entry label for this block
277 * @return the entry label
278 */
279 public Label getEntryLabel() {
280 return entryLabel;
281 }
282
283 @Override
284 public Label getBreakLabel() {
285 return breakLabel;
286 }
287
288 @Override
289 public Block setLocalVariableConversion(final LexicalContext lc, final LocalVariableConversion conversion) {
290 if(this.conversion == conversion) {
291 return this;
292 }
293 return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags, symbols, conversion));
294 }
295
296 @Override
297 public LocalVariableConversion getLocalVariableConversion() {
298 return conversion;
299 }
300
301 /**
302 * Get the list of statements in this block
303 *
304 * @return a list of statements
305 */
306 public List<Statement> getStatements() {
307 return Collections.unmodifiableList(statements);
308 }
309
310 /**
311 * Returns the number of statements in the block.
312 * @return the number of statements in the block.
313 */
314 public int getStatementCount() {
315 return statements.size();
316 }
317
318 /**
319 * Returns the line number of the first statement in the block.
320 * @return the line number of the first statement in the block, or -1 if the block has no statements.
321 */
322 public int getFirstStatementLineNumber() {
323 if(statements == null || statements.isEmpty()) {
324 return -1;
325 }
326 return statements.get(0).getLineNumber();
327 }
328
329 /**
330 * Returns the last statement in the block.
331 * @return the last statement in the block, or null if the block has no statements.
332 */
333 public Statement getLastStatement() {
334 return statements.isEmpty() ? null : statements.get(statements.size() - 1);
335 }
336
337 /**
338 * Reset the statement list for this block
339 *
340 * @param lc lexical context
341 * @param statements new statement list
342 * @return new block if statements changed, identity of statements == block.statements
343 */
344 public Block setStatements(final LexicalContext lc, final List<Statement> statements) {
345 if (this.statements == statements) {
346 return this;
347 }
348 int lastFinish = 0;
349 if (!statements.isEmpty()) {
350 lastFinish = statements.get(statements.size() - 1).getFinish();
351 }
352 return Node.replaceInLexicalContext(lc, this, new Block(this, Math.max(finish, lastFinish), statements, flags, symbols, conversion));
353 }
354
355 /**
356 * Add or overwrite an existing symbol in the block
357 *
358 * @param lc get lexical context
359 * @param symbol symbol
360 */
361 public void putSymbol(final LexicalContext lc, final Symbol symbol) {
362 symbols.put(symbol.getName(), symbol);
363 }
364
365 /**
366 * Check whether scope is necessary for this Block
367 *
368 * @return true if this function needs a scope
369 */
370 public boolean needsScope() {
371 return (flags & NEEDS_SCOPE) == NEEDS_SCOPE;
372 }
373
374 /**
375 * Check whether this block is synthetic or not.
376 *
377 * @return true if this is a synthetic block
378 */
379 public boolean isSynthetic() {
380 return (flags & IS_SYNTHETIC) == IS_SYNTHETIC;
381 }
382
383 @Override
384 public Block setFlags(final LexicalContext lc, final int flags) {
385 if (this.flags == flags) {
386 return this;
387 }
388 return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags, symbols, conversion));
389 }
390
391 @Override
392 public Block clearFlag(final LexicalContext lc, final int flag) {
393 return setFlags(lc, flags & ~flag);
394 }
395
396 @Override
397 public Block setFlag(final LexicalContext lc, final int flag) {
398 return setFlags(lc, flags | flag);
399 }
400
401 @Override
402 public boolean getFlag(final int flag) {
403 return (flags & flag) == flag;
404 }
405
406 /**
407 * Set the needs scope flag.
408 * @param lc lexicalContext
409 * @return new block if state changed, otherwise this
410 */
411 public Block setNeedsScope(final LexicalContext lc) {
412 if (needsScope()) {
413 return this;
414 }
415
416 return Node.replaceInLexicalContext(lc, this, new Block(this, finish, statements, flags | NEEDS_SCOPE, symbols, conversion));
417 }
418
419 /**
420 * Computationally determine the next slot for this block,
421 * indexed from 0. Use this as a relative base when computing
422 * frames
423 * @return next slot
424 */
425 public int nextSlot() {
426 int next = 0;
427 for (final Symbol symbol : getSymbols()) {
428 if (symbol.hasSlot()) {
429 next += symbol.slotCount();
430 }
431 }
432 return next;
433 }
434
435 @Override
436 public boolean isBreakableWithoutLabel() {
437 return false;
438 }
439
440 @Override
441 public List<Label> getLabels() {
442 return Collections.unmodifiableList(Arrays.asList(entryLabel, breakLabel));
443 }
444
445 @Override
446 public Node accept(final NodeVisitor<? extends LexicalContext> visitor) {
447 return Acceptor.accept(this, visitor);
448 }
449 }