Merge remote-tracking branch 'antlr/master' into optimized

sharwell · Apr 7, 2014 · 2ef1828 · 2ef1828
2 parents f1e98fb + 9c6023b
commit 2ef1828
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Showing 4 changed files with 53 additions and 5 deletions.
diff --git a/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java b/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java
@@ -1101,9 +1101,9 @@ protected Tuple2<DFAState, ParserRuleContext> computeTargetState(@NotNull DFA df
 			 * The conditions assume that intermediate
 			 * contains all configurations relevant to the reach set, but this
 			 * condition is not true when one or more configurations have been
-			 * withheld in skippedStopStates.
+			 * withheld in skippedStopStates, or when the current symbol is EOF.
 			 */
-			if (optimize_unique_closure && skippedStopStates == null && reachIntermediate.getUniqueAlt() != ATN.INVALID_ALT_NUMBER) {
+			if (optimize_unique_closure && skippedStopStates == null && t != Token.EOF && reachIntermediate.getUniqueAlt() != ATN.INVALID_ALT_NUMBER) {
 				reachIntermediate.setOutermostConfigSet(reach.isOutermostConfigSet());
 				reach = reachIntermediate;
 				break;
@@ -1712,6 +1712,11 @@ else if (!hasMoreContexts) {
 					}
 				}
 
+				if (!t.isEpsilon() && !closureBusy.add(c)) {
+					// avoid infinite recursion for EOF* and EOF+
+					continue;
+				}
+
 				int newDepth = depth;
 				if ( config.getState() instanceof RuleStopState ) {
 					// target fell off end of rule; mark resulting c as having dipped into outer context

diff --git a/runtime/Java/src/org/antlr/v4/runtime/atn/PredictionMode.java b/runtime/Java/src/org/antlr/v4/runtime/atn/PredictionMode.java
@@ -562,7 +562,7 @@ public static BitSet getAlts(@NotNull Collection<BitSet> altsets) {
 	 * </pre>
 	 */
 	@NotNull
-	public static Collection<BitSet> getConflictingAltSubsets(ATNConfigSet configs) {
+	public static Collection<BitSet> getConflictingAltSubsets(@NotNull ATNConfigSet configs) {
 		AltAndContextMap configToAlts = new AltAndContextMap();
 		for (ATNConfig c : configs) {
 			BitSet alts = configToAlts.get(c);

diff --git a/runtime/Java/src/org/antlr/v4/runtime/atn/Transition.java b/runtime/Java/src/org/antlr/v4/runtime/atn/Transition.java
@@ -110,8 +110,18 @@ protected Transition(@NotNull ATNState target) {
 
 	public abstract int getSerializationType();
 
-	/** Are we epsilon, action, sempred? */
-	public boolean isEpsilon() { return false; }
+	/**
+	 * Determines if the transition is an "epsilon" transition.
+	 *
+	 * <p>The default implementation returns {@code false}.</p>
+	 *
+	 * @return {@code true} if traversing this transition in the ATN does not
+	 * consume an input symbol; otherwise, {@code false} if traversing this
+	 * transition consumes (matches) an input symbol.
+	 */
+	public boolean isEpsilon() {
+		return false;
+	}
 
 	@Nullable
 	public IntervalSet label() { return null; }

diff --git a/tool/test/org/antlr/v4/test/TestParserExec.java b/tool/test/org/antlr/v4/test/TestParserExec.java
@@ -407,4 +407,37 @@ public void testPredicatedIfIfElse() throws Exception {
 		assertEquals("", found);
 		assertNull(stderrDuringParse);
 	}
+
+	/**
+	 * This test ensures that {@link ParserATNSimulator} produces a correct
+	 * result when the grammar contains multiple explicit references to
+	 * {@code EOF} inside of parser rules.
+	 */
+	@Test
+	public void testMultipleEOFHandling() throws Exception {
+		String grammar =
+			"grammar T;\n" +
+			"prog : ('x' | 'x' 'y') EOF EOF;\n";
+		String input = "x";
+		String found = execParser("T.g4", grammar, "TParser", "TLexer", "prog", input, false);
+		assertEquals("", found);
+		assertNull(stderrDuringParse);
+	}
+
+	/**
+	 * This test ensures that {@link ParserATNSimulator} does not produce a
+	 * {@link StackOverflowError} when it encounters an {@code EOF} transition
+	 * inside a closure.
+	 */
+	@Test
+	public void testEOFInClosure() throws Exception {
+		String grammar =
+			"grammar T;\n" +
+			"prog : stat EOF;\n" +
+			"stat : 'x' ('y' | EOF)*?;\n";
+		String input = "x";
+		String found = execParser("T.g4", grammar, "TParser", "TLexer", "prog", input, false);
+		assertEquals("", found);
+		assertNull(stderrDuringParse);
+	}
 }