Add the StarLoopEntryState.precedenceRuleDecision field so the information can be shared between ParserATNSimulator and ParserInterpreter

runtime/Java/src/org/antlr/v4/runtime/ParserInterpreter.java

@@ -41,7 +41,6 @@ import org.antlr.v4.runtime.atn.PrecedencePredicateTransition;
 import org.antlr.v4.runtime.atn.PredicateTransition;
 import org.antlr.v4.runtime.atn.PredictionContextCache;
 import org.antlr.v4.runtime.atn.RuleStartState;
-import org.antlr.v4.runtime.atn.RuleStopState;
 import org.antlr.v4.runtime.atn.RuleTransition;
 import org.antlr.v4.runtime.atn.StarLoopEntryState;
 import org.antlr.v4.runtime.atn.Transition;
@@ -100,17 +99,7 @@ public class ParserInterpreter extends Parser {
 				continue;
 			}
 
-			RuleStartState ruleStartState = atn.ruleToStartState[state.ruleIndex];
-			if (!ruleStartState.isPrecedenceRule) {
-				continue;
-			}
-
-			ATNState maybeLoopEndState = state.transition(state.getNumberOfTransitions() - 1).target;
-			if (!(maybeLoopEndState instanceof LoopEndState)) {
-				continue;
-			}
-
-			if (maybeLoopEndState.epsilonOnlyTransitions && maybeLoopEndState.transition(0).target instanceof RuleStopState) {
+			if (((StarLoopEntryState)state).precedenceRuleDecision) {
 				this.pushRecursionContextStates.set(state.stateNumber);
 			}
 		}

runtime/Java/src/org/antlr/v4/runtime/atn/ATNDeserializer.java

@@ -358,6 +358,8 @@ public class ATNDeserializer {
 			decState.decision = i-1;
 		}
 
+		markPrecedenceDecisions(atn);
+
 		if (deserializationOptions.isVerifyATN()) {
 			verifyATN(atn);
 		}
@@ -455,6 +457,34 @@ public class ATNDeserializer {
 		return atn;
 	}
 
+	/**
+	 * Analyze the {@link StarLoopEntryState} states in the specified ATN to set
+	 * the {@link StarLoopEntryState#precedenceRuleDecision} field to the
+	 * correct value.
+	 *
+	 * @param atn The ATN.
+	 */
+	protected void markPrecedenceDecisions(@NotNull ATN atn) {
+		for (ATNState state : atn.states) {
+			if (!(state instanceof StarLoopEntryState)) {
+				continue;
+			}
+
+			/* We analyze the ATN to determine if this ATN decision state is the
+			 * decision for the closure block that determines whether a
+			 * precedence rule should continue or complete.
+			 */
+			if (atn.ruleToStartState[state.ruleIndex].isPrecedenceRule) {
+				ATNState maybeLoopEndState = state.transition(state.getNumberOfTransitions() - 1).target;
+				if (maybeLoopEndState instanceof LoopEndState) {
+					if (maybeLoopEndState.epsilonOnlyTransitions && maybeLoopEndState.transition(0).target instanceof RuleStopState) {
+						((StarLoopEntryState)state).precedenceRuleDecision = true;
+					}
+				}
+			}
+		}
+	}
+
 	protected void verifyATN(ATN atn) {
 		// verify assumptions
 		for (ATNState state : atn.states) {

runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java

@@ -344,22 +344,14 @@ public class ParserATNSimulator extends ATNSimulator {
 									   ", outerContext="+ outerContext.toString(parser));
 				}
 
-				/* If this is not a precedence DFA, we analyze the ATN to
-				 * determine if this ATN start state is the decision for the
+				/* If this is not a precedence DFA, we check the ATN start state
+				 * to determine if this ATN start state is the decision for the
 				 * closure block that determines whether a precedence rule
 				 * should continue or complete.
-				 *
-				 * This analysis is also in ParserInterpreter to initialize the
-				 * pushRecursionContextStates field.
 				 */
 				if (!dfa.isPrecedenceDfa() && dfa.atnStartState instanceof StarLoopEntryState) {
-					if (atn.ruleToStartState[dfa.atnStartState.ruleIndex].isPrecedenceRule) {
-						ATNState maybeLoopEndState = dfa.atnStartState.transition(dfa.atnStartState.getNumberOfTransitions() - 1).target;
-						if (maybeLoopEndState instanceof LoopEndState) {
-							if (maybeLoopEndState.epsilonOnlyTransitions && maybeLoopEndState.transition(0).target instanceof RuleStopState) {
-								dfa.setPrecedenceDfa(true);
-							}
-						}
+					if (((StarLoopEntryState)dfa.atnStartState).precedenceRuleDecision) {
+						dfa.setPrecedenceDfa(true);
 					}
 				}
 

runtime/Java/src/org/antlr/v4/runtime/atn/StarLoopEntryState.java

@@ -30,9 +30,24 @@
 
 package org.antlr.v4.runtime.atn;
 
+import org.antlr.v4.runtime.ParserInterpreter;
+import org.antlr.v4.runtime.dfa.DFA;
+
 public final class StarLoopEntryState extends DecisionState {
 	public StarLoopbackState loopBackState;
 
+	/**
+	 * Indicates whether this state can benefit from a precedence DFA during SLL
+	 * decision making.
+	 * <p/>
+	 * This is a computed property that is calculated during ATN deserialization
+	 * and stored for use in {@link ParserATNSimulator} and
+	 * {@link ParserInterpreter}.
+	 *
+	 * @see DFA#isPrecedenceDfa()
+	 */
+	public boolean precedenceRuleDecision;
+
 	@Override
 	public int getStateType() {
 		return STAR_LOOP_ENTRY;