From 06d7c150fd11e22aaa8ecb0a1c5d001e4f564c63 Mon Sep 17 00:00:00 2001
From: Terence Parr <parrt@antlr.org>
Date: Thu, 2 Aug 2012 17:01:53 -0700
Subject: [PATCH] slow again since i had to remove full LL context->alt cache
 (wasn't correct). But, threaded now makes bigger diff than before.

---
 .../antlr/v4/runtime/atn/ParserATNSimulator.java    | 13 +------------
 .../Java/src/org/antlr/v4/runtime/dfa/DFAState.java |  7 -------
 2 files changed, 1 insertion(+), 19 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
index 1e47b197d..a6a9533e0 100755
--- a/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java
@@ -282,12 +282,6 @@ public class ParserATNSimulator<Symbol extends Token> extends ATNSimulator {
 			if ( dfa_debug ) System.out.println("DFA state "+s.stateNumber+" LA(1)=="+getLookaheadName(input));
 			if ( s.isCtxSensitive && !SLL ) {
 				if ( dfa_debug ) System.out.println("ctx sensitive state "+outerContext+" in "+s);
-				PredictionContext predictionCtx = PredictionContext.fromRuleContext(outerContext);
-				predictionCtx = getCachedContext(predictionCtx);
-				Integer predI = s.contextToPredictedAlt.get(predictionCtx);
-				if ( predI!=null ) {
-					return predI; // ha! quick exit :)
-				}
 				boolean loopsSimulateTailRecursion = true;
 				boolean fullCtx = true;
 				ATNConfigSet s0_closure =
@@ -301,7 +295,6 @@ public class ParserATNSimulator<Symbol extends Token> extends ATNSimulator {
 										   outerContext,
 										   ATN.INVALID_ALT_NUMBER,
 										   greedy);
-				s.contextToPredictedAlt.put(predictionCtx, fullCtxSet.uniqueAlt);
 				return fullCtxSet.uniqueAlt;
 			}
 			if ( s.isAcceptState ) {
@@ -540,13 +533,9 @@ public class ParserATNSimulator<Symbol extends Token> extends ATNSimulator {
 																D.configs.conflictingAlts.getMinElement(),
 																greedy);
 							// not accept state: isCtxSensitive
-							PredictionContext predictionCtx = PredictionContext.fromRuleContext(outerContext);
-							predictionCtx = getCachedContext(predictionCtx);
 							D.isCtxSensitive = true; // always force DFA to ATN simulate
 							predictedAlt = fullCtxSet.uniqueAlt;
 							D.prediction = ATN.INVALID_ALT_NUMBER;
-							// TODO: have to cache pred list to test also
-							D.contextToPredictedAlt.put(predictionCtx, predictedAlt); // CACHE
 							addDFAEdge(dfa, previousD, t, D);
 							return predictedAlt; // all done with preds, etc...
 						}
@@ -810,7 +799,7 @@ public class ParserATNSimulator<Symbol extends Token> extends ATNSimulator {
 		}
 
 		int nPredAlts = 0;
-		for (int i = 0; i < n; i++) {
+		for (int i = 1; i < n; i++) {
 			if (altToPred[i] == null) {
 				altToPred[i] = SemanticContext.NONE;
 			}
diff --git a/runtime/Java/src/org/antlr/v4/runtime/dfa/DFAState.java b/runtime/Java/src/org/antlr/v4/runtime/dfa/DFAState.java
index e60cb20ce..5d07fd31f 100644
--- a/runtime/Java/src/org/antlr/v4/runtime/dfa/DFAState.java
+++ b/runtime/Java/src/org/antlr/v4/runtime/dfa/DFAState.java
@@ -31,15 +31,11 @@ package org.antlr.v4.runtime.dfa;
 
 import org.antlr.v4.runtime.atn.ATNConfig;
 import org.antlr.v4.runtime.atn.ATNConfigSet;
-import org.antlr.v4.runtime.atn.PredictionContext;
 import org.antlr.v4.runtime.atn.SemanticContext;
 import org.antlr.v4.runtime.misc.Nullable;
 
-import java.util.Collections;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
-import java.util.Map;
 import java.util.Set;
 
 /** A DFA state represents a set of possible ATN configurations.
@@ -110,9 +106,6 @@ public class DFAState {
 	@Nullable
 	public List<PredPrediction> predicates;
 
-	public Map<PredictionContext,Integer> contextToPredictedAlt =
-		Collections.synchronizedMap(new HashMap<PredictionContext, Integer>());
-
 	/** Map a predicate to a predicted alternative */
 	public static class PredPrediction {
 		public SemanticContext pred; // never null; at least SemanticContext.NONE