/**
* Track backtracking decisions. You'll see a fixed or cyclic decision and then a backtrack.
*
* <p>enter rule ... enter decision LA and possibly consumes (for cyclic DFAs) begin backtrack
* level mark m rewind m end backtrack level, success exit decision ... exit rule
*/
public void beginBacktrack(int level) {
if (dump) System.out.println("enter backtrack " + level);
backtrackDepth++;
DecisionEvent e = currentDecision();
if (e.decision.couldBacktrack) {
stats.numBacktrackOccurrences++;
e.decision.numBacktrackOccurrences++;
e.backtracks = true;
}
}
public void semanticPredicate(boolean result, String predicate) {
stats.numSemanticPredicates++;
if (inDecision()) {
DecisionEvent d = currentDecision();
d.evalSemPred = true;
d.decision.numSemPredEvals++;
if (dump)
System.out.println(
"eval " + predicate + " in " + d.decision.ruleName + "-" + d.decision.decision);
}
}
public void exitDecision(int decisionNumber) {
DecisionEvent d = decisionStack.pop();
d.stopTime = System.currentTimeMillis();
int lastTokenIndex = lastRealTokenTouchedInDecision.getTokenIndex();
int numHidden = getNumberOfHiddenTokens(d.startIndex, lastTokenIndex);
int depth =
lastTokenIndex - d.startIndex - numHidden + 1; // +1 counts consuming start token as 1
d.k = depth;
d.decision.maxk = Math.max(d.decision.maxk, depth);
if (dump)
System.out.println(
"exitDecision "
+ decisionNumber
+ " in "
+ d.decision.ruleName
+ " lookahead "
+ d.k
+ " max token "
+ lastRealTokenTouchedInDecision);
decisionEvents.add(d); // done with decision; track all
}
public void enterDecision(int decisionNumber, boolean couldBacktrack) {
lastRealTokenTouchedInDecision = null;
stats.numDecisionEvents++;
int startingLookaheadIndex = parser.getTokenStream().index();
TokenStream input = parser.getTokenStream();
if (dump)
System.out.println(
"enterDecision canBacktrack="
+ couldBacktrack
+ " "
+ decisionNumber
+ " backtrack depth "
+ backtrackDepth
+ " @ "
+ input.get(input.index())
+ " rule "
+ locationDescription());
String g = (String) currentGrammarFileName.peek();
DecisionDescriptor descriptor = decisions.get(g, decisionNumber);
if (descriptor == null) {
descriptor = new DecisionDescriptor();
decisions.put(g, decisionNumber, descriptor);
descriptor.decision = decisionNumber;
descriptor.fileName = (String) currentGrammarFileName.peek();
descriptor.ruleName = (String) currentRuleName.peek();
descriptor.line = (Integer) currentLine.peek();
descriptor.pos = (Integer) currentPos.peek();
descriptor.couldBacktrack = couldBacktrack;
}
descriptor.n++;
DecisionEvent d = new DecisionEvent();
decisionStack.push(d);
d.decision = descriptor;
d.startTime = System.currentTimeMillis();
d.startIndex = startingLookaheadIndex;
}
