ProfilingATNSimulator class

Inheritance

• Object
• ATNSimulator
• ParserATNSimulator
• ProfilingATNSimulator

Constructors

ProfilingATNSimulator(Parser parser)

Properties

atn → ATN

final, inherited

conflictingAltResolvedBySLL ↔ int?

At the point of LL failover, we record how SLL would resolve the conflict so that we can determine whether or not a decision / input pair is context-sensitive. If LL gives a different result than SLL's predicted alternative, we have a context sensitivity for sure. The converse is not necessarily true, however. It's possible that after conflict resolution chooses minimum alternatives, SLL could get the same answer as LL. Regardless of whether or not the result indicates an ambiguity, it is not treated as a context sensitivity because LL prediction was not required in order to produce a correct prediction for this decision and input sequence. It may in fact still be a context sensitivity but we don't know by looking at the minimum alternatives for the current input.

getter/setter pair

currentDecision ↔ int

getter/setter pair

currentState ↔ DFAState?

getter/setter pair

decisionInfo → List<DecisionInfo>

no setter

decisions ↔ List<DecisionInfo>

getter/setter pair

decisionToDFA → List<DFA>

final, inherited

hashCode → int

The hash code for this object.

no setter, inherited

input ↔ TokenStream

getter/setter pair, inherited

mergeCache ↔ Map<Pair<PredictionContext, PredictionContext>, PredictionContext>?

Each prediction operation uses a cache for merge of prediction contexts. Don't keep around as it wastes huge amounts of memory. DoubleKeyMap isn't synchronized but we're ok since two threads shouldn't reuse same parser/atnsim object because it can only handle one input at a time. This maps graphs a and b to merged result c. (a,b)→c. We can avoid the merge if we ever see a and b again. Note that (b,a)→c should also be examined during cache lookup.

getter/setter pair, inherited

numDecisions ↔ int

getter/setter pair

parser → Parser

final, inherited

predictionMode ↔ PredictionMode

SLL, LL, or LL + exact ambig detection? */

getter/setter pair, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

sharedContextCache → PredictionContextCache?

The context cache maps all PredictionContext objects that are equals() to a single cached copy. This cache is shared across all contexts in all ATNConfigs in all DFA states. We rebuild each ATNConfigSet to use only cached nodes/graphs in addDFAState(). We don't want to fill this during closure() since there are lots of contexts that pop up but are not used ever again. It also greatly slows down closure().

final, inherited

startIndex ↔ int

getter/setter pair, inherited

Methods

actionTransition(ATNConfig config, ActionTransition t) → ATNConfig

inherited

adaptivePredict(TokenStream input, int decision, ParserRuleContext? outerContext) → int

override

addDFAEdge(DFA dfa, DFAState? from, int t, DFAState to) → DFAState?

Add an edge to the DFA, if possible. This method calls {@link #addDFAState} to ensure the to state is present in the DFA. If from is null, or if t is outside the range of edges that can be represented in the DFA tables, this method returns without adding the edge to the DFA.

inherited

addDFAState(DFA dfa, DFAState D) → DFAState

Add state D to the DFA if it is not already present, and return the actual instance stored in the DFA. If a state equivalent to D is already in the DFA, the existing state is returned. Otherwise this method returns D after adding it to the DFA.

inherited

applyPrecedenceFilter(ATNConfigSet configs) → ATNConfigSet

This method transforms the start state computed by {@link #computeStartState} to the special start state used by a precedence DFA for a particular precedence value. The transformation process applies the following changes to the start state's configuration set.

inherited

canDropLoopEntryEdgeInLeftRecursiveRule(ATNConfig config) → bool

Implements first-edge (loop entry) elimination as an optimization during closure operations. See antlr/antlr4#1398.

inherited

clearDFA() → void

Clear the DFA cache used by the current instance. Since the DFA cache may be shared by multiple ATN simulators, this method may affect the performance (but not accuracy) of other parsers which are being used concurrently.

inherited

closure(ATNConfig config, ATNConfigSet configs, Set<ATNConfig> closureBusy, bool collectPredicates, bool fullCtx, bool treatEofAsEpsilon) → void

inherited

closure_(ATNConfig config, ATNConfigSet configs, Set<ATNConfig> closureBusy, bool collectPredicates, bool fullCtx, int depth, bool treatEofAsEpsilon) → void

Do the actual work of walking epsilon edges */

inherited

closureCheckingStopState(ATNConfig config, ATNConfigSet configs, Set<ATNConfig> closureBusy, bool collectPredicates, bool fullCtx, int depth, bool treatEofAsEpsilon) → void

inherited

computeReachSet(ATNConfigSet closure, int t, bool fullCtx) → ATNConfigSet?

override

computeStartState(ATNState p, RuleContext ctx, bool fullCtx) → ATNConfigSet

inherited

computeTargetState(DFA dfa, DFAState previousD, int t) → DFAState?

Compute a target state for an edge in the DFA, and attempt to add the computed state and corresponding edge to the DFA.

override

dumpDeadEndConfigs(NoViableAltException nvae) → void

Used for debugging in adaptivePredict around execATN but I cut it out for clarity now that alg. works well. We can leave this "dead" code for a bit.

inherited

evalSemanticContext(List<PredPrediction> predPredictions, ParserRuleContext outerContext, bool complete) → BitSet

Look through a list of predicate/alt pairs, returning alts for the pairs that win. A Instance predicate indicates an alt containing an unpredicated config which behaves as "always true." If !complete then we stop at the first predicate that evaluates to true. This includes pairs with null predicates.

inherited

evalSemanticContextOne(SemanticContext pred, ParserRuleContext? parserCallStack, int alt, bool fullCtx) → bool

Evaluate a semantic context within a specific parser context.

override

execATN(DFA dfa, DFAState s0, TokenStream input, int startIndex, ParserRuleContext outerContext) → int

Performs ATN simulation to compute a predicted alternative based upon the remaining input, but also updates the DFA cache to avoid having to traverse the ATN again for the same input sequence.

inherited

execATNWithFullContext(DFA dfa, DFAState D, ATNConfigSet s0, TokenStream input, int startIndex, ParserRuleContext outerContext) → int

inherited

getAltThatFinishedDecisionEntryRule(ATNConfigSet configs) → int

inherited

getCachedContext(PredictionContext context) → PredictionContext

inherited

getConflictingAlts(ATNConfigSet configs) → BitSet

Gets a BitSet containing the alternatives in configs which are part of one or more conflicting alternative subsets.

inherited

getConflictingAltsOrUniqueAlt(ATNConfigSet configs) → BitSet

Sam pointed out a problem with the previous definition, v3, of ambiguous states. If we have another state associated with conflicting alternatives, we should keep going. For example, the following grammar

inherited

getEpsilonTarget(ATNConfig config, Transition t, bool collectPredicates, bool inContext, bool fullCtx, bool treatEofAsEpsilon) → ATNConfig?

inherited

getExistingTargetState(DFAState previousD, int t) → DFAState?

Get an existing target state for an edge in the DFA. If the target state for the edge has not yet been computed or is otherwise not available, this method returns null.

override

getLookaheadName(TokenStream input) → String

inherited

getPredicatePredictions(BitSet? ambigAlts, List<SemanticContext?> altToPred) → List<PredPrediction>?

inherited

getPredsForAmbigAlts(BitSet ambigAlts, ATNConfigSet configs, int nalts) → List<SemanticContext?>?

inherited

getReachableTarget(Transition trans, int ttype) → ATNState?

inherited

getRuleName(int index) → String

inherited

getSynValidOrSemInvalidAltThatFinishedDecisionEntryRule(ATNConfigSet configs, ParserRuleContext outerContext) → int

This method is used to improve the localization of error messages by choosing an alternative rather than throwing a NoViableAltException in particular prediction scenarios where the {@link #ERROR} state was reached during ATN simulation.

inherited

getTokenName(int t) → String

inherited

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

noViableAlt(TokenStream input, ParserRuleContext outerContext, ATNConfigSet configs, int startIndex) → NoViableAltException

inherited

precedenceTransition(ATNConfig config, PrecedencePredicateTransition pt, bool collectPredicates, bool inContext, bool fullCtx) → ATNConfig?

inherited

predicateDFAState(DFAState dfaState, DecisionState? decisionState) → void

inherited

predTransition(ATNConfig config, PredicateTransition pt, bool collectPredicates, bool inContext, bool fullCtx) → ATNConfig?

inherited

removeAllConfigsNotInRuleStopState(ATNConfigSet configs, bool lookToEndOfRule) → ATNConfigSet

Return a configuration set containing only the configurations from configs which are in a RuleStopState. If all configurations in configs are already in a rule stop state, this method simply returns configs.

inherited

reportAmbiguity(DFA dfa, DFAState D, int startIndex, int stopIndex, bool exact, BitSet? ambigAlts, ATNConfigSet configs) → void

If context sensitive parsing, we know it's ambiguity not conflict */

override

reportAttemptingFullContext(DFA dfa, BitSet? conflictingAlts, ATNConfigSet configs, int startIndex, int stopIndex) → void

override

reportContextSensitivity(DFA dfa, int prediction, ATNConfigSet configs, int startIndex, int stopIndex) → void

override

reset() → void

inherited

ruleTransition(ATNConfig config, RuleTransition t) → ATNConfig

inherited

splitAccordingToSemanticValidity(ATNConfigSet configs, ParserRuleContext outerContext) → Pair<ATNConfigSet, ATNConfigSet>

Walk the list of configurations and split them according to those that have preds evaluating to true/false. If no pred, assume true pred and include in succeeded set. Returns Pair of sets.

inherited

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited