public virtual NFAConfiguration AddNFAConfiguration(NFAState state,
int alt,
NFAContext context,
SemanticContext semanticContext)
{
NFAConfiguration c = new NFAConfiguration(state.StateNumber,
alt,
context,
semanticContext);
AddNFAConfiguration(state, c);
return(c);
}
public static SemanticContext And(SemanticContext a, SemanticContext b)
{
//System.Console.Out.WriteLine( "AND: " + a + "&&" + b );
if (a == EmptySemanticContext || a == null)
{
return(b);
}
if (b == EmptySemanticContext || b == null)
{
return(a);
}
if (a.Equals(b))
{
return(a); // if same, just return left one
}
//System.Console.Out.WriteLine( "## have to AND" );
return(new AND(a, b));
}
public static SemanticContext Or(SemanticContext a, SemanticContext b)
{
//System.Console.Out.WriteLine( "OR: " + a + "||" + b );
if (a == EmptySemanticContext || a == null)
{
return(b);
}
if (b == EmptySemanticContext || b == null)
{
return(a);
}
if (a is TruePredicate)
{
return(a);
}
if (b is TruePredicate)
{
return(b);
}
if (a is NOT && b is Predicate)
{
NOT n = (NOT)a;
// check for !p||p
if (n.ctx.Equals(b))
{
return(new TruePredicate());
}
}
else if (b is NOT && a is Predicate)
{
NOT n = (NOT)b;
// check for p||!p
if (n.ctx.Equals(a))
{
return(new TruePredicate());
}
}
else if (a.Equals(b))
{
return(a);
}
//System.Console.Out.WriteLine( "## have to OR" );
return(new OR(a, b));
}
/** Two predicates are the same if they are literally the same
* text rather than same node in the grammar's AST.
* Or, if they have the same constant value, return equal.
* As of July 2006 I'm not sure these are needed.
*/
public override bool Equals(SemanticContext other)
{
Predicate p = other as Predicate;
if (p == null)
{
return(false);
}
if (this._constantValue != InvalidPredValue)
{
return(this._constantValue == p._constantValue);
}
else if (p._constantValue != InvalidPredValue)
{
return(false);
}
return(StringComparer.Ordinal.Equals(_predicateAST.Text, p._predicateAST.Text));
}
public OR(SemanticContext a, SemanticContext b)
{
_operands = new HashSet <object>();
if (a is OR)
{
_operands.addAll(((OR)a)._operands);
}
else if (a != null)
{
_operands.Add(a);
}
if (b is OR)
{
_operands.addAll(((OR)b)._operands);
}
else if (b != null)
{
_operands.Add(b);
}
}
/** For gated productions, we need an OR'd list of all predicates for the
* target of an edge so we can gate the edge based upon the predicates
* associated with taking that path (if any).
*
* For syntactic predicates, we only want to generate predicate
* evaluations as it transitions to an accept state; waste to
* do it earlier. So, only add gated preds derived from manually-
* specified syntactic predicates if this is an accept state.
*
* Also, since configurations w/o gated predicates are like true
* gated predicates, finding a configuration whose alt has no gated
* predicate implies we should evaluate the predicate to true. This
* means the whole edge has to be ungated. Consider:
*
* X : ('a' | {p}?=> 'a')
* | 'a' 'b'
* ;
*
* Here, you 'a' gets you from s0 to s1 but you can't test p because
* plain 'a' is ok. It's also ok for starting alt 2. Hence, you can't
* test p. Even on the edge going to accept state for alt 1 of X, you
* can't test p. You can get to the same place with and w/o the context.
* Therefore, it is never ok to test p in this situation.
*
* TODO: cache this as it's called a lot; or at least set bit if >1 present in state
*/
public virtual SemanticContext GetGatedPredicatesInNFAConfigurations()
{
SemanticContext unionOfPredicatesFromAllAlts = null;
int numConfigs = _nfaConfigurations.Count;
for (int i = 0; i < numConfigs; i++)
{
NFAConfiguration configuration = (NFAConfiguration)_nfaConfigurations[i];
SemanticContext gatedPredExpr =
configuration.SemanticContext.GatedPredicateContext;
if (gatedPredExpr == null)
{
// if we ever find a configuration w/o a gated predicate
// (even if it's a nongated predicate), we cannot gate
// the indident edges.
return(null);
}
else if (IsAcceptState || !configuration.SemanticContext.IsSyntacticPredicate)
{
// at this point we have a gated predicate and, due to elseif,
// we know it's an accept or not a syn pred. In this case,
// it's safe to add the gated predicate to the union. We
// only want to add syn preds if it's an accept state. Other
// gated preds can be used with edges leading to accept states.
if (unionOfPredicatesFromAllAlts == null)
{
unionOfPredicatesFromAllAlts = gatedPredExpr;
}
else
{
unionOfPredicatesFromAllAlts =
SemanticContext.Or(unionOfPredicatesFromAllAlts, gatedPredExpr);
}
}
}
if (unionOfPredicatesFromAllAlts is SemanticContext.TruePredicate)
{
return(null);
}
return(unionOfPredicatesFromAllAlts);
}
public virtual HashSet <SemanticContext> GetGatedSyntacticPredicatesInNFAConfigurations()
{
int numConfigs = _nfaConfigurations.Count;
HashSet <SemanticContext> synpreds = new HashSet <SemanticContext>();
for (int i = 0; i < numConfigs; i++)
{
NFAConfiguration configuration = (NFAConfiguration)_nfaConfigurations[i];
SemanticContext gatedPredExpr =
configuration.SemanticContext.GatedPredicateContext;
// if this is a manual syn pred (gated and syn pred), add
if (gatedPredExpr != null &&
configuration.SemanticContext.IsSyntacticPredicate)
{
synpreds.Add(configuration.SemanticContext);
}
}
if (synpreds.Count == 0)
{
return(null);
}
return(synpreds);
}
/** Make a semantic predicate label */
public PredicateLabel(GrammarAST predicateASTNode)
: base(SEMPRED)
{
this._semanticContext = new SemanticContext.Predicate(predicateASTNode);
}
/** Make a semantic predicates label */
public PredicateLabel( SemanticContext semCtx )
: base(SEMPRED)
{
this._semanticContext = semCtx;
}
/** Make a semantic predicate label */
public PredicateLabel( GrammarAST predicateASTNode )
: base(SEMPRED)
{
this._semanticContext = new SemanticContext.Predicate( predicateASTNode );
}
public static SemanticContext Or(SemanticContext a, SemanticContext b)
{
//System.Console.Out.WriteLine( "OR: " + a + "||" + b );
if ( a == EmptySemanticContext || a == null )
{
return b;
}
if ( b == EmptySemanticContext || b == null )
{
return a;
}
if ( a is TruePredicate )
{
return a;
}
if ( b is TruePredicate )
{
return b;
}
if ( a is NOT && b is Predicate )
{
NOT n = (NOT)a;
// check for !p||p
if ( n.ctx.Equals( b ) )
{
return new TruePredicate();
}
}
else if ( b is NOT && a is Predicate )
{
NOT n = (NOT)b;
// check for p||!p
if ( n.ctx.Equals( a ) )
{
return new TruePredicate();
}
}
else if ( a.Equals( b ) )
{
return a;
}
//System.Console.Out.WriteLine( "## have to OR" );
return new OR( a, b );
}
public static SemanticContext Not(SemanticContext a)
{
NOT nota = a as NOT;
if ( nota != null )
return nota.ctx;
return new NOT( a );
}
public AND( SemanticContext a, SemanticContext b )
{
this._left = a;
this._right = b;
}
public virtual NFAConfiguration AddNFAConfiguration( NFAState state,
int alt,
NFAContext context,
SemanticContext semanticContext )
{
NFAConfiguration c = new NFAConfiguration( state.stateNumber,
alt,
context,
semanticContext );
AddNFAConfiguration( state, c );
return c;
}
/** Make a semantic predicates label */
public PredicateLabel(SemanticContext semCtx)
: base(SEMPRED)
{
this._semanticContext = semCtx;
}
public virtual void SynPredUsedInDFA( DFA dfa, SemanticContext semCtx )
{
decisionsWhoseDFAsUsesSynPreds.Add( dfa );
semCtx.TrackUseOfSyntacticPredicates( this ); // walk ctx looking for preds
}
protected virtual SemanticContext GetPredicatesCore(NFAState s, NFAState altStartState)
{
//[email protected]("_getPredicates("+s+")");
if (s.IsAcceptState)
{
return(null);
}
// avoid infinite loops from (..)* etc...
if (_lookBusy.Contains(s))
{
return(null);
}
_lookBusy.Add(s);
Transition transition0 = s.transition[0];
// no transitions
if (transition0 == null)
{
return(null);
}
// not a predicate and not even an epsilon
if (!(transition0.label.IsSemanticPredicate ||
transition0.label.IsEpsilon))
{
return(null);
}
SemanticContext p = null;
SemanticContext p0 = null;
SemanticContext p1 = null;
if (transition0.label.IsSemanticPredicate)
{
//[email protected]("pred "+transition0.label);
p = transition0.label.SemanticContext;
// ignore backtracking preds not on left edge for this decision
if (((SemanticContext.Predicate)p).predicateAST.Type ==
ANTLRParser.BACKTRACK_SEMPRED &&
s == altStartState.transition[0].target)
{
p = null; // don't count
}
}
// get preds from beyond this state
p0 = GetPredicatesCore((NFAState)transition0.target, altStartState);
// get preds from other transition
Transition transition1 = s.transition[1];
if (transition1 != null)
{
p1 = GetPredicatesCore((NFAState)transition1.target, altStartState);
}
// join this&following-right|following-down
return(SemanticContext.And(p, SemanticContext.Or(p0, p1)));
}
protected virtual int DetectConfoundingPredicatesCore(NFAState s,
Rule enclosingRule,
bool chaseFollowTransitions)
{
//[email protected]("_detectNonAutobacktrackPredicates("+s+")");
if (!chaseFollowTransitions && s.IsAcceptState)
{
if (_grammar.type == GrammarType.Lexer)
{
// FOLLOW makes no sense (at the moment!) for lexical rules.
// assume all char can follow
return(DETECT_PRED_NOT_FOUND);
}
return(DETECT_PRED_EOR);
}
if (_lookBusy.Contains(s))
{
// return a copy of an empty set; we may modify set inline
return(DETECT_PRED_NOT_FOUND);
}
_lookBusy.Add(s);
Transition transition0 = s.transition[0];
if (transition0 == null)
{
return(DETECT_PRED_NOT_FOUND);
}
if (!(transition0.label.IsSemanticPredicate ||
transition0.label.IsEpsilon))
{
return(DETECT_PRED_NOT_FOUND);
}
if (transition0.label.IsSemanticPredicate)
{
//[email protected]("pred "+transition0.label);
SemanticContext ctx = transition0.label.SemanticContext;
SemanticContext.Predicate p = (SemanticContext.Predicate)ctx;
if (p.predicateAST.Type != ANTLRParser.BACKTRACK_SEMPRED)
{
return(DETECT_PRED_FOUND);
}
}
/*
* if ( transition0.label.isSemanticPredicate() ) {
* [email protected]("pred "+transition0.label);
* SemanticContext ctx = transition0.label.getSemanticContext();
* SemanticContext.Predicate p = (SemanticContext.Predicate)ctx;
* // if a non-syn-pred found not in enclosingRule, say we found one
* if ( p.predicateAST.getType() != ANTLRParser.BACKTRACK_SEMPRED &&
* !p.predicateAST.enclosingRuleName.equals(enclosingRule.name) )
* {
* [email protected]("found pred "+p+" not in "+enclosingRule.name);
* return DETECT_PRED_FOUND;
* }
* }
*/
int result = DetectConfoundingPredicatesCore((NFAState)transition0.target,
enclosingRule,
chaseFollowTransitions);
if (result == DETECT_PRED_FOUND)
{
return(DETECT_PRED_FOUND);
}
if (result == DETECT_PRED_EOR)
{
if (transition0 is RuleClosureTransition)
{
// we called a rule that found the end of the rule.
// That means the rule is nullable and we need to
// keep looking at what follows the rule ref. E.g.,
// a : b A ; where b is nullable means that LOOK(a)
// should include A.
RuleClosureTransition ruleInvocationTrans =
(RuleClosureTransition)transition0;
NFAState following = (NFAState)ruleInvocationTrans.followState;
int afterRuleResult =
DetectConfoundingPredicatesCore(following,
enclosingRule,
chaseFollowTransitions);
if (afterRuleResult == DETECT_PRED_FOUND)
{
return(DETECT_PRED_FOUND);
}
}
}
Transition transition1 = s.transition[1];
if (transition1 != null)
{
int t1Result =
DetectConfoundingPredicatesCore((NFAState)transition1.target,
enclosingRule,
chaseFollowTransitions);
if (t1Result == DETECT_PRED_FOUND)
{
return(DETECT_PRED_FOUND);
}
}
return(DETECT_PRED_NOT_FOUND);
}
public OR( SemanticContext a, SemanticContext b )
{
_operands = new HashSet<object>();
if ( a is OR )
{
_operands.addAll( ( (OR)a )._operands );
}
else if ( a != null )
{
_operands.Add( a );
}
if ( b is OR )
{
_operands.addAll( ( (OR)b )._operands );
}
else if ( b != null )
{
_operands.Add( b );
}
}
public NOT( SemanticContext ctx )
{
this.ctx = ctx;
}
public AND(SemanticContext a, SemanticContext b)
{
this._left = a;
this._right = b;
}
protected abstract SemanticContext CombinePredicates(SemanticContext a, SemanticContext b);
public NOT(SemanticContext ctx)
{
this.ctx = ctx;
}
public OR(SemanticContext a, SemanticContext b)
: base(a, b)
{
}
protected override SemanticContext CombinePredicates(SemanticContext a, SemanticContext b)
{
return(Or(a, b));
}
public static SemanticContext And(SemanticContext a, SemanticContext b)
{
//System.Console.Out.WriteLine( "AND: " + a + "&&" + b );
if ( a == EmptySemanticContext || a == null )
{
return b;
}
if ( b == EmptySemanticContext || b == null )
{
return a;
}
if ( a.Equals( b ) )
{
return a; // if same, just return left one
}
//System.Console.Out.WriteLine( "## have to AND" );
return new AND( a, b );
}
