Add graph dfa complementing; not used yet.

git-svn-id: file://localhost/svn/verilator/trunk/verilator@1005 77ca24e4-aefa-0310-84f0-b9a241c72d87

src/V3GraphDfa.cpp

@@ -480,3 +480,97 @@ public:
 void DfaGraph::dfaReduce() {
     DfaGraphReduce (this, &V3GraphEdge::followAlwaysTrue);
 }
+
+//######################################################################
+//######################################################################
+// Algorithms - complement a DFA
+//
+// The traditional algorithm is to make a rejecting state, add edges to
+// reject from all missing values, then swap accept and reject.  Rather
+// than swap at the end, it's faster if we swap up front, then do the edge
+// changes.
+//
+// 1. Since we didn't log rejecting states, make a temp state (this will be
+// the old accept, and new reject).
+//
+// 2. All vertexes except start/accept get edges to NEW accept for any
+// non-existing case.  Weedely we don't have a nice way of representing
+// this so we just create a edge for each case and mark it "complemented."
+// 
+// 3. Delete temp vertex (old accept/new reject) and related edges.
+// The user's old accept is now the new accept.  This is imporant as
+// we want the virtual type of it to be intact.
+
+class DfaGraphComplement : GraphAlg {
+private:
+    // MEMBERS
+    DfaVertex* m_tempNewerReject;
+
+    // METHODS
+    int debug() { return 9; }
+    DfaGraph* graphp() { return static_cast<DfaGraph*>(m_graphp); }
+
+    void add_complement_edges() {
+	// Find accepting vertex
+	DfaVertex* acceptp = NULL;
+ 	for (V3GraphVertex* vertexp = m_graphp->verticesBeginp(); vertexp; vertexp=vertexp->verticesNextp()) {
+	    if (DfaVertex* vvertexp = dynamic_cast<DfaVertex*>(vertexp)) {
+		if (vvertexp->accepting()) {
+		    acceptp = vvertexp;
+		    break;
+		}
+	    }
+	}
+ 	if (!acceptp) v3fatalSrc("No accepting vertex in DFA\n");
+
+	// Remap edges
+	for (V3GraphVertex* vertexp = m_graphp->verticesBeginp(); vertexp; vertexp=vertexp->verticesNextp()) {
+	    if (DfaVertex* vvertexp = dynamic_cast<DfaVertex*>(vertexp)) {
+		//UINFO(0, "FIX   on vertex "<<vvertexp->name()<<endl);
+		if (!vvertexp->accepting() && vvertexp != m_tempNewerReject) {
+		    for (V3GraphEdge* nextp, *edgep = vertexp->outBeginp(); edgep; edgep=nextp) {
+			nextp = edgep->outNextp();
+			if (!edgep->user()) { // Not processed
+			    // Old edges to accept now go to new reject
+			    DfaEdge* vedgep = static_cast<DfaEdge*>(edgep);
+			    DfaVertex* tovertexp = static_cast<DfaVertex*>(edgep->top());
+			    if (tovertexp->accepting()) {
+				new DfaEdge(graphp(), vvertexp, m_tempNewerReject, vedgep);
+				edgep->unlinkDelete(); edgep=NULL;
+			    }
+
+			    // NOT of all values goes to accept
+			    // We make a edge for each value to OR, IE
+			    // edge(complemented,a) edge(complemented,b) means !(a | b)
+			    if (!tovertexp->accepting()) {  // Note we must include edges moved above to reject
+				DfaEdge* newp = new DfaEdge (graphp(), vvertexp, acceptp, vedgep);
+				newp->complement(!newp->complement());
+				newp->user(1);
+			    }
+			}
+		    }
+		}
+	    }
+	}
+    }
+public:
+    DfaGraphComplement(V3Graph* dfagraphp, V3EdgeFuncP edgeFuncp)
+	: GraphAlg(dfagraphp, edgeFuncp) {
+	if (debug()>=6) m_graphp->dumpDotFilePrefixed("comp_in");
+
+	// Vertex::m_user begin: 1 indicates new edge, no more processing
+	m_graphp->userClearEdges();
+
+	m_tempNewerReject = new DfaVertex(graphp());
+	add_complement_edges();
+	if (debug()>=6) m_graphp->dumpDotFilePrefixed("comp_preswap");
+
+	m_tempNewerReject->unlinkDelete(graphp()); m_tempNewerReject=NULL;
+	if (debug()>=6) m_graphp->dumpDotFilePrefixed("comp_out");
+    }
+    ~DfaGraphComplement() {}
+};
+
+void DfaGraph::dfaComplement() {
+    DfaGraphComplement (this, &V3GraphEdge::followAlwaysTrue);
+}

src/V3GraphDfa.h

@@ -43,7 +43,9 @@ class DfaEdge;
 /// or epsilon, represented as a empty list of inputs.
 ///
 /// We're only looking for matches, so the only accepting states are
-/// at the end of the transformations.
+/// at the end of the transformations.  (If we want the complement, we
+/// call complement and the algorithm makes a REJECT state, then flips
+/// accept and reject for you.)
 ///	
 /// Common transforms:
 ///
@@ -51,8 +53,8 @@ class DfaEdge;
 ///
 ///	"L":	...->[ON_L]-->DfaVtx-->[epsilon]-->DfaVtx(ACCEPT)
 ///
-///	"LR":	...->[ON_L]-->DfaVtx-->[epsilon]-->DfaVtx()
-///		   ->[ON_R]-->DfaVtx-->[epsilon]-->DfaVtx(ACCEPT)
+///	"LR":	...->[ON_L]-->DfaVtx-->[epsilon]-->DfaVtx(ACCEPT)
+///		   ->[ON_R]-->DfaVtx-->[epsilon]-/
 ///
 ///	"L|R":	...->DfaVtx-->[epsilon]-->DfaVtx-->[ON_L]-->DfaVtx()->[epsilon]-->DfaVtx(ACCEPT)
 ///			   \->[epsilon]-->DfaVtx-->[ON_R]-->DfaVtx()->[epsilon]-/
@@ -76,6 +78,9 @@ public:
 
     /// Simplify a DFA automata
     void dfaReduce();
+
+    /// Complement result (must already be dfa)
+    void dfaComplement();
 };
 
 //=============================================================================
@@ -113,20 +118,33 @@ typedef AstNUser* DfaInput;
 
 class DfaEdge : public V3GraphEdge {
     DfaInput	m_input;
+    bool	m_complement;	// Invert value when doing compare
 public:
     static DfaInput EPSILON() { return NULL; }
     static DfaInput NA() { return AstNUser::fromInt(1); }	// as in not-applicable
     // CONSTRUCTORS
     DfaEdge(DfaGraph* graphp, DfaVertex* fromp, DfaVertex* top, DfaInput input)
 	: V3GraphEdge(graphp, fromp, top, 1)
-	, m_input(input) {}
+	, m_input(input), m_complement(false) {}
+    DfaEdge(DfaGraph* graphp, DfaVertex* fromp, DfaVertex* top, const DfaEdge* copyfrom)
+	: V3GraphEdge(graphp, fromp, top, copyfrom->weight())
+	, m_input(copyfrom->input()), m_complement(copyfrom->complement()) {}
     virtual ~DfaEdge() {}
     // METHODS
-    virtual string dotColor() const { return na()?"yellow":epsilon()?"green":"black"; }
-    virtual string dotLabel() const { return na()?"":epsilon()?"e":cvtToStr((void*)(input())); }
+    virtual string dotColor() const {
+	return (na() ? "yellow"
+		: epsilon() ? "green"
+		: "black"); }
+    virtual string dotLabel() const {
+	return (na() ? ""
+		: epsilon() ? "e"
+		: complement() ? ("not "+cvtToStr((void*)(input())))
+		: cvtToStr((void*)(input()))); }
     virtual string dotStyle() const { return (na()||cutable())?"dashed":""; }
     bool epsilon() const { return input()==EPSILON(); }
     bool na() const { return input()==NA(); }
+    bool complement() const { return m_complement; }
+    void complement(bool value) { m_complement=value; }
     DfaInput	input() const { return m_input; }
 };
 

src/V3GraphTest.cpp

@@ -309,6 +309,12 @@ public:
 	gp->nfaToDfa();
 	dump();
 	gp->dfaReduce();
+	dump();
+
+	gp->dfaComplement();
+	dump();
+	gp->dfaReduce();
+	dump();
     }
 };