Support string len() method.

src/V3AstNodes.h

@@ -3545,6 +3545,18 @@ public:
     virtual int instrCount()	const { return 1+V3Number::log2b(width()); }
 };
 
+class AstLenN : public AstNodeUniop {
+    // Length of a string
+public:
+    AstLenN(FileLine* fl, AstNode* lhsp) : AstNodeUniop(fl, lhsp) {
+        dtypeSetSigned32(); }
+    ASTNODE_NODE_FUNCS(LenN)
+    virtual void numberOperate(V3Number& out, const V3Number& lhs) { out.opLenN(lhs); }
+    virtual string emitVerilog() { return "%f(%l)"; }
+    virtual string emitC() { return "VL_LEN_IN(%li)"; }
+    virtual bool cleanOut() {return true;} virtual bool cleanLhs() {return true;}
+    virtual bool sizeMattersLhs() {return false;}
+};
 class AstLogNot : public AstNodeUniop {
 public:
     AstLogNot(FileLine* fl, AstNode* lhsp) : AstNodeUniop(fl, lhsp) {

src/V3Number.cpp

@@ -1035,6 +1035,11 @@ V3Number& V3Number::opConcat (const V3Number& lhs, const V3Number& rhs) {
     return *this;
 }
 
+V3Number& V3Number::opLenN (const V3Number& lhs) {
+    setQuad(lhs.toString().length());
+    return *this;
+}
+
 V3Number& V3Number::opRepl (const V3Number& lhs, const V3Number& rhs) {	// rhs is # of times to replicate
     // Hopefully the using routine has a error check too.
     // See also error in V3Width

src/V3Number.h

@@ -242,6 +242,7 @@ public:
     V3Number& opCLog2	(const V3Number& lhs);
     V3Number& opClean	(const V3Number& lhs, uint32_t bits);
     V3Number& opConcat	(const V3Number& lhs, const V3Number& rhs);
+    V3Number& opLenN	(const V3Number& lhs);
     V3Number& opRepl	(const V3Number& lhs, const V3Number& rhs);
     V3Number& opRepl	(const V3Number& lhs, uint32_t rhs);
     V3Number& opStreamL	(const V3Number& lhs, const V3Number& rhs);

src/V3Width.cpp

@@ -330,6 +330,9 @@ private:
     // Widths: Output integer unsigned, input real
     virtual void visit(AstRealToBits* nodep) {	visit_Ou64_Lr(nodep); }
 
+    // Output integer, input string
+    virtual void visit(AstLenN* nodep) { visit_Os32_string(nodep); }
+
     // Widths: Constant, terminal
     virtual void visit(AstTime* nodep) {	nodep->dtypeSetUInt64(); }
     virtual void visit(AstTimeD* nodep) {	nodep->dtypeSetDouble(); }
@@ -1497,6 +1500,7 @@ private:
 	// Find the fromp dtype - should be a class
 	if (!nodep->fromp() || !nodep->fromp()->dtypep()) nodep->v3fatalSrc("Unsized expression");
 	AstNodeDType* fromDtp = nodep->fromp()->dtypep()->skipRefToEnump();
+	AstBasicDType* basicp = fromDtp ? fromDtp->basicp() : NULL;
 	UINFO(9,"     from dt "<<fromDtp<<endl);
 	if (AstEnumDType* adtypep = fromDtp->castEnumDType()) {
 	    // Method call on enum without following parenthesis, e.g. "ENUM.next"
@@ -1613,6 +1617,17 @@ private:
 		nodep->v3error("Unknown built-in array method '"<<nodep->fromp()->prettyTypeName()<<"'");
 	    }
 	}
+	else if (basicp && basicp->isString()) {
+            // Method call on string
+            if (nodep->name() == "len") {
+                // Constant value
+                AstNode* newp = new AstLenN(nodep->fileline(), nodep->fromp()->unlinkFrBack());
+                nodep->replaceWith(newp);
+                pushDeletep(nodep); VL_DANGLING(nodep);
+            } else {
+                nodep->v3error("Unsupported: built-in string method '"<<nodep->fromp()->prettyTypeName()<<"'");
+            }
+	}
 	else {
 	    nodep->v3error("Unsupported: Member call on non-enum object '"
 			   <<nodep->fromp()->prettyTypeName()<<"' which is a '"<<nodep->fromp()->dtypep()->prettyTypeName()<<"'");
@@ -2646,6 +2661,16 @@ private:
 	    nodep->dtypeSetLogicBool();
 	}
     }
+    void visit_Os32_string(AstNodeUniop* nodep) {
+        // CALLER: LenN
+        // Widths: 32 bit out
+        if (!nodep->lhsp()) nodep->v3fatalSrc("For unary ops only!");
+        if (m_vup->prelim()) {
+            // See similar handling in visit_cmp_eq_gt where created
+            iterateCheckString(nodep,"LHS",nodep->lhsp(),BOTH);
+            nodep->dtypeSetSigned32();
+        }
+    }
 
     void visit_negate_not(AstNodeUniop* nodep, bool real_ok) {
 	// CALLER: (real_ok=false) Not