DPI: Constify new $sformatf

src/V3AstNodes.h

@@ -83,6 +83,34 @@ public:
     virtual int instrCount() const { return widthInstrs(); }
 };
 
+struct AstConstString : public AstNodeMath {
+    // A constant string
+private:
+    string	m_name;
+public:
+    AstConstString(FileLine* fl, const string& name)
+	: AstNodeMath(fl), m_name(name) {
+	rewidth();
+    }
+    void rewidth() {
+	if (m_name.length()==0) {
+	    width(1,1);  // 0 width isn't allowed due to historic special cases
+	} else {
+	    width(m_name.length()*8, m_name.length()*8);
+	}
+    }
+    ASTNODE_NODE_FUNCS(ConstString, CONSTSTRING)
+    virtual string emitVerilog() { V3ERROR_NA; return ""; }  // Implemented specially
+    virtual string emitC() { V3ERROR_NA; return ""; }
+    virtual bool cleanOut() { return true; }
+    virtual V3Hash sameHash() const { return V3Hash(name()); }
+    virtual bool same(AstNode* samep) const {
+	return name()==samep->castConstString()->name(); }
+    virtual int instrCount() const { return 2; }  // C just loads a pointer
+    virtual string name() const { return m_name; }
+    void name(const string& flag) { m_name = flag; rewidth(); }
+};
+
 struct AstRange : public AstNode {
     // Range specification, for use under variables and cells
 private:
@@ -1511,10 +1539,12 @@ public:
 
 class AstSFormatF : public AstNode {
     // Convert format to string, generally under a AstDisplay or AstSFormat
+    // Also used as "real" function for /*verilator sformat*/ functions
     string	m_text;
+    bool	m_hidden;	// Under display, etc
 public:
-    AstSFormatF(FileLine* fl, const string& text, AstNode* exprsp)
-	: AstNode(fl), m_text(text) {
+    AstSFormatF(FileLine* fl, const string& text, bool hidden, AstNode* exprsp)
+	: AstNode(fl), m_text(text), m_hidden(hidden) {
 	addNOp1p(exprsp); addNOp2p(NULL); }
     ASTNODE_NODE_FUNCS(SFormatF, SFORMATF)
     virtual string name() const { return m_text; }
@@ -1530,6 +1560,7 @@ public:
     void scopeNamep(AstNode* nodep) { setNOp2p(nodep); }
     bool formatScopeTracking() const {  // Track scopeNamep();  Ok if false positive
 	return (name().find("%m") != string::npos || name().find("%M") != string::npos); }
+    bool hidden() const { return m_hidden; }
 };
 
 struct AstDisplay : public AstNode {
@@ -1541,7 +1572,7 @@ private:
 public:
     AstDisplay(FileLine* fileline, AstDisplayType dispType, const string& text, AstNode* filep, AstNode* exprsp)
 	: AstNode (fileline) {
-	setNOp1p(new AstSFormatF(fileline,text,exprsp));
+	setOp1p(new AstSFormatF(fileline,text,true,exprsp));
 	setNOp3p(filep);
 	m_displayType = dispType;
     }
@@ -1573,7 +1604,7 @@ struct AstSFormat : public AstNode {
     // Children: SFORMATF to generate print string
     AstSFormat(FileLine* fileline, AstNode* lhsp, const string& text, AstNode* exprsp)
 	: AstNode (fileline) {
-	setOp1p(new AstSFormatF(fileline,text,exprsp));
+	setOp1p(new AstSFormatF(fileline,text,true,exprsp));
 	setOp3p(lhsp);
     }
     ASTNODE_NODE_FUNCS(SFormat, SFORMAT)

src/V3Const.cpp

@@ -432,6 +432,15 @@ private:
 	replaceNum(nodep, num); nodep=NULL;
     }
 
+    void replaceConstString (AstNode* oldp, const string& num) {
+	// Replace oldp node with a constant set to specified value
+	UASSERT (oldp, "Null old\n");
+	AstNode* newp = new AstConstString(oldp->fileline(), num);
+	if (debug()>5) oldp->dumpTree(cout,"  const_old: ");
+	if (debug()>5) newp->dumpTree(cout,"       _new: ");
+	oldp->replaceWith(newp);
+	oldp->deleteTree(); oldp=NULL;
+    }
     //----------------------------------------
     // Replacement functions.
     // These all take a node and replace it with something else
@@ -1459,6 +1468,12 @@ private:
 	    nodep->text(dispout);
 	    //UINFO(9,"  Display out "<<nodep->text()<<endl);
 	}
+	if (!nodep->exprsp()
+	    && nodep->name().find("%") == string::npos
+	    && !nodep->hidden()) {
+	    // Just a simple constant string - the formatting is pointless
+	    replaceConstString(nodep, nodep->name()); nodep=NULL;
+	}
     }
 
     virtual void visit(AstFuncRef* nodep, AstNUser*) {
@@ -1712,6 +1727,9 @@ private:
     TREEOPV("AstRedXnor{$lhsp}",		"AstNot{AstRedXor{$lhsp}}");  // Just eliminate XNOR's
     TREEOPV("AstLogIf {$lhsp, $rhsp}",		"AstLogOr{AstLogNot{$lhsp},$rhsp}");
     TREEOPV("AstLogIff{$lhsp, $rhsp}",		"AstLogNot{AstXor{$lhsp,$rhsp}}");
+    // Strings
+    TREEOP ("AstCvtPackString{$lhsp.castConst}",	"replaceConstString(nodep, nodep->lhsp()->castConst()->num().toString())");
+
 
     // Possible futures:
     // (a?(b?y:x):y) -> (a&&!b)?x:y

src/V3EmitC.cpp

@@ -563,6 +563,9 @@ public:
 	    emitConstant(nodep, NULL, "");
 	}
     }
+    virtual void visit(AstConstString* nodep, AstNUser*) {
+	putsQuoted(nodep->name());
+    }
 
     // Just iterate
     virtual void visit(AstNetlist* nodep, AstNUser*) {

src/V3EmitV.cpp

@@ -456,6 +456,10 @@ class EmitVBaseVisitor : public EmitCBaseVisitor {
     virtual void visit(AstConst* nodep, AstNUser*) {
 	putfs(nodep,nodep->num().ascii(true,true));
     }
+    virtual void visit(AstConstString* nodep, AstNUser*) {
+	putfs(nodep,"");
+	putsQuoted(nodep->name());
+    }
 
     // Just iterate
     virtual void visit(AstTopScope* nodep, AstNUser*) {

src/V3Width.cpp

@@ -448,6 +448,9 @@ private:
 	// We don't size the constant until we commit the widths, as need parameters
 	// to remain unsized, and numbers to remain unsized to avoid backp() warnings
     }
+    virtual void visit(AstConstString* nodep, AstNUser* vup) {
+	nodep->rewidth();
+    }
     virtual void visit(AstRand* nodep, AstNUser* vup) {
 	if (vup->c()->prelim()) {
 	    nodep->width(32,32);  // Says the spec
@@ -962,7 +965,7 @@ private:
 			    string format;
 			    if (pinp->castConst()) format = pinp->castConst()->num().toString();
 			    else pinp->v3error("Format to $display-like function must have constant format string");
-			    AstSFormatF* newp = new AstSFormatF(nodep->fileline(), format, argsp);
+			    AstSFormatF* newp = new AstSFormatF(nodep->fileline(), format, false, argsp);
 			    if (!newp->scopeNamep() && newp->formatScopeTracking()) {
 				newp->scopeNamep(new AstScopeName(newp->fileline()));
 			    }

src/verilog.y

@@ -2066,7 +2066,7 @@ system_f_call<nodep>:		// IEEE: system_tf_call (as func)
 	|	yD_ONEHOT0 '(' expr ')'			{ $$ = new AstOneHot0($1,$3); }
 	|	yD_RANDOM '(' expr ')'			{ $1->v3error("Unsupported: Seeding $random doesn't map to C++, use $c(\"srand\")"); }
 	|	yD_RANDOM parenE			{ $$ = new AstRand($1); }
-	//|	yD_SFORMATF '(' str commaEListE ')'	{ $$ = new AstSFormatF($1,*$3,$4); }  // Have AST, just need testing and debug
+	//|	yD_SFORMATF '(' str commaEListE ')'	{ $$ = new AstSFormatF($1,*$3,false,$4); }  // Have AST, just need testing and debug
 	|	yD_SIGNED '(' expr ')'			{ $$ = new AstSigned($1,$3); }
 	|	yD_STIME parenE				{ $$ = new AstSel($1,new AstTime($1),0,32); }
 	|	yD_TIME	parenE				{ $$ = new AstTime($1); }

test_regress/t/t_dpi_import.v

@@ -98,6 +98,8 @@ module t ();
 
    bit [127:0] wide;
 
+   bit [6*8:1] string6;
+
    initial begin
       wide = 128'h36f3e51d15caff7a73c48afee4ffcb57;
 
@@ -165,6 +167,11 @@ module t ();
       if (dpii_f_strlen ("stri")!=4) $stop;
       if (dpii_f_strlen ("string_l")!=8) $stop;
       if (dpii_f_strlen ("string_len")!=10) $stop;
+      string6 = "hello6";
+`ifdef VERILATOR
+      string6 = $c48(string6); // Don't optimize away - want to see the constant conversion function
+`endif
+      if (dpii_f_strlen (string6) != 6) $stop;
 
       dpii_f_void();
       dpii_t_void();