Support passing strings to DPI imports.

include/verilated.cpp

@@ -769,6 +769,14 @@ void VL_SFORMAT_X(int obits, void* destp, const char* formatp, ...) {
     _VL_STRING_TO_VINT(obits, destp, (int)output.length(), output.c_str());
 }
 
+void VL_SFORMAT_X(int obits_ignored, string &output, const char* formatp, ...) {
+    output = "";
+    va_list ap;
+    va_start(ap,formatp);
+    _vl_vsformat(output, formatp, ap);
+    va_end(ap);
+}
+
 string VL_SFORMATF_NX(const char* formatp, ...) {
     VL_STATIC_OR_THREAD string output;  // static only for speed
     output = "";

include/verilated_heavy.h

@@ -41,11 +41,15 @@ inline string VL_CVT_PACK_STR_NQ(QData lhs) {
     IData lw[2];  VL_SET_WQ(lw, lhs);
     return VL_CVT_PACK_STR_NW(2, lw);
 }
+inline string VL_CVT_PACK_STR_NQ(string lhs) {
+    return lhs;
+}
 inline string VL_CVT_PACK_STR_NI(IData lhs) {
     IData lw[1];  lw[0] = lhs;
     return VL_CVT_PACK_STR_NW(1, lw);
 }
 
+extern void VL_SFORMAT_X(int obits_ignored, string &output, const char* formatp, ...);
 extern string VL_SFORMATF_NX(const char* formatp, ...);
 
 #endif // Guard

test_regress/t/t_dpi_string.pl

@@ -0,0 +1,19 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+compile (
+    	 v_flags2 => ["t/t_dpi_string_c.cpp"],
+	 );
+
+execute (
+	 check_finished=>1,
+     );
+
+ok(1);
+1;

test_regress/t/t_dpi_string.v

@@ -0,0 +1,26 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// Copyright 2009 by Wilson Snyder. This program is free software; you can
+// redistribute it and/or modify it under the terms of either the GNU
+// Lesser General Public License Version 3 or the Perl Artistic License
+// Version 2.0.
+
+module t ();
+
+   import "DPI-C" function int dpii_string(input string DSM_NAME);
+
+   generate
+      begin : DSM
+	 string SOME_STRING;
+      end
+   endgenerate
+
+   initial begin
+      $sformat(DSM.SOME_STRING, "%m");
+      if (dpii_string(DSM.SOME_STRING) != 5) $stop;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule

test_regress/t/t_dpi_string_c.cpp

@@ -0,0 +1,44 @@
+// -*- mode: C++; c-file-style: "cc-mode" -*-
+//*************************************************************************
+//
+// Copyright 2009-2009 by Wilson Snyder. This program is free software; you can
+// redistribute it and/or modify it under the terms of either the GNU
+// Lesser General Public License Version 3 or the Perl Artistic License.
+// Version 2.0.
+//
+// Verilator is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+//*************************************************************************
+
+#include <cstdio>
+#include "svdpi.h"
+
+//======================================================================
+
+#if defined(VERILATOR)
+# include "Vt_dpi_string__Dpi.h"
+#elif defined(VCS)
+# include "../vc_hdrs.h"
+#elif defined(CADENCE)
+# define NEED_EXTERNS
+#else
+# error "Unknown simulator for DPI test"
+#endif
+
+#ifdef NEED_EXTERNS
+extern "C" {
+
+    extern int dpii_string (const char* s);
+
+}
+#endif
+
+//======================================================================
+
+int dpii_string(const char* s) {
+    printf("dpii_string: %s\n",s);
+    return strlen(s);
+}