Stub class object variables.

Create stub class objects at the vvp level and generate the code
to invoke that stub. Implement the routines needed to implement
a test for null object references.

sv_vpi_user.h

@@ -48,6 +48,7 @@ EXTERN_C_START
 #define vpiIntVar           612
 #define vpiByteVar          614
 #define vpiLogicVar         vpiReg
+#define vpiClassVar         615
 #define vpiStringVar        616
 #define vpiBitVar           620
 #define vpiArrayVar         vpiRegArray

tgt-vvp/eval_expr.c

@@ -485,6 +485,53 @@ static struct vector_info draw_binary_expr_eq_string(ivl_expr_t expr)
       return res;
 }
 
+static struct vector_info draw_binary_expr_eq_class(ivl_expr_t expr)
+{
+      ivl_expr_t le = ivl_expr_oper1(expr);
+      ivl_expr_t re = ivl_expr_oper2(expr);
+
+      struct vector_info res;
+      res.base = allocate_vector(1);
+      res.wid = 1;
+      assert(res.base);
+
+      if (ivl_expr_type(le) == IVL_EX_NULL) {
+	    ivl_expr_t tmp = le;
+	    le = re;
+	    re = tmp;
+      }
+
+	/* Special case: If both operands are null, then the
+	   expression has a constant value. */
+      if (ivl_expr_type(le)==IVL_EX_NULL && ivl_expr_type(re)==IVL_EX_NULL) {
+	    switch (ivl_expr_opcode(expr)) {
+		case 'e': /* == */
+		  fprintf(vvp_out, "    %%mov %u, 1, 1;\n", res.base);
+		  break;
+		case 'n': /* != */
+		  fprintf(vvp_out, "    %%mov %u, 0, 1;\n", res.base);
+		  break;
+		default:
+		  assert(0);
+		  break;
+	    }
+	    return res;
+      }
+
+      if (ivl_expr_type(re) == IVL_EX_NULL && ivl_expr_type(le)==IVL_EX_SIGNAL) {
+	    fprintf(vvp_out, "    %%test_nul v%p_0;\n", ivl_expr_signal(le));
+	    fprintf(vvp_out, "    %%mov %u, 4, 1;\n", res.base);
+	    if (ivl_expr_opcode(expr) == 'n')
+		  fprintf(vvp_out, "    %%inv %u, 1;\n", res.base);
+	    return res;
+      }
+
+      fprintf(stderr, "SORRY: Compare class handles not implemented\n");
+      fprintf(vvp_out, " ; XXXX compare class handles.\n");
+      vvp_errors += 1;
+      return res;
+}
+
 static struct vector_info draw_binary_expr_eq(ivl_expr_t expr,
 					      unsigned ewid,
 					      int stuff_ok_flag)
@@ -517,6 +564,11 @@ static struct vector_info draw_binary_expr_eq(ivl_expr_t expr,
 	    return draw_binary_expr_eq_string(expr);
       }
 
+      if ((ivl_expr_value(le) == IVL_VT_CLASS)
+	  && (ivl_expr_value(re) == IVL_VT_CLASS)) {
+	    return draw_binary_expr_eq_class(expr);
+      }
+
       if (number_is_immediate(re,16,0) && !number_is_unknown(re))
 	    return draw_eq_immediate(expr, ewid, le, re, stuff_ok_flag);
 

tgt-vvp/vvp_scope.c

@@ -512,6 +512,11 @@ static void draw_reg_in_scope(ivl_signal_t sig)
 		    vvp_mangle_name(ivl_signal_basename(sig)),
 		    ivl_signal_local(sig)? " Local signal" : "");
 
+      } else if (ivl_signal_data_type(sig) == IVL_VT_CLASS) {
+	    fprintf(vvp_out, "v%p_0 .var/cobj \"%s\";%s\n", sig,
+		    vvp_mangle_name(ivl_signal_basename(sig)),
+		    ivl_signal_local(sig)? " Local signal" : "");
+
       } else {
 
 	    fprintf(vvp_out, "v%p_0 .var%s %s\"%s\", %d %d;%s\n",

vvp/Makefile.in

@@ -65,7 +65,8 @@ dllib=@DLLIB@
 
 MDIR1 = -DMODULE_DIR1='"$(libdir)/ivl$(suffix)"'
 
-V = vpi_modules.o vpi_callback.o vpi_const.o vpi_darray.o vpi_event.o vpi_iter.o vpi_mcd.o \
+V = vpi_modules.o vpi_callback.o vpi_cobject.o vpi_const.o vpi_darray.o \
+    vpi_event.o vpi_iter.o vpi_mcd.o \
     vpi_priv.o vpi_scope.o vpi_real.o vpi_signal.o vpi_string.o vpi_tasks.o vpi_time.o \
     vpi_vthr_vector.o vpip_bin.o vpip_hex.o vpip_oct.o \
     vpip_to_dec.o vpip_format.o vvp_vpi.o

vvp/codes.h

@@ -185,6 +185,7 @@ extern bool of_SUB(vthread_t thr, vvp_code_t code);
 extern bool of_SUB_WR(vthread_t thr, vvp_code_t code);
 extern bool of_SUBI(vthread_t thr, vvp_code_t code);
 extern bool of_SUBSTR_V(vthread_t thr, vvp_code_t code);
+extern bool of_TEST_NUL(vthread_t thr, vvp_code_t code);
 extern bool of_VPI_CALL(vthread_t thr, vvp_code_t code);
 extern bool of_WAIT(vthread_t thr, vvp_code_t code);
 extern bool of_XNOR(vthread_t thr, vvp_code_t code);

vvp/compile.cc

@@ -232,6 +232,7 @@ static const struct opcode_table_s opcode_table[] = {
       { "%sub/wr", of_SUB_WR, 0,  {OA_NONE,     OA_NONE,     OA_NONE} },
       { "%subi",   of_SUBI,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%substr/v",of_SUBSTR_V,3,{OA_BIT1,     OA_BIT2,     OA_NUMBER} },
+      { "%test_nul",  of_TEST_NUL, 1,{OA_FUNC_PTR,OA_NONE,     OA_NONE} },
       { "%wait",   of_WAIT,   1,  {OA_FUNC_PTR, OA_NONE,     OA_NONE} },
       { "%xnor",   of_XNOR,   3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
       { "%xnor/r", of_XNORR,  3,  {OA_BIT1,     OA_BIT2,     OA_NUMBER} },
@@ -334,8 +335,10 @@ vvp_net_t* vvp_net_lookup(const char*label)
 		      return sig->net;
 		}
 
-		case vpiStringVar: {
-		      __vpiStringVar*sig = dynamic_cast<__vpiStringVar*>(vpi);
+		case vpiStringVar:
+		case vpiArrayVar:
+		case vpiClassVar: {
+		      __vpiBaseVar*sig = dynamic_cast<__vpiBaseVar*>(vpi);
 		      return sig->get_net();
 		}
 
@@ -344,11 +347,6 @@ vvp_net_t* vvp_net_lookup(const char*label)
 		      return tmp->funct;
 		}
 
-		case vpiArrayVar: {
-		      __vpiDarrayVar*tmp = dynamic_cast<__vpiDarrayVar*>(vpi);
-		      return tmp->get_net();
-		}
-
 		default:
 		  fprintf(stderr, "Unsupported type %d.\n",
 		          vpi->get_type_code());

vvp/compile.h

@@ -463,6 +463,7 @@ extern void compile_variable(char*label, char*name,
 extern void compile_var_real(char*label, char*name);
 extern void compile_var_string(char*label, char*name);
 extern void compile_var_darray(char*label, char*name);
+extern void compile_var_cobject(char*label, char*name);
 
 /*
  * This function is used to create a scope port

vvp/lexor.lex

@@ -195,6 +195,7 @@ static char* strdupnew(char const *str)
 ".ufunc"    { return K_UFUNC; }
 ".ufunc/e"  { return K_UFUNC_E; }
 ".var"      { return K_VAR; }
+".var/cobj" { return K_VAR_COBJECT; }
 ".var/darray" { return K_VAR_DARRAY; }
 ".var/real" { return K_VAR_R; }
 ".var/s"    { return K_VAR_S; }

vvp/opcodes.txt

@@ -1022,6 +1022,14 @@ that holds the index. This is the general method for getting string
 values into the vector space. The string value is NOT popped.
 
 
+* %test_nul <var-label>
+
+This instruction tests the contents of the addressed variable to see
+if it is null. If it is, set bit 4 to 1. Otherwise, set bit 4 to 0.
+
+This is intended to implement the SystemVerilog expression
+(<var>==null), where <var> is a class variable.
+
 * %vpi_call <name> [, ...] {<real> <str>}
 
 This instruction makes a call to a system task that was declared using

vvp/parse.y

@@ -91,7 +91,8 @@ static struct __vpiModPath*modpath_dst = 0;
 %token K_RESOLV K_SCOPE K_SFUNC K_SFUNC_E K_SHIFTL K_SHIFTR K_SHIFTRS
 %token K_THREAD K_TIMESCALE K_TRAN K_TRANIF0 K_TRANIF1 K_TRANVP
 %token K_UFUNC K_UFUNC_E K_UDP K_UDP_C K_UDP_S
-%token K_VAR K_VAR_DARRAY K_VAR_S K_VAR_STR K_VAR_I K_VAR_R K_VAR_2S K_VAR_2U
+%token K_VAR K_VAR_COBJECT K_VAR_DARRAY
+%token K_VAR_S K_VAR_STR K_VAR_I K_VAR_R K_VAR_2S K_VAR_2U
 %token K_vpi_call K_vpi_call_w K_vpi_call_i
 %token K_vpi_func K_vpi_func_r
 %token K_disable K_fork
@@ -709,6 +710,9 @@ statement
   | T_LABEL K_VAR_DARRAY T_STRING ';'
       { compile_var_darray($1, $3); }
 
+  | T_LABEL K_VAR_COBJECT T_STRING ';'
+      { compile_var_cobject($1, $3); }
+
   /* Net statements are similar to .var statements, except that they
      declare nets, and they have an input list. */
 

vvp/vpi_cobject.cc

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2012 Picture Elements, Inc.
+ *    Stephen Williams (steve@icarus.com)
+ *
+ *    This source code is free software; you can redistribute it
+ *    and/or modify it in source code form under the terms of the GNU
+ *    General Public License as published by the Free Software
+ *    Foundation; either version 2 of the License, or (at your option)
+ *    any later version.
+ *
+ *    This program 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.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+# include  "compile.h"
+# include  "vpi_priv.h"
+
+__vpiCobjectVar::__vpiCobjectVar(__vpiScope*sc, const char*na, vvp_net_t*ne)
+: __vpiBaseVar(sc, na, ne)
+{
+}
+
+int __vpiCobjectVar::get_type_code(void) const
+{ return vpiClassVar; }
+
+int __vpiCobjectVar::vpi_get(int)
+{
+      return 0;
+}
+
+void __vpiCobjectVar::vpi_get_value(p_vpi_value val)
+{
+      val->format = vpiSuppressVal;
+}
+
+vpiHandle vpip_make_cobject_var(const char*name, vvp_net_t*net)
+{
+      struct __vpiScope*scope = vpip_peek_current_scope();
+      const char*use_name = name ? vpip_name_string(name) : 0;
+
+      class __vpiCobjectVar*obj = new __vpiCobjectVar(scope, use_name, net);
+
+      return obj;
+}

vvp/vpi_darray.cc

@@ -34,7 +34,7 @@
 using namespace std;
 
 __vpiDarrayVar::__vpiDarrayVar(__vpiScope*sc, const char*na, vvp_net_t*ne)
-: scope_(sc), name_(na), net_(ne)
+: __vpiBaseVar(sc, na, ne)
 {
 }
 
@@ -44,7 +44,7 @@ int __vpiDarrayVar::get_type_code(void) const
 
 int __vpiDarrayVar::vpi_get(int code)
 {
-      vvp_fun_signal_object*fun = dynamic_cast<vvp_fun_signal_object*> (net_->fun);
+      vvp_fun_signal_object*fun = dynamic_cast<vvp_fun_signal_object*> (get_net()->fun);
       assert(fun);
       vvp_object_t val = fun->get_object();
       vvp_darray*aval = dynamic_cast<vvp_darray*> (val);

vvp/vpi_priv.cc

@@ -64,6 +64,11 @@ void __vpiHandle::vpi_get_delays(p_vpi_delay)
 void __vpiHandle::vpi_put_delays(p_vpi_delay)
 { }
 
+__vpiBaseVar::__vpiBaseVar(__vpiScope*scope, const char*name, vvp_net_t*net)
+: scope_(scope), name_(name), net_(net)
+{
+}
+
 /*
  * The default behavior for the vpi_free_object to an object is to
  * suppress the actual operation. This is because handles are

vvp/vpi_priv.h

@@ -476,7 +476,20 @@ struct __vpiRealVar : public __vpiHandle {
 extern struct __vpiScope* vpip_scope(__vpiRealVar*sig);
 extern vpiHandle vpip_make_real_var(const char*name, vvp_net_t*net);
 
-class __vpiStringVar : public __vpiHandle {
+class __vpiBaseVar : public __vpiHandle {
+
+    public:
+      __vpiBaseVar(__vpiScope*scope, const char*name, vvp_net_t*net);
+
+      inline vvp_net_t* get_net() const { return net_; }
+
+    private:
+      struct __vpiScope* scope_;
+      const char*name_;
+      vvp_net_t*net_;
+};
+
+class __vpiStringVar : public __vpiBaseVar {
 
     public:
       __vpiStringVar(__vpiScope*scope, const char*name, vvp_net_t*net);
@@ -484,18 +497,11 @@ class __vpiStringVar : public __vpiHandle {
       int get_type_code(void) const;
       int vpi_get(int code);
       void vpi_get_value(p_vpi_value val);
-
-      inline vvp_net_t* get_net() const { return net_; }
-
-    private:
-      struct __vpiScope* scope_;
-      const char*name_;
-      vvp_net_t*net_;
 };
 
 extern vpiHandle vpip_make_string_var(const char*name, vvp_net_t*net);
 
-class __vpiDarrayVar : public __vpiHandle {
+class __vpiDarrayVar : public __vpiBaseVar {
 
     public:
       __vpiDarrayVar(__vpiScope*scope, const char*name, vvp_net_t*net);
@@ -503,17 +509,22 @@ class __vpiDarrayVar : public __vpiHandle {
       int get_type_code(void) const;
       int vpi_get(int code);
       void vpi_get_value(p_vpi_value val);
-
-      inline vvp_net_t* get_net() const { return net_; }
-
-    private:
-      struct __vpiScope* scope_;
-      const char*name_;
-      vvp_net_t*net_;
 };
 
 extern vpiHandle vpip_make_darray_var(const char*name, vvp_net_t*net);
 
+class __vpiCobjectVar : public __vpiBaseVar {
+
+    public:
+      __vpiCobjectVar(__vpiScope*scope, const char*name, vvp_net_t*net);
+
+      int get_type_code(void) const;
+      int vpi_get(int code);
+      void vpi_get_value(p_vpi_value val);
+};
+
+extern vpiHandle vpip_make_cobject_var(const char*name, vvp_net_t*net);
+
 /*
  * When a loaded VPI module announces a system task/function, one
  * __vpiUserSystf object is created to hold the definition of that

vvp/vpi_string.cc

@@ -33,7 +33,7 @@
 using namespace std;
 
 __vpiStringVar::__vpiStringVar(__vpiScope*sc, const char*na, vvp_net_t*ne)
-: scope_(sc), name_(na), net_(ne)
+: __vpiBaseVar(sc, na, ne)
 {
 }
 
@@ -42,7 +42,7 @@ int __vpiStringVar::get_type_code(void) const
 
 int __vpiStringVar::vpi_get(int code)
 {
-      vvp_fun_signal_string*fun = dynamic_cast<vvp_fun_signal_string*> (net_->fun);
+      vvp_fun_signal_string*fun = dynamic_cast<vvp_fun_signal_string*> (get_net()->fun);
       assert(fun);
       string str = fun->get_string();
 
@@ -58,7 +58,7 @@ int __vpiStringVar::vpi_get(int code)
 
 void __vpiStringVar::vpi_get_value(p_vpi_value val)
 {
-      vvp_fun_signal_string*fun = dynamic_cast<vvp_fun_signal_string*> (net_->fun);
+      vvp_fun_signal_string*fun = dynamic_cast<vvp_fun_signal_string*> (get_net()->fun);
       assert(fun);
       string str = fun->get_string();
 

vvp/vthread.cc

@@ -5108,6 +5108,25 @@ bool of_FILE_LINE(vthread_t, vvp_code_t cp)
       return true;
 }
 
+/*
+ * %test_nul <var-label>;
+ */
+bool of_TEST_NUL(vthread_t thr, vvp_code_t cp)
+{
+      vvp_net_t*net = cp->net;
+
+      assert(net);
+      vvp_fun_signal_object*obj = dynamic_cast<vvp_fun_signal_object*> (net->fun);
+      assert(obj);
+
+      if (obj->get_object() == 0)
+	    thr_put_bit(thr, 4, BIT4_1);
+      else
+	    thr_put_bit(thr, 4, BIT4_0);
+
+      return true;
+}
+
 bool of_VPI_CALL(vthread_t thr, vvp_code_t cp)
 {
       vpip_execute_vpi_call(thr, cp->handle);

vvp/words.cc

@@ -78,8 +78,7 @@ void compile_varw_real(char*label, vvp_array_t array,
       __compile_var_real(label, 0, array, addr);
 }
 
-static void __compile_var_string(char*label, char*name,
-				 vvp_array_t array, unsigned long array_addr)
+void compile_var_string(char*label, char*name)
 {
       vvp_net_t*net = new vvp_net_t;
 
@@ -97,25 +96,12 @@ static void __compile_var_string(char*label, char*name,
       vpiHandle obj = vpip_make_string_var(name, net);
       compile_vpi_symbol(label, obj);
 
-      if (name) {
-	    assert(!array);
-	    vpip_attach_to_current_scope(obj);
-      }
-      if (array) {
-	    assert(!name);
-	    array_attach_word(array, array_addr, obj);
-      }
+      vpip_attach_to_current_scope(obj);
       free(label);
       delete[] name;
 }
 
-void compile_var_string(char*label, char*name)
-{
-      __compile_var_string(label, name, 0, 0);
-}
-
-static void __compile_var_darray(char*label, char*name,
-				 vvp_array_t array, unsigned long array_addr)
+void compile_var_darray(char*label, char*name)
 {
       vvp_net_t*net = new vvp_net_t;
 
@@ -133,21 +119,32 @@ static void __compile_var_darray(char*label, char*name,
       vpiHandle obj = vpip_make_darray_var(name, net);
       compile_vpi_symbol(label, obj);
 
-      if (name) {
-	    assert(!array);
-	    vpip_attach_to_current_scope(obj);
-      }
-      if (array) {
-	    assert(!name);
-	    array_attach_word(array, array_addr, obj);
-      }
+      vpip_attach_to_current_scope(obj);
       free(label);
       delete[] name;
 }
 
-void compile_var_darray(char*label, char*name)
+void compile_var_cobject(char*label, char*name)
 {
-      __compile_var_darray(label, name, 0, 0);
+      vvp_net_t*net = new vvp_net_t;
+
+      if (vpip_peek_current_scope()->is_automatic) {
+	    vvp_fun_signal_object_aa*tmp = new vvp_fun_signal_object_aa;
+	    net->fil = tmp;
+	    net->fun = tmp;
+      } else {
+	    net->fil = 0;
+	    net->fun = new vvp_fun_signal_object_sa;
+      }
+
+      define_functor_symbol(label, net);
+
+      vpiHandle obj = vpip_make_cobject_var(name, net);
+      compile_vpi_symbol(label, obj);
+
+      vpip_attach_to_current_scope(obj);
+      free(label);
+      delete[] name;
 }
 
 /*