Merge pull request #815 from larsclausen/class-virtual-new

Do not allow to create objects of virtual classes

elab_expr.cc

@@ -6652,6 +6652,14 @@ NetExpr* PENewClass::elaborate_expr(Design*des, NetScope*scope,
 	    return 0;
       }
 
+      if (ctype->is_virtual()) {
+	    cerr << get_fileline() << ": error: "
+	         << "Can not create object of virtual class `"
+		 << ctype->get_name() << "`." << endl;
+	    des->errors++;
+	    return 0;
+      }
+
       NetExpr*obj = new NetENew(ntype);
       obj->set_line(*this);
 

elab_scope.cc

@@ -493,6 +493,7 @@ static void elaborate_scope_class(Design*des, NetScope*scope, PClass*pclass)
       class_scope->set_class_def(use_class);
       use_class->set_class_scope(class_scope);
       use_class->set_definition_scope(scope);
+      use_class->set_virtual(use_type->virtual_class);
       set_scope_timescale(des, class_scope, pclass);
 
       class_scope->add_typedefs(&pclass->typedefs);

ivtest/ivltests/sv_class_virt_new_fail.v

@@ -0,0 +1,15 @@
+// Check that an error is reported when trying to create an object of a virtual
+// class.
+
+module test;
+
+  virtual class C;
+  endclass
+
+  C c;
+
+  initial begin
+    c = new; // This should fail
+  end
+
+endmodule

ivtest/regress-sv.list

@@ -555,6 +555,7 @@ sv_class_static_prop3	normal,-g2009		ivltests
 sv_class_super1		normal,-g2009		ivltests
 sv_class_super2		normal,-g2009		ivltests
 sv_class_task1		normal,-g2009		ivltests
+sv_class_virt_new_fail	CE,-g2009		ivltests
 sv_darray1		normal,-g2009		ivltests
 sv_darray2		normal,-g2009		ivltests
 sv_darray3		normal,-g2009		ivltests

netclass.h

@@ -116,6 +116,9 @@ class netclass_t : public ivl_type_s {
       const NetExpr* get_parameter(Design *des, perm_string name,
 				   ivl_type_t &par_type) const;
 
+      void set_virtual(bool virtual_class) { virtual_class_ = virtual_class; }
+      bool is_virtual() const { return virtual_class_; }
+
     private:
       perm_string name_;
 	// If this is derived from another base class, point to it
@@ -137,6 +140,8 @@ class netclass_t : public ivl_type_s {
 
 	// This holds the context for the class type definition.
       NetScope*definition_scope_;
+
+      bool virtual_class_;
 };
 
 inline NetScope*netclass_t::definition_scope(void)

parse.y

@@ -797,7 +797,7 @@ class_declaration /* IEEE1800-2005: A.1.2 */
 	class_type_t *class_type= new class_type_t(name);
 	FILE_NAME(class_type, @4);
 	pform_set_typedef(@4, name, class_type, nullptr);
-	pform_start_class_declaration(@2, class_type, $5.type, $5.exprs, $3);
+	pform_start_class_declaration(@2, class_type, $5.type, $5.exprs, $3, $1);
       }
     class_items_opt K_endclass
       { // Process a class.

pform.h

@@ -173,7 +173,8 @@ extern void pform_start_class_declaration(const struct vlltype&loc,
 					  class_type_t*type,
 					  data_type_t*base_type,
 					  std::list<PExpr*>*base_exprs,
-					  LexicalScope::lifetime_t lifetime);
+					  LexicalScope::lifetime_t lifetime,
+					  bool virtual_class);
 extern void pform_class_property(const struct vlltype&loc,
 				 property_qualifier_t pq,
 				 data_type_t*data_type,

pform_pclass.cc

@@ -43,7 +43,8 @@ void pform_start_class_declaration(const struct vlltype&loc,
 				   class_type_t*type,
 				   data_type_t*base_type,
 				   list<PExpr*>*base_exprs,
-				   LexicalScope::lifetime_t lifetime)
+				   LexicalScope::lifetime_t lifetime,
+				   bool virtual_class)
 {
       PClass*class_scope = pform_push_class_scope(loc, type->name, lifetime);
       class_scope->type = type;
@@ -52,6 +53,7 @@ void pform_start_class_declaration(const struct vlltype&loc,
 
       assert(type->base_type == 0);
       type->base_type.reset(base_type);
+      type->virtual_class = virtual_class;
 
       assert(type->base_args.empty());
       if (base_exprs) {

pform_types.h

@@ -379,6 +379,8 @@ struct class_type_t : public data_type_t {
       std::unique_ptr<data_type_t> base_type;
       std::list<PExpr*>base_args;
 
+      bool virtual_class;
+
 	// This is a map of the properties. Map the name to the type.
       struct prop_info_t : public LineInfo {
 	    inline prop_info_t() : qual(property_qualifier_t::make_none()) { }