Support type parameters

SystemVerilog supports type parameters. These are similar to value
parameters, but they allow to pass a type to a module or similar when
instantiating it.

E.g.

```
module A #(parameter type T = int);
endmodule

module B;
  A #(.T(real)) i_a;
endmodule
```

Add support for handling type parameters.

For the vlog95 and vhdl backends type parameters, similar to typedefs, get
replaced with their actual value. For modules with non-local type
parameters for each module instance a unique module or architecture is
generated with the actual type.

Querying type parameters through VPI is not yet supported.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

PScope.h

@@ -113,6 +113,8 @@ class LexicalScope {
 	    bool local_flag;
 	      // Whether the parameter can be overridden
 	    bool overridable;
+	      // Whether the parameter is a type parameter
+	    bool type_flag = false;
 
 	    SymbolType symbol_type() const;
       };

elab_scope.cc

@@ -128,9 +128,7 @@ static void collect_parm_item(Design*des, NetScope*scope, perm_string name,
       // not yet known, don't try to guess here, put the type guess off. Also
       // don't try to elaborate it here, because there may be references to
       // other parameters still being located during scope elaboration.
-      scope->set_parameter(name, is_annotatable, cur.expr, cur.data_type,
+      scope->set_parameter(name, is_annotatable, cur, range_list);
-			   cur.local_flag, cur.overridable, range_list, cur);
-
 }
 
 static void collect_scope_parameters(Design*des, NetScope*scope,

elab_type.cc

@@ -476,3 +476,16 @@ ivl_type_t typedef_t::elaborate_type(Design *des, NetScope *scope)
 
       return elab_type;
 }
+
+ivl_type_t type_parameter_t::elaborate_type_raw(Design *des, NetScope*scope) const
+{
+      ivl_type_t type;
+
+      scope->get_parameter(des, name, type);
+
+      // Recover
+      if (!type)
+	    return netvector_t::integer_type();
+
+      return type;
+}

ivl.def

@@ -172,6 +172,7 @@ ivl_nexus_ptr_switch
 ivl_parameter_basename
 ivl_parameter_expr
 ivl_parameter_file
+ivl_parameter_is_type
 ivl_parameter_lineno
 ivl_parameter_local
 ivl_parameter_lsb

ivl_target.h

@@ -1695,6 +1695,9 @@ extern ivl_signal_t ivl_nexus_ptr_sig(ivl_nexus_ptr_t net);
  *    Return whether parameter was local (localparam, implicit genvar etc)
  *    or not.
  *
+ * ivl_parameter_is_type
+ *    Return whether the parameter is a type parameter or not.
+ *
  * ivl_parameter_file
  * ivl_parameter_lineno
  *    Returns the file and line where this parameter is defined
@@ -1707,6 +1710,7 @@ extern int         ivl_parameter_lsb(ivl_parameter_t net);
 extern unsigned    ivl_parameter_width(ivl_parameter_t net);
 extern int         ivl_parameter_signed(ivl_parameter_t net);
 extern int         ivl_parameter_local(ivl_parameter_t net);
+extern int         ivl_parameter_is_type(ivl_parameter_t net);
 extern const char* ivl_parameter_file(ivl_parameter_t net);
 extern unsigned    ivl_parameter_lineno(ivl_parameter_t net);
 

net_design.cc

@@ -433,7 +433,7 @@ void NetScope::run_defparams(Design*des)
 		  continue;
 	    }
 
-	    targ_scope->replace_parameter(des, perm_name, val, this);
+	    targ_scope->replace_parameter(des, perm_name, val, this, true);
       }
 
 	// If some of the defparams didn't find a scope in the name,
@@ -468,7 +468,7 @@ void NetScope::run_defparams_later(Design*des)
 		  continue;
 	    }
 
-	    targ_scope->replace_parameter(des, name, val, this);
+	    targ_scope->replace_parameter(des, name, val, this, true);
 
 	      // We'll need to re-evaluate parameters in this scope
 	    target_scopes.insert(targ_scope);
@@ -814,20 +814,31 @@ void NetScope::evaluate_parameter_string_(Design*des, param_ref_t cur)
       }
 }
 
-void NetScope::evaluate_parameter_(Design*des, param_ref_t cur)
+void NetScope::evaluate_type_parameter_(Design *des, param_ref_t cur)
 {
-      ivl_type_t param_type = cur->second.ivl_type;
+      const PETypename *type_expr = dynamic_cast<const PETypename*>(cur->second.val_expr);
+      if (!type_expr) {
+	    cerr << this->get_fileline() << ": error: "
+		 << "Type parameter `" << cur->first << "` value `"
+	         << *cur->second.val_expr << "` is not a type."
+		 << endl;
+	    des->errors++;
 
-      // If the parameter type is present, then elaborate it now. Elaborate
+	    // Recover
-      // the type in the current scope, and not the scope of the expression.
+	    cur->second.ivl_type = netvector_t::integer_type();
-      if (cur->second.val_type) {
+	    return;
-	    param_type = cur->second.val_type->elaborate_type(des, this);
-	    cur->second.ivl_type = param_type;
-	    cur->second.val_type = 0;
       }
 
+      data_type_t *type = type_expr->get_type();
+      NetScope *type_scope = cur->second.val_scope;
+      cur->second.ivl_type = type->elaborate_type(des, type_scope);
+}
+
+void NetScope::evaluate_parameter_(Design*des, param_ref_t cur)
+{
+
       // If the parameter has already been evaluated, quietly return.
-      if (cur->second.val != 0)
+      if (cur->second.val || cur->second.ivl_type)
             return;
 
       if (cur->second.val_expr == 0) {
@@ -840,6 +851,21 @@ void NetScope::evaluate_parameter_(Design*des, param_ref_t cur)
 	    return;
       }
 
+      if (cur->second.type_flag) {
+	    evaluate_type_parameter_(des, cur);
+	    return;
+      }
+
+      ivl_type_t param_type = cur->second.ivl_type;
+
+      // If the parameter type is present, then elaborate it now. Elaborate
+      // the type in the current scope, and not the scope of the expression.
+      if (cur->second.val_type) {
+	    param_type = cur->second.val_type->elaborate_type(des, this);
+	    cur->second.ivl_type = param_type;
+	    cur->second.val_type = 0;
+      }
+
       // Guess the varaiable type of the parameter. If the parameter has no
       // given type, then guess the type from the expression and use that to
       // evaluate (this is currently handled in evaluate_parameter_logic_()).

net_scope.cc

@@ -269,23 +269,22 @@ NetScope*NetScope::find_typedef_scope(const Design*des, const typedef_t*type)
  * member.
  */
 void NetScope::set_parameter(perm_string key, bool is_annotatable,
-			     PExpr*val, data_type_t*val_type,
+			     const LexicalScope::param_expr_t &param,
-			     bool local_flag, bool overridable,
+			     NetScope::range_t *range_list)
-			     NetScope::range_t*range_list,
-			     const LineInfo&file_line)
 {
       param_expr_t&ref = parameters[key];
       ref.is_annotatable = is_annotatable;
-      ref.val_expr = val;
+      ref.val_expr = param.expr;
-      ref.val_type = val_type;
+      ref.val_type = param.data_type;
       ref.val_scope = this;
-      ref.local_flag = local_flag;
+      ref.local_flag = param.local_flag;
-      ref.overridable = overridable;
+      ref.overridable = param.overridable;
-      ivl_assert(file_line, ref.range == 0);
+      ref.type_flag = param.type_flag;
+      ivl_assert(param, !ref.range);
       ref.range = range_list;
       ref.val = 0;
       ref.ivl_type = 0;
-      ref.set_line(file_line);
+      ref.set_line(param);
 }
 
 /*
@@ -348,7 +347,8 @@ bool NetScope::auto_name(const char*prefix, char pad, const char* suffix)
  * Return false if the parameter does not already exist.
  * A parameter is not automatically created.
  */
-void NetScope::replace_parameter(Design *des, perm_string key, PExpr*val, NetScope*scope)
+void NetScope::replace_parameter(Design *des, perm_string key, PExpr*val,
+			         NetScope*scope, bool defparam)
 {
       if (parameters.find(key) == parameters.end()) {
 	    cerr << val->get_fileline() << ": error: parameter `"
@@ -376,6 +376,16 @@ void NetScope::replace_parameter(Design *des, perm_string key, PExpr*val, NetSco
 	    return;
       }
 
+      if (ref.type_flag && defparam) {
+	    cerr << val->get_fileline() << ": error: "
+		 << "Cannot override type parameter `" << key << "` in `"
+		 << scope_path(this) << "`. It is not allowed to override type"
+		 << " parameters using a defparam statement."
+		 << endl;
+	    des->errors++;
+	    return;
+      }
+
       ref.val_expr = val;
       ref.val_scope = scope;
 }

netlist.h

@@ -44,6 +44,7 @@
 # include  "HName.h"
 # include  "LineInfo.h"
 # include  "Attrib.h"
+# include  "PScope.h"
 # include  "PUdp.h"
 
 #ifdef HAVE_IOSFWD
@@ -952,10 +953,8 @@ class NetScope : public Definitions, public Attrib {
 
       struct range_t;
       void set_parameter(perm_string name, bool is_annotatable,
-			 PExpr*val, data_type_t*data_type,
+			 const LexicalScope::param_expr_t &param,
-			 bool local_flag, bool overridable,
+			 NetScope::range_t *range_list);
-			 NetScope::range_t*range_list,
-			 const LineInfo&file_line);
       void set_parameter(perm_string name, NetExpr*val,
 			 const LineInfo&file_line);
 
@@ -968,7 +967,8 @@ class NetScope : public Definitions, public Attrib {
 	   expression with a new expression, without affecting the
 	   range or signed_flag. Return false if the name does not
 	   exist. */
-      void replace_parameter(Design *des, perm_string name, PExpr*val, NetScope*scope);
+      void replace_parameter(Design *des, perm_string name, PExpr*val,
+			     NetScope*scope, bool defparam = false);
 
 	/* This is used to ensure the value of a parameter cannot be
 	   changed at run-time. This is required if a specparam is used
@@ -1213,11 +1213,19 @@ class NetScope : public Definitions, public Attrib {
 	    // Is this a localparam?
 	    bool local_flag;
 	    // Can it be overriden?
-	    bool overridable;
+	    bool overridable = false;
+	    // Is it a type parameter
+	    bool type_flag = false;
 	    // range constraints
 	    struct range_t*range;
-	    // Expression value and type (elaborated versoins of val_expr/val_type)
+
+	    // Expression value. Elaborated version of val_expr.
+	    // For type parameters this will always be 0.
 	    NetExpr*val;
+
+	    // For non-type parameter this contains the elaborate type of the
+	    // parameter itself. For type parameters this contains the
+	    // elaborated assigned type value.
 	    ivl_type_t ivl_type;
       };
       std::map<perm_string,param_expr_t>parameters;
@@ -1240,6 +1248,7 @@ class NetScope : public Definitions, public Attrib {
       std::map<perm_string,LocalVar> loop_index_tmp;
 
     private:
+      void evaluate_type_parameter_(Design*des, param_ref_t cur);
       void evaluate_parameter_logic_(Design*des, param_ref_t cur);
       void evaluate_parameter_real_(Design*des, param_ref_t cur);
       void evaluate_parameter_string_(Design*des, param_ref_t cur);

parse.y

@@ -41,6 +41,7 @@ extern void lex_end_table();
 
 static data_type_t* param_data_type = 0;
 static bool param_is_local = false;
+static bool param_is_type = false;
 static std::list<pform_range_t>* specparam_active_range = 0;
 
 /* Port declaration lists use this structure for context. */
@@ -4730,6 +4731,10 @@ module_parameter_port_list_opt
     ')'
   ;
 
+type_param
+  : K_type { param_is_type = true; }
+  ;
+
 module_parameter
   : parameter param_type parameter_assign
   | localparam param_type parameter_assign
@@ -4742,20 +4747,28 @@ module_parameter_port_list
   | data_type_opt
     { param_data_type = $1;
       param_is_local = false;
+      param_is_type = false;
     }
     parameter_assign
     { pform_requires_sv(@3, "Omitting initial `parameter` in parameter port "
 			    "list");
     }
+  | type_param
+    {
+      param_is_local = false;
+    }
+    parameter_assign
   | module_parameter_port_list ',' module_parameter
   | module_parameter_port_list ',' data_type_opt
     { if ($3) {
 	    pform_requires_sv(@3, "Omitting `parameter`/`localparam` before "
 				  "data type in parameter port list");
 	    param_data_type = $3;
+	    param_is_type = false;
       }
     }
     parameter_assign
+  | module_parameter_port_list ',' type_param parameter_assign
   ;
 
 module_item
@@ -5375,7 +5388,12 @@ net_type_or_var_opt
      This is used by parameter_assign, which is found to the right of
      the param_type in various rules. */
 
-param_type : data_type_or_implicit { param_data_type = $1; }
+param_type
+  : data_type_or_implicit
+    { param_is_type = false;
+      param_data_type = $1;
+    }
+  | type_param
 
 parameter : K_parameter { param_is_local = false; };
 localparam : K_localparam { param_is_local = true; };
@@ -5401,7 +5419,7 @@ parameter_assign_list
 parameter_assign
   : IDENTIFIER initializer_opt parameter_value_ranges_opt
       { pform_set_parameter(@1, lex_strings.make($1), param_is_local,
-			    param_data_type, $2, $3);
+			    param_is_type, param_data_type, $2, $3);
 	delete[]$1;
       }
   ;

pform.cc

@@ -2961,8 +2961,21 @@ LexicalScope::range_t* pform_parameter_value_range(bool exclude_flag,
       return tmp;
 }
 
+static void pform_set_type_parameter(const struct vlltype&loc, perm_string name,
+				     LexicalScope::range_t*value_range)
+{
+      pform_requires_sv(loc, "Type parameter");
+
+      if (value_range)
+	    VLerror(loc, "error: type parameter must not have value range.");
+
+      type_parameter_t *type = new type_parameter_t(name);
+      pform_set_typedef(loc, name, type, 0);
+}
+
 void pform_set_parameter(const struct vlltype&loc,
-			 perm_string name, bool is_local, data_type_t*data_type, PExpr*expr,
+			 perm_string name, bool is_local, bool is_type,
+			 data_type_t*data_type, PExpr*expr,
 			 LexicalScope::range_t*value_range)
 {
       LexicalScope*scope = lexical_scope;
@@ -3008,6 +3021,9 @@ void pform_set_parameter(const struct vlltype&loc,
       Module::param_expr_t*parm = new Module::param_expr_t();
       FILE_NAME(parm, loc);
 
+      if (is_type)
+	    pform_set_type_parameter(loc, name, value_range);
+      else
 	    add_local_symbol(scope, name, parm);
 
       parm->expr = expr;
@@ -3015,6 +3031,7 @@ void pform_set_parameter(const struct vlltype&loc,
       parm->range = value_range;
       parm->local_flag = is_local;
       parm->overridable = overridable;
+      parm->type_flag = is_type;
 
       scope->parameters[name] = parm;
 

pform.h

@@ -390,7 +390,7 @@ extern LexicalScope::range_t* pform_parameter_value_range(bool exclude_flag,
 
 extern void pform_set_parameter(const struct vlltype&loc,
 				perm_string name,
-				bool is_local,
+				bool is_local, bool is_type,
 				data_type_t*data_type,
 				PExpr*expr, LexicalScope::range_t*value_range);
 extern void pform_set_specparam(const struct vlltype&loc,

pform_types.h

@@ -212,6 +212,13 @@ private:
       typedef_t *type;
 };
 
+struct type_parameter_t : data_type_t {
+      explicit type_parameter_t(perm_string n) : name(n) { }
+      ivl_type_t elaborate_type_raw(Design *des, NetScope *scope) const;
+
+      perm_string name;
+};
+
 struct void_type_t : public data_type_t {
       virtual void pform_dump(std::ostream&out, unsigned indent) const;
 };

t-dll-api.cc

@@ -1877,6 +1877,12 @@ extern "C" int ivl_parameter_local(ivl_parameter_t net)
       return net->local;
 }
 
+extern "C" int ivl_parameter_is_type(ivl_parameter_t net)
+{
+      assert(net);
+      return net->is_type;
+}
+
 extern "C" int ivl_parameter_signed(ivl_parameter_t net)
 {
       assert(net);

t-dll.cc

@@ -509,10 +509,7 @@ void dll_target::make_scope_parameters(ivl_scope_t scop, const NetScope*net)
 	    cur_par->basename = cur_pit->first;
 	    cur_par->local = cur_pit->second.local_flag ||
 			     !cur_pit->second.overridable;
-	    calculate_param_range(cur_pit->second,
+	    cur_par->is_type = cur_pit->second.type_flag;
-				  cur_pit->second.ivl_type,
-				  cur_par->msb, cur_par->lsb,
-				  cur_pit->second.val->expr_width());
 
 	    if (cur_pit->second.ivl_type == 0) {
 		  cerr << "?:?: internal error: "
@@ -525,6 +522,13 @@ void dll_target::make_scope_parameters(ivl_scope_t scop, const NetScope*net)
 	    cur_par->scope = scop;
 	    FILE_NAME(cur_par, &(cur_pit->second));
 
+	      // Type parameters don't have a range or expression
+	    if (!cur_pit->second.type_flag) {
+		  calculate_param_range(cur_pit->second,
+					cur_pit->second.ivl_type,
+					cur_par->msb, cur_par->lsb,
+					cur_pit->second.val->expr_width());
+
 		  NetExpr*etmp = cur_pit->second.val;
 		  if (etmp == 0) {
 			cerr << "?:?: internal error: What is the parameter "
@@ -533,6 +537,8 @@ void dll_target::make_scope_parameters(ivl_scope_t scop, const NetScope*net)
 		  }
 		  assert(etmp);
 		  make_scope_param_expr(cur_par, etmp);
+	    }
+
 	    idx += 1;
       }
 }

t-dll.h

@@ -638,6 +638,7 @@ struct ivl_parameter_s {
       long          lsb;
       bool  signed_flag;
       bool        local;
+      bool      is_type;
       perm_string file;
       unsigned lineno;
 };

tgt-vhdl/scope.cc

@@ -940,9 +940,15 @@ static void create_skeleton_entity_for(ivl_scope_t scope, int depth)
    unsigned nparams = ivl_scope_params(scope);
    for (unsigned i = 0; i < nparams; i++) {
       ivl_parameter_t param = ivl_scope_param(scope, i);
-      ss << "\n  " << ivl_parameter_basename(param) << " = ";
+
+      // Type parameter usages get replaced with their actual type
+      if (ivl_parameter_is_type(param))
+	    continue;
 
       ivl_expr_t value = ivl_parameter_expr(param);
+
+      ss << "\n  " << ivl_parameter_basename(param) << " = ";
+
       switch (ivl_expr_type(value)) {
          case IVL_EX_STRING:
             ss << "\"" << ivl_expr_string(value) << "\"";

tgt-vhdl/state.cc

@@ -264,6 +264,14 @@ static bool same_scope_type_name(ivl_scope_t a, ivl_scope_t b)
                  ivl_parameter_basename(param_b)) != 0)
          return false;
 
+      if (ivl_parameter_local(param_a) && ivl_parameter_local(param_b))
+	    continue;
+
+      // If this is a type parameter consider the scopes not equal since we do
+      // not have support for comparing the actual types yet.
+      if (ivl_parameter_is_type(param_a) || ivl_parameter_is_type(param_b))
+	    return false;
+
       ivl_expr_t value_a = ivl_parameter_expr(param_a);
       ivl_expr_t value_b = ivl_parameter_expr(param_b);
 

tgt-vlog95/scope.c

@@ -309,6 +309,13 @@ void emit_scope_variables(ivl_scope_t scope)
       count = ivl_scope_params(scope);
       for (idx = 0; idx < count; idx += 1) {
 	    ivl_parameter_t par = ivl_scope_param(scope, idx);
+	      // vlog95 does not support type parameters. Places where type
+	      // parameters have been used it will be replaced with the actual
+	      // type that the module was instantiated with. Similar to
+	      // typedefs.
+	    if (ivl_parameter_is_type(par))
+		  continue;
+
 	    ivl_expr_t pex = ivl_parameter_expr(par);
 	    fprintf(vlog_out, "%*cparameter ", indent, ' ');
 	    emit_id(ivl_parameter_basename(par));

tgt-vvp/vvp_scope.c

@@ -2415,6 +2415,13 @@ int draw_scope(ivl_scope_t net, ivl_scope_t parent)
 
       for (idx = 0 ;  idx < ivl_scope_params(net) ;  idx += 1) {
 	    ivl_parameter_t par = ivl_scope_param(net, idx);
+
+	      // Skip type parameters for now. Support for type parameters
+	      // should be added together with support for quering types through
+	      // VPI.
+	    if (ivl_parameter_is_type(par))
+		  continue;
+
 	    ivl_expr_t pex = ivl_parameter_expr(par);
 	    switch (ivl_expr_type(pex)) {
 		case IVL_EX_STRING: