Add support for signed packed structs/unions

packed structs and packed unions as a whole can either be signed or
unsigned. This information is used when it is used as a primary in an
expression, i.e. without accessing any of the members.

Add support for parsing and elaborating signed structs.

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

elab_type.cc

@@ -180,6 +180,7 @@ netstruct_t* struct_type_t::elaborate_type_raw(Design*des, NetScope*scope) const
       netstruct_t*res = new netstruct_t;
 
       res->packed(packed_flag);
+      res->set_signed(signed_flag);
 
       if (union_flag)
 	    res->union_flag(true);

netstruct.h

@@ -51,6 +51,10 @@ class netstruct_t : public LineInfo, public ivl_type_s {
       void packed(bool flag);
       bool packed(void) const;
 
+        // When the struct is accessed as a primary it can be signed or unsigned
+      void set_signed(bool flag) { signed_ = flag; }
+      bool get_signed(void) const { return signed_; }
+
 	// Append a new member to the struct/union. This must be done
 	// after the union_flag and packed settings are set. This
 	// function does error checking, and the "des" argument is
@@ -74,6 +78,7 @@ class netstruct_t : public LineInfo, public ivl_type_s {
     private:
       bool union_;
       bool packed_;
+      bool signed_;
       std::vector<member_t>members_;
 };
 

parse.y

@@ -457,6 +457,11 @@ static void current_function_set_statement(const YYLTYPE&loc, std::vector<Statem
 	    PExpr*expr;
       } genvar_iter;
 
+      struct {
+	    bool packed_flag;
+	    bool signed_flag;
+      } packed_signing;
+
       verinum* number;
 
       verireal* realtime;
@@ -571,7 +576,7 @@ static void current_function_set_statement(const YYLTYPE&loc, std::vector<Statem
 %type <number>  number pos_neg_number
 %type <flag>    signing unsigned_signed_opt signed_unsigned_opt
 %type <flag>    import_export
-%type <flag>    K_genvar_opt K_packed_opt K_reg_opt K_static_opt K_virtual_opt
+%type <flag>    K_genvar_opt K_reg_opt K_static_opt K_virtual_opt
 %type <flag>    udp_reg_opt edge_operator
 %type <drive>   drive_strength drive_strength_opt dr_strength0 dr_strength1
 %type <letter>  udp_input_sym udp_output_sym
@@ -642,6 +647,7 @@ static void current_function_set_statement(const YYLTYPE&loc, std::vector<Statem
 %type <struct_member>  struct_union_member
 %type <struct_members> struct_union_member_list
 %type <struct_type>    struct_data_type
+%type <packed_signing> packed_signing
 
 %type <class_declaration_extends> class_declaration_extends_opt
 
@@ -2988,38 +2994,54 @@ enum_name
       }
   ;
 
-struct_data_type
-  : K_struct K_packed_opt '{' struct_union_member_list '}'
+/* `signed` and `unsigned` are only valid if preceded by `packed` */
+packed_signing /* IEEE 1800-2012 A.2.2.1 */
+  : K_packed unsigned_signed_opt
+      { $$.packed_flag = true;
+        $$.signed_flag = $2;
+      }
+  |
+      { $$.packed_flag = false;
+        $$.signed_flag = false;
+      }
+  ;
+
+struct_data_type /* IEEE 1800-2012 A.2.2.1 */
+  : K_struct packed_signing '{' struct_union_member_list '}'
       { struct_type_t*tmp = new struct_type_t;
 	FILE_NAME(tmp, @1);
-	tmp->packed_flag = $2;
+	tmp->packed_flag = $2.packed_flag;
+	tmp->signed_flag = $2.signed_flag;
 	tmp->union_flag = false;
 	tmp->members .reset($4);
 	$$ = tmp;
       }
-  | K_union K_packed_opt '{' struct_union_member_list '}'
+  | K_union packed_signing '{' struct_union_member_list '}'
       { struct_type_t*tmp = new struct_type_t;
 	FILE_NAME(tmp, @1);
-	tmp->packed_flag = $2;
+	tmp->packed_flag = $2.packed_flag;
+	tmp->signed_flag = $2.signed_flag;
 	tmp->union_flag = true;
 	tmp->members .reset($4);
 	$$ = tmp;
       }
-  | K_struct K_packed_opt '{' error '}'
+  | K_struct packed_signing '{' error '}'
       { yyerror(@3, "error: Errors in struct member list.");
 	yyerrok;
 	struct_type_t*tmp = new struct_type_t;
 	FILE_NAME(tmp, @1);
-	tmp->packed_flag = $2;
+	tmp->packed_flag = $2.packed_flag;
+	tmp->signed_flag = $2.signed_flag;
 	tmp->union_flag = false;
 	$$ = tmp;
       }
-  | K_union K_packed_opt '{' error '}'
+  | K_union packed_signing '{' error '}'
       { yyerror(@3, "error: Errors in union member list.");
 	yyerrok;
 	struct_type_t*tmp = new struct_type_t;
 	FILE_NAME(tmp, @1);
-	tmp->packed_flag = $2;
+	tmp->packed_flag = $2.packed_flag;
+	tmp->signed_flag = $2.signed_flag;
 	tmp->union_flag = true;
 	$$ = tmp;
       }
@@ -7453,7 +7475,6 @@ unique_priority
      collect those rules here. */
 
 K_genvar_opt   : K_genvar    { $$ = true; } | { $$ = false; } ;
-K_packed_opt   : K_packed    { $$ = true; } | { $$ = false; } ;
 K_reg_opt      : K_reg       { $$ = true; } | { $$ = false; } ;
 K_static_opt   : K_static    { $$ = true; } | { $$ = false; } ;
 K_virtual_opt  : K_virtual   { $$ = true; } | { $$ = false; } ;

pform_types.h

@@ -207,6 +207,7 @@ struct struct_type_t : public data_type_t {
 
       bool packed_flag;
       bool union_flag;
+      bool signed_flag;
       std::unique_ptr< std::list<struct_member_t*> > members;
 };