SystemVerilog: Parsing and type checking for queue types

This adds parsing and type checking for 1800-2017 7.10 queues.

Author: kroening

regression/verilog/data-types/queue1.desc

@@ -1,8 +1,8 @@
-KNOWNBUG
+CORE
 queue1.sv
 
-^EXIT=0$
+^no properties$
+^EXIT=10$
 ^SIGNAL=0$
 --
 --
-Parsing fails.

regression/verilog/data-types/queue1.sv

@@ -1,6 +1,6 @@
 module main;
 
   byte queue_of_bytes[$];
-  string queue_of_strings[$:10] = { "foobar" };
+  string queue_of_strings[$:10];
 
 endmodule

src/hw_cbmc_irep_ids.h

@@ -94,6 +94,7 @@ IREP_ID_ONE(verilog_inside)
 IREP_ID_ONE(verilog_unique)
 IREP_ID_ONE(verilog_unique0)
 IREP_ID_ONE(verilog_priority)
+IREP_ID_ONE(verilog_queue)
 IREP_ID_ONE(verilog_new)
 IREP_ID_ONE(verilog_non_indexed_part_select)
 IREP_ID_ONE(verilog_indexed_part_select_plus)

src/verilog/expr2verilog.cpp

@@ -2074,6 +2074,12 @@ std::string expr2verilogt::convert(const typet &type)
   {
     return "enum";
   }
+  else if(type.id() == ID_verilog_queue)
+  {
+    std::string dest = "queue of ";
+    dest += convert(to_type_with_subtype(type).subtype());
+    return dest;
+  }
   else if(type.id() == ID_struct)
   {
     return "struct";

src/verilog/parser.y

@@ -2114,6 +2114,7 @@ variable_dimension:
 	  unsized_dimension
 	| unpacked_dimension
 	| associative_dimension
+	| queue_dimension
 	;
 
 variable_dimension_brace:
@@ -2126,6 +2127,13 @@ variable_dimension_brace:
 	  }
 	;
 
+queue_dimension:
+	  '[' '$' ']'
+		{ init($$, ID_verilog_queue); stack_type($$).add_subtype().make_nil(); }
+	| '[' '$' TOK_COLON constant_expression ']'
+		{ init($$, ID_verilog_queue); stack_type($$).add_subtype().make_nil(); }
+	;
+
 unsized_dimension: '[' ']'
                 { init($$, "unsized"); }
 	;

src/verilog/verilog_elaborate_type.cpp

@@ -447,6 +447,13 @@ typet verilog_typecheck_exprt::elaborate_type(const typet &src)
     // package::typedef
     return elaborate_package_scope_typedef(to_type_with_subtypes(src));
   }
+  else if(src.id() == ID_verilog_queue)
+  {
+    // The subtype is the element type.
+    auto tmp = to_type_with_subtype(src);
+    tmp.subtype() = elaborate_type(tmp.subtype());
+    return std::move(tmp);
+  }
   else
   {
     throw errort().with_location(source_location)

src/verilog/verilog_expr.cpp

@@ -34,7 +34,7 @@ typet verilog_declaratort::merged_type(const typet &declaration_type) const
   typet *p = &result;
 
   while(p->id() == ID_verilog_unpacked_array ||
-        p->id() == ID_verilog_associative_array)
+        p->id() == ID_verilog_associative_array || p->id() == ID_verilog_queue)
   {
     p = &to_type_with_subtype(*p).subtype();
   }