compiler: generate dummy names for blank-named constants.

Otherwise such const declarations are not checked.

From-SVN: r200381

gcc/go/gofrontend/gogo-tree.cc

@@ -814,6 +814,15 @@ Gogo::write_globals()
 	  continue;
 	}
 
+      // Skip blank named functions and constants.
+      if ((no->is_function() && no->func_value()->is_sink())
+	  || (no->is_const() && no->const_value()->is_sink()))
+        {
+          --i;
+          --count;
+          continue;
+        }
+
       // There is nothing useful we can output for constants which
       // have ideal or non-integral type.
       if (no->is_const())
@@ -829,14 +838,6 @@ Gogo::write_globals()
 	    }
 	}
 
-      // Skip blank named functions.
-      if (no->is_function() && no->func_value()->is_sink())
-        {
-          --i;
-          --count;
-          continue;
-        }
-
       if (!no->is_variable())
 	{
 	  vec[i] = no->get_tree(this, NULL);

gcc/go/gofrontend/gogo.h

@@ -1687,7 +1687,7 @@ class Named_constant
   Named_constant(Type* type, Expression* expr, int iota_value,
 		 Location location)
     : type_(type), expr_(expr), iota_value_(iota_value), location_(location),
-      lowering_(false)
+      lowering_(false), is_sink_(false)
   { }
 
   Type*
@@ -1721,6 +1721,14 @@ class Named_constant
   clear_lowering()
   { this->lowering_ = false; }
 
+  bool
+  is_sink() const
+  { return this->is_sink_; }
+
+  void
+  set_is_sink()
+  { this->is_sink_ = true; }
+
   // Traverse the expression.
   int
   traverse_expression(Traverse*);
@@ -1756,6 +1764,8 @@ class Named_constant
   Location location_;
   // Whether we are currently lowering this constant.
   bool lowering_;
+  // Whether this constant is blank named and needs only type checking.
+  bool is_sink_;
 };
 
 // A type declaration.

gcc/go/gofrontend/parse.cc

@@ -1457,6 +1457,16 @@ Parse::const_spec(Type** last_type, Expression_list** last_expr_list)
 
       if (!Gogo::is_sink_name(pi->name()))
 	this->gogo_->add_constant(*pi, *pe, this->iota_value());
+      else
+	{
+	  static int count;
+	  char buf[30];
+	  snprintf(buf, sizeof buf, ".$sinkconst%d", count);
+	  ++count;
+	  Typed_identifier ti(std::string(buf), type, pi->location());
+	  Named_object* no = this->gogo_->add_constant(ti, *pe, this->iota_value());
+	  no->const_value()->set_is_sink();
+	}
     }
   if (pe != expr_list->end())
     error_at(this->location(), "too many initializers");