[X10-commits] SF.net SVN: x10:[12750] trunk

[<dgr...@us...>]

Revision: 12750
          http://x10.svn.sourceforge.net/x10/?rev=12750&view=rev
Author:   dgrove-oss
Date:     2010-01-27 17:01:38 +0000 (Wed, 27 Jan 2010)

Log Message:
-----------
Intorduce an explicit C++ level class to stand for the NullType
instead of using x10::lang::Reference.  This enables us to get
an RTT object for the NullType while still maintaining the 
useful implementation invariant that there is no RTT 
for x10::lang::Reference because it does not exist at the X10 level.

Modified Paths:
--------------
    trunk/x10.compiler/src/x10cpp/visit/Emitter.java
    trunk/x10.runtime/src-cpp/x10/lang/Reference.cc
    trunk/x10.runtime/src-cpp/x10/lang/Reference.h
    trunk/x10.runtime/src-cpp/x10aux/ref.h

Modified: trunk/x10.compiler/src/x10cpp/visit/Emitter.java
===================================================================
--- trunk/x10.compiler/src/x10cpp/visit/Emitter.java	2010-01-27 16:36:04 UTC (rev 12749)
+++ trunk/x10.compiler/src/x10cpp/visit/Emitter.java	2010-01-27 17:01:38 UTC (rev 12750)
@@ -301,7 +301,7 @@
 			name = ((ParameterType)type).name().toString();
 			return mangled_parameter_type_name(name); // parameter types shouldn't be refs
 		} else if (type.isNull()) {
-			return "x10aux::NullType"; // typedef to something sensible
+			return "x10aux::ref<x10::lang::NullType>"; // typedef to something sensible
 		} else
 			assert false : type; // unhandled type.
 		assert (name != null);

Modified: trunk/x10.runtime/src-cpp/x10/lang/Reference.cc
===================================================================
--- trunk/x10.runtime/src-cpp/x10/lang/Reference.cc	2010-01-27 16:36:04 UTC (rev 12749)
+++ trunk/x10.runtime/src-cpp/x10/lang/Reference.cc	2010-01-27 17:01:38 UTC (rev 12750)
@@ -40,4 +40,10 @@
     }
 }
 
+x10aux::RuntimeType x10::lang::NullType::rtt;
+
+void x10::lang::NullType::_initRTT() {
+    rtt.init(&rtt, "null", 0, NULL, 0, NULL, NULL);
+}
+
 // vim:tabstop=4:shiftwidth=4:expandtab

Modified: trunk/x10.runtime/src-cpp/x10/lang/Reference.h
===================================================================
--- trunk/x10.runtime/src-cpp/x10/lang/Reference.h	2010-01-27 16:36:04 UTC (rev 12749)
+++ trunk/x10.runtime/src-cpp/x10/lang/Reference.h	2010-01-27 17:01:38 UTC (rev 12750)
@@ -116,6 +116,20 @@
                 " (expecting id " << id << ") from buf: "<<&buf);
             return x10aux::DeserializationDispatcher::create<T>(buf);
         }
+
+        /**
+         * This is a class that exists only at the C++ implementation level,
+         * not at the X10 language level.  It's only real purpose is to
+         * provide a C++ level type for x10aux::NullType and therefore permit
+         * a unique RTT object to be associated with the X10 value null.
+         * 
+         * This is an abstract class because no instance of it will ever be
+         * created (we use NULL as the value for X10's null).
+         */
+        class NullType : public Reference {
+          public:
+            RTT_H_DECLS_CLASS;
+        };
     }
 }
 

Modified: trunk/x10.runtime/src-cpp/x10aux/ref.h
===================================================================
--- trunk/x10.runtime/src-cpp/x10aux/ref.h	2010-01-27 16:36:04 UTC (rev 12749)
+++ trunk/x10.runtime/src-cpp/x10aux/ref.h	2010-01-27 17:01:38 UTC (rev 12750)
@@ -9,7 +9,7 @@
 #include <x10aux/RTT.h>
 #include <x10aux/network.h>
 
-namespace x10 { namespace lang { class Reference; } }
+namespace x10 { namespace lang { class NullType; } }
 
 namespace x10aux {
 
@@ -181,9 +181,8 @@
         return obj;
     }
 
-    // will be initialised to null
-    typedef ref<x10::lang::Reference> NullType;
-    static NullType null;
+    // will be initialised to NULL
+    static ref<x10::lang::NullType> null;
 
     template<class F, class T> bool operator!=(F f, T t) { return !(f == t); }
     // comparison of a primitive with a ref


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