Bugfixes to the expression parser.  Fixes include:

 - If you put a semicolon at the end of an expression,
   this no longer causes the expression parser to
   error out.  This was a two-part fix: first,
   ClangExpressionDeclMap::Materialize now handles
   an empty struct (such as when there is no return
   value); second, ASTResultSynthesizer walks backward
   from the end of the ASTs until it reaches something
   that's not a NullStmt.

 - ClangExpressionVariable now properly byte-swaps when
   printing itself.

 - ClangUtilityFunction now cleans up after itself when
   it's done compiling itself.

 - Utility functions can now use external functions just
   like user expressions.

 - If you end your expression with a statement that does
   not return a value, the expression now runs correctly
   anyway.

Also, added the beginnings of an Objective-C object
validator function, which is neither installed nor used
as yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvdb/trunk@113789 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/source/Expression/ClangUserExpression.cpp b/source/Expression/ClangUserExpression.cpp
index d8841d3..4e49c48 100644
--- a/source/Expression/ClangUserExpression.cpp
+++ b/source/Expression/ClangUserExpression.cpp
@@ -196,13 +196,16 @@
             
             Error dump_error;
             
-            if (!m_expr_decl_map->DumpMaterializedStruct(&exe_ctx, args, dump_error))
+            if (struct_address)
             {
-                log->Printf("Couldn't extract variable values : %s", dump_error.AsCString("unknown error"));
-            }
-            else
-            {
-                log->Printf("Structure contents:\n%s", args.GetData());
+                if (!m_expr_decl_map->DumpMaterializedStruct(&exe_ctx, args, dump_error))
+                {
+                    log->Printf("Couldn't extract variable values : %s", dump_error.AsCString("unknown error"));
+                }
+                else
+                {
+                    log->Printf("Structure contents:\n%s", args.GetData());
+                }
             }
         }