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.

llvm-svn: 113789

lldb/source/Expression/ClangExpressionDeclMap.cpp

@@ -401,6 +401,16 @@ ClangExpressionDeclMap::DoMaterialize (bool dematerialize,
         return LLDB_INVALID_ADDRESS;
     }
     
+    if (!m_struct_size)
+    {
+        if (log)
+            log->PutCString("Not bothering to allocate a struct because no arguments are needed");
+        
+        m_allocated_area = NULL;
+        
+        return true;
+    }
+    
     const SymbolContext &sym_ctx(exe_ctx->frame->GetSymbolContext(lldb::eSymbolContextEverything));
     
     if (!dematerialize)