libclang: introduce cxstring::createNull()


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@174173 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/CIndexCodeCompletion.cpp b/tools/libclang/CIndexCodeCompletion.cpp
index 1ffd023..07c04ac 100644
--- a/tools/libclang/CIndexCodeCompletion.cpp
+++ b/tools/libclang/CIndexCodeCompletion.cpp
@@ -112,7 +112,7 @@
                                       unsigned chunk_number) {
   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
   if (!CCStr || chunk_number >= CCStr->size())
-    return createCXString((const char*)0);
+    return cxstring::createNull();
 
   switch ((*CCStr)[chunk_number].Kind) {
   case CodeCompletionString::CK_TypedText:
@@ -211,7 +211,7 @@
                                        unsigned annotation_number) {
   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
   return CCStr ? createCXString(CCStr->getAnnotation(annotation_number))
-               : createCXString((const char *) 0);
+               : cxstring::createNull();
 }
 
 CXString
@@ -222,7 +222,7 @@
   
   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
   if (!CCStr)
-    return createCXString((const char *)0);
+    return cxstring::createNull();
   
   return createCXString(CCStr->getParentContextName(), /*DupString=*/false);
 }
@@ -232,7 +232,7 @@
   CodeCompletionString *CCStr = (CodeCompletionString *)completion_string;
 
   if (!CCStr)
-    return createCXString((const char *) NULL);
+    return cxstring::createNull();
 
   return createCXString(CCStr->getBriefComment(), /*DupString=*/false);
 }