libclang: factor out the frequent pattern static_cast<ASTUnit *>(TU->TUData)
into a getter cxtu::getASTUnit(TU)

llvm-svn: 173585
diff --git a/clang/tools/libclang/CIndexCodeCompletion.cpp b/clang/tools/libclang/CIndexCodeCompletion.cpp
index 57588c7..9b0af2e 100644
--- a/clang/tools/libclang/CIndexCodeCompletion.cpp
+++ b/clang/tools/libclang/CIndexCodeCompletion.cpp
@@ -688,7 +688,7 @@
 
   bool EnableLogging = getenv("LIBCLANG_CODE_COMPLETION_LOGGING") != 0;
   
-  ASTUnit *AST = static_cast<ASTUnit *>(TU->TUData);
+  ASTUnit *AST = cxtu::getASTUnit(TU);
   if (!AST)
     return;
 
@@ -841,7 +841,7 @@
 
   if (!RunSafely(CRC, clang_codeCompleteAt_Impl, &CCAI)) {
     fprintf(stderr, "libclang: crash detected in code completion\n");
-    static_cast<ASTUnit *>(TU->TUData)->setUnsafeToFree(true);
+    cxtu::getASTUnit(TU)->setUnsafeToFree(true);
     return 0;
   } else if (getenv("LIBCLANG_RESOURCE_USAGE"))
     PrintLibclangResourceUsage(TU);