diff --git a/include/clang-c/Index.h b/include/clang-c/Index.h
index dac8b54..65e98ad 100644
--- a/include/clang-c/Index.h
+++ b/include/clang-c/Index.h
@@ -620,6 +620,15 @@
                                                 unsigned Index);
 
 /**
+ * \brief Retrieve the complete set of diagnostics associated with a
+ *        translation unit.
+ *
+ * \param Unit the translation unit to query.
+ */
+CINDEX_LINKAGE CXDiagnosticSet
+  clang_getDiagnosticSetFromTU(CXTranslationUnit Unit);  
+
+/**
  * \brief Destroy a diagnostic.
  */
 CINDEX_LINKAGE void clang_disposeDiagnostic(CXDiagnostic Diagnostic);
diff --git a/tools/libclang/CIndexDiagnostic.cpp b/tools/libclang/CIndexDiagnostic.cpp
index a29e3a6..ceb6405 100644
--- a/tools/libclang/CIndexDiagnostic.cpp
+++ b/tools/libclang/CIndexDiagnostic.cpp
@@ -98,15 +98,22 @@
 }
 
 CXDiagnostic clang_getDiagnostic(CXTranslationUnit Unit, unsigned Index) {
-  if (!Unit->TUData)
+  CXDiagnosticSet D = clang_getDiagnosticSetFromTU(Unit);
+  if (!D)
     return 0;
 
-  CXDiagnosticSetImpl *Diags = lazyCreateDiags(Unit);
+  CXDiagnosticSetImpl *Diags = static_cast<CXDiagnosticSetImpl*>(D);
   if (Index >= Diags->getNumDiagnostics())
     return 0;
 
   return Diags->getDiagnostic(Index);
 }
+  
+CXDiagnosticSet clang_getDiagnosticSetFromTU(CXTranslationUnit Unit) {
+  if (!Unit->TUData)
+    return 0;
+  return static_cast<CXDiagnostic>(lazyCreateDiags(Unit));
+}
 
 void clang_disposeDiagnostic(CXDiagnostic Diagnostic) {
   // No-op.  Kept as a legacy API.  CXDiagnostics are now managed
diff --git a/tools/libclang/libclang.exports b/tools/libclang/libclang.exports
index 5d37b59..b028bb4 100644
--- a/tools/libclang/libclang.exports
+++ b/tools/libclang/libclang.exports
@@ -97,6 +97,7 @@
 clang_getDiagnosticNumRanges
 clang_getDiagnosticOption
 clang_getDiagnosticRange
+clang_getDiagnosticSetFromTU
 clang_getDiagnosticSeverity
 clang_getDiagnosticSpelling
 clang_getElementType