diff --git a/mlir/include/mlir-c/IR.h b/mlir/include/mlir-c/IR.h
--- a/mlir/include/mlir-c/IR.h
+++ b/mlir/include/mlir-c/IR.h
@@ -74,17 +74,6 @@
 };
 typedef struct MlirNamedAttribute MlirNamedAttribute;
 
-/** A callback for returning string references.
- *
- * This function is called back by the functions that need to return a reference
- * to the portion of the string with the following arguments:
- *   - a pointer to the beginning of a string;
- *   - the length of the string (the pointer may point to a larger buffer, not
- *     necessarily null-terminated);
- *   - a pointer to user data forwarded from the printing call.
- */
-typedef void (*MlirStringCallback)(const char *, intptr_t, void *);
-
 //===----------------------------------------------------------------------===//
 // Context API.
 //===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir-c/Support.h b/mlir/include/mlir-c/Support.h
--- a/mlir/include/mlir-c/Support.h
+++ b/mlir/include/mlir-c/Support.h
@@ -50,6 +50,17 @@
  */
 MlirStringRef mlirStringRefCreateFromCString(const char *str);
 
+/** A callback for returning string references.
+ *
+ * This function is called back by the functions that need to return a reference
+ * to the portion of the string with the following arguments:
+ *   - a pointer to the beginning of a string;
+ *   - the length of the string (the pointer may point to a larger buffer, not
+ *     necessarily null-terminated);
+ *   - a pointer to user data forwarded from the printing call.
+ */
+typedef void (*MlirStringCallback)(const char *, intptr_t, void *);
+
 //===----------------------------------------------------------------------===//
 // MlirLogicalResult.
 //===----------------------------------------------------------------------===//