[ADT] Delete the Twine assignment operator

This makes it slightly harder to misuse Twines.  It is still possible to
refer to destroyed temporaries with the regular constructors, though.

Patch by Marco Alesiani!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209832 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/ADT/Twine.h b/include/llvm/ADT/Twine.h
index a54fd743ad6874002b0a2eb79500e0c1d0a779e4..4be3ee6f82dbdfdd168100677b35f9207260d831 100644 (file)
--- a/include/llvm/ADT/Twine.h
+++ b/include/llvm/ADT/Twine.h
@@ -182,6 +182,10 @@ namespace llvm {
       assert(isValid() && "Invalid twine!");
     }
 
+    /// Since the intended use of twines is as temporary objects, assignments
+    /// when concatenating might cause undefined behavior or stack corruptions
+    Twine &operator=(const Twine &Other) LLVM_DELETED_FUNCTION;
+
     /// isNull - Check for the null twine.
     bool isNull() const {
       return getLHSKind() == NullKind;