[llvm] r243932 - [UB] Fix another place where we would pass a null pointer to memcpy.

[Chandler Carruth]

Author: chandlerc
Date: Mon Aug  3 19:53:01 2015
New Revision: 243932

URL: http://llvm.org/viewvc/llvm-project?rev=243932&view=rev
Log:
[UB] Fix another place where we would pass a null pointer to memcpy.

This too was found by UBSan. Down to 35 failures for me.

Modified:
    llvm/trunk/include/llvm/ADT/StringMap.h

Modified: llvm/trunk/include/llvm/ADT/StringMap.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/StringMap.h?rev=243932&r1=243931&r2=243932&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/StringMap.h (original)
+++ llvm/trunk/include/llvm/ADT/StringMap.h Mon Aug  3 19:53:01 2015
@@ -158,7 +158,8 @@ public:
 
     // Copy the string information.
     char *StrBuffer = const_cast<char*>(NewItem->getKeyData());
-    memcpy(StrBuffer, Key.data(), KeyLength);
+    if (KeyLength > 0)
+      memcpy(StrBuffer, Key.data(), KeyLength);
     StrBuffer[KeyLength] = 0;  // Null terminate for convenience of clients.
     return NewItem;
   }