r243947 - [UB] When attaching empty strings to the AST, use an empty StringRef

[Chandler Carruth]

Author: chandlerc
Date: Mon Aug  3 22:52:58 2015
New Revision: 243947

URL: http://llvm.org/viewvc/llvm-project?rev=243947&view=rev
Log:
[UB] When attaching empty strings to the AST, use an empty StringRef
rather than forcing the bump pointer allocator to produce a viable
pointer. This also fixes UB when we would try to memcpy from the null
incoming StringRef.

Modified:
    cfe/trunk/lib/AST/Stmt.cpp

Modified: cfe/trunk/lib/AST/Stmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Stmt.cpp?rev=243947&r1=243946&r2=243947&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Stmt.cpp (original)
+++ cfe/trunk/lib/AST/Stmt.cpp Mon Aug  3 22:52:58 2015
@@ -724,6 +724,8 @@ MSAsmStmt::MSAsmStmt(const ASTContext &C
 }
 
 static StringRef copyIntoContext(const ASTContext &C, StringRef str) {
+  if (str.empty())
+    return StringRef();
   size_t size = str.size();
   char *buffer = new (C) char[size];
   memcpy(buffer, str.data(), size);