[UB] Fix yet another use of memcpy with a null pointer argument. I think

this is the last of them in my build of LLVM. Haven't tried Clang yet.

Found via UBSan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243934 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/MemoryBuffer.cpp b/lib/Support/MemoryBuffer.cpp
index 98862e96b74923bb930f741d7a9074db8582cdcf..d09ef3a4c0bc595cd0dd95265cb89819f11057fb 100644 (file)
--- a/lib/Support/MemoryBuffer.cpp
+++ b/lib/Support/MemoryBuffer.cpp
@@ -57,7 +57,8 @@ void MemoryBuffer::init(const char *BufStart, const char *BufEnd,
 /// CopyStringRef - Copies contents of a StringRef into a block of memory and
 /// null-terminates it.
 static void CopyStringRef(char *Memory, StringRef Data) {
 /// CopyStringRef - Copies contents of a StringRef into a block of memory and
 /// null-terminates it.
 static void CopyStringRef(char *Memory, StringRef Data) {

-  memcpy(Memory, Data.data(), Data.size());
+  if (!Data.empty())
+    memcpy(Memory, Data.data(), Data.size());

   Memory[Data.size()] = 0; // Null terminate string.
 }
 
   Memory[Data.size()] = 0; // Null terminate string.
 }