1 files changed, 14 insertions, 1 deletions
diff --git a/include/llvm/Support/MD5.h b/include/llvm/Support/MD5.h
index f6e1e92c9fa82..42d8ca8a1ebb1 100644
--- a/include/llvm/Support/MD5.h
+++ b/include/llvm/Support/MD5.h
@@ -28,11 +28,12 @@
 #ifndef LLVM_SUPPORT_MD5_H
 #define LLVM_SUPPORT_MD5_H
 
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/Endian.h"
 
 namespace llvm {
+template <typename T> class ArrayRef;
 
 class MD5 {
   // Any 32-bit or wider unsigned integer data type will do.
@@ -65,6 +66,18 @@ private:
   const uint8_t *body(ArrayRef<uint8_t> Data);
 };
 
+/// Helper to compute and return lower 64 bits of the given string's MD5 hash.
+inline uint64_t MD5Hash(StringRef Str) {
+  MD5 Hash;
+  Hash.update(Str);
+  llvm::MD5::MD5Result Result;
+  Hash.final(Result);
+  // Return the least significant 8 bytes. Our MD5 implementation returns the
+  // result in little endian, so we may need to swap bytes.
+  using namespace llvm::support;
+  return endian::read<uint64_t, little, unaligned>(Result);
+}
+
 }
 
 #endif