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diff --git a/compiler/GHC/Utils/Fingerprint.hs b/compiler/GHC/Utils/Fingerprint.hs
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+{-# LANGUAGE CPP #-}
+{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
+
+-- ----------------------------------------------------------------------------
+--
+--  (c) The University of Glasgow 2006
+--
+-- Fingerprints for recompilation checking and ABI versioning.
+--
+-- https://gitlab.haskell.org/ghc/ghc/wikis/commentary/compiler/recompilation-avoidance
+--
+-- ----------------------------------------------------------------------------
+
+module GHC.Utils.Fingerprint (
+        readHexFingerprint,
+        fingerprintByteString,
+        -- * Re-exported from GHC.Fingerprint
+        Fingerprint(..), fingerprint0,
+        fingerprintFingerprints,
+        fingerprintData,
+        fingerprintString,
+        getFileHash
+   ) where
+
+#include "HsVersions.h"
+
+import GHC.Prelude
+
+import Foreign
+import GHC.IO
+import Numeric          ( readHex )
+
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Unsafe as BS
+
+import GHC.Fingerprint
+
+-- useful for parsing the output of 'md5sum', should we want to do that.
+readHexFingerprint :: String -> Fingerprint
+readHexFingerprint s = Fingerprint w1 w2
+ where (s1,s2) = splitAt 16 s
+       [(w1,"")] = readHex s1
+       [(w2,"")] = readHex (take 16 s2)
+
+fingerprintByteString :: BS.ByteString -> Fingerprint
+fingerprintByteString bs = unsafeDupablePerformIO $
+  BS.unsafeUseAsCStringLen bs $ \(ptr, len) -> fingerprintData (castPtr ptr) len