Implement BoxedRep proposalwip/boxed-rep

This implements the BoxedRep proposal, refactoring the `RuntimeRep`
hierarchy from:

```haskell
data RuntimeRep = LiftedPtrRep | UnliftedPtrRep | ...
```

to

```haskell
data RuntimeRep = BoxedRep Levity | ...
data Levity = Lifted | Unlifted
```

Updates binary, haddock submodules.

Closes #17526.

Metric Increase:
    T12545

2 files changed, 13 insertions, 1 deletions

diff --git a/compiler/GHC/Utils/Binary.hs b/compiler/GHC/Utils/Binary.hs
index ce533ed127..5ee0806cc1 100644
--- a/compiler/GHC/Utils/Binary.hs
+++ b/compiler/GHC/Utils/Binary.hs
@@ -876,7 +876,6 @@ instance Binary (Bin a) where
   get bh = do i <- getWord32 bh; return (BinPtr (fromIntegral (i :: Word32)))
 
 
-
 -- -----------------------------------------------------------------------------
 -- Lazy reading/writing
 
diff --git a/compiler/GHC/Utils/Binary/Typeable.hs b/compiler/GHC/Utils/Binary/Typeable.hs
index c5b89bf35a..ebee92e211 100644
--- a/compiler/GHC/Utils/Binary/Typeable.hs
+++ b/compiler/GHC/Utils/Binary/Typeable.hs
@@ -22,6 +22,9 @@ import GHC.Prelude
 import GHC.Utils.Binary
 
 import GHC.Exts (TYPE, RuntimeRep(..), VecCount(..), VecElem(..))
+#if __GLASGOW_HASKELL__ >= 901
+import GHC.Exts (Levity(Lifted, Unlifted))
+#endif
 import GHC.Serialized
 
 import Foreign
@@ -115,8 +118,13 @@ instance Binary RuntimeRep where
     put_ bh (VecRep a b)    = putByte bh 0 >> put_ bh a >> put_ bh b
     put_ bh (TupleRep reps) = putByte bh 1 >> put_ bh reps
     put_ bh (SumRep reps)   = putByte bh 2 >> put_ bh reps
+#if __GLASGOW_HASKELL__ >= 901
+    put_ bh (BoxedRep Lifted)   = putByte bh 3
+    put_ bh (BoxedRep Unlifted) = putByte bh 4
+#else
     put_ bh LiftedRep       = putByte bh 3
     put_ bh UnliftedRep     = putByte bh 4
+#endif
     put_ bh IntRep          = putByte bh 5
     put_ bh WordRep         = putByte bh 6
     put_ bh Int64Rep        = putByte bh 7
@@ -139,8 +147,13 @@ instance Binary RuntimeRep where
           0  -> VecRep <$> get bh <*> get bh
           1  -> TupleRep <$> get bh
           2  -> SumRep <$> get bh
+#if __GLASGOW_HASKELL__ >= 901
+          3  -> pure (BoxedRep Lifted)
+          4  -> pure (BoxedRep Unlifted)
+#else
           3  -> pure LiftedRep
           4  -> pure UnliftedRep
+#endif
           5  -> pure IntRep
           6  -> pure WordRep
           7  -> pure Int64Rep