Add DWARF address space to DIDerivedType (added in LLVM 5)

This lays the foundation towards an eventual fix for
GaloisInc/llvm-pretty-bc-parser#85.

GitHub commit: llvm/llvm-project@d5561e0
It's an unsigned int: https://github.com/llvm/llvm-project/blob/d5561e0a0bbd484da17d3b68ae5fedc0a057246b/llvm/include/llvm/IR/DebugInfoMetadata.h#L783

Co-authored-by: Ryan Scott <rscott@galois.com>

src/Text/LLVM/AST.hs

@@ -1276,17 +1276,22 @@ data DICompositeType' lab = DICompositeType
 type DICompositeType = DICompositeType' BlockLabel
 
 data DIDerivedType' lab = DIDerivedType
-  { didtTag :: DwarfTag
-  , didtName :: Maybe String
-  , didtFile :: Maybe (ValMd' lab)
-  , didtLine :: Word32
-  , didtScope :: Maybe (ValMd' lab)
-  , didtBaseType :: Maybe (ValMd' lab)
-  , didtSize :: Word64
-  , didtAlign :: Word64
-  , didtOffset :: Word64
-  , didtFlags :: DIFlags
-  , didtExtraData :: Maybe (ValMd' lab)
+  { didtTag               :: DwarfTag
+  , didtName              :: Maybe String
+  , didtFile              :: Maybe (ValMd' lab)
+  , didtLine              :: Word32
+  , didtScope             :: Maybe (ValMd' lab)
+  , didtBaseType          :: Maybe (ValMd' lab)
+  , didtSize              :: Word64
+  , didtAlign             :: Word64
+  , didtOffset            :: Word64
+  , didtFlags             :: DIFlags
+  , didtExtraData         :: Maybe (ValMd' lab)
+  , didtDwarfAddressSpace :: Maybe Word32
+  -- ^ Introduced in LLVM 5.
+  --
+  -- The 'Maybe' encodes the possibility that there is no associated address
+  -- space (in LLVM, the sentinel value @0@ is used for this).
   } deriving (Data, Eq, Functor, Generic, Generic1, Ord, Show, Typeable)
 
 type DIDerivedType = DIDerivedType' BlockLabel

src/Text/LLVM/PP.hs

@@ -1070,6 +1070,7 @@ ppDIDerivedType' pp dt = "!DIDerivedType"
        , pure ("offset:"    <+> integral (didtOffset dt))
        , pure ("flags:"     <+> integral (didtFlags dt))
        ,     (("extraData:" <+>) . ppValMd' pp) <$> (didtExtraData dt)
+       ,     (("dwarfAddressSpace:" <+>) . integral) <$> didtDwarfAddressSpace dt
        ])
 
 ppDIDerivedType :: LLVM => DIDerivedType -> Doc