Initial ShortText code and conversion of package db code

Metric Decrease:
    Naperian
    T10421
    T10421a
    T10547
    T12150
    T12234
    T12425
    T13035
    T18140
    T18304
    T5837
    T6048
    T13253-spj
    T18282
    T18223
    T3064
    T9961
Metric Increase
    T13701

HFSKJH

9 files changed, 51 insertions, 568 deletions

diff --git a/compiler/GHC/Driver/Backpack.hs b/compiler/GHC/Driver/Backpack.hs
index 5b418d9166..cd9cb8672b 100644
--- a/compiler/GHC/Driver/Backpack.hs
+++ b/compiler/GHC/Driver/Backpack.hs
@@ -1,6 +1,8 @@
 {-# LANGUAGE CPP #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE NondecreasingIndentation #-}
+{-# LANGUAGE OverloadedStrings #-}
+
 
 -- | This is the driver for the 'ghc --backpack' mode, which
 -- is a reimplementation of the "package manager" bits of
@@ -38,6 +40,7 @@ import GHC.Unit.State
 import GHC.Driver.Types
 import GHC.Data.StringBuffer
 import GHC.Data.FastString
+import qualified GHC.Data.ShortText as ST
 import GHC.Utils.Error
 import GHC.Types.SrcLoc
 import GHC.Driver.Main
@@ -340,8 +343,8 @@ buildUnit session cid insts lunit = do
             unitAbiDepends = [],
             unitLinkerOptions = case session of
                                  TcSession -> []
-                                 _ -> obj_files,
-            unitImportDirs = [ hi_dir ],
+                                 _ -> map ST.pack $ obj_files,
+            unitImportDirs = [ ST.pack $ hi_dir ],
             unitIsExposed = False,
             unitIsIndefinite = case session of
                                  TcSession -> True
diff --git a/compiler/GHC/Driver/CodeOutput.hs b/compiler/GHC/Driver/CodeOutput.hs
index 0e43b64c77..cee81b900e 100644
--- a/compiler/GHC/Driver/CodeOutput.hs
+++ b/compiler/GHC/Driver/CodeOutput.hs
@@ -32,6 +32,7 @@ import GHC.Cmm.CLabel
 import GHC.Driver.Types
 import GHC.Driver.Session
 import GHC.Driver.Ppr
+import qualified GHC.Data.ShortText as ST
 import GHC.Data.Stream           ( Stream )
 import qualified GHC.Data.Stream as Stream
 import GHC.SysTools.FileCleanup
@@ -211,7 +212,7 @@ outputForeignStubs dflags mod location stubs
         let rts_includes =
                let rts_pkg = unsafeLookupUnitId (unitState dflags) rtsUnitId in
                concatMap mk_include (unitIncludes rts_pkg)
-            mk_include i = "#include \"" ++ i ++ "\"\n"
+            mk_include i = "#include \"" ++ ST.unpack i ++ "\"\n"
 
             -- wrapper code mentions the ffi_arg type, which comes from ffi.h
             ffi_includes
diff --git a/compiler/GHC/Driver/Finder.hs b/compiler/GHC/Driver/Finder.hs
index ffcd8d9359..57a9551b0f 100644
--- a/compiler/GHC/Driver/Finder.hs
+++ b/compiler/GHC/Driver/Finder.hs
@@ -43,6 +43,7 @@ import GHC.Unit.State
 
 import GHC.Driver.Types
 import GHC.Data.FastString
+import qualified GHC.Data.ShortText as ST
 import GHC.Utils.Misc
 import GHC.Builtin.Names ( gHC_PRIM )
 import GHC.Driver.Session
@@ -380,7 +381,7 @@ findPackageModule_ hsc_env mod pkg_conf =
 
      mk_hi_loc = mkHiOnlyModLocation dflags package_hisuf
 
-     import_dirs = unitImportDirs pkg_conf
+     import_dirs = map ST.unpack $ unitImportDirs pkg_conf
       -- we never look for a .hi-boot file in an external package;
       -- .hi-boot files only make sense for the home package.
   in
diff --git a/compiler/GHC/Runtime/Linker.hs b/compiler/GHC/Runtime/Linker.hs
index aaa74b3625..4477a0ad2f 100644
--- a/compiler/GHC/Runtime/Linker.hs
+++ b/compiler/GHC/Runtime/Linker.hs
@@ -61,6 +61,7 @@ import GHC.Types.SrcLoc
 import qualified GHC.Data.Maybe as Maybes
 import GHC.Types.Unique.DSet
 import GHC.Data.FastString
+import qualified GHC.Data.ShortText as ST
 import GHC.Platform
 import GHC.SysTools
 import GHC.SysTools.FileCleanup
@@ -1282,10 +1283,10 @@ linkPackage hsc_env pkg
         let dflags    = hsc_dflags hsc_env
             platform  = targetPlatform dflags
             is_dyn    = interpreterDynamic (hscInterp hsc_env)
-            dirs | is_dyn    = Packages.unitLibraryDynDirs pkg
-                 | otherwise = Packages.unitLibraryDirs pkg
+            dirs | is_dyn    = map ST.unpack $ Packages.unitLibraryDynDirs pkg
+                 | otherwise = map ST.unpack $ Packages.unitLibraryDirs pkg
 
-        let hs_libs   =  Packages.unitLibraries pkg
+        let hs_libs   = map ST.unpack $ Packages.unitLibraries pkg
             -- The FFI GHCi import lib isn't needed as
             -- GHC.Runtime.Linker + rts/Linker.c link the
             -- interpreted references to FFI to the compiled FFI.
@@ -1300,11 +1301,12 @@ linkPackage hsc_env pkg
         -- libs do not exactly match the .so/.dll equivalents. So if the
         -- package file provides an "extra-ghci-libraries" field then we use
         -- that instead of the "extra-libraries" field.
-            extra_libs =
-                      (if null (Packages.unitExtDepLibsGhc pkg)
-                            then Packages.unitExtDepLibsSys pkg
-                            else Packages.unitExtDepLibsGhc pkg)
-                      ++ [ lib | '-':'l':lib <- Packages.unitLinkerOptions pkg ]
+            extdeplibs = map ST.unpack (if null (Packages.unitExtDepLibsGhc pkg)
+                                      then Packages.unitExtDepLibsSys pkg
+                                      else Packages.unitExtDepLibsGhc pkg)
+            linkerlibs = [ lib | '-':'l':lib <- (map ST.unpack $ Packages.unitLinkerOptions pkg) ]
+            extra_libs = extdeplibs ++ linkerlibs
+
         -- See Note [Fork/Exec Windows]
         gcc_paths <- getGCCPaths dflags (platformOS platform)
         dirs_env <- addEnvPaths "LIBRARY_PATH" dirs
@@ -1434,8 +1436,8 @@ loadFrameworks :: HscEnv -> Platform -> UnitInfo -> IO ()
 loadFrameworks hsc_env platform pkg
     = when (platformUsesFrameworks platform) $ mapM_ load frameworks
   where
-    fw_dirs    = Packages.unitExtDepFrameworkDirs pkg
-    frameworks = Packages.unitExtDepFrameworks pkg
+    fw_dirs    = map ST.unpack $ Packages.unitExtDepFrameworkDirs pkg
+    frameworks = map ST.unpack $ Packages.unitExtDepFrameworks pkg
 
     load fw = do  r <- loadFramework hsc_env fw_dirs fw
                   case r of
diff --git a/compiler/GHC/SysTools/ExtraObj.hs b/compiler/GHC/SysTools/ExtraObj.hs
index 94443824e3..9208c3870d 100644
--- a/compiler/GHC/SysTools/ExtraObj.hs
+++ b/compiler/GHC/SysTools/ExtraObj.hs
@@ -25,6 +25,7 @@ import GHC.Unit
 import GHC.SysTools.Elf
 import GHC.Utils.Misc
 import GHC.Prelude
+import qualified GHC.Data.ShortText as ST
 
 import Control.Monad
 import Data.Maybe
@@ -57,7 +58,7 @@ mkExtraObj dflags extn xs
       -- we're compiling C or assembler. When compiling C, we pass the usual
       -- set of include directories and PIC flags.
       cOpts = map Option (picCCOpts dflags)
-                    ++ map (FileOption "-I")
+                    ++ map (FileOption "-I" . ST.unpack)
                             (unitIncludeDirs $ unsafeLookupUnit pkgs rtsUnit)
 
       -- When compiling assembler code, we drop the usual C options, and if the
diff --git a/compiler/GHC/Unit/Info.hs b/compiler/GHC/Unit/Info.hs
index abb2122ef0..1f2366f292 100644
--- a/compiler/GHC/Unit/Info.hs
+++ b/compiler/GHC/Unit/Info.hs
@@ -31,6 +31,7 @@ import Data.Version
 import Data.Bifunctor
 
 import GHC.Data.FastString
+import qualified GHC.Data.ShortText as ST
 import GHC.Utils.Outputable
 import GHC.Unit.Module as Module
 import GHC.Types.Unique
@@ -124,21 +125,21 @@ pprUnitInfo GenericUnitInfo {..} =
       field "exposed-modules"      (ppr unitExposedModules),
       field "hidden-modules"       (fsep (map ppr unitHiddenModules)),
       field "trusted"              (ppr unitIsTrusted),
-      field "import-dirs"          (fsep (map text unitImportDirs)),
-      field "library-dirs"         (fsep (map text unitLibraryDirs)),
-      field "dynamic-library-dirs" (fsep (map text unitLibraryDynDirs)),
-      field "hs-libraries"         (fsep (map text unitLibraries)),
-      field "extra-libraries"      (fsep (map text unitExtDepLibsSys)),
-      field "extra-ghci-libraries" (fsep (map text unitExtDepLibsGhc)),
-      field "include-dirs"         (fsep (map text unitIncludeDirs)),
-      field "includes"             (fsep (map text unitIncludes)),
+      field "import-dirs"          (fsep (map (text . ST.unpack) unitImportDirs)),
+      field "library-dirs"         (fsep (map (text . ST.unpack) unitLibraryDirs)),
+      field "dynamic-library-dirs" (fsep (map (text . ST.unpack) unitLibraryDynDirs)),
+      field "hs-libraries"         (fsep (map (text . ST.unpack) unitLibraries)),
+      field "extra-libraries"      (fsep (map (text . ST.unpack) unitExtDepLibsSys)),
+      field "extra-ghci-libraries" (fsep (map (text . ST.unpack) unitExtDepLibsGhc)),
+      field "include-dirs"         (fsep (map (text . ST.unpack) unitIncludeDirs)),
+      field "includes"             (fsep (map (text . ST.unpack) unitIncludes)),
       field "depends"              (fsep (map ppr  unitDepends)),
-      field "cc-options"           (fsep (map text unitCcOptions)),
-      field "ld-options"           (fsep (map text unitLinkerOptions)),
-      field "framework-dirs"       (fsep (map text unitExtDepFrameworkDirs)),
-      field "frameworks"           (fsep (map text unitExtDepFrameworks)),
-      field "haddock-interfaces"   (fsep (map text unitHaddockInterfaces)),
-      field "haddock-html"         (fsep (map text unitHaddockHTMLs))
+      field "cc-options"           (fsep (map (text . ST.unpack) unitCcOptions)),
+      field "ld-options"           (fsep (map (text . ST.unpack) unitLinkerOptions)),
+      field "framework-dirs"       (fsep (map (text . ST.unpack) unitExtDepFrameworkDirs)),
+      field "frameworks"           (fsep (map (text . ST.unpack) unitExtDepFrameworks)),
+      field "haddock-interfaces"   (fsep (map (text . ST.unpack) unitHaddockInterfaces)),
+      field "haddock-html"         (fsep (map (text . ST.unpack) unitHaddockHTMLs))
     ]
   where
     field name body = text name <> colon <+> nest 4 body
diff --git a/compiler/GHC/Unit/State.hs b/compiler/GHC/Unit/State.hs
index be5b08110d..78f96c90f3 100644
--- a/compiler/GHC/Unit/State.hs
+++ b/compiler/GHC/Unit/State.hs
@@ -99,6 +99,7 @@ import GHC.Data.Maybe
 
 import System.Environment ( getEnv )
 import GHC.Data.FastString
+import qualified GHC.Data.ShortText as ST
 import GHC.Utils.Error  ( debugTraceMsg, MsgDoc, dumpIfSet_dyn,
                           withTiming, DumpFormat (..) )
 import GHC.Utils.Exception
@@ -749,7 +750,7 @@ mungeUnitInfo :: FilePath -> FilePath
                    -> UnitInfo -> UnitInfo
 mungeUnitInfo top_dir pkgroot =
     mungeDynLibFields
-  . mungeUnitInfoPaths top_dir pkgroot
+  . mungeUnitInfoPaths (ST.pack top_dir) (ST.pack pkgroot)
 
 mungeDynLibFields :: UnitInfo -> UnitInfo
 mungeDynLibFields pkg =
@@ -1797,7 +1798,7 @@ getUnitIncludePath ctx unit_state home_unit pkgs =
   collectIncludeDirs `fmap` getPreloadUnitsAnd ctx unit_state home_unit pkgs
 
 collectIncludeDirs :: [UnitInfo] -> [FilePath]
-collectIncludeDirs ps = ordNub (filter notNull (concatMap unitIncludeDirs ps))
+collectIncludeDirs ps = map ST.unpack $ ordNub (filter (not . ST.null) (concatMap unitIncludeDirs ps))
 
 -- | Find all the library paths in these and the preload packages
 getUnitLibraryPath :: SDocContext -> UnitState -> HomeUnit -> Ways -> [UnitId] -> IO [String]
@@ -1822,8 +1823,8 @@ collectLinkOpts :: DynFlags -> [UnitInfo] -> ([String], [String], [String])
 collectLinkOpts dflags ps =
     (
         concatMap (map ("-l" ++) . packageHsLibs dflags) ps,
-        concatMap (map ("-l" ++) . unitExtDepLibsSys) ps,
-        concatMap unitLinkerOptions ps
+        concatMap (map ("-l" ++) . map ST.unpack . unitExtDepLibsSys) ps,
+        concatMap (map ST.unpack . unitLinkerOptions) ps
     )
 collectArchives :: DynFlags -> UnitInfo -> IO [FilePath]
 collectArchives dflags pc =
@@ -1831,7 +1832,7 @@ collectArchives dflags pc =
                         | searchPath <- searchPaths
                         , lib <- libs ]
   where searchPaths = ordNub . filter notNull . libraryDirsForWay (ways dflags) $ pc
-        libs        = packageHsLibs dflags pc ++ unitExtDepLibsSys pc
+        libs        = packageHsLibs dflags pc ++ (map ST.unpack $ unitExtDepLibsSys pc)
 
 getLibs :: DynFlags -> [UnitId] -> IO [(String,String)]
 getLibs dflags pkgs = do
@@ -1846,7 +1847,7 @@ getLibs dflags pkgs = do
     filterM (doesFileExist . fst) candidates
 
 packageHsLibs :: DynFlags -> UnitInfo -> [String]
-packageHsLibs dflags p = map (mkDynName . addSuffix) (unitLibraries p)
+packageHsLibs dflags p = map (mkDynName . addSuffix . ST.unpack) (unitLibraries p)
   where
         ways0 = ways dflags
 
@@ -1895,27 +1896,27 @@ packageHsLibs dflags p = map (mkDynName . addSuffix) (unitLibraries p)
 
 -- | Either the 'unitLibraryDirs' or 'unitLibraryDynDirs' as appropriate for the way.
 libraryDirsForWay :: Ways -> UnitInfo -> [String]
-libraryDirsForWay ws
-  | WayDyn `elem` ws = unitLibraryDynDirs
-  | otherwise        = unitLibraryDirs
+libraryDirsForWay ws ui
+  | WayDyn `elem` ws = map ST.unpack $ unitLibraryDynDirs ui
+  | otherwise        = map ST.unpack $ unitLibraryDirs ui
 
 -- | Find all the C-compiler options in these and the preload packages
 getUnitExtraCcOpts :: SDocContext -> UnitState -> HomeUnit -> [UnitId] -> IO [String]
 getUnitExtraCcOpts ctx unit_state home_unit pkgs = do
   ps <- getPreloadUnitsAnd ctx unit_state home_unit pkgs
-  return (concatMap unitCcOptions ps)
+  return $ map ST.unpack (concatMap unitCcOptions ps)
 
 -- | Find all the package framework paths in these and the preload packages
 getUnitFrameworkPath :: SDocContext -> UnitState -> HomeUnit -> [UnitId] -> IO [String]
 getUnitFrameworkPath ctx unit_state home_unit pkgs = do
   ps <- getPreloadUnitsAnd ctx unit_state home_unit pkgs
-  return (ordNub (filter notNull (concatMap unitExtDepFrameworkDirs ps)))
+  return $ map ST.unpack (ordNub (filter (not . ST.null) (concatMap unitExtDepFrameworkDirs ps)))
 
 -- | Find all the package frameworks in these and the preload packages
 getUnitFrameworks :: SDocContext -> UnitState -> HomeUnit -> [UnitId] -> IO [String]
 getUnitFrameworks ctx unit_state home_unit pkgs = do
   ps <- getPreloadUnitsAnd ctx unit_state home_unit pkgs
-  return (concatMap unitExtDepFrameworks ps)
+  return $ map ST.unpack (concatMap unitExtDepFrameworks ps)
 
 -- -----------------------------------------------------------------------------
 -- Package Utils
diff --git a/compiler/GHC/Utils/Encoding.hs b/compiler/GHC/Utils/Encoding.hs
deleted file mode 100644
index 68ebeedaf7..0000000000
--- a/compiler/GHC/Utils/Encoding.hs
+++ /dev/null
@@ -1,526 +0,0 @@
-{-# LANGUAGE BangPatterns, MagicHash, UnboxedTuples #-}
-{-# OPTIONS_GHC -O2 #-}
--- We always optimise this, otherwise performance of a non-optimised
--- compiler is severely affected
-
--- -----------------------------------------------------------------------------
---
--- (c) The University of Glasgow, 1997-2006
---
--- Character encodings
---
--- -----------------------------------------------------------------------------
-
-module GHC.Utils.Encoding (
-        -- * UTF-8
-        utf8DecodeCharAddr#,
-        utf8PrevChar,
-        utf8CharStart,
-        utf8DecodeChar,
-        utf8DecodeByteString,
-        utf8DecodeShortByteString,
-        utf8CompareShortByteString,
-        utf8DecodeStringLazy,
-        utf8EncodeChar,
-        utf8EncodeString,
-        utf8EncodeShortByteString,
-        utf8EncodedLength,
-        countUTF8Chars,
-
-        -- * Z-encoding
-        zEncodeString,
-        zDecodeString,
-
-        -- * Base62-encoding
-        toBase62,
-        toBase62Padded
-  ) where
-
-import GHC.Prelude
-
-import Foreign
-import Foreign.ForeignPtr.Unsafe (unsafeForeignPtrToPtr)
-import Data.Char
-import qualified Data.Char as Char
-import Numeric
-import GHC.IO
-import GHC.ST
-
-import Data.ByteString (ByteString)
-import qualified Data.ByteString.Internal as BS
-import Data.ByteString.Short.Internal (ShortByteString(..))
-
-import GHC.Exts
-
--- -----------------------------------------------------------------------------
--- UTF-8
-
--- We can't write the decoder as efficiently as we'd like without
--- resorting to unboxed extensions, unfortunately.  I tried to write
--- an IO version of this function, but GHC can't eliminate boxed
--- results from an IO-returning function.
---
--- We assume we can ignore overflow when parsing a multibyte character here.
--- To make this safe, we add extra sentinel bytes to unparsed UTF-8 sequences
--- before decoding them (see "GHC.Data.StringBuffer").
-
-{-# INLINE utf8DecodeChar# #-}
-utf8DecodeChar# :: (Int# -> Word#) -> (# Char#, Int# #)
-utf8DecodeChar# indexWord8# =
-  let !ch0 = word2Int# (indexWord8# 0#) in
-  case () of
-    _ | isTrue# (ch0 <=# 0x7F#) -> (# chr# ch0, 1# #)
-
-      | isTrue# ((ch0 >=# 0xC0#) `andI#` (ch0 <=# 0xDF#)) ->
-        let !ch1 = word2Int# (indexWord8# 1#) in
-        if isTrue# ((ch1 <# 0x80#) `orI#` (ch1 >=# 0xC0#)) then fail 1# else
-        (# chr# (((ch0 -# 0xC0#) `uncheckedIShiftL#` 6#) +#
-                  (ch1 -# 0x80#)),
-           2# #)
-
-      | isTrue# ((ch0 >=# 0xE0#) `andI#` (ch0 <=# 0xEF#)) ->
-        let !ch1 = word2Int# (indexWord8# 1#) in
-        if isTrue# ((ch1 <# 0x80#) `orI#` (ch1 >=# 0xC0#)) then fail 1# else
-        let !ch2 = word2Int# (indexWord8# 2#) in
-        if isTrue# ((ch2 <# 0x80#) `orI#` (ch2 >=# 0xC0#)) then fail 2# else
-        (# chr# (((ch0 -# 0xE0#) `uncheckedIShiftL#` 12#) +#
-                 ((ch1 -# 0x80#) `uncheckedIShiftL#` 6#)  +#
-                  (ch2 -# 0x80#)),
-           3# #)
-
-     | isTrue# ((ch0 >=# 0xF0#) `andI#` (ch0 <=# 0xF8#)) ->
-        let !ch1 = word2Int# (indexWord8# 1#) in
-        if isTrue# ((ch1 <# 0x80#) `orI#` (ch1 >=# 0xC0#)) then fail 1# else
-        let !ch2 = word2Int# (indexWord8# 2#) in
-        if isTrue# ((ch2 <# 0x80#) `orI#` (ch2 >=# 0xC0#)) then fail 2# else
-        let !ch3 = word2Int# (indexWord8# 3#) in
-        if isTrue# ((ch3 <# 0x80#) `orI#` (ch3 >=# 0xC0#)) then fail 3# else
-        (# chr# (((ch0 -# 0xF0#) `uncheckedIShiftL#` 18#) +#
-                 ((ch1 -# 0x80#) `uncheckedIShiftL#` 12#) +#
-                 ((ch2 -# 0x80#) `uncheckedIShiftL#` 6#)  +#
-                  (ch3 -# 0x80#)),
-           4# #)
-
-      | otherwise -> fail 1#
-  where
-        -- all invalid sequences end up here:
-        fail :: Int# -> (# Char#, Int# #)
-        fail nBytes# = (# '\0'#, nBytes# #)
-        -- '\xFFFD' would be the usual replacement character, but
-        -- that's a valid symbol in Haskell, so will result in a
-        -- confusing parse error later on.  Instead we use '\0' which
-        -- will signal a lexer error immediately.
-
-utf8DecodeCharAddr# :: Addr# -> Int# -> (# Char#, Int# #)
-utf8DecodeCharAddr# a# off# =
-    utf8DecodeChar# (\i# -> indexWord8OffAddr# a# (i# +# off#))
-
-utf8DecodeCharByteArray# :: ByteArray# -> Int# -> (# Char#, Int# #)
-utf8DecodeCharByteArray# ba# off# =
-    utf8DecodeChar# (\i# -> indexWord8Array# ba# (i# +# off#))
-
-utf8DecodeChar :: Ptr Word8 -> (Char, Int)
-utf8DecodeChar !(Ptr a#) =
-  case utf8DecodeCharAddr# a# 0# of
-    (# c#, nBytes# #) -> ( C# c#, I# nBytes# )
-
--- UTF-8 is cleverly designed so that we can always figure out where
--- the start of the current character is, given any position in a
--- stream.  This function finds the start of the previous character,
--- assuming there *is* a previous character.
-utf8PrevChar :: Ptr Word8 -> IO (Ptr Word8)
-utf8PrevChar p = utf8CharStart (p `plusPtr` (-1))
-
-utf8CharStart :: Ptr Word8 -> IO (Ptr Word8)
-utf8CharStart p = go p
- where go p = do w <- peek p
-                 if w >= 0x80 && w < 0xC0
-                        then go (p `plusPtr` (-1))
-                        else return p
-
-{-# INLINE utf8DecodeLazy# #-}
-utf8DecodeLazy# :: (IO ()) -> (Int# -> (# Char#, Int# #)) -> Int# -> IO [Char]
-utf8DecodeLazy# retain decodeChar# len#
-  = unpack 0#
-  where
-    unpack i#
-        | isTrue# (i# >=# len#) = retain >> return []
-        | otherwise =
-            case decodeChar# i# of
-              (# c#, nBytes# #) -> do
-                rest <- unsafeDupableInterleaveIO $ unpack (i# +# nBytes#)
-                return (C# c# : rest)
-
-utf8DecodeByteString :: ByteString -> [Char]
-utf8DecodeByteString (BS.PS fptr offset len)
-  = utf8DecodeStringLazy fptr offset len
-
-utf8DecodeStringLazy :: ForeignPtr Word8 -> Int -> Int -> [Char]
-utf8DecodeStringLazy fp offset (I# len#)
-  = unsafeDupablePerformIO $ do
-      let !(Ptr a#) = unsafeForeignPtrToPtr fp `plusPtr` offset
-      utf8DecodeLazy# (touchForeignPtr fp) (utf8DecodeCharAddr# a#) len#
--- Note that since utf8DecodeLazy# returns a thunk the lifetime of the
--- ForeignPtr actually needs to be longer than the lexical lifetime
--- withForeignPtr would provide here. That's why we use touchForeignPtr to
--- keep the fp alive until the last character has actually been decoded.
-
-utf8CompareShortByteString :: ShortByteString -> ShortByteString -> Ordering
-utf8CompareShortByteString (SBS a1) (SBS a2) = go 0# 0#
-   -- UTF-8 has the property that sorting by bytes values also sorts by
-   -- code-points.
-   -- BUT we use "Modified UTF-8" which encodes \0 as 0xC080 so this property
-   -- doesn't hold and we must explicitly check this case here.
-   -- Note that decoding every code point would also work but it would be much
-   -- more costly.
-   where
-       !sz1 = sizeofByteArray# a1
-       !sz2 = sizeofByteArray# a2
-       go off1 off2
-         | isTrue# ((off1 >=# sz1) `andI#` (off2 >=# sz2)) = EQ
-         | isTrue# (off1 >=# sz1)                          = LT
-         | isTrue# (off2 >=# sz2)                          = GT
-         | otherwise =
-               let !b1_1 = indexWord8Array# a1 off1
-                   !b2_1 = indexWord8Array# a2 off2
-               in case b1_1 of
-                  0xC0## -> case b2_1 of
-                     0xC0## -> go (off1 +# 1#) (off2 +# 1#)
-                     _      -> case indexWord8Array# a1 (off1 +# 1#) of
-                        0x80## -> LT
-                        _      -> go (off1 +# 1#) (off2 +# 1#)
-                  _      -> case b2_1 of
-                     0xC0## -> case indexWord8Array# a2 (off2 +# 1#) of
-                        0x80## -> GT
-                        _      -> go (off1 +# 1#) (off2 +# 1#)
-                     _   | isTrue# (b1_1 `gtWord#` b2_1) -> GT
-                         | isTrue# (b1_1 `ltWord#` b2_1) -> LT
-                         | otherwise                     -> go (off1 +# 1#) (off2 +# 1#)
-
-utf8DecodeShortByteString :: ShortByteString -> [Char]
-utf8DecodeShortByteString (SBS ba#)
-  = unsafeDupablePerformIO $
-      let len# = sizeofByteArray# ba# in
-      utf8DecodeLazy# (return ()) (utf8DecodeCharByteArray# ba#) len#
-
-countUTF8Chars :: ShortByteString -> IO Int
-countUTF8Chars (SBS ba) = go 0# 0#
-  where
-    len# = sizeofByteArray# ba
-    go i# n#
-      | isTrue# (i# >=# len#) =
-          return (I# n#)
-      | otherwise = do
-          case utf8DecodeCharByteArray# ba i# of
-            (# _, nBytes# #) -> go (i# +# nBytes#) (n# +# 1#)
-
-{-# INLINE utf8EncodeChar #-}
-utf8EncodeChar :: (Int# -> Word# -> State# s -> State# s)
-               -> Char -> ST s Int
-utf8EncodeChar write# c =
-  let x = ord c in
-  case () of
-    _ | x > 0 && x <= 0x007f -> do
-          write 0 x
-          return 1
-        -- NB. '\0' is encoded as '\xC0\x80', not '\0'.  This is so that we
-        -- can have 0-terminated UTF-8 strings (see GHC.Base.unpackCStringUtf8).
-      | x <= 0x07ff -> do
-          write 0 (0xC0 .|. ((x `shiftR` 6) .&. 0x1F))
-          write 1 (0x80 .|. (x .&. 0x3F))
-          return 2
-      | x <= 0xffff -> do
-          write 0 (0xE0 .|. (x `shiftR` 12) .&. 0x0F)
-          write 1 (0x80 .|. (x `shiftR` 6) .&. 0x3F)
-          write 2 (0x80 .|. (x .&. 0x3F))
-          return 3
-      | otherwise -> do
-          write 0 (0xF0 .|. (x `shiftR` 18))
-          write 1 (0x80 .|. ((x `shiftR` 12) .&. 0x3F))
-          write 2 (0x80 .|. ((x `shiftR` 6) .&. 0x3F))
-          write 3 (0x80 .|. (x .&. 0x3F))
-          return 4
-  where
-    {-# INLINE write #-}
-    write (I# off#) (I# c#) = ST $ \s ->
-      case write# off# (int2Word# c#) s of
-        s -> (# s, () #)
-
-utf8EncodeString :: Ptr Word8 -> String -> IO ()
-utf8EncodeString (Ptr a#) str = go a# str
-  where go !_   []   = return ()
-        go a# (c:cs) = do
-          I# off# <- stToIO $ utf8EncodeChar (writeWord8OffAddr# a#) c
-          go (a# `plusAddr#` off#) cs
-
-utf8EncodeShortByteString :: String -> IO ShortByteString
-utf8EncodeShortByteString str = IO $ \s ->
-  case utf8EncodedLength str         of { I# len# ->
-  case newByteArray# len# s          of { (# s, mba# #) ->
-  case go mba# 0# str                of { ST f_go ->
-  case f_go s                        of { (# s, () #) ->
-  case unsafeFreezeByteArray# mba# s of { (# s, ba# #) ->
-  (# s, SBS ba# #) }}}}}
-  where
-    go _ _ [] = return ()
-    go mba# i# (c:cs) = do
-      I# off# <- utf8EncodeChar (\j# -> writeWord8Array# mba# (i# +# j#)) c
-      go mba# (i# +# off#) cs
-
-utf8EncodedLength :: String -> Int
-utf8EncodedLength str = go 0 str
-  where go !n [] = n
-        go n (c:cs)
-          | ord c > 0 && ord c <= 0x007f = go (n+1) cs
-          | ord c <= 0x07ff = go (n+2) cs
-          | ord c <= 0xffff = go (n+3) cs
-          | otherwise       = go (n+4) cs
-
--- -----------------------------------------------------------------------------
--- Note [Z-Encoding]
--- ~~~~~~~~~~~~~~~~~
-
-{-
-This is the main name-encoding and decoding function.  It encodes any
-string into a string that is acceptable as a C name.  This is done
-right before we emit a symbol name into the compiled C or asm code.
-Z-encoding of strings is cached in the FastString interface, so we
-never encode the same string more than once.
-
-The basic encoding scheme is this.
-
-* Tuples (,,,) are coded as Z3T
-
-* Alphabetic characters (upper and lower) and digits
-        all translate to themselves;
-        except 'Z', which translates to 'ZZ'
-        and    'z', which translates to 'zz'
-  We need both so that we can preserve the variable/tycon distinction
-
-* Most other printable characters translate to 'zx' or 'Zx' for some
-        alphabetic character x
-
-* The others translate as 'znnnU' where 'nnn' is the decimal number
-        of the character
-
-        Before          After
-        --------------------------
-        Trak            Trak
-        foo_wib         foozuwib
-        >               zg
-        >1              zg1
-        foo#            foozh
-        foo##           foozhzh
-        foo##1          foozhzh1
-        fooZ            fooZZ
-        :+              ZCzp
-        ()              Z0T     0-tuple
-        (,,,,)          Z5T     5-tuple
-        (# #)           Z1H     unboxed 1-tuple (note the space)
-        (#,,,,#)        Z5H     unboxed 5-tuple
-                (NB: There is no Z1T nor Z0H.)
--}
-
-type UserString = String        -- As the user typed it
-type EncodedString = String     -- Encoded form
-
-
-zEncodeString :: UserString -> EncodedString
-zEncodeString cs = case maybe_tuple cs of
-                Just n  -> n            -- Tuples go to Z2T etc
-                Nothing -> go cs
-          where
-                go []     = []
-                go (c:cs) = encode_digit_ch c ++ go' cs
-                go' []     = []
-                go' (c:cs) = encode_ch c ++ go' cs
-
-unencodedChar :: Char -> Bool   -- True for chars that don't need encoding
-unencodedChar 'Z' = False
-unencodedChar 'z' = False
-unencodedChar c   =  c >= 'a' && c <= 'z'
-                  || c >= 'A' && c <= 'Z'
-                  || c >= '0' && c <= '9'
-
--- If a digit is at the start of a symbol then we need to encode it.
--- Otherwise package names like 9pH-0.1 give linker errors.
-encode_digit_ch :: Char -> EncodedString
-encode_digit_ch c | c >= '0' && c <= '9' = encode_as_unicode_char c
-encode_digit_ch c | otherwise            = encode_ch c
-
-encode_ch :: Char -> EncodedString
-encode_ch c | unencodedChar c = [c]     -- Common case first
-
--- Constructors
-encode_ch '('  = "ZL"   -- Needed for things like (,), and (->)
-encode_ch ')'  = "ZR"   -- For symmetry with (
-encode_ch '['  = "ZM"
-encode_ch ']'  = "ZN"
-encode_ch ':'  = "ZC"
-encode_ch 'Z'  = "ZZ"
-
--- Variables
-encode_ch 'z'  = "zz"
-encode_ch '&'  = "za"
-encode_ch '|'  = "zb"
-encode_ch '^'  = "zc"
-encode_ch '$'  = "zd"
-encode_ch '='  = "ze"
-encode_ch '>'  = "zg"
-encode_ch '#'  = "zh"
-encode_ch '.'  = "zi"
-encode_ch '<'  = "zl"
-encode_ch '-'  = "zm"
-encode_ch '!'  = "zn"
-encode_ch '+'  = "zp"
-encode_ch '\'' = "zq"
-encode_ch '\\' = "zr"
-encode_ch '/'  = "zs"
-encode_ch '*'  = "zt"
-encode_ch '_'  = "zu"
-encode_ch '%'  = "zv"
-encode_ch c    = encode_as_unicode_char c
-
-encode_as_unicode_char :: Char -> EncodedString
-encode_as_unicode_char c = 'z' : if isDigit (head hex_str) then hex_str
-                                                           else '0':hex_str
-  where hex_str = showHex (ord c) "U"
-  -- ToDo: we could improve the encoding here in various ways.
-  -- eg. strings of unicode characters come out as 'z1234Uz5678U', we
-  -- could remove the 'U' in the middle (the 'z' works as a separator).
-
-zDecodeString :: EncodedString -> UserString
-zDecodeString [] = []
-zDecodeString ('Z' : d : rest)
-  | isDigit d = decode_tuple   d rest
-  | otherwise = decode_upper   d : zDecodeString rest
-zDecodeString ('z' : d : rest)
-  | isDigit d = decode_num_esc d rest
-  | otherwise = decode_lower   d : zDecodeString rest
-zDecodeString (c   : rest) = c : zDecodeString rest
-
-decode_upper, decode_lower :: Char -> Char
-
-decode_upper 'L' = '('
-decode_upper 'R' = ')'
-decode_upper 'M' = '['
-decode_upper 'N' = ']'
-decode_upper 'C' = ':'
-decode_upper 'Z' = 'Z'
-decode_upper ch  = {-pprTrace "decode_upper" (char ch)-} ch
-
-decode_lower 'z' = 'z'
-decode_lower 'a' = '&'
-decode_lower 'b' = '|'
-decode_lower 'c' = '^'
-decode_lower 'd' = '$'
-decode_lower 'e' = '='
-decode_lower 'g' = '>'
-decode_lower 'h' = '#'
-decode_lower 'i' = '.'
-decode_lower 'l' = '<'
-decode_lower 'm' = '-'
-decode_lower 'n' = '!'
-decode_lower 'p' = '+'
-decode_lower 'q' = '\''
-decode_lower 'r' = '\\'
-decode_lower 's' = '/'
-decode_lower 't' = '*'
-decode_lower 'u' = '_'
-decode_lower 'v' = '%'
-decode_lower ch  = {-pprTrace "decode_lower" (char ch)-} ch
-
--- Characters not having a specific code are coded as z224U (in hex)
-decode_num_esc :: Char -> EncodedString -> UserString
-decode_num_esc d rest
-  = go (digitToInt d) rest
-  where
-    go n (c : rest) | isHexDigit c = go (16*n + digitToInt c) rest
-    go n ('U' : rest)           = chr n : zDecodeString rest
-    go n other = error ("decode_num_esc: " ++ show n ++  ' ':other)
-
-decode_tuple :: Char -> EncodedString -> UserString
-decode_tuple d rest
-  = go (digitToInt d) rest
-  where
-        -- NB. recurse back to zDecodeString after decoding the tuple, because
-        -- the tuple might be embedded in a longer name.
-    go n (c : rest) | isDigit c = go (10*n + digitToInt c) rest
-    go 0 ('T':rest)     = "()" ++ zDecodeString rest
-    go n ('T':rest)     = '(' : replicate (n-1) ',' ++ ")" ++ zDecodeString rest
-    go 1 ('H':rest)     = "(# #)" ++ zDecodeString rest
-    go n ('H':rest)     = '(' : '#' : replicate (n-1) ',' ++ "#)" ++ zDecodeString rest
-    go n other = error ("decode_tuple: " ++ show n ++ ' ':other)
-
-{-
-Tuples are encoded as
-        Z3T or Z3H
-for 3-tuples or unboxed 3-tuples respectively.  No other encoding starts
-        Z<digit>
-
-* "(# #)" is the tycon for an unboxed 1-tuple (not 0-tuple)
-  There are no unboxed 0-tuples.
-
-* "()" is the tycon for a boxed 0-tuple.
-  There are no boxed 1-tuples.
--}
-
-maybe_tuple :: UserString -> Maybe EncodedString
-
-maybe_tuple "(# #)" = Just("Z1H")
-maybe_tuple ('(' : '#' : cs) = case count_commas (0::Int) cs of
-                                 (n, '#' : ')' : _) -> Just ('Z' : shows (n+1) "H")
-                                 _                  -> Nothing
-maybe_tuple "()" = Just("Z0T")
-maybe_tuple ('(' : cs)       = case count_commas (0::Int) cs of
-                                 (n, ')' : _) -> Just ('Z' : shows (n+1) "T")
-                                 _            -> Nothing
-maybe_tuple _                = Nothing
-
-count_commas :: Int -> String -> (Int, String)
-count_commas n (',' : cs) = count_commas (n+1) cs
-count_commas n cs         = (n,cs)
-
-
-{-
-************************************************************************
-*                                                                      *
-                        Base 62
-*                                                                      *
-************************************************************************
-
-Note [Base 62 encoding 128-bit integers]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Instead of base-62 encoding a single 128-bit integer
-(ceil(21.49) characters), we'll base-62 a pair of 64-bit integers
-(2 * ceil(10.75) characters).  Luckily for us, it's the same number of
-characters!
--}
-
---------------------------------------------------------------------------
--- Base 62
-
--- The base-62 code is based off of 'locators'
--- ((c) Operational Dynamics Consulting, BSD3 licensed)
-
--- | Size of a 64-bit word when written as a base-62 string
-word64Base62Len :: Int
-word64Base62Len = 11
-
--- | Converts a 64-bit word into a base-62 string
-toBase62Padded :: Word64 -> String
-toBase62Padded w = pad ++ str
-  where
-    pad = replicate len '0'
-    len = word64Base62Len - length str -- 11 == ceil(64 / lg 62)
-    str = toBase62 w
-
-toBase62 :: Word64 -> String
-toBase62 w = showIntAtBase 62 represent w ""
-  where
-    represent :: Int -> Char
-    represent x
-        | x < 10 = Char.chr (48 + x)
-        | x < 36 = Char.chr (65 + x - 10)
-        | x < 62 = Char.chr (97 + x - 36)
-        | otherwise = error "represent (base 62): impossible!"
diff --git a/compiler/ghc.cabal.in b/compiler/ghc.cabal.in
index d12c2ca45e..4efae27e97 100644
--- a/compiler/ghc.cabal.in
+++ b/compiler/ghc.cabal.in
@@ -547,7 +547,6 @@ Library
         GHC.Data.BooleanFormula
         GHC.Utils.BufHandle
         GHC.Data.Graph.Directed
-        GHC.Utils.Encoding
         GHC.Utils.IO.Unsafe
         GHC.Data.FastMutInt
         GHC.Data.FastString