pkgs/development/compilers/ghc/Cabal-at-least-3.6-paths-fix-cycle-aarch64-darwin.patch

   1 This patch is based on https://github.com/sternenseemann/cabal/compare/982646d67b95b32813b89ab5d2d2f4d4dc03fb2b..7c49047f253e1f128e2df356400ec5da6f11066b
   2 and has been postprocessed with `filterdiff --strip=1 --addoldprefix=a/libraries/Cabal/ --addnewprefix=b/libraries/Cabal/`.
   3 Note that the base for the diff is not the Cabal 3.6.3.0 release tag, but
   4 982646d67b95b32813b89ab5d2d2f4d4dc03fb2b which is obtained by applying
   5 https://github.com/haskell/cabal/commit/6c796218c92f93c95e94d5ec2d077f6956f68e98
   6 on top of said release tag. That patch is applied to all our GHCs in the 9.2 series.
   7
   8 Reasoning and explanation of the patch can be found in the comment in the diff for PathsModule.hs below.
   9
  10 diffCabal/src/Distribution/Simple/Build/PathsModule.hs b/Cabal/src/Distribution/Simple/Build/PathsModule.hs
  11 index b2be7e1a8..9b63e9850 100644
  12 --- a/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule.hs
  13 +++ b/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule.hs
  14 @@ -46,6 +46,7 @@ generatePathsModule pkg_descr lbi clbi = Z.render Z.Z
  15      , Z.zIsWindows                  = isWindows
  16      , Z.zIsI386                     = buildArch == I386
  17      , Z.zIsX8664                    = buildArch == X86_64
  18 +    , Z.zOr                         = (||)
  19      , Z.zNot                        = not
  20      , Z.zManglePkgName              = showPkgName
  21
  22 @@ -56,8 +57,112 @@ generatePathsModule pkg_descr lbi clbi = Z.render Z.Z
  23      , Z.zDatadir    = zDatadir
  24      , Z.zLibexecdir = zLibexecdir
  25      , Z.zSysconfdir = zSysconfdir
  26 +
  27 +    -- Sadly we can't be cleverer about this – we can't have literals in the template
  28 +    , Z.zShouldEmitDataDir    = shouldEmit "DataDir"
  29 +    , Z.zShouldEmitLibDir     = shouldEmit "LibDir"
  30 +    , Z.zShouldEmitDynLibDir  = shouldEmit "DynLibDir"
  31 +    , Z.zShouldEmitLibexecDir = shouldEmit "LibexecDir"
  32 +    , Z.zShouldEmitSysconfDir = shouldEmit "SysconfDir"
  33 +
  34 +    , Z.zWarning           = zWarning
  35 +    , Z.zShouldEmitWarning = zShouldEmitWarning
  36      }
  37    where
  38 +    -- GHC's NCG backend for aarch64-darwin does not support link-time dead code
  39 +    -- elimination to the extent that NCG does for other targets. Consequently,
  40 +    -- we struggle with unnecessarily retained store path references due to the
  41 +    -- use of `Paths_*` modules – even if `getLibDir` is not used, it'll end up
  42 +    -- in the final library or executables we build.
  43 +    --
  44 +    -- When using a different output for the executables and library, this
  45 +    -- becomes more sinister: The library will contain a reference to the bin
  46 +    -- output and itself due to `getLibDir` and `getBinDir`, but the executables
  47 +    -- will do so, too. Either due to linking dynamically or because the library
  48 +    -- is linked statically into the executable and retains those references.
  49 +    -- Since Nix disallows cyclical references between two outputs, it becomes
  50 +    -- impossible to use the `Paths_*` module and a separate `bin` output for
  51 +    -- aarch64-darwin.
  52 +    --
  53 +    -- The solution we have resorted to for now, is to trim the `Paths_*` module
  54 +    -- dynamically depending on what references *could* be used without causing
  55 +    -- a cyclical reference. That has the effect that any code that would not
  56 +    -- cause a cyclical reference with dead code elimination will compile and
  57 +    -- work for aarch64-darwin. If the code would use a `get*Dir` function that
  58 +    -- has been omitted, this would indicate that the code would have caused a
  59 +    -- cyclical reference anyways.
  60 +    --
  61 +    -- The logic for this makes some pretty big assumptions about installation
  62 +    -- prefixes that probably only hold fully in nixpkgs with
  63 +    -- `haskellPackages.mkDerivation`. Simple uses outside nixpkgs that have
  64 +    -- everything below the same prefix should continue to work as expected,
  65 +    -- though.
  66 +    --
  67 +    -- We assume the following:
  68 +    --
  69 +    -- - flat_prefix is `$out`.
  70 +    -- - flat_libdir etc. are always below `$out`.
  71 +    --
  72 +    -- Since in the normal case due to static linking `$bin` and `$out` will
  73 +    -- have the same references in libraries/executables, we need to either
  74 +    -- prevent usage of `getBinDir` or `getLibDir` to break the cycle in case
  75 +    -- `flat_bindir` is not below `$out`. We have decided to always allow usage
  76 +    -- of `getBinDir`, so `getLibDir` gets dropped if a separate `bin` output is
  77 +    -- used. This has the simple reason that `$out` which contains `flat_libdir`
  78 +    -- tends to be quite big – we would like to have a `bin` output that doesn't
  79 +    -- require keeping that around.
  80 +    pathEmittable :: FilePath -> Bool
  81 +    pathEmittable p
  82 +      -- If the executable installation target is below `$out` the reference
  83 +      -- cycle is within a single output (since libs are installed to `$out`)
  84 +      -- and thus unproblematic. We can use any and all `get*Dir` functions.
  85 +      | flat_prefix `isPrefixOf` flat_bindir = True
  86 +      -- Otherwise, we need to disallow all `get*Dir` functions that would cause
  87 +      -- a reference to `$out` which contains the libraries that would in turn
  88 +      -- reference `$bin`. This always include `flat_libdir` and friends, but
  89 +      -- can also include `flat_datadir` if no separate output for data files is
  90 +      -- used.
  91 +      | otherwise = not (flat_prefix `isPrefixOf` p)
  92 +
  93 +    -- This list maps the "name" of the directory to whether we want to include
  94 +    -- it in the `Paths_*` module or not. `shouldEmit` performs a lookup in this.
  95 +    dirs :: [(String, Bool)]
  96 +    dirs =
  97 +      map
  98 +       (\(name, path) -> (name, pathEmittable path))
  99 +       [ ("LibDir", flat_libdir)
 100 +       , ("DynLibDir", flat_dynlibdir)
 101 +       , ("DataDir", flat_datadir)
 102 +       , ("LibexecDir", flat_libexecdir)
 103 +       , ("SysconfDir", flat_sysconfdir)
 104 +       ]
 105 +
 106 +    shouldEmit :: String -> Bool
 107 +    shouldEmit name =
 108 +      case lookup name dirs of
 109 +        Just b -> b
 110 +        Nothing -> error "panic! BUG in Cabal Paths_ patch for aarch64-darwin, report this at https://github.com/nixos/nixpkgs/issues"
 111 +
 112 +    -- This is a comma separated list of all functions that have been omitted.
 113 +    -- This is included in a GHC warning which will be attached to the `Paths_*`
 114 +    -- module in case we are dropping any `get*Dir` functions that would
 115 +    -- normally exist.
 116 +    --
 117 +    -- TODO: getDataFileName is not accounted for at the moment.
 118 +    omittedFunctions :: String
 119 +    omittedFunctions =
 120 +      intercalate ", "
 121 +      $ map (("get" ++) . fst)
 122 +      $ filter (not . snd) dirs
 123 +
 124 +    zWarning :: String
 125 +    zWarning =
 126 +      show $
 127 +        "The following functions have been omitted by a nixpkgs-specific patch to Cabal: "
 128 +        ++ omittedFunctions
 129 +    zShouldEmitWarning :: Bool
 130 +    zShouldEmitWarning = any (not . snd) dirs
 131 +
 132      supports_cpp                 = supports_language_pragma
 133      supports_rebindable_syntax   = ghc_newer_than (mkVersion [7,0,1])
 134      supports_language_pragma     = ghc_newer_than (mkVersion [6,6,1])
 135 diffCabal/src/Distribution/Simple/Build/PathsModule/Z.hs b/Cabal/src/Distribution/Simple/Build/PathsModule/Z.hs
 136 index 6488ea061..a6cdc8e31 100644
 137 --- a/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule/Z.hs
 138 +++ b/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule/Z.hs
 139 @@ -18,6 +18,14 @@ data Z
 140           zDatadir :: FilePath,
 141           zLibexecdir :: FilePath,
 142           zSysconfdir :: FilePath,
 143 +         zShouldEmitLibDir :: Bool,
 144 +         zShouldEmitDynLibDir :: Bool,
 145 +         zShouldEmitLibexecDir :: Bool,
 146 +         zShouldEmitDataDir :: Bool,
 147 +         zShouldEmitSysconfDir :: Bool,
 148 +         zShouldEmitWarning :: Bool,
 149 +         zWarning :: String,
 150 +         zOr :: (Bool -> Bool -> Bool),
 151           zNot :: (Bool -> Bool),
 152           zManglePkgName :: (PackageName -> String)}
 153      deriving Generic
 154 @@ -45,10 +53,51 @@ render z_root = execWriter $ do
 155    tell "{-# OPTIONS_GHC -w #-}\n"
 156    tell "module Paths_"
 157    tell (zManglePkgName z_root (zPackageName z_root))
 158 -  tell " (\n"
 159 +  tell "\n"
 160 +  tell "  "
 161 +  if (zShouldEmitWarning z_root)
 162 +  then do
 163 +    tell "{-# WARNING "
 164 +    tell (zWarning z_root)
 165 +    tell " #-}"
 166 +    return ()
 167 +  else do
 168 +    return ()
 169 +  tell "\n"
 170 +  tell "  (\n"
 171    tell "    version,\n"
 172 -  tell "    getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir,\n"
 173 -  tell "    getDataFileName, getSysconfDir\n"
 174 +  tell "    getBinDir,\n"
 175 +  if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitLibDir z_root))
 176 +  then do
 177 +    tell "    getLibDir,\n"
 178 +    return ()
 179 +  else do
 180 +    return ()
 181 +  if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitDynLibDir z_root))
 182 +  then do
 183 +    tell "    getDynLibDir,\n"
 184 +    return ()
 185 +  else do
 186 +    return ()
 187 +  if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitLibexecDir z_root))
 188 +  then do
 189 +    tell "    getLibexecDir,\n"
 190 +    return ()
 191 +  else do
 192 +    return ()
 193 +  if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitDataDir z_root))
 194 +  then do
 195 +    tell "    getDataFileName,\n"
 196 +    tell "    getDataDir,\n"
 197 +    return ()
 198 +  else do
 199 +    return ()
 200 +  if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitSysconfDir z_root))
 201 +  then do
 202 +    tell "    getSysconfDir\n"
 203 +    return ()
 204 +  else do
 205 +    return ()
 206    tell "  ) where\n"
 207    tell "\n"
 208    if (zNot z_root (zAbsolute z_root))
 209 @@ -97,12 +146,15 @@ render z_root = execWriter $ do
 210    tell (zVersionDigits z_root)
 211    tell " []\n"
 212    tell "\n"
 213 -  tell "getDataFileName :: FilePath -> IO FilePath\n"
 214 -  tell "getDataFileName name = do\n"
 215 -  tell "  dir <- getDataDir\n"
 216 -  tell "  return (dir `joinFileName` name)\n"
 217 -  tell "\n"
 218 -  tell "getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir, getSysconfDir :: IO FilePath\n"
 219 +  if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitDataDir z_root))
 220 +  then do
 221 +    tell "getDataFileName :: FilePath -> IO FilePath\n"
 222 +    tell "getDataFileName name = do\n"
 223 +    tell "  dir <- getDataDir\n"
 224 +    tell "  return (dir `joinFileName` name)\n"
 225 +    return ()
 226 +  else do
 227 +    return ()
 228    tell "\n"
 229    let
 230      z_var0_function_defs = do
 231 @@ -130,6 +182,7 @@ render z_root = execWriter $ do
 232    tell "\n"
 233    if (zRelocatable z_root)
 234    then do
 235 +    tell "\n"
 236      tell "\n"
 237      tell "getPrefixDirReloc :: FilePath -> IO FilePath\n"
 238      tell "getPrefixDirReloc dirRel = do\n"
 239 @@ -139,31 +192,37 @@ render z_root = execWriter $ do
 240      tell (zBindir z_root)
 241      tell ") `joinFileName` dirRel)\n"
 242      tell "\n"
 243 +    tell "getBinDir     :: IO FilePath\n"
 244      tell "getBinDir     = catchIO (getEnv \""
 245      tell (zManglePkgName z_root (zPackageName z_root))
 246      tell "_bindir\")     (\\_ -> getPrefixDirReloc $ "
 247      tell (zBindir z_root)
 248      tell ")\n"
 249 +    tell "getLibDir     :: IO FilePath\n"
 250      tell "getLibDir     = catchIO (getEnv \""
 251      tell (zManglePkgName z_root (zPackageName z_root))
 252      tell "_libdir\")     (\\_ -> getPrefixDirReloc $ "
 253      tell (zLibdir z_root)
 254      tell ")\n"
 255 +    tell "getDynLibDir  :: IO FilePath\n"
 256      tell "getDynLibDir  = catchIO (getEnv \""
 257      tell (zManglePkgName z_root (zPackageName z_root))
 258      tell "_dynlibdir\")  (\\_ -> getPrefixDirReloc $ "
 259      tell (zDynlibdir z_root)
 260      tell ")\n"
 261 +    tell "getDataDir    :: IO FilePath\n"
 262      tell "getDataDir    = catchIO (getEnv \""
 263      tell (zManglePkgName z_root (zPackageName z_root))
 264      tell "_datadir\")    (\\_ -> getPrefixDirReloc $ "
 265      tell (zDatadir z_root)
 266      tell ")\n"
 267 +    tell "getLibexecDir :: IO FilePath\n"
 268      tell "getLibexecDir = catchIO (getEnv \""
 269      tell (zManglePkgName z_root (zPackageName z_root))
 270      tell "_libexecdir\") (\\_ -> getPrefixDirReloc $ "
 271      tell (zLibexecdir z_root)
 272      tell ")\n"
 273 +    tell "getSysconfDir :: IO FilePath\n"
 274      tell "getSysconfDir = catchIO (getEnv \""
 275      tell (zManglePkgName z_root (zPackageName z_root))
 276      tell "_sysconfdir\") (\\_ -> getPrefixDirReloc $ "
 277 @@ -177,72 +236,119 @@ render z_root = execWriter $ do
 278      if (zAbsolute z_root)
 279      then do
 280        tell "\n"
 281 -      tell "bindir, libdir, dynlibdir, datadir, libexecdir, sysconfdir :: FilePath\n"
 282 +      tell "bindir     :: FilePath\n"
 283        tell "bindir     = "
 284        tell (zBindir z_root)
 285        tell "\n"
 286 -      tell "libdir     = "
 287 -      tell (zLibdir z_root)
 288 -      tell "\n"
 289 -      tell "dynlibdir  = "
 290 -      tell (zDynlibdir z_root)
 291 +      tell "getBinDir     :: IO FilePath\n"
 292 +      tell "getBinDir     = catchIO (getEnv \""
 293 +      tell (zManglePkgName z_root (zPackageName z_root))
 294 +      tell "_bindir\")     (\\_ -> return bindir)\n"
 295        tell "\n"
 296 -      tell "datadir    = "
 297 -      tell (zDatadir z_root)
 298 +      if (zShouldEmitLibDir z_root)
 299 +      then do
 300 +        tell "libdir     :: FilePath\n"
 301 +        tell "libdir     = "
 302 +        tell (zLibdir z_root)
 303 +        tell "\n"
 304 +        tell "getLibDir     :: IO FilePath\n"
 305 +        tell "getLibDir     = catchIO (getEnv \""
 306 +        tell (zManglePkgName z_root (zPackageName z_root))
 307 +        tell "_libdir\")     (\\_ -> return libdir)\n"
 308 +        return ()
 309 +      else do
 310 +        return ()
 311        tell "\n"
 312 -      tell "libexecdir = "
 313 -      tell (zLibexecdir z_root)
 314 +      if (zShouldEmitDynLibDir z_root)
 315 +      then do
 316 +        tell "dynlibdir  :: FilePath\n"
 317 +        tell "dynlibdir  = "
 318 +        tell (zDynlibdir z_root)
 319 +        tell "\n"
 320 +        tell "getDynLibDir  :: IO FilePath\n"
 321 +        tell "getDynLibDir  = catchIO (getEnv \""
 322 +        tell (zManglePkgName z_root (zPackageName z_root))
 323 +        tell "_dynlibdir\")  (\\_ -> return dynlibdir)\n"
 324 +        return ()
 325 +      else do
 326 +        return ()
 327        tell "\n"
 328 -      tell "sysconfdir = "
 329 -      tell (zSysconfdir z_root)
 330 +      if (zShouldEmitDataDir z_root)
 331 +      then do
 332 +        tell "datadir    :: FilePath\n"
 333 +        tell "datadir    = "
 334 +        tell (zDatadir z_root)
 335 +        tell "\n"
 336 +        tell "getDataDir    :: IO FilePath\n"
 337 +        tell "getDataDir    = catchIO (getEnv \""
 338 +        tell (zManglePkgName z_root (zPackageName z_root))
 339 +        tell "_datadir\")    (\\_ -> return datadir)\n"
 340 +        return ()
 341 +      else do
 342 +        return ()
 343        tell "\n"
 344 +      if (zShouldEmitLibexecDir z_root)
 345 +      then do
 346 +        tell "libexecdir :: FilePath\n"
 347 +        tell "libexecdir = "
 348 +        tell (zLibexecdir z_root)
 349 +        tell "\n"
 350 +        tell "getLibexecDir :: IO FilePath\n"
 351 +        tell "getLibexecDir = catchIO (getEnv \""
 352 +        tell (zManglePkgName z_root (zPackageName z_root))
 353 +        tell "_libexecdir\") (\\_ -> return libexecdir)\n"
 354 +        return ()
 355 +      else do
 356 +        return ()
 357        tell "\n"
 358 -      tell "getBinDir     = catchIO (getEnv \""
 359 -      tell (zManglePkgName z_root (zPackageName z_root))
 360 -      tell "_bindir\")     (\\_ -> return bindir)\n"
 361 -      tell "getLibDir     = catchIO (getEnv \""
 362 -      tell (zManglePkgName z_root (zPackageName z_root))
 363 -      tell "_libdir\")     (\\_ -> return libdir)\n"
 364 -      tell "getDynLibDir  = catchIO (getEnv \""
 365 -      tell (zManglePkgName z_root (zPackageName z_root))
 366 -      tell "_dynlibdir\")  (\\_ -> return dynlibdir)\n"
 367 -      tell "getDataDir    = catchIO (getEnv \""
 368 -      tell (zManglePkgName z_root (zPackageName z_root))
 369 -      tell "_datadir\")    (\\_ -> return datadir)\n"
 370 -      tell "getLibexecDir = catchIO (getEnv \""
 371 -      tell (zManglePkgName z_root (zPackageName z_root))
 372 -      tell "_libexecdir\") (\\_ -> return libexecdir)\n"
 373 -      tell "getSysconfDir = catchIO (getEnv \""
 374 -      tell (zManglePkgName z_root (zPackageName z_root))
 375 -      tell "_sysconfdir\") (\\_ -> return sysconfdir)\n"
 376 +      if (zShouldEmitSysconfDir z_root)
 377 +      then do
 378 +        tell "sysconfdir :: FilePath\n"
 379 +        tell "sysconfdir = "
 380 +        tell (zSysconfdir z_root)
 381 +        tell "\n"
 382 +        tell "getSysconfDir :: IO FilePath\n"
 383 +        tell "getSysconfDir = catchIO (getEnv \""
 384 +        tell (zManglePkgName z_root (zPackageName z_root))
 385 +        tell "_sysconfdir\") (\\_ -> return sysconfdir)\n"
 386 +        return ()
 387 +      else do
 388 +        return ()
 389        tell "\n"
 390        return ()
 391      else do
 392        if (zIsWindows z_root)
 393        then do
 394 +        tell "\n"
 395          tell "\n"
 396          tell "prefix :: FilePath\n"
 397          tell "prefix = "
 398          tell (zPrefix z_root)
 399          tell "\n"
 400          tell "\n"
 401 +        tell "getBinDir     :: IO FilePath\n"
 402          tell "getBinDir     = getPrefixDirRel $ "
 403          tell (zBindir z_root)
 404          tell "\n"
 405 +        tell "getLibDir     :: IO FilePath\n"
 406          tell "getLibDir     = "
 407          tell (zLibdir z_root)
 408          tell "\n"
 409 +        tell "getDynLibDir  :: IO FilePath\n"
 410          tell "getDynLibDir  = "
 411          tell (zDynlibdir z_root)
 412          tell "\n"
 413 +        tell "getDataDir    :: IO FilePath\n"
 414          tell "getDataDir    = catchIO (getEnv \""
 415          tell (zManglePkgName z_root (zPackageName z_root))
 416          tell "_datadir\")    (\\_ -> "
 417          tell (zDatadir z_root)
 418          tell ")\n"
 419 +        tell "getLibexecDir :: IO FilePath\n"
 420          tell "getLibexecDir = "
 421          tell (zLibexecdir z_root)
 422          tell "\n"
 423 +        tell "getSysconfDir :: IO FilePath\n"
 424          tell "getSysconfDir = "
 425          tell (zSysconfdir z_root)
 426          tell "\n"
 427 diffcabal-dev-scripts/src/GenPathsModule.hs b/cabal-dev-scripts/src/GenPathsModule.hs
 428 index e4b930635..9b978f284 100644
 429 --- a/libraries/Cabal/cabal-dev-scripts/src/GenPathsModule.hs
 430 +++ b/libraries/Cabal/cabal-dev-scripts/src/GenPathsModule.hs
 431 @@ -41,6 +41,16 @@ $(capture "decls" [d|
 432          , zLibexecdir :: FilePath
 433          , zSysconfdir :: FilePath
 434
 435 +        , zShouldEmitLibDir     :: Bool
 436 +        , zShouldEmitDynLibDir  :: Bool
 437 +        , zShouldEmitLibexecDir :: Bool
 438 +        , zShouldEmitDataDir    :: Bool
 439 +        , zShouldEmitSysconfDir :: Bool
 440 +
 441 +        , zShouldEmitWarning :: Bool
 442 +        , zWarning           :: String
 443 +
 444 +        , zOr                         :: Bool -> Bool -> Bool
 445          , zNot                        :: Bool -> Bool
 446          , zManglePkgName              :: PackageName -> String
 447          }
 448 difftemplates/Paths_pkg.template.hs b/templates/Paths_pkg.template.hs
 449 index 6bc6b7875..aa90a9382 100644
 450 --- a/libraries/Cabal/templates/Paths_pkg.template.hs
 451 +++ b/libraries/Cabal/templates/Paths_pkg.template.hs
 452 @@ -9,10 +9,31 @@
 453  {% endif %}
 454  {-# OPTIONS_GHC -fno-warn-missing-import-lists #-}
 455  {-# OPTIONS_GHC -w #-}
 456 -module Paths_{{ manglePkgName packageName }} (
 457 +module Paths_{{ manglePkgName packageName }}
 458 +  {% if shouldEmitWarning %}{-# WARNING {{ warning }} #-}{% endif %}
 459 +  (
 460      version,
 461 -    getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir,
 462 -    getDataFileName, getSysconfDir
 463 +    getBinDir,
 464 +{# We only care about the absolute case for our emit logic, since only in this
 465 +   case references are incurred. We are not going to hit isWindows and relocatable
 466 +   has no absolute references to begin with.
 467 +#}
 468 +{% if or (not absolute) shouldEmitLibDir %}
 469 +    getLibDir,
 470 +{% endif %}
 471 +{% if or (not absolute) shouldEmitDynLibDir %}
 472 +    getDynLibDir,
 473 +{% endif %}
 474 +{% if or (not absolute) shouldEmitLibexecDir %}
 475 +    getLibexecDir,
 476 +{% endif %}
 477 +{% if or (not absolute) shouldEmitDataDir %}
 478 +    getDataFileName,
 479 +    getDataDir,
 480 +{% endif %}
 481 +{% if or (not absolute) shouldEmitSysconfDir %}
 482 +    getSysconfDir
 483 +{% endif %}
 484    ) where
 485
 486  {% if not absolute %}
 487 @@ -51,12 +72,12 @@ catchIO = Exception.catch
 488  version :: Version
 489  version = Version {{ versionDigits }} []
 490
 491 +{% if or (not absolute) shouldEmitDataDir %}
 492  getDataFileName :: FilePath -> IO FilePath
 493  getDataFileName name = do
 494    dir <- getDataDir
 495    return (dir `joinFileName` name)
 496 -
 497 -getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir, getSysconfDir :: IO FilePath
 498 +{% endif %}
 499
 500  {% defblock function_defs %}
 501  minusFileName :: FilePath -> String -> FilePath
 502 @@ -85,48 +106,93 @@ splitFileName p = (reverse (path2++drive), reverse fname)
 503
 504  {% if relocatable %}
 505
 506 +{# Relocatable can not incur any absolute references, so we can ignore it.
 507 +   Additionally, --enable-relocatable is virtually useless in Nix builds
 508 +#}
 509 +
 510  getPrefixDirReloc :: FilePath -> IO FilePath
 511  getPrefixDirReloc dirRel = do
 512    exePath <- getExecutablePath
 513    let (dir,_) = splitFileName exePath
 514    return ((dir `minusFileName` {{ bindir }}) `joinFileName` dirRel)
 515
 516 +getBinDir     :: IO FilePath
 517  getBinDir     = catchIO (getEnv "{{ manglePkgName packageName }}_bindir")     (\_ -> getPrefixDirReloc $ {{ bindir }})
 518 +getLibDir     :: IO FilePath
 519  getLibDir     = catchIO (getEnv "{{ manglePkgName packageName }}_libdir")     (\_ -> getPrefixDirReloc $ {{ libdir }})
 520 +getDynLibDir  :: IO FilePath
 521  getDynLibDir  = catchIO (getEnv "{{ manglePkgName packageName }}_dynlibdir")  (\_ -> getPrefixDirReloc $ {{ dynlibdir }})
 522 +getDataDir    :: IO FilePath
 523  getDataDir    = catchIO (getEnv "{{ manglePkgName packageName }}_datadir")    (\_ -> getPrefixDirReloc $ {{ datadir }})
 524 +getLibexecDir :: IO FilePath
 525  getLibexecDir = catchIO (getEnv "{{ manglePkgName packageName }}_libexecdir") (\_ -> getPrefixDirReloc $ {{ libexecdir }})
 526 +getSysconfDir :: IO FilePath
 527  getSysconfDir = catchIO (getEnv "{{ manglePkgName packageName }}_sysconfdir") (\_ -> getPrefixDirReloc $ {{ sysconfdir }})
 528
 529  {% useblock function_defs %}
 530
 531  {% elif absolute %}
 532
 533 -bindir, libdir, dynlibdir, datadir, libexecdir, sysconfdir :: FilePath
 534 +bindir     :: FilePath
 535  bindir     = {{ bindir }}
 536 -libdir     = {{ libdir }}
 537 -dynlibdir  = {{ dynlibdir }}
 538 -datadir    = {{ datadir }}
 539 -libexecdir = {{ libexecdir }}
 540 -sysconfdir = {{ sysconfdir }}
 541 -
 542 +getBinDir     :: IO FilePath
 543  getBinDir     = catchIO (getEnv "{{ manglePkgName packageName }}_bindir")     (\_ -> return bindir)
 544 +
 545 +{% if shouldEmitLibDir %}
 546 +libdir     :: FilePath
 547 +libdir     = {{ libdir }}
 548 +getLibDir     :: IO FilePath
 549  getLibDir     = catchIO (getEnv "{{ manglePkgName packageName }}_libdir")     (\_ -> return libdir)
 550 +{% endif %}
 551 +
 552 +{% if shouldEmitDynLibDir %}
 553 +dynlibdir  :: FilePath
 554 +dynlibdir  = {{ dynlibdir }}
 555 +getDynLibDir  :: IO FilePath
 556  getDynLibDir  = catchIO (getEnv "{{ manglePkgName packageName }}_dynlibdir")  (\_ -> return dynlibdir)
 557 +{% endif %}
 558 +
 559 +{% if shouldEmitDataDir %}
 560 +datadir    :: FilePath
 561 +datadir    = {{ datadir }}
 562 +getDataDir    :: IO FilePath
 563  getDataDir    = catchIO (getEnv "{{ manglePkgName packageName }}_datadir")    (\_ -> return datadir)
 564 +{% endif %}
 565 +
 566 +{% if shouldEmitLibexecDir %}
 567 +libexecdir :: FilePath
 568 +libexecdir = {{ libexecdir }}
 569 +getLibexecDir :: IO FilePath
 570  getLibexecDir = catchIO (getEnv "{{ manglePkgName packageName }}_libexecdir") (\_ -> return libexecdir)
 571 +{% endif %}
 572 +
 573 +{% if shouldEmitSysconfDir %}
 574 +sysconfdir :: FilePath
 575 +sysconfdir = {{ sysconfdir }}
 576 +getSysconfDir :: IO FilePath
 577  getSysconfDir = catchIO (getEnv "{{ manglePkgName packageName }}_sysconfdir") (\_ -> return sysconfdir)
 578 +{% endif %}
 579
 580  {% elif isWindows %}
 581
 582 +{# We are only trying to fix the problem for aarch64-darwin with this patch,
 583 +   so let's ignore Windows which we can reach via pkgsCross, for example.
 584 +#}
 585 +
 586  prefix :: FilePath
 587  prefix = {{ prefix }}
 588
 589 +getBinDir     :: IO FilePath
 590  getBinDir     = getPrefixDirRel $ {{ bindir }}
 591 +getLibDir     :: IO FilePath
 592  getLibDir     = {{ libdir }}
 593 +getDynLibDir  :: IO FilePath
 594  getDynLibDir  = {{ dynlibdir }}
 595 +getDataDir    :: IO FilePath
 596  getDataDir    = catchIO (getEnv "{{ manglePkgName packageName }}_datadir")    (\_ -> {{ datadir }})
 597 +getLibexecDir :: IO FilePath
 598  getLibexecDir = {{ libexecdir }}
 599 +getSysconfDir :: IO FilePath
 600  getSysconfDir = {{ sysconfdir }}
 601
 602  getPrefixDirRel :: FilePath -> IO FilePath