···
+
This patch is based on https://github.com/sternenseemann/cabal/compare/Cabal-v3.12.0.0..e836ef53c1f80bf99a70f9c4ee5976e9f3830215
+
and has been postprocessed with `filterdiff --strip=1 --addoldprefix=a/libraries/Cabal/ --addnewprefix=b/libraries/Cabal/`.
+
Reasoning and explanation of the patch can be found in the comment in the diff for PathsModule.hs below.
+
diffCabal/src/Distribution/Simple/Build/PathsModule.hs b/Cabal/src/Distribution/Simple/Build/PathsModule.hs
+
index 892e5bd38..391f5b130 100644
+
--- a/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule.hs
+
+++ b/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule.hs
+
@@ -51,6 +51,7 @@ generatePathsModule pkg_descr lbi clbi =
+
, Z.zIsWindows = isWindows
+
, Z.zIsI386 = buildArch == I386
+
, Z.zIsX8664 = buildArch == X86_64
+
, Z.zManglePkgName = showPkgName
+
, Z.zPrefix = show flat_prefix
+
@@ -60,8 +61,110 @@ generatePathsModule pkg_descr lbi clbi =
+
, Z.zDatadir = zDatadir
+
, Z.zLibexecdir = zLibexecdir
+
, Z.zSysconfdir = zSysconfdir
+
+ , -- Sadly we can't be cleverer about this – we can't have literals in the template
+
+ Z.zShouldEmitDataDir = shouldEmit "DataDir"
+
+ , Z.zShouldEmitLibDir = shouldEmit "LibDir"
+
+ , Z.zShouldEmitDynLibDir = shouldEmit "DynLibDir"
+
+ , Z.zShouldEmitLibexecDir = shouldEmit "LibexecDir"
+
+ , Z.zShouldEmitSysconfDir = shouldEmit "SysconfDir"
+
+ , Z.zWarning = zWarning
+
+ , Z.zShouldEmitWarning = zShouldEmitWarning
+
+ -- GHC's NCG backend for aarch64-darwin does not support link-time dead code
+
+ -- elimination to the extent that NCG does for other targets. Consequently,
+
+ -- we struggle with unnecessarily retained store path references due to the
+
+ -- use of `Paths_*` modules – even if `getLibDir` is not used, it'll end up
+
+ -- in the final library or executables we build.
+
+ -- When using a different output for the executables and library, this
+
+ -- becomes more sinister: The library will contain a reference to the bin
+
+ -- output and itself due to `getLibDir` and `getBinDir`, but the executables
+
+ -- will do so, too. Either due to linking dynamically or because the library
+
+ -- is linked statically into the executable and retains those references.
+
+ -- Since Nix disallows cyclical references between two outputs, it becomes
+
+ -- impossible to use the `Paths_*` module and a separate `bin` output for
+
+ -- The solution we have resorted to for now, is to trim the `Paths_*` module
+
+ -- dynamically depending on what references *could* be used without causing
+
+ -- a cyclical reference. That has the effect that any code that would not
+
+ -- cause a cyclical reference with dead code elimination will compile and
+
+ -- work for aarch64-darwin. If the code would use a `get*Dir` function that
+
+ -- has been omitted, this would indicate that the code would have caused a
+
+ -- cyclical reference anyways.
+
+ -- The logic for this makes some pretty big assumptions about installation
+
+ -- prefixes that probably only hold fully in nixpkgs with
+
+ -- `haskellPackages.mkDerivation`. Simple uses outside nixpkgs that have
+
+ -- everything below the same prefix should continue to work as expected,
+
+ -- We assume the following:
+
+ -- - flat_prefix is `$out`.
+
+ -- - flat_libdir etc. are always below `$out`.
+
+ -- Since in the normal case due to static linking `$bin` and `$out` will
+
+ -- have the same references in libraries/executables, we need to either
+
+ -- prevent usage of `getBinDir` or `getLibDir` to break the cycle in case
+
+ -- `flat_bindir` is not below `$out`. We have decided to always allow usage
+
+ -- of `getBinDir`, so `getLibDir` gets dropped if a separate `bin` output is
+
+ -- used. This has the simple reason that `$out` which contains `flat_libdir`
+
+ -- tends to be quite big – we would like to have a `bin` output that doesn't
+
+ -- require keeping that around.
+
+ pathEmittable :: FilePath -> Bool
+
+ -- If the executable installation target is below `$out` the reference
+
+ -- cycle is within a single output (since libs are installed to `$out`)
+
+ -- and thus unproblematic. We can use any and all `get*Dir` functions.
+
+ | flat_prefix `isPrefixOf` flat_bindir = True
+
+ -- Otherwise, we need to disallow all `get*Dir` functions that would cause
+
+ -- a reference to `$out` which contains the libraries that would in turn
+
+ -- reference `$bin`. This always include `flat_libdir` and friends, but
+
+ -- can also include `flat_datadir` if no separate output for data files is
+
+ | otherwise = not (flat_prefix `isPrefixOf` p)
+
+ -- This list maps the "name" of the directory to whether we want to include
+
+ -- it in the `Paths_*` module or not. `shouldEmit` performs a lookup in this.
+
+ dirs :: [(String, Bool)]
+
+ (\(name, path) -> (name, pathEmittable path))
+
+ [ ("LibDir", flat_libdir)
+
+ , ("DynLibDir", flat_dynlibdir)
+
+ , ("DataDir", flat_datadir)
+
+ , ("LibexecDir", flat_libexecdir)
+
+ , ("SysconfDir", flat_sysconfdir)
+
+ shouldEmit :: String -> Bool
+
+ case lookup name dirs of
+
+ Nothing -> error "panic! BUG in Cabal Paths_ patch for aarch64-darwin, report this at https://github.com/nixos/nixpkgs/issues"
+
+ -- This is a comma separated list of all functions that have been emitted.
+
+ -- This is included in a GHC warning which will be attached to the `Paths_*`
+
+ -- module in case we are dropping any `get*Dir` functions that would
+
+ -- TODO: getDataFileName is not accounted for at the moment.
+
+ omittedFunctions :: String
+
+ map (("get" ++) . fst) $
+
+ filter (not . snd) dirs
+
+ "The following functions have been omitted by a nixpkgs-specific patch to Cabal: "
+
+ zShouldEmitWarning :: Bool
+
+ zShouldEmitWarning = any (not . snd) dirs
+
supports_cpp = supports_language_pragma
+
supports_rebindable_syntax = ghc_newer_than (mkVersion [7, 0, 1])
+
supports_language_pragma = ghc_newer_than (mkVersion [6, 6, 1])
+
diffCabal/src/Distribution/Simple/Build/PathsModule/Z.hs b/Cabal/src/Distribution/Simple/Build/PathsModule/Z.hs
+
index 25c924720..a8278675e 100644
+
--- a/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule/Z.hs
+
+++ b/libraries/Cabal/Cabal/src/Distribution/Simple/Build/PathsModule/Z.hs
+
@@ -19,6 +19,14 @@ data Z
+
zLibexecdir :: FilePath,
+
zSysconfdir :: FilePath,
+
+ zShouldEmitLibDir :: Bool,
+
+ zShouldEmitDynLibDir :: Bool,
+
+ zShouldEmitLibexecDir :: Bool,
+
+ zShouldEmitDataDir :: Bool,
+
+ zShouldEmitSysconfDir :: Bool,
+
+ zShouldEmitWarning :: Bool,
+
+ zOr :: (Bool -> Bool -> Bool),
+
zNot :: (Bool -> Bool),
+
zManglePkgName :: (PackageName -> String)}
+
@@ -54,10 +62,51 @@ render z_root = execWriter $ do
+
tell "{-# OPTIONS_GHC -w #-}\n"
+
tell (zManglePkgName z_root (zPackageName z_root))
+
+ if (zShouldEmitWarning z_root)
+
+ tell (zWarning z_root)
+
- tell " getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir,\n"
+
- tell " getDataFileName, getSysconfDir\n"
+
+ if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitLibDir z_root))
+
+ if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitDynLibDir z_root))
+
+ tell " getDynLibDir,\n"
+
+ if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitLibexecDir z_root))
+
+ tell " getLibexecDir,\n"
+
+ if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitDataDir z_root))
+
+ tell " getDataFileName,\n"
+
+ tell " getDataDir,\n"
+
+ if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitSysconfDir z_root))
+
+ tell " getSysconfDir\n"
+
if (zNot z_root (zAbsolute z_root))
+
@@ -106,12 +155,15 @@ render z_root = execWriter $ do
+
tell (zVersionDigits z_root)
+
- tell "getDataFileName :: FilePath -> IO FilePath\n"
+
- tell "getDataFileName name = do\n"
+
- tell " dir <- getDataDir\n"
+
- tell " return (dir `joinFileName` name)\n"
+
- tell "getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir, getSysconfDir :: IO FilePath\n"
+
+ if (zOr z_root (zNot z_root (zAbsolute z_root)) (zShouldEmitDataDir z_root))
+
+ tell "getDataFileName :: FilePath -> IO FilePath\n"
+
+ tell "getDataFileName name = do\n"
+
+ tell " dir <- getDataDir\n"
+
+ tell " return (dir `joinFileName` name)\n"
+
z_var0_function_defs = do
+
@@ -139,6 +191,7 @@ render z_root = execWriter $ do
+
if (zRelocatable z_root)
+
tell "getPrefixDirReloc :: FilePath -> IO FilePath\n"
+
tell "getPrefixDirReloc dirRel = do\n"
+
@@ -148,31 +201,37 @@ render z_root = execWriter $ do
+
tell ") `joinFileName` dirRel)\n"
+
+ tell "getBinDir :: IO FilePath\n"
+
tell "getBinDir = catchIO (getEnv \""
+
tell (zManglePkgName z_root (zPackageName z_root))
+
tell "_bindir\") (\\_ -> getPrefixDirReloc $ "
+
+ tell "getLibDir :: IO FilePath\n"
+
tell "getLibDir = catchIO (getEnv \""
+
tell (zManglePkgName z_root (zPackageName z_root))
+
tell "_libdir\") (\\_ -> getPrefixDirReloc $ "
+
+ tell "getDynLibDir :: IO FilePath\n"
+
tell "getDynLibDir = catchIO (getEnv \""
+
tell (zManglePkgName z_root (zPackageName z_root))
+
tell "_dynlibdir\") (\\_ -> getPrefixDirReloc $ "
+
tell (zDynlibdir z_root)
+
+ tell "getDataDir :: IO FilePath\n"
+
tell "getDataDir = catchIO (getEnv \""
+
tell (zManglePkgName z_root (zPackageName z_root))
+
tell "_datadir\") (\\_ -> getPrefixDirReloc $ "
+
+ tell "getLibexecDir :: IO FilePath\n"
+
tell "getLibexecDir = catchIO (getEnv \""
+
tell (zManglePkgName z_root (zPackageName z_root))
+
tell "_libexecdir\") (\\_ -> getPrefixDirReloc $ "
+
tell (zLibexecdir z_root)
+
+ tell "getSysconfDir :: IO FilePath\n"
+
tell "getSysconfDir = catchIO (getEnv \""
+
tell (zManglePkgName z_root (zPackageName z_root))
+
tell "_sysconfdir\") (\\_ -> getPrefixDirReloc $ "
+
@@ -186,72 +245,119 @@ render z_root = execWriter $ do
+
- tell "bindir, libdir, dynlibdir, datadir, libexecdir, sysconfdir :: FilePath\n"
+
+ tell "bindir :: FilePath\n"
+
- tell (zLibdir z_root)
+
- tell (zDynlibdir z_root)
+
+ tell "getBinDir :: IO FilePath\n"
+
+ tell "getBinDir = catchIO (getEnv \""
+
+ tell (zManglePkgName z_root (zPackageName z_root))
+
+ tell "_bindir\") (\\_ -> return bindir)\n"
+
- tell (zDatadir z_root)
+
+ if (zShouldEmitLibDir z_root)
+
+ tell "libdir :: FilePath\n"
+
+ tell (zLibdir z_root)
+
+ tell "getLibDir :: IO FilePath\n"
+
+ tell "getLibDir = catchIO (getEnv \""
+
+ tell (zManglePkgName z_root (zPackageName z_root))
+
+ tell "_libdir\") (\\_ -> return libdir)\n"
+
- tell (zLibexecdir z_root)
+
+ if (zShouldEmitDynLibDir z_root)
+
+ tell "dynlibdir :: FilePath\n"
+
+ tell (zDynlibdir z_root)
+
+ tell "getDynLibDir :: IO FilePath\n"
+
+ tell "getDynLibDir = catchIO (getEnv \""
+
+ tell (zManglePkgName z_root (zPackageName z_root))
+
+ tell "_dynlibdir\") (\\_ -> return dynlibdir)\n"
+
- tell (zSysconfdir z_root)
+
+ if (zShouldEmitDataDir z_root)
+
+ tell "datadir :: FilePath\n"
+
+ tell (zDatadir z_root)
+
+ tell "getDataDir :: IO FilePath\n"
+
+ tell "getDataDir = catchIO (getEnv \""
+
+ tell (zManglePkgName z_root (zPackageName z_root))
+
+ tell "_datadir\") (\\_ -> return datadir)\n"
+
+ if (zShouldEmitLibexecDir z_root)
+
+ tell "libexecdir :: FilePath\n"
+
+ tell (zLibexecdir z_root)
+
+ tell "getLibexecDir :: IO FilePath\n"
+
+ tell "getLibexecDir = catchIO (getEnv \""
+
+ tell (zManglePkgName z_root (zPackageName z_root))
+
+ tell "_libexecdir\") (\\_ -> return libexecdir)\n"
+
- tell "getBinDir = catchIO (getEnv \""
+
- tell (zManglePkgName z_root (zPackageName z_root))
+
- tell "_bindir\") (\\_ -> return bindir)\n"
+
- tell "getLibDir = catchIO (getEnv \""
+
- tell (zManglePkgName z_root (zPackageName z_root))
+
- tell "_libdir\") (\\_ -> return libdir)\n"
+
- tell "getDynLibDir = catchIO (getEnv \""
+
- tell (zManglePkgName z_root (zPackageName z_root))
+
- tell "_dynlibdir\") (\\_ -> return dynlibdir)\n"
+
- tell "getDataDir = catchIO (getEnv \""
+
- tell (zManglePkgName z_root (zPackageName z_root))
+
- tell "_datadir\") (\\_ -> return datadir)\n"
+
- tell "getLibexecDir = catchIO (getEnv \""
+
- tell (zManglePkgName z_root (zPackageName z_root))
+
- tell "_libexecdir\") (\\_ -> return libexecdir)\n"
+
- tell "getSysconfDir = catchIO (getEnv \""
+
- tell (zManglePkgName z_root (zPackageName z_root))
+
- tell "_sysconfdir\") (\\_ -> return sysconfdir)\n"
+
+ if (zShouldEmitSysconfDir z_root)
+
+ tell "sysconfdir :: FilePath\n"
+
+ tell (zSysconfdir z_root)
+
+ tell "getSysconfDir :: IO FilePath\n"
+
+ tell "getSysconfDir = catchIO (getEnv \""
+
+ tell (zManglePkgName z_root (zPackageName z_root))
+
+ tell "_sysconfdir\") (\\_ -> return sysconfdir)\n"
+
tell "prefix :: FilePath\n"
+
+ tell "getBinDir :: IO FilePath\n"
+
tell "getBinDir = getPrefixDirRel $ "
+
+ tell "getLibDir :: IO FilePath\n"
+
+ tell "getDynLibDir :: IO FilePath\n"
+
tell (zDynlibdir z_root)
+
+ tell "getDataDir :: IO FilePath\n"
+
tell "getDataDir = catchIO (getEnv \""
+
tell (zManglePkgName z_root (zPackageName z_root))
+
tell "_datadir\") (\\_ -> "
+
+ tell "getLibexecDir :: IO FilePath\n"
+
tell "getLibexecDir = "
+
tell (zLibexecdir z_root)
+
+ tell "getSysconfDir :: IO FilePath\n"
+
tell "getSysconfDir = "
+
tell (zSysconfdir z_root)
+
diffcabal-dev-scripts/src/GenPathsModule.hs b/cabal-dev-scripts/src/GenPathsModule.hs
+
index 46ef779e2..e9f5e099f 100644
+
--- a/libraries/Cabal/cabal-dev-scripts/src/GenPathsModule.hs
+
+++ b/libraries/Cabal/cabal-dev-scripts/src/GenPathsModule.hs
+
@@ -41,6 +41,16 @@ $(capture "decls" [d|
+
, zLibexecdir :: FilePath
+
, zSysconfdir :: FilePath
+
+ , zShouldEmitLibDir :: Bool
+
+ , zShouldEmitDynLibDir :: Bool
+
+ , zShouldEmitLibexecDir :: Bool
+
+ , zShouldEmitDataDir :: Bool
+
+ , zShouldEmitSysconfDir :: Bool
+
+ , zShouldEmitWarning :: Bool
+
+ , zOr :: Bool -> Bool -> Bool
+
, zManglePkgName :: PackageName -> String
+
difftemplates/Paths_pkg.template.hs b/templates/Paths_pkg.template.hs
+
index 8e1e03d27..cc5c86701 100644
+
--- a/libraries/Cabal/templates/Paths_pkg.template.hs
+
+++ b/libraries/Cabal/templates/Paths_pkg.template.hs
+
{-# OPTIONS_GHC -fno-warn-missing-import-lists #-}
+
-module Paths_{{ manglePkgName packageName }} (
+
+module Paths_{{ manglePkgName packageName }}
+
+ {% if shouldEmitWarning %}{-# WARNING {{ warning }} #-}{% endif %}
+
- getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir,
+
- getDataFileName, getSysconfDir
+
+{# We only care about the absolute case for our emit logic, since only in this
+
+ case references are incurred. We are not going to hit isWindows and relocatable
+
+ has no absolute references to begin with.
+
+{% if or (not absolute) shouldEmitLibDir %}
+
+{% if or (not absolute) shouldEmitDynLibDir %}
+
+{% if or (not absolute) shouldEmitLibexecDir %}
+
+{% if or (not absolute) shouldEmitDataDir %}
+
+{% if or (not absolute) shouldEmitSysconfDir %}
+
@@ -56,12 +77,12 @@ catchIO = Exception.catch
+
version = Version {{ versionDigits }} []
+
+{% if or (not absolute) shouldEmitDataDir %}
+
getDataFileName :: FilePath -> IO FilePath
+
getDataFileName name = do
+
return (dir `joinFileName` name)
+
-getBinDir, getLibDir, getDynLibDir, getDataDir, getLibexecDir, getSysconfDir :: IO FilePath
+
{% defblock function_defs %}
+
minusFileName :: FilePath -> String -> FilePath
+
@@ -90,48 +111,93 @@ splitFileName p = (reverse (path2++drive), reverse fname)
+
+{# Relocatable can not incur any absolute references, so we can ignore it.
+
+ Additionally, --enable-relocatable is virtually useless in Nix builds
+
getPrefixDirReloc :: FilePath -> IO FilePath
+
getPrefixDirReloc dirRel = do
+
exePath <- getExecutablePath
+
let (dir,_) = splitFileName exePath
+
return ((dir `minusFileName` {{ bindir }}) `joinFileName` dirRel)
+
+getBinDir :: IO FilePath
+
getBinDir = catchIO (getEnv "{{ manglePkgName packageName }}_bindir") (\_ -> getPrefixDirReloc $ {{ bindir }})
+
+getLibDir :: IO FilePath
+
getLibDir = catchIO (getEnv "{{ manglePkgName packageName }}_libdir") (\_ -> getPrefixDirReloc $ {{ libdir }})
+
+getDynLibDir :: IO FilePath
+
getDynLibDir = catchIO (getEnv "{{ manglePkgName packageName }}_dynlibdir") (\_ -> getPrefixDirReloc $ {{ dynlibdir }})
+
+getDataDir :: IO FilePath
+
getDataDir = catchIO (getEnv "{{ manglePkgName packageName }}_datadir") (\_ -> getPrefixDirReloc $ {{ datadir }})
+
+getLibexecDir :: IO FilePath
+
getLibexecDir = catchIO (getEnv "{{ manglePkgName packageName }}_libexecdir") (\_ -> getPrefixDirReloc $ {{ libexecdir }})
+
+getSysconfDir :: IO FilePath
+
getSysconfDir = catchIO (getEnv "{{ manglePkgName packageName }}_sysconfdir") (\_ -> getPrefixDirReloc $ {{ sysconfdir }})
+
{% useblock function_defs %}
+
-bindir, libdir, dynlibdir, datadir, libexecdir, sysconfdir :: FilePath
+
-dynlibdir = {{ dynlibdir }}
+
-datadir = {{ datadir }}
+
-libexecdir = {{ libexecdir }}
+
-sysconfdir = {{ sysconfdir }}
+
+getBinDir :: IO FilePath
+
getBinDir = catchIO (getEnv "{{ manglePkgName packageName }}_bindir") (\_ -> return bindir)
+
+{% if shouldEmitLibDir %}
+
+getLibDir :: IO FilePath
+
getLibDir = catchIO (getEnv "{{ manglePkgName packageName }}_libdir") (\_ -> return libdir)
+
+{% if shouldEmitDynLibDir %}
+
+dynlibdir = {{ dynlibdir }}
+
+getDynLibDir :: IO FilePath
+
getDynLibDir = catchIO (getEnv "{{ manglePkgName packageName }}_dynlibdir") (\_ -> return dynlibdir)
+
+{% if shouldEmitDataDir %}
+
+datadir = {{ datadir }}
+
+getDataDir :: IO FilePath
+
getDataDir = catchIO (getEnv "{{ manglePkgName packageName }}_datadir") (\_ -> return datadir)
+
+{% if shouldEmitLibexecDir %}
+
+libexecdir :: FilePath
+
+libexecdir = {{ libexecdir }}
+
+getLibexecDir :: IO FilePath
+
getLibexecDir = catchIO (getEnv "{{ manglePkgName packageName }}_libexecdir") (\_ -> return libexecdir)
+
+{% if shouldEmitSysconfDir %}
+
+sysconfdir :: FilePath
+
+sysconfdir = {{ sysconfdir }}
+
+getSysconfDir :: IO FilePath
+
getSysconfDir = catchIO (getEnv "{{ manglePkgName packageName }}_sysconfdir") (\_ -> return sysconfdir)
+
+{# We are only trying to fix the problem for aarch64-darwin with this patch,
+
+ so let's ignore Windows which we can reach via pkgsCross, for example.
+
+getBinDir :: IO FilePath
+
getBinDir = getPrefixDirRel $ {{ bindir }}
+
+getLibDir :: IO FilePath
+
getLibDir = {{ libdir }}
+
+getDynLibDir :: IO FilePath
+
getDynLibDir = {{ dynlibdir }}
+
+getDataDir :: IO FilePath
+
getDataDir = catchIO (getEnv "{{ manglePkgName packageName }}_datadir") (\_ -> {{ datadir }})
+
+getLibexecDir :: IO FilePath
+
getLibexecDir = {{ libexecdir }}
+
+getSysconfDir :: IO FilePath
+
getSysconfDir = {{ sysconfdir }}
+
getPrefixDirRel :: FilePath -> IO FilePath
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