[commit: ghc] wip/angerman/llvmng: Relocatable GHC (0c31b32)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/angerman/llvmng
Link       : http://ghc.haskell.org/trac/ghc/changeset/0c31b32607ca8829793b355420759284d2d64d2e/ghc

>---------------------------------------------------------------

commit 0c31b32607ca8829793b355420759284d2d64d2e
Author: Moritz Angermann <moritz.angermann at gmail.com>
Date:   Fri Nov 10 10:00:09 2017 +0800

    Relocatable GHC
    
    GHC and the binary distribution that's produced is
    not relocatable outside of Windows.  This diff tries to
    address this for at least Linux and macOS.
    
    Reviewers: austin, hvr, bgamari, erikd
    
    Subscribers: rwbarton, thomie, erikd
    
    Differential Revision: https://phabricator.haskell.org/D4121


>---------------------------------------------------------------

0c31b32607ca8829793b355420759284d2d64d2e
 compiler/main/SysTools.hs | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/compiler/main/SysTools.hs b/compiler/main/SysTools.hs
index 21ed03b..625552b 100644
--- a/compiler/main/SysTools.hs
+++ b/compiler/main/SysTools.hs
@@ -48,6 +48,7 @@ import Platform
 import Util
 import DynFlags
 
+import System.Environment (getExecutablePath)
 import System.FilePath
 import System.IO
 import System.Directory
@@ -530,6 +531,26 @@ type GetFinalPath = HANDLE -> LPTSTR -> DWORD -> DWORD -> IO DWORD
 
 foreign import WINDOWS_CCONV unsafe "dynamic"
   makeGetFinalPathNameByHandle :: FunPtr GetFinalPath -> GetFinalPath
+#elif defined(darwin_HOST_OS) || defined(linux_HOST_OS)
+-- on unix, this is a bit more confusing.
+-- The layout right now is somehting like
+--
+--   /bin/ghc-X.Y.Z <- wrapper script (1)
+--   /bin/ghc       <- symlink to wrapper script (2)
+--   /lib/ghc-X.Y.Z/bin/ghc <- ghc executable (3)
+--   /lib/ghc-X.Y.Z <- $topdir (4)
+--
+-- As such, we fist need to find the absolute location to the
+-- binary.
+--
+-- getExecutablePath will return (3). One takeDirectory will
+-- give use /lib/ghc-X.Y.Z/bin, and another will give us (4).
+--
+-- This of course only works due to the current layout. If
+-- the layout is changed, such that we have ghc-X.Y.Z/{bin,lib}
+-- this would need to be changed accordingly.
+--
+getBaseDir = Just . (\p -> p </> "lib") . takeDirectory . takeDirectory <$> getExecutablePath
 #else
 getBaseDir = return Nothing
 #endif