[commit: packages/Cabal] ghc-head: Take the opportunity to simplify the ghc tool configuration (1648fa4)

[git at git.haskell.org]

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

On branch  : ghc-head
Link       : http://git.haskell.org/?p=packages/Cabal.git;a=commit;h=1648fa419d6d4e8972d7a3ff9c61e066cc980898

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

commit 1648fa419d6d4e8972d7a3ff9c61e066cc980898
Author: Duncan Coutts <duncan at community.haskell.org>
Date:   Sat Aug 10 21:52:07 2013 +0100

    Take the opportunity to simplify the ghc tool configuration
    
    When we configure ghc we have to find a bunch of related tools (like gcc
    on windows). We do that by looking in some extra locations first, and
    that's now simpler to do with the new infrastructure by just tacking an
    extra directory on the front of the search path.


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

1648fa419d6d4e8972d7a3ff9c61e066cc980898
 Cabal/Distribution/Simple/GHC.hs |   55 +++++++++++++++++---------------------
 1 file changed, 25 insertions(+), 30 deletions(-)

diff --git a/Cabal/Distribution/Simple/GHC.hs b/Cabal/Distribution/Simple/GHC.hs
index ffc1bc7..7877001 100644
--- a/Cabal/Distribution/Simple/GHC.hs
+++ b/Cabal/Distribution/Simple/GHC.hs
@@ -98,7 +98,7 @@ import Distribution.Package
 import qualified Distribution.ModuleName as ModuleName
 import Distribution.Simple.Program
          ( Program(..), ConfiguredProgram(..), ProgramConfiguration
-         , ProgramLocation(..), ProgramSearchPath
+         , ProgramLocation(..), ProgramSearchPath, ProgramSearchPathEntry(..)
          , rawSystemProgram
          , rawSystemProgramStdout, rawSystemProgramStdoutConf
          , getProgramInvocationOutput
@@ -282,30 +282,18 @@ configureToolchain :: ConfiguredProgram -> [(String, String)]
                                         -> ProgramConfiguration
 configureToolchain ghcProg ghcInfo =
     addKnownProgram gccProgram {
-      programFindLocation = findProg gccProgram
-                              [ if ghcVersion >= Version [6,12] []
-                                  then mingwBinDir </> binPrefix ++ "gcc.exe"
-                                  else baseDir     </> "gcc.exe" ],
+      programFindLocation = findProg gccProgram extraGccPath,
       programPostConf     = configureGcc
     }
   . addKnownProgram ldProgram {
-      programFindLocation = findProg ldProgram
-                              [ if ghcVersion >= Version [6,12] []
-                                  then mingwBinDir </> binPrefix ++ "ld.exe"
-                                  else libDir      </> "ld.exe" ],
+      programFindLocation = findProg ldProgram extraLdPath,
       programPostConf     = configureLd
     }
   . addKnownProgram arProgram {
-      programFindLocation = findProg arProgram
-                              [ if ghcVersion >= Version [6,12] []
-                                  then mingwBinDir </> binPrefix ++ "ar.exe"
-                                  else libDir      </> "ar.exe" ]
+      programFindLocation = findProg arProgram extraArPath
     }
   . addKnownProgram stripProgram {
-      programFindLocation = findProg stripProgram
-                              [ if ghcVersion >= Version [6,12] []
-                                  then mingwBinDir </> binPrefix ++ "strip.exe"
-                                  else libDir      </> "strip.exe" ]
+      programFindLocation = findProg stripProgram extraStripPath
     }
   where
     Just ghcVersion = programVersion ghcProg
@@ -317,20 +305,27 @@ configureToolchain ghcProg ghcInfo =
     isWindows   = case buildOS of Windows -> True; _ -> False
     binPrefix   = ""
 
-    -- on Windows finding and configuring ghc's gcc and ld is a bit special
-    findProg :: Program -> [FilePath] -> Verbosity -> ProgramSearchPath -> IO (Maybe FilePath)
-    findProg prog locations
-      | isWindows = \verbosity -> look locations verbosity
-      | otherwise = programFindLocation prog
+    -- on Windows finding and configuring ghc's gcc & binutils is a bit special
+    extraGccPath
+      | ghcVersion >= Version [6,12] [] = mingwBinDir </> binPrefix ++ "gcc.exe"
+      | otherwise                       = baseDir     </> "gcc.exe"
+    extraLdPath
+      | ghcVersion >= Version [6,12] [] = mingwBinDir </> binPrefix ++ "ld.exe"
+      | otherwise                       = libDir      </> "ld.exe"
+    extraArPath
+      | ghcVersion >= Version [6,12] [] = mingwBinDir </> binPrefix ++ "ar.exe"
+      | otherwise                       = libDir      </> "ar.exe"
+    extraStripPath
+      | ghcVersion >= Version [6,12] [] = mingwBinDir </> binPrefix ++ "strip.exe"
+      | otherwise                       = libDir      </> "strip.exe"
+
+    findProg :: Program -> FilePath
+             -> Verbosity -> ProgramSearchPath -> IO (Maybe FilePath)
+    findProg prog extraPath v searchpath =
+        programFindLocation prog v searchpath'
       where
-        look [] verbosity searchpath = do
-          warn verbosity ("Couldn't find " ++ programName prog
-                          ++ " where I expected it. Trying the search path.")
-          programFindLocation prog verbosity searchpath
-        look (f:fs) verbosity searchpath = do
-          exists <- doesFileExist f
-          if exists then return (Just f)
-                    else look fs verbosity searchpath
+        searchpath' | isWindows = ProgramSearchPathDir extraPath : searchpath
+                    | otherwise = searchpath
 
     ccFlags        = getFlags "C compiler flags"
     gccLinkerFlags = getFlags "Gcc Linker flags"