Experimental: parallel batch compilation of grammars

On my laptop these changes speed up the full build of the RGL and example
grammars with 'cabal build' from ~95s to ~43s and the zero build from ~18s
to ~5s.

The main change is the introduction of the module GF.CompileInParallel that
replaces GF.Compile and the function GF.Compile.ReadFiles.getAllFiles. At
present, it is activated with the new -j flag, and it is only used when
combined with --make or --batch. In addition, to get parallel computations,
you need to add GHC run-time flags, e.g., +RTS -N -A20M -RTS, to the command
line.

The Setup.hs script has been modified to pass the appropriate flags to GF
for parallel compilation when compiling the RGL and example grammars, but you
need a recent version of Cabal for this to work (probably >=1.20).

Some additonal refactoring were made during this work. A new monad is used to
avoid warnings/error messages from different modules to be intertwined when
compiling in parallel, so some functios that were hardiwred to the IO or IOE
monads have been lifted to work in arbitrary monads that are instances in
the appropriate classes.

Setup.hs

@@ -9,11 +9,10 @@ import Data.List(isPrefixOf,intersect)
 import Data.Maybe(listToMaybe)
 --import System.IO
 import qualified Control.Exception as E
-import System.Process
+import System.Process(readProcess)
 import System.FilePath
 import System.Directory
-import System.Process
-import System.Exit
+--import System.Exit
 --import Control.Concurrent(forkIO)
 --import Control.Concurrent.Chan(newChan,writeChan,readChan)
 
@@ -42,19 +41,19 @@ main = defaultMainWithHooks simpleUserHooks{ preBuild  = gfPreBuild
 
     gfPostBuild args flags pkg lbi =
       do --writeFile "running" ""
-         buildRGL args flags (pkg,lbi)
---       let gf = default_gf (pkg,lbi)
+         buildRGL args flags (flags,pkg,lbi)
+--       let gf = default_gf lbi
 --       buildWeb gf (pkg,lbi)
 
     gfPostInst args flags pkg lbi =
       do installRGL args flags (pkg,lbi)
-         let gf = default_gf (pkg,lbi)
-         installWeb gf args flags (pkg,lbi)
+         let gf = default_gf lbi
+         installWeb (pkg,lbi)
 
     gfPostCopy args flags  pkg lbi =
-      do copyRGL args flags (pkg,lbi)
-         let gf = default_gf (pkg,lbi)
-         copyWeb gf args flags (pkg,lbi)
+      do let gf = default_gf lbi
+         copyRGL args flags (pkg,lbi)
+         copyWeb flags (pkg,lbi)
 
 --------------------------------------------------------
 -- Commands for building the Resource Grammar Library
@@ -71,13 +70,16 @@ data RGLCommand
       , cmdAction :: [Mode] -> [String] -> Info -> IO ()
       }
 
-type Info = (PackageDescription,LocalBuildInfo)
+type Info = (BuildFlags,PackageDescription,LocalBuildInfo)
+bf (i,_,_) = i
+--pd (_,i,_) = i
+lbi (_,_,i) = i
 
 rglCommands =
   [ RGLCommand "prelude" True  $ \mode args bi -> do
        putStrLn $ "Compiling [prelude]"
        let prelude_src_dir = rgl_src_dir    </> "prelude"
-           prelude_dst_dir = rgl_dst_dir bi </> "prelude"
+           prelude_dst_dir = rgl_dst_dir (lbi bi) </> "prelude"
        createDirectoryIfMissing True prelude_dst_dir
        files <- ls prelude_src_dir
        run_gfc bi (["-s", "--gfo-dir="++prelude_dst_dir] ++ [prelude_src_dir </> file | file <- files])
@@ -86,11 +88,11 @@ rglCommands =
   , RGLCommand "lang"    False $ gfcp [l,s]
   , RGLCommand "api"     False $ gfcp [t,sc]
   , RGLCommand "compat"  False $ gfcp [c]
-  , RGLCommand "web"     True  $ \ _ _ bi -> buildWeb (default_gf bi) bi
+  , RGLCommand "web"     True  $ \ _ _ bi -> buildWeb (default_gf (lbi bi)) bi
 
   , RGLCommand "pgf"     False $ \modes args bi ->
      parallel_ [
-       do let dir = getRGLBuildDir bi mode
+       do let dir = getRGLBuildDir (lbi bi) mode
           createDirectoryIfMissing True dir
           sequence_ [run_gfc bi ["-s","-make","-name=Lang"++la,
                                        dir ++ "/Lang" ++ la ++ ".gfo"]
@@ -146,8 +148,8 @@ buildRGL args flags bi = do
 installRGL args flags bi = do
   let modes = getOptMode args
   let inst_gf_lib_dir = datadir (uncurry absoluteInstallDirs bi NoCopyDest) </> "lib"
-  copyAll "prelude"   (rgl_dst_dir bi </> "prelude") (inst_gf_lib_dir </> "prelude")
-  sequence_ [copyAll (show mode) (getRGLBuildDir bi mode) (inst_gf_lib_dir </> getRGLBuildSubDir bi mode)|mode<-modes]
+  copyAll "prelude"   (rgl_dst_dir (snd bi) </> "prelude") (inst_gf_lib_dir </> "prelude")
+  sequence_ [copyAll (show mode) (getRGLBuildDir (snd bi) mode) (inst_gf_lib_dir </> getRGLBuildSubDir mode)|mode<-modes]
 
 copyRGL args flags bi = do
   let modes = getOptMode args
@@ -155,8 +157,8 @@ copyRGL args flags bi = do
                NoFlag -> NoCopyDest
                Flag d -> d
   let inst_gf_lib_dir = datadir (uncurry absoluteInstallDirs bi dest) </> "lib"
-  copyAll "prelude"   (rgl_dst_dir bi </> "prelude") (inst_gf_lib_dir </> "prelude")
-  sequence_ [copyAll (show mode) (getRGLBuildDir bi mode) (inst_gf_lib_dir </> getRGLBuildSubDir bi mode)|mode<-modes]
+  copyAll "prelude"   (rgl_dst_dir (snd bi) </> "prelude") (inst_gf_lib_dir </> "prelude")
+  sequence_ [copyAll (show mode) (getRGLBuildDir (snd bi) mode) (inst_gf_lib_dir </> getRGLBuildSubDir mode)|mode<-modes]
 
 copyAll s from to = do
   putStrLn $ "Installing [" ++ s ++ "] " ++ to
@@ -181,7 +183,7 @@ sdistRGL pkg mb_lbi hooks flags = do
         else getRGLFiles path paths
 
 rgl_src_dir         = "lib" </> "src"
-rgl_dst_dir (_,lbi) = buildDir lbi </> "rgl"
+rgl_dst_dir lbi = buildDir lbi </> "rgl"
 
 -- the languages have long directory names and short ISO codes (3 letters)
 -- we also give the decodings for postprocessing linearizations, as long as grammars
@@ -258,7 +260,7 @@ langsCompat = langsLang `only` ["Cat","Eng","Fin","Fre","Ita","Lav","Spa","Swe"]
 gfc bi modes summary files = 
     parallel_ [gfcn bi mode summary files | mode<-modes]
 gfcn bi mode summary files = do
-  let dir = getRGLBuildDir bi mode
+  let dir = getRGLBuildDir (lbi bi) mode
       preproc = case mode of
                   AllTenses -> ""
                   Present   -> "-preproc="++({-rgl_src_dir </>-} "mkPresent")
@@ -268,7 +270,7 @@ gfcn bi mode summary files = do
 
 gf bi comm files = do
   putStrLn $ "Reading " ++ unwords files
-  let gf = default_gf bi
+  let gf = default_gf (lbi bi)
   putStrLn ("executing: " ++ comm ++ "\n" ++
             "in " ++ gf)
   out <- readProcess gf ("-s":files) comm
@@ -318,13 +320,14 @@ getOptLangs defaultLangs args =
                    then findLangs langs [l]++ls
                    else ls
 
-getRGLBuildSubDir (_,lbi) mode =
+getRGLBuildSubDir mode =
   case mode of
     AllTenses -> "alltenses"
     Present   -> "present"
 
 
-getRGLBuildDir bi mode = rgl_dst_dir bi </> getRGLBuildSubDir bi mode
+getRGLBuildDir :: LocalBuildInfo -> Mode -> FilePath
+getRGLBuildDir lbi mode = rgl_dst_dir lbi </> getRGLBuildSubDir mode
 
 getRGLCommands args =
   let cmds0 = [cmd | arg <- args,
@@ -350,22 +353,13 @@ unlexer abstr ls =
 -- | Runs the gf executable in compile mode with the given arguments.
 run_gfc :: Info -> [String] -> IO ()
 run_gfc bi args =
-    do let args' = ["-batch","-gf-lib-path="++rgl_src_dir]
-                   ++ ["+RTS","-A20M","-RTS"]
+    do let args' = numJobs (bf bi)++["-batch","-gf-lib-path="++rgl_src_dir]
                    ++ filter (not . null) args
-           gf = default_gf bi
-           gf_cmdline = gf ++ " " ++ unwords (map showArg args')
---     putStrLn $ "Running: " ++ gf_cmdline
---     appendFile "running" (gf_cmdline++"\n")
-       e <- rawSystem gf args'
-       case e of
-         ExitSuccess   -> return ()
-         ExitFailure i -> do putStrLn $ "Ran: " ++ gf_cmdline
-                             die $ "gf exited with exit code: " ++ show i
-  where
-    showArg arg = if ' ' `elem` arg then "'" ++ arg ++ "'" else arg
+           gf = default_gf (lbi bi)
+       execute gf args'
 
-default_gf (_,lbi) = buildDir lbi </> exeName' </> exeNameReal
+default_gf :: LocalBuildInfo -> FilePath
+default_gf lbi = buildDir lbi </> exeName' </> exeNameReal
   where
     exeName' = "gf"
     exeNameReal = exeName' <.> exeExtension