move GF.Devel.OptimizeGF to GF.Compile.OptimizeGF

2 files changed, 277 insertions, 1 deletions

diff --git a/src-3.0/GF/Compile/GrammarToGFCC.hs b/src-3.0/GF/Compile/GrammarToGFCC.hs
index 92b76771c..23c210f28 100644
--- a/src-3.0/GF/Compile/GrammarToGFCC.hs
+++ b/src-3.0/GF/Compile/GrammarToGFCC.hs
@@ -1,7 +1,7 @@
 {-# LANGUAGE PatternGuards #-}
 module GF.Compile.GrammarToGFCC (prGrammar2gfcc,mkCanon2gfcc,addParsers) where
 
-import GF.Devel.OptimizeGF (unshareModule)
+import GF.Compile.OptimizeGF (unshareModule)
 
 import GF.Grammar.Grammar
 import qualified GF.Grammar.Lookup as Look
diff --git a/src-3.0/GF/Compile/OptimizeGF.hs b/src-3.0/GF/Compile/OptimizeGF.hs
new file mode 100644
index 000000000..8872a5105
--- /dev/null
+++ b/src-3.0/GF/Compile/OptimizeGF.hs
@@ -0,0 +1,276 @@
+----------------------------------------------------------------------
+-- |
+-- Module      : OptimizeGF
+-- Maintainer  : AR
+-- Stability   : (stable)
+-- Portability : (portable)
+--
+-- > CVS $Date: 2005/04/21 16:21:33 $ 
+-- > CVS $Author: bringert $
+-- > CVS $Revision: 1.6 $
+--
+-- Optimizations on GF source code: sharing, parametrization, value sets.
+--
+-- optimization: sharing branches in tables. AR 25\/4\/2003.
+-- following advice of Josef Svenningsson
+-----------------------------------------------------------------------------
+
+module GF.Compile.OptimizeGF (
+  optModule,unshareModule,unsubexpModule,unoptModule,subexpModule,shareModule
+  ) where 
+
+import GF.Grammar.Grammar
+import GF.Grammar.Lookup
+import GF.Infra.Ident
+import qualified GF.Grammar.Macros as C
+import GF.Grammar.PrGrammar (prt)
+import qualified GF.Infra.Modules as M
+import GF.Data.Operations
+
+import Control.Monad
+import Data.Map (Map)
+import qualified Data.Map as Map
+import qualified Data.ByteString.Char8 as BS
+import Data.List
+
+optModule :: (Ident, SourceModInfo) -> (Ident, SourceModInfo)
+optModule = subexpModule . shareModule
+
+shareModule = processModule optim
+
+unoptModule :: SourceGrammar -> (Ident, SourceModInfo) -> (Ident, SourceModInfo)
+unoptModule gr = unshareModule gr . unsubexpModule
+
+unshareModule :: SourceGrammar -> (Ident, SourceModInfo) -> (Ident, SourceModInfo)
+unshareModule gr = processModule (const (unoptim gr))
+
+processModule :: 
+  (Ident -> Term -> Term) -> (Ident, SourceModInfo) -> (Ident, SourceModInfo)
+processModule opt (i,m) = case m of
+  M.ModMod (M.Module mt st fs me ops js) -> 
+    (i,M.ModMod (M.Module mt st fs me ops (mapTree (shareInfo opt) js)))
+  _ -> (i,m)
+
+shareInfo opt (c, CncCat ty (Yes t) m) = (c,CncCat ty (Yes (opt c t)) m)
+shareInfo opt (c, CncFun kxs (Yes t) m) = (c,CncFun kxs (Yes (opt c t)) m)
+shareInfo opt (c, ResOper ty (Yes t)) = (c,ResOper ty (Yes (opt c t)))
+shareInfo _ i = i
+
+-- the function putting together optimizations
+optim :: Ident -> Term -> Term
+optim c = values . factor c 0
+
+-- we need no counter to create new variable names, since variables are 
+-- local to tables (only true in GFC) ---
+
+-- factor parametric branches
+
+factor :: Ident -> Int -> Term -> Term
+factor c i t = case t of
+  T _ [_] -> t
+  T _ []  -> t
+  T (TComp ty) cs -> 
+    T (TTyped ty) $ factors i [(p, factor c (i+1) v) | (p, v) <- cs]
+  _ -> C.composSafeOp (factor c i) t
+ where
+
+   factors i psvs =   -- we know psvs has at least 2 elements
+     let p   = qqIdent c i
+         vs' = map (mkFun p) psvs
+     in if   allEqs vs'
+        then mkCase p vs' 
+        else psvs
+
+   mkFun p (patt, val) = replace (C.patt2term patt) (Vr p) val
+
+   allEqs (v:vs) = all (==v) vs
+
+   mkCase p (v:_) = [(PV p, v)]
+
+--- we hope this will be fresh and don't check... in GFC would be safe
+
+qqIdent c i = identC (BS.pack ("q_" ++ prt c ++ "__" ++ show i))
+
+
+--  we need to replace subterms
+
+replace :: Term -> Term -> Term -> Term
+replace old new trm = case trm of
+  
+  -- these are the important cases, since they can correspond to patterns  
+  QC _ _   | trm == old -> new
+  App t ts | trm == old -> new
+  App t ts              -> App (repl t) (repl ts)
+  R _ | isRec && trm == old -> new
+  _ -> C.composSafeOp repl trm
+ where
+   repl = replace old new
+   isRec = case trm of
+     R _ -> True
+     _ -> False
+
+-- It is very important that this is performed only after case
+-- expansion since otherwise the order and number of values can
+-- be incorrect. Guaranteed by the TComp flag.
+
+values :: Term -> Term
+values t = case t of
+  T ty [(ps,t)]    -> T ty [(ps,values t)] -- don't destroy parametrization
+  T (TComp ty)  cs -> V ty [values t | (_, t) <- cs]
+  T (TTyped ty) cs -> V ty [values t | (_, t) <- cs] 
+        ---- why are these left?
+        ---- printing with GrammarToSource does not preserve the distinction
+  _ -> C.composSafeOp values t
+
+
+-- to undo the effect of factorization
+
+unoptim :: SourceGrammar -> Term -> Term
+unoptim gr = unfactor gr
+
+unfactor :: SourceGrammar -> Term -> Term
+unfactor gr t = case t of
+  T (TTyped ty) [(PV x,u)] -> V ty [restore x v (unfac u) | v <- vals ty]
+  _ -> C.composSafeOp unfac t
+ where
+   unfac = unfactor gr
+   vals  = err error id . allParamValues gr
+   restore x u t = case t of
+     Vr y | y == x -> u
+     _ -> C.composSafeOp (restore x u) t
+
+
+----------------------------------------------------------------------
+
+{-
+This module implements a simple common subexpression elimination
+ for gfc grammars, to factor out shared subterms in lin rules.
+It works in three phases: 
+
+  (1) collectSubterms collects recursively all subterms of forms table and (P x..y)
+      from lin definitions (experience shows that only these forms
+      tend to get shared) and counts how many times they occur
+  (2) addSubexpConsts takes those subterms t that occur more than once
+      and creates definitions of form "oper A''n = t" where n is a
+      fresh number; notice that we assume no ids of this form are in
+      scope otherwise
+  (3) elimSubtermsMod goes through lins and the created opers by replacing largest
+      possible subterms by the newly created identifiers
+
+The optimization is invoked in gf by the flag i -subs.
+
+If an application does not support GFC opers, the effect of this
+optimization can be undone by the function unSubelimCanon.
+
+The function unSubelimCanon can be used to diagnostisize how much
+cse is possible in the grammar. It is used by the flag pg -printer=subs.
+
+-}
+
+subexpModule :: SourceModule -> SourceModule
+subexpModule (mo,m) = errVal (mo,m) $ case m of
+  M.ModMod (M.Module mt st fs me ops js) -> do
+    (tree,_) <- appSTM (getSubtermsMod mo (tree2list js)) (Map.empty,0)
+    js2 <- liftM buildTree $ addSubexpConsts mo tree $ tree2list js
+    return (mo,M.ModMod (M.Module mt st fs me ops js2))
+  _ -> return (mo,m)
+
+unsubexpModule :: SourceModule -> SourceModule
+unsubexpModule mo@(i,m) = case m of
+    M.ModMod (M.Module mt st fs me ops js) | hasSub ljs ->
+      (i, M.ModMod (M.Module mt st fs me ops 
+                     (rebuild (map unparInfo ljs)))) 
+                        where ljs = tree2list js
+    _ -> (i,m)
+  where
+    -- perform this iff the module has opers
+    hasSub ljs = not $ null [c | (c,ResOper _ _) <- ljs]
+    unparInfo (c,info) = case info of
+      CncFun xs (Yes t) m -> [(c, CncFun xs (Yes (unparTerm t)) m)]
+      ResOper (Yes (EInt 8)) _ -> [] -- subexp-generated opers
+      ResOper pty (Yes t) -> [(c, ResOper pty (Yes (unparTerm t)))]
+      _ -> [(c,info)]
+    unparTerm t = case t of
+      Q m c | isOperIdent c -> --- name convention of subexp opers
+        errVal t $ liftM unparTerm $ lookupResDef gr m c 
+      _ -> C.composSafeOp unparTerm t
+    gr = M.MGrammar [mo] 
+    rebuild = buildTree . concat
+
+-- implementation
+
+type TermList = Map Term (Int,Int) -- number of occs, id
+type TermM a = STM (TermList,Int) a
+
+addSubexpConsts :: 
+  Ident -> Map Term (Int,Int) -> [(Ident,Info)] -> Err [(Ident,Info)]
+addSubexpConsts mo tree lins = do
+  let opers = [oper id trm | (trm,(_,id)) <- list]
+  mapM mkOne $ opers ++ lins
+ where
+
+   mkOne (f,def) = case def of
+     CncFun xs (Yes trm) pn -> do
+       trm' <- recomp f trm
+       return (f,CncFun xs (Yes trm') pn)
+     ResOper ty (Yes trm) -> do
+       trm' <- recomp f trm
+       return (f,ResOper ty (Yes trm'))
+     _ -> return (f,def)
+   recomp f t = case Map.lookup t tree of
+     Just (_,id) | operIdent id /= f -> return $ Q mo (operIdent id)
+     _ -> C.composOp (recomp f) t
+
+   list = Map.toList tree
+
+   oper id trm = (operIdent id, ResOper (Yes (EInt 8)) (Yes trm)) 
+   --- impossible type encoding generated opers
+
+getSubtermsMod :: Ident -> [(Ident,Info)] -> TermM (Map Term (Int,Int))
+getSubtermsMod mo js = do
+  mapM (getInfo (collectSubterms mo)) js
+  (tree0,_) <- readSTM
+  return $ Map.filter (\ (nu,_) -> nu > 1) tree0
+ where
+   getInfo get fi@(f,i) = case i of
+     CncFun xs (Yes trm) pn -> do
+       get trm
+       return $ fi
+     ResOper ty (Yes trm) -> do
+       get trm
+       return $ fi
+     _ -> return fi
+
+collectSubterms :: Ident -> Term -> TermM Term
+collectSubterms mo t = case t of
+  App f a -> do
+    collect f
+    collect a
+    add t 
+  T ty cs -> do
+    let (_,ts) = unzip cs
+    mapM collect ts
+    add t
+  V ty ts -> do
+    mapM collect ts
+    add t
+----  K (KP _ _)  -> add t
+  _ -> C.composOp (collectSubterms mo) t
+ where
+   collect = collectSubterms mo
+   add t = do
+     (ts,i) <- readSTM
+     let 
+       ((count,id),next) = case Map.lookup t ts of
+         Just (nu,id) -> ((nu+1,id), i)
+         _ ->            ((1,   i ), i+1)
+     writeSTM (Map.insert t (count,id) ts, next)
+     return t --- only because of composOp
+
+operIdent :: Int -> Ident
+operIdent i = identC (operPrefix `BS.append` (BS.pack (show i))) ---
+
+isOperIdent :: Ident -> Bool
+isOperIdent id = BS.isPrefixOf operPrefix (ident2bs id)
+
+operPrefix = BS.pack ("A''")