Utils.hs

{-# LANGUAGE TupleSections, ViewPatterns, NoMonomorphismRestriction #-}

module Compile.Utils where

import Compile.State as CS
import qualified My.Data.Graph as G
import My.Prelude
import My.Control.Monad
import My.Control.Monad.State
import My.Data.List

import qualified Data.Map as M
import qualified Data.Set as S
import Data.Maybe
import PCode
import Syntax  

import Debug.Trace

simplify :: Monad m => [Node] -> StateT CompileState m [Node]
simplify start = do
  oldDep <- getF depGraphF ; purgeAll ; newDep <- getF depGraphF
  return $ concatMap (newStart oldDep newDep) start
  where 
    purgeAll = do
      mapM_ (purgeNode isNoop) =<< getNodeList         
      mapM_ (purgeNode isEmptyBranch) =<< getNodeList
    purgeNode p n = do
      c <- getContext n              
      if p c then remove (n,c) else return ()
    isNoop c = tag c==Instr Noop
    isEmptyBranch c = case tag c of 
      BrPart _ -> not (null o) && all p i && all p' o
      _ -> False
      where (i,o) = edges c 
            p  (_,BranchAlt _ _) = True ; p  _ = False
            p' (_,BranchAlt _ 0) = True ; p' _ = False
    remove (n',c) = do
      let 
        (lies,loes) = edges c
        least Forward Forward = Forward   
        least _       _       = Backward  
        mergeEdge (BranchAlt t x) (BranchAlt t' _) = BranchAlt (least t t') x
        mergeEdge TimeDep         b                = b
        mergeEdge e               t                = mergeEdge t e
      sequence_ [createEdge (mergeEdge t t')  n  n'' | (n  ,t) <- lies, (n'',t') <- loes ]
      sequence_ [deleteEdge                   n  n'  | (n  ,_) <- lies                   ]
      sequence_ [deleteEdge                   n' n'' | (n'',_) <- loes                   ]
      deleteNode n'
    newStart old new = newStart
      where 
        newStart n = 
          maybe (maybe [] (\c -> concat [newStart n | (n,_) <- outEdges c])
                 (lookupContext n old)) 
          (const [n])
          (lookupContext n new)

data ANode = ANode {
  weight :: Int,
  erNum :: Int,
  instr :: NodeData
  }
           deriving Show
linearize start = getsF depGraphF (linearize' start)
linearize' start depG = instrs
  where 
    aG = annotate depG
    getContext n = G.getContext n aG
    withContext n = (n,getContext n)
    
    isBrPart (instr . tag . getContext -> BrPart _) = True
    isBrPart _ = False
    instrMap = M.fromList [(n,i) | (i,(n,_)) <- zip [0..] $ concat [map (n,) (getInstr n) | n <- concat blocks]]
    instrs = concatMap (concatMap getInstr) blocks    

    getInstr (getContext -> c) = case tag c of
      ANode { instr = BrPart v } -> [Branch v $ map branch (classesBy (===) oes)]
        where branch ns = minimum $ catMaybes [M.lookup n instrMap | (n,_) <- ns]
              (_,e) === (_,e') = e==e'
      ANode { instr = Instr i } -> i : if null oes then [ret] else []
      where oes = outEdges c

    selectHeads l = [n | (n,c) <- l, weight (tag c)==1]
    startHeads = selectHeads $ map withContext $ nub start
    heads = startHeads : deleteBy headsEq startHeads heads
      where eq n1 n2 = if n1`elem`start then n2`elem`start else c'
              where c' = n2 `elem` [n | (n,e') <- outEdges $ getContext prev, e==e']
                    (prev,e) = fromMaybe (error $ "Couldn't find edge of "++show n1++" in graph "++show aG) $ find isBackEdge $ inEdges $ getContext n1
            headsEq a b = sort a==sort b
            heads = classesBy eq $ selectHeads $ nodeListFull aG
    tails = map (nub . concatMap saturate) heads
    saturate n = if null nexts then [n] else concatMap saturate nexts
      where nexts = [n' | let c = getContext n                                
                        , (n',c') <- map withContext $ nextNodes c
                        , weight (tag c') > weight (tag c)]
    
    blocks = map blockFromTails tails
    blockFromTails tails = evalState (concat $< mapM makeBlock tails) S.empty
      where 
        visited n = gets (S.member n) ; visit n = modify (S.insert n)
    
        makeBlock n = ifM (visited n) (return []) $ do 
          prevs <- mapM makeBlock (getPrevs n)
          visit n
          return $ concat prevs ++ [n]
        getPrevs n = map fst $ sortBy cmp $ filter p $ map withContext $ prevNodes language
          where cmp (_,c) (_,c') = compare (erNum $ tag c') (erNum $ tag c)
                p (_,c) = weight (tag c) < weight (tag language)
                language = getContext n

annotate depG = newdepG
  where 
    newdepG = mapNodes depCalc depG
    depCalc (depCalc' -> (a,b)) i = ANode a b i
    depCalc' (flip G.getContext depG -> c)
      | any isBackEdge <||> null $ inEdges c = (1,1)
      | otherwise = (1+maximum a, maximum $ zipWith (+) [0..] (reverse $ sort b))
      where (a,b) = unzip [(weight t,erNum t) 
                          | n' <- prevNodes c
                          , let t = tag $ G.getContext n' newdepG]
            
    maximum = foldl max 0



-- Copyright (c) 2012, Coiffier Marc <marc.coiffier@gmail.com>
-- All rights reserved.

-- Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

--     Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
--     Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.