tock-mirror/backends/BackendPasses.hs
Neil Brown acd57d74de Changed the A.Structured type to be parameterised
This patch is actually an amalgam of multiple (already large) patches.  Those patches conflicted (parameterised Structured vs. changes to usage checking and FlowGraph) and encountered a nasty bug in darcs 1 involving exponential time (see http://wiki.darcs.net/DarcsWiki/ConflictsFAQ for more details).  Reasoning that half an hour (of 100% CPU use) was too long to apply patches, I opted to re-record the parameterised Structured changes as this new large patch.  Here are the commit messages originally used for the patches (which, as mentioned, were already large patches):

A gigantic patch switching all the non-test modules over to using parameterised A.Structured
Changed the FlowGraph module again to handle any sort of Structured you want to pass to it (mainly for testing)
A further gigantic patch changing all the tests to work with the new parameterised Structured
Fixed a nasty bug involving functions being named incorrectly inside transformInputCase
Added a hand-written instance of Data for Structured that allows us to use ext1M properly
Fixed a few warnings in the code
2008-02-05 19:40:27 +00:00

71 lines
2.8 KiB
Haskell

{-
Tock: a compiler for parallel languages
Copyright (C) 2007 University of Kent
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program. If not, see <http://www.gnu.org/licenses/>.
-}
-- | Passes associated with the backends
module BackendPasses where
import Control.Monad.State
import Data.Generics
import qualified Data.Set as Set
import qualified AST as A
import CompState
import Pass
-- | Identify processes that we'll need to compute the stack size of.
identifyParProcs :: Pass
identifyParProcs = everywhereM (mkM doProcess)
where
doProcess :: A.Process -> PassM A.Process
doProcess p@(A.Par _ _ s) = findProcs s >> return p
doProcess p = return p
findProcs :: A.Structured A.Process -> PassM ()
findProcs (A.Rep _ _ s) = findProcs s
findProcs (A.Spec _ _ s) = findProcs s
findProcs (A.ProcThen _ _ s) = findProcs s
findProcs (A.Several _ ss) = sequence_ $ map findProcs ss
findProcs (A.Only _ (A.ProcCall _ n _))
= modify (\cs -> cs { csParProcs = Set.insert n (csParProcs cs) })
transformWaitFor :: Data t => t -> PassM t
transformWaitFor = everywhereM (mkM doAlt)
where
doAlt :: A.Process -> PassM A.Process
doAlt a@(A.Alt m pri s)
= do (a',(specs,code)) <- runStateT (everywhereM (mkM doWaitFor) a) ([],[])
if (null specs && null code)
then return a
else return $ A.Seq m $ foldr addSpec (A.Several m (code ++ [A.Only m a'])) specs
doAlt p = return p
addSpec :: Data a => (A.Structured a -> A.Structured a) -> A.Structured a -> A.Structured a
addSpec spec inner = spec inner
doWaitFor :: A.Alternative -> StateT ([A.Structured A.Process -> A.Structured A.Process], [A.Structured A.Process]) PassM A.Alternative
doWaitFor a@(A.AlternativeWait m A.WaitFor e p)
= do (specs, init) <- get
id <- lift $ makeNonce "waitFor"
let n = (A.Name m A.VariableName id)
let var = A.Variable m n
put (specs ++ [A.Spec m (A.Specification m n (A.Declaration m A.Time Nothing))],
init ++ [A.Only m $ A.GetTime m var, A.Only m $ A.Assign m [var] $ A.ExpressionList m [A.Dyadic m A.Plus (A.ExprVariable m var) e]])
return $ A.AlternativeWait m A.WaitUntil (A.ExprVariable m var) p
doWaitFor a = return a