Agda-2.4.0.2: src/full/Agda/Compiler/Epic/Injection.hs
{-# LANGUAGE CPP #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE PatternGuards #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE TypeSynonymInstances #-}
{-# LANGUAGE OverlappingInstances #-}
module Agda.Compiler.Epic.Injection where
import Control.Monad.State
import Control.Monad.Reader
import Data.List
import Data.Map(Map)
import qualified Data.Map as M
import Data.Maybe
import Data.Set(Set)
import qualified Data.Set as S
import Agda.Syntax.Common
import Agda.Syntax.Internal as I
import Agda.Syntax.Internal.Pattern (FunArity(..))
import Agda.Syntax.Literal
import Agda.TypeChecking.CompiledClause
import Agda.TypeChecking.Monad
import Agda.TypeChecking.Monad.Builtin
import Agda.TypeChecking.Pretty hiding (empty)
import Agda.TypeChecking.Reduce
import Agda.TypeChecking.Substitute
import Agda.Utils.List
import Agda.Utils.Monad
import Agda.Utils.Null
import qualified Agda.Utils.HashMap as HM
import Agda.Compiler.Epic.CompileState
import Agda.Compiler.Epic.Interface as Interface
#include "../../undefined.h"
import Agda.Utils.Impossible
-- | Find potentially injective functions, solve constraints to fix some constructor
-- tags and make functions whose constraints are fulfilled injections
findInjection :: [(QName, Definition)] -> Compile TCM [(QName, Definition)]
findInjection defs = do
funs <- forM defs $ \(name, def) -> case theDef def of
f@(Function{}) -> isInjective name (funClauses f)
_ -> return Nothing
newNames <- M.keys <$> gets (Interface.conArity . curModule)
injFuns <- solve newNames (catMaybes funs)
defs' <- forM defs $ \(q, def) -> case q `isIn` injFuns of
Nothing -> return (q, def)
Just inj@(InjectiveFun nvar arity) -> case theDef def of
f@(Function{}) -> do
modifyEI $ \s -> s { injectiveFuns = M.insert q inj (injectiveFuns s) }
let ns = replicate arity (defaultArg empty)
return $ (,) q $ def { theDef = f { funCompiled = Just $ Done ns $
var $ arity - nvar - 1 } }
_ -> __IMPOSSIBLE__
lift $ reportSLn "epic.injection" 10 $ "injfuns: " ++ show injFuns
return defs'
where
q `isIn` funs = case filter (\(nam, _) -> q == nam) funs of
[] -> Nothing
(_,x):_ -> Just x
replaceFunCC :: QName -> CompiledClauses -> Compile TCM ()
replaceFunCC name cc = do
lift $ modify $ \s ->
s { stSignature = (stSignature s) { sigDefinitions = HM.adjust replaceDef name (sigDefinitions (stSignature s)) }
, stImports = (stImports s) { sigDefinitions = HM.adjust replaceDef name (sigDefinitions (stImports s)) }
}
where
replaceDef :: Definition -> Definition
replaceDef def = case theDef def of
f@(Function{}) -> def {theDef = f { funCompiled = Just $ cc } }
x -> __IMPOSSIBLE__
-- | If the pairs of constructor names have the same tags, the function is
-- injective. If Nothing, the function is not injective.
type InjConstraints = Maybe [(QName,QName)]
isInjective :: QName -- ^ Name of the function being tested
-> [Clause] -- ^ The function's clauses
-> Compile TCM (Maybe ((QName, InjectiveFun)
, [(QName, QName)] -- These construtors should have the same name
))
isInjective nam [] = return Nothing
isInjective nam cls@(cl : _) = do
lift $ reportSLn "epic.injection" 20 $ "checking isInjective " ++ show nam
let total = funArity cls
(listToMaybe . catMaybes <$>) . forM [0 .. total - 1] $ \i -> do
cli <- forM cls $ \ cl -> isInjectiveHere nam i cl
let cli' = catMaybes cli
return $ if length cli == length cli'
then Just ((nam, InjectiveFun i total), concat cli')
else Nothing
patternToTerm :: Nat -> Pattern -> Term
patternToTerm n p = case p of
VarP v -> var n
DotP t -> t
ConP c typ args -> Con c $ zipWith (\ arg t -> arg {unArg = t}) args
$ snd
$ foldr (\ arg (n, ts) -> (n + nrBinds arg, patternToTerm n arg : ts))
(n , [])
$ map namedArg args
LitP l -> Lit l
ProjP d -> Def d [] -- Andreas, 2012-10-31 that might not be enought to get a term from list of patterns (TODO)
nrBinds :: Num i => Pattern -> i
nrBinds p = case p of
VarP v -> 1
DotP t -> 0
ConP c typ args -> sum $ map (nrBinds . namedArg) args
LitP l -> 0
ProjP{} -> 0
substForDot :: [I.NamedArg Pattern] -> Substitution
substForDot = makeSubst 0 0 . reverse . calcDots
where
makeSubst i accum [] = raiseS (i + accum)
makeSubst i accum (True : ps) = makeSubst i (accum +1) ps
makeSubst i accum (False : ps) = var (i + accum) :# makeSubst (i+1) accum ps
calcDots = concatMap calcDots' . map namedArg
calcDots' p = case p of
VarP v -> [False]
DotP t -> [True]
ConP c typ args -> calcDots args
LitP l -> [False]
ProjP{} -> [False]
isInjectiveHere :: QName -- ^ Name of the function being tested
-> Int -- ^ The current argument
-> Clause
-> Compile TCM InjConstraints
isInjectiveHere nam idx clause = do
lift $ reportSDoc "epic.injection" 40 $ sep
[ text "isInjectiveHere"
, prettyTCM nam
, text ("argumentNo=" ++ show idx)
-- , prettyTCM (clausePats clause)
]
case getBody clause of
Nothing -> return emptyC
Just body -> do
let t = patternToTerm idxR $ unArg $ fromMaybe __IMPOSSIBLE__ $
clausePats clause !!! idx
t' = applySubst (substForDot $ namedClausePats clause) t
idxR = sum . map (nrBinds . unArg) . genericDrop (idx + 1) $ clausePats clause
body' <- lift $ reduce body
lift $ reportSLn "epic.injection" 40 "reduced body"
injFs <- gets (injectiveFuns . importedModules)
lift $ reportSLn "epic.injection" 40 "calculated injFs"
res <- (t' <: body') `runReaderT` (M.insert nam (InjectiveFun idx
(length (clausePats clause))) injFs)
lift $ reportSDoc "epic.injection" 20 $ vcat
[ text "isInjective:" <+> text (show nam)
, text "at Index :" <+> text (show idx)
, nest 2 $ vcat
[ text "clause :" <+> text (show clause)
, text "t :" <+> prettyTCM t
, text "idxR :" <+> (text . show) idxR
, text "body' :" <+> (text . show) body'
]
, text "res :" <+> text (show res)
]
return res
-- | Turn NATURAL literal n into suc^n zero.
litToCon :: Literal -> TCM Term
litToCon l = case l of
LitInt r n | n > 0 -> do
inner <- litToCon (LitInt r (n - 1))
suc <- primSuc
return $ suc `apply` [defaultArg inner]
| otherwise -> primZero
-- LitLevel _ n -> -- Does not really matter
lit -> return $ Lit lit
litInt :: Literal -> Bool
litInt LitInt{} = True
litInt _ = False
insertAt :: (Nat,Term) -> Term -> Term
insertAt (index, ins) =
applySubst ([var i | i <- [0 .. index - 1]] ++# ins :# raiseS (index + 1))
solve :: [QName] -> [((QName, InjectiveFun), [(QName,QName)])] -> Compile TCM [(QName, InjectiveFun)]
solve newNames xs = do
lift $ reportSDoc "epic.injection" 30 $
sep $ text "Epic.Injection.solve" : map prettyTCM newNames
-- Only primitive lists should be in the current module at this point,
-- but we still want them
conGraph <- M.union <$> gets (constrTags . curModule) <*> gets (constrTags . importedModules)
(funs, mconstr) <- ($ xs) $ flip foldM ([] , Just $ initialTags conGraph newNames) $ \ (xs , prev) (fun , con) -> do
m <- foldM solvable prev con
return $ case m of
Nothing -> (xs, prev)
Just next -> (fun : xs, m)
case mconstr of
Nothing -> __IMPOSSIBLE__
Just constr -> updateTags constr
return funs
where
solvable :: Maybe Tags -> (QName, QName)
-> Compile TCM (Maybe Tags)
solvable Nothing _ = return Nothing
solvable (Just st) (c1, c2) = unify c1 c2 st
updateTags :: Tags -> Compile TCM ()
updateTags tags = do
let (hasTags, eqs) = M.partition isTag (constrGroup tags)
isTag (IsTag _) = True
isTag _ = False
forM (M.toList hasTags) $ \ (c, tagged) -> case tagged of
IsTag tag -> putCon c tag
_ -> __IMPOSSIBLE__
case M.toList eqs of
(c, Same n) : _ -> do
let grp = eqGroups tags !!!! n
tag <- assignConstrTag' c (S.toList grp)
updateTags . fromMaybe __IMPOSSIBLE__ =<< setTag n tag tags { constrGroup = eqs }
_ -> return ()
putCon :: QName -> Tag -> Compile TCM ()
putCon con tag = do
m <- gets (constrTags . importedModules)
case M.lookup con m of
Nothing -> putConstrTag con tag
Just _ -> return () -- old
emptyC :: InjConstraints
emptyC = Just []
addConstraint :: QName -> QName -> InjConstraints -> InjConstraints
addConstraint q1 q2 Nothing = Nothing
addConstraint q1 q2 (Just xs) = Just (if q1 == q2 then xs else (q1,q2) : xs)
unionConstraints :: [InjConstraints] -> InjConstraints
unionConstraints [] = Just []
unionConstraints (Nothing : _) = Nothing
unionConstraints (Just c : cs) = do
cs' <- unionConstraints cs
return (c ++ cs')
-- | Are two terms injectible?
-- Tries to find a mapping between constructors that equates the terms.
--
-- Precondition: t1 is normalised, t2 is in WHNF
-- When reducing t2, it may become a literal, which makes this not work in some cases...
class Injectible a where
(<:) :: a -> a -> ReaderT (QName :-> InjectiveFun) (Compile TCM) InjConstraints
instance Injectible a => Injectible (I.Arg a) where
a1 <: a2 = unArg a1 <: unArg a2
instance Injectible a => Injectible [a] where
l1 <: l2
| length l1 == length l2 = unionConstraints <$> zipWithM (<:) l1 l2
| otherwise = return Nothing
instance Injectible a => Injectible (Elim' a) where
e1 <: e2 =
case (e1, e2) of
(Proj f1 , Proj f2 ) | f1 == f2 -> return $ Just []
(Apply a1, Apply a2) -> a1 <: a2
_ -> return Nothing
instance Injectible Term where
t1 <: t2 = do
injs <- ask
-- Andreas, 2013-10-18: ignoring the precondition (NF, WHNF) since I am not maintaining it
-- in recursive calls.
-- The original code did not follow this invariant in the Var-Var and Def-Def case,
-- thus, I am not trusting it. Also the call site does not seem to ensure it.
-- It could be restored by only reducing the right argument in the Arg-instance.
-- (t1, t2) <- lift . lift . reduce $ (t1, t2) -- NOTE: reduce *introduces* Lit! Loops!
case (t1, t2) of
(Lit l, Lit l') | l == l' -> return $ Just []
(Lit l, _) | litInt l -> do
l' <- lift . lift $ litToCon l
l' <: t2
(_, Lit l) | litInt l -> do
l' <- lift . lift $ litToCon l
t1 <: l'
(_, Def n2 es2) | Just (InjectiveFun argn arit) <- M.lookup n2 injs -> do
if genericLength es2 /= arit
then return Nothing
else do
case es2 !!! argn of
Nothing -> __IMPOSSIBLE__
Just (Proj{}) -> __IMPOSSIBLE__
Just (Apply a) -> t1 <: unArg a
(Var i1 es1, Var i2 es2) | i1 == i2 -> es1 <: es2
(Def q1 es1, Def q2 es2) | q1 == q2 -> es1 <: es2
(Con con1 args1, Con con2 args2) -> do
let c1 = conName con1
c2 = conName con2
args1' <- flip notForced args1 <$> do lift . getForcedArgs $ c1
args2' <- flip notForced args2 <$> do lift . getForcedArgs $ c2
addConstraint c1 c2 <$> do
args1' <: args2'
_ -> return Nothing
{-
(_, Def n2 args2) | Just (InjectiveFun argn arit) <- M.lookup n2 injs -> do
if genericLength args2 /= arit
then return Nothing
else do
arg <- lift . lift . reduce $ unArg $ args2 !! argn
t1 <: arg
(Var n1 args1, Var n2 args2) | n1 == n2 && length args1 == length args2 -> do
args1' <- map unArg <$> mapM (lift . lift . reduce) args1
args2' <- map unArg <$> mapM (lift . lift . reduce) args2
unionConstraints <$> zipWithM (\a b -> (a <: b)) args1' args2'
(Def q1 args1, Def q2 args2) | q1 == q2 && length args1 == length args2 -> do
args1' <- map unArg <$> mapM (lift . lift . reduce) args1
args2' <- map unArg <$> mapM (lift . lift . reduce) args2
unionConstraints <$> zipWithM (\a b -> (a <: b)) args1' args2'
(Con con1 args1, Con con2 args2) -> do
let c1 = conName con1
c2 = conName con2
args1' <- map unArg <$> flip notForced args1 <$> getForcedArgs c1
args2' <- map unArg <$> (mapM (lift . lift . reduce) =<< flip notForced args2 <$> getForcedArgs c2)
if length args1' == length args2'
then addConstraint c1 c2 <$> unionConstraints <$> zipWithM (\a b -> (a <: b)) args1' args2'
else return Nothing
_ -> return Nothing
-}
data TagEq
= Same Int
| IsTag Tag
deriving Eq
data Tags = Tags
{ eqGroups :: Int :-> Set QName
, constrGroup :: QName :-> TagEq
}
initialTags :: Map QName Tag -> [QName] -> Tags
initialTags setTags newNames = Tags
{ eqGroups = M.fromList $ zip [0..] (map S.singleton newNames)
, constrGroup = M.map IsTag setTags `M.union` M.fromList (zip newNames (map Same [0..]))
}
unify :: QName -> QName -> Tags -> Compile TCM (Maybe Tags)
unify c1 c2 ts = do
let g1 = constrGroup ts !!!! c1
g2 = constrGroup ts !!!! c2
case (g1, g2) of
(Same n1, Same n2) | n1 == n2 -> return $ Just ts
(IsTag t1, IsTag t2) | t1 == t2 -> return $ Just ts
(Same n1, Same n2) -> mergeGroups n1 n2 ts
(Same n1, IsTag t2) -> setTag n1 t2 ts
(IsTag t1 , Same n2) -> setTag n2 t1 ts
_ -> return $ Nothing
setTag :: Int -> Tag -> Tags -> Compile TCM (Maybe Tags)
setTag gid tag ts = return $ Just $ ts
{ constrGroup = foldr (\c -> M.insert c (IsTag tag)) (constrGroup ts) (S.toList $ eqGroups ts !!!! gid)}
mergeGroups :: Int -> Int -> Tags -> Compile TCM (Maybe Tags)
mergeGroups n1 n2 ts = do
let g1s = eqGroups ts !!!! n1
g2s = eqGroups ts !!!! n2
gs = S.union g1s g2s
g1l = S.toList g1s
g2l = S.toList g2s
ifNotM (andM $ zipWith unifiable g1l g2l)
(return Nothing) $
return $ Just $ ts
{ eqGroups = M.delete n2 $ M.insert n1 gs (eqGroups ts)
, constrGroup = M.fromList [ (e2, Same n1) | e2 <- g2l ] `M.union` constrGroup ts
}
unifiable :: QName -> QName -> Compile TCM Bool
unifiable c1 c2 = do
d1 <- getConData c1
d2 <- getConData c2
return $ d1 /= d2
(!!!!) :: Ord k => k :-> v -> k -> v
m !!!! k = case M.lookup k m of
Nothing -> __IMPOSSIBLE__
Just x -> x