liquidhaskell-0.8.10.7: src/Language/Haskell/Liquid/Constraint/ToFixpoint.hs
{-# LANGUAGE FlexibleContexts #-}
module Language.Haskell.Liquid.Constraint.ToFixpoint
( cgInfoFInfo
, fixConfig
, refinementEQs
, canRewrite
) where
import Prelude hiding (error)
import qualified Language.Haskell.Liquid.GHC.API as Ghc
import Language.Haskell.Liquid.GHC.API (Var, Id, TyCon)
import qualified Language.Fixpoint.Types.Config as FC
import System.Console.CmdArgs.Default (def)
import qualified Language.Fixpoint.Types as F
import Language.Fixpoint.Solver.Rewrite (unify)
import Language.Haskell.Liquid.Constraint.Types
import qualified Language.Haskell.Liquid.Types.RefType as RT
import Language.Haskell.Liquid.Constraint.Qualifier
import Control.Monad (guard)
import qualified Data.Maybe as Mb
-- AT: Move to own module?
-- imports for AxiomEnv
import qualified Language.Haskell.Liquid.UX.Config as Config
import Language.Haskell.Liquid.UX.DiffCheck (coreDefs, coreDeps, dependsOn, Def(..))
import qualified Language.Haskell.Liquid.GHC.Misc as GM -- (simplesymbol)
import qualified Data.List as L
import qualified Data.HashMap.Strict as M
import qualified Data.HashSet as S
-- import Language.Fixpoint.Misc
import qualified Language.Haskell.Liquid.Misc as Misc
import Language.Haskell.Liquid.Types hiding ( binds )
fixConfig :: FilePath -> Config -> FC.Config
fixConfig tgt cfg = def
{ FC.solver = Mb.fromJust (smtsolver cfg)
, FC.linear = linear cfg
, FC.eliminate = eliminate cfg
, FC.nonLinCuts = not (higherOrderFlag cfg) -- eliminate cfg /= FC.All
, FC.save = saveQuery cfg
, FC.srcFile = tgt
, FC.cores = cores cfg
, FC.minPartSize = minPartSize cfg
, FC.maxPartSize = maxPartSize cfg
, FC.elimStats = elimStats cfg
, FC.elimBound = elimBound cfg
, FC.allowHO = higherOrderFlag cfg
, FC.allowHOqs = higherorderqs cfg
, FC.smtTimeout = smtTimeout cfg
, FC.stringTheory = stringTheory cfg
, FC.gradual = gradual cfg
, FC.ginteractive = ginteractive cfg
, FC.noslice = noslice cfg
, FC.rewriteAxioms = Config.allowPLE cfg
, FC.etaElim = not (exactDC cfg) && extensionality cfg -- SEE: https://github.com/ucsd-progsys/liquidhaskell/issues/1601
, FC.extensionality = extensionality cfg
, FC.oldPLE = oldPLE cfg
, FC.rwTerminationCheck = rwTerminationCheck cfg
, FC.noLazyPLE = noLazyPLE cfg
, FC.fuel = fuel cfg
, FC.noEnvironmentReduction = not (environmentReduction cfg)
, FC.inlineANFBindings = inlineANFBindings cfg
}
cgInfoFInfo :: TargetInfo -> CGInfo -> IO (F.FInfo Cinfo)
cgInfoFInfo info cgi = return (targetFInfo info cgi)
targetFInfo :: TargetInfo -> CGInfo -> F.FInfo Cinfo
targetFInfo info cgi = mappend (mempty { F.ae = ax }) fi
where
fi = F.fi cs ws bs ls consts ks qs bi aHO aHOqs es mempty adts ebs
cs = fixCs cgi
ws = fixWfs cgi
bs = binds cgi
ebs = ebinds cgi
ls = fEnv cgi
consts = cgConsts cgi
ks = kuts cgi
adts = cgADTs cgi
qs = giQuals info (fEnv cgi)
bi = (\x -> Ci x Nothing Nothing) <$> bindSpans cgi
aHO = allowHO cgi
aHOqs = higherOrderFlag info
es = [] -- makeAxioms info
ax = makeAxiomEnvironment info (dataConTys cgi) (F.cm fi)
-- msg = show . map F.symbol . M.keys . tyConInfo
makeAxiomEnvironment :: TargetInfo -> [(Var, SpecType)] -> M.HashMap F.SubcId (F.SubC Cinfo) -> F.AxiomEnv
makeAxiomEnvironment info xts fcs
= F.AEnv eqs
(concatMap makeSimplify xts)
(doExpand sp cfg <$> fcs)
(makeRewrites info <$> fcs)
where
eqs = if oldPLE cfg
then makeEquations (typeclass cfg) sp ++ map (uncurry $ specTypeEq emb) xts
else axioms
emb = gsTcEmbeds (gsName sp)
cfg = getConfig info
sp = giSpec info
axioms = gsMyAxioms refl ++ gsImpAxioms refl
refl = gsRefl sp
makeRewrites :: TargetInfo -> F.SubC Cinfo -> [F.AutoRewrite]
makeRewrites info sub = concatMap (makeRewriteOne tce) $ filter ((`S.member` rws) . fst) sigs
where
tce = gsTcEmbeds (gsName spec)
spec = giSpec info
sig = gsSig spec
sigs = gsTySigs sig ++ gsAsmSigs sig
isGlobalRw = Mb.maybe False (`elem` globalRws) parentFunction
parentFunction :: Maybe Var
parentFunction =
case subVar sub of
Just v -> Just v
Nothing ->
Mb.listToMaybe $ do
D s e v <- coreDefs $ giCbs $ giSrc info
let (Ghc.RealSrcSpan cc _) = (ci_loc $ F.sinfo sub)
guard $ s <= Ghc.srcSpanStartLine cc && e >= Ghc.srcSpanEndLine cc
return v
rws =
if isGlobalRw
then S.empty
else S.difference
(S.union localRws globalRws)
(Mb.maybe S.empty forbiddenRWs parentFunction)
allDeps = coreDeps $ giCbs $ giSrc info
forbiddenRWs sv =
S.insert sv $ dependsOn allDeps [sv]
localRws = Mb.fromMaybe S.empty $ do
var <- parentFunction
usable <- M.lookup var $ gsRewritesWith $ gsRefl spec
return $ S.fromList usable
globalRws = S.map val $ gsRewrites $ gsRefl spec
canRewrite :: S.HashSet F.Symbol -> F.Expr -> F.Expr -> Bool
canRewrite freeVars from to = noFreeSyms && doesNotDiverge
where
fromSyms = S.intersection freeVars (S.fromList $ F.syms from)
toSyms = S.intersection freeVars (S.fromList $ F.syms to)
noFreeSyms = S.null $ S.difference toSyms fromSyms
doesNotDiverge = Mb.isNothing (unify (S.toList freeVars) from to)
|| Mb.isJust (unify (S.toList freeVars) to from)
refinementEQs :: LocSpecType -> [(F.Expr, F.Expr)]
refinementEQs t =
case stripRTypeBase tres of
Just r ->
[ (lhs, rhs) | (F.EEq lhs rhs) <- F.splitPAnd $ F.reftPred (F.toReft r) ]
Nothing ->
[]
where
tres = ty_res tRep
tRep = toRTypeRep $ val t
makeRewriteOne :: (F.TCEmb TyCon) -> (Var, LocSpecType) -> [F.AutoRewrite]
makeRewriteOne tce (_, t)
= [rw | (lhs, rhs) <- refinementEQs t , rw <- rewrites lhs rhs ]
where
rewrites :: F.Expr -> F.Expr -> [F.AutoRewrite]
rewrites lhs rhs =
(guard (canRewrite freeVars lhs rhs) >> [F.AutoRewrite xs lhs rhs])
++ (guard (canRewrite freeVars rhs lhs) >> [F.AutoRewrite xs rhs lhs])
freeVars = S.fromList (ty_binds tRep)
xs = do
(sym, arg) <- zip (ty_binds tRep) (ty_args tRep)
let e = maybe F.PTrue (F.reftPred . F.toReft) (stripRTypeBase arg)
return $ F.RR (rTypeSort tce arg) (F.Reft (sym, e))
tRep = toRTypeRep $ val t
_isClassOrDict :: Id -> Bool
_isClassOrDict x = F.tracepp ("isClassOrDict: " ++ F.showpp x)
$ (hasClassArg x || GM.isDictionary x || Mb.isJust (Ghc.isClassOpId_maybe x))
hasClassArg :: Id -> Bool
hasClassArg x = F.tracepp msg $ (GM.isDataConId x && any Ghc.isClassPred (t:ts'))
where
msg = "hasClassArg: " ++ showpp (x, t:ts')
(ts, t) = Ghc.splitFunTys . snd . Ghc.splitForAllTys . Ghc.varType $ x
ts' = map Ghc.irrelevantMult ts
doExpand :: TargetSpec -> Config -> F.SubC Cinfo -> Bool
doExpand sp cfg sub = Config.allowGlobalPLE cfg
|| (Config.allowLocalPLE cfg && maybe False (isPLEVar sp) (subVar sub))
-- [TODO:missing-sorts] data-constructors often have unelaboratable 'define' so either
-- 1. Make `elaborate` robust so it doesn't crash and returns maybe or
-- 2. Make the `ctor` well-sorted or
-- 3. Don't create `define` for the ctor.
-- Unfortunately 3 breaks a bunch of tests...
specTypeEq :: F.TCEmb TyCon -> Var -> SpecType -> F.Equation
specTypeEq emb f t = F.mkEquation (F.symbol f) xts body tOut
where
xts = Misc.safeZipWithError "specTypeEq" xs (RT.rTypeSort emb <$> ts)
body = specTypeToResultRef bExp t
tOut = RT.rTypeSort emb (ty_res tRep)
tRep = toRTypeRep t
xs = ty_binds tRep
ts = ty_args tRep
bExp = F.eApps (F.eVar f) (F.EVar <$> xs)
makeSimplify :: (Var, SpecType) -> [F.Rewrite]
makeSimplify (x, t)
| not (GM.isDataConId x)
= []
| otherwise
= go $ specTypeToResultRef (F.eApps (F.EVar $ F.symbol x) (F.EVar <$> ty_binds (toRTypeRep t))) t
where
go (F.PAnd es) = concatMap go es
go (F.PAtom eq (F.EApp (F.EVar f) dc) bd)
| eq `elem` [F.Eq, F.Ueq]
, (F.EVar dc, xs) <- F.splitEApp dc
, dc == F.symbol x
, all isEVar xs
= [F.SMeasure f dc (fromEVar <$> xs) bd]
go (F.PIff (F.EApp (F.EVar f) dc) bd)
| (F.EVar dc, xs) <- F.splitEApp dc
, dc == F.symbol x
, all isEVar xs
= [F.SMeasure f dc (fromEVar <$> xs) bd]
go (F.EApp (F.EVar f) dc)
| (F.EVar dc, xs) <- F.splitEApp dc
, dc == F.symbol x
, all isEVar xs
= [F.SMeasure f dc (fromEVar <$> xs) F.PTrue]
go (F.PNot (F.EApp (F.EVar f) dc))
| (F.EVar dc, xs) <- F.splitEApp dc
, dc == F.symbol x
, all isEVar xs
= [F.SMeasure f dc (fromEVar <$> xs) F.PFalse]
go _ = []
isEVar (F.EVar _) = True
isEVar _ = False
fromEVar (F.EVar x) = x
fromEVar _ = impossible Nothing "makeSimplify.fromEVar"
makeEquations :: Bool -> TargetSpec -> [F.Equation]
makeEquations allowTC sp = [ F.mkEquation f xts (equationBody allowTC (F.EVar f) xArgs e mbT) t
| F.Equ f xts e t _ <- axioms
, let xArgs = F.EVar . fst <$> xts
, let mbT = if null xArgs then Nothing else M.lookup f sigs
]
where
axioms = gsMyAxioms refl ++ gsImpAxioms refl
refl = gsRefl sp
sigs = M.fromList [ (GM.simplesymbol v, t) | (v, t) <- gsTySigs (gsSig sp) ]
equationBody :: Bool -> F.Expr -> [F.Expr] -> F.Expr -> Maybe LocSpecType -> F.Expr
equationBody allowTC f xArgs e mbT
| Just t <- mbT = F.pAnd [eBody, rBody t]
| otherwise = eBody
where
eBody = F.PAtom F.Eq (F.eApps f xArgs) e
rBody t = specTypeToLogic allowTC xArgs (F.eApps f xArgs) (val t)
-- NV Move this to types?
-- sound but imprecise approximation of a type in the logic
specTypeToLogic :: Bool -> [F.Expr] -> F.Expr -> SpecType -> F.Expr
specTypeToLogic allowTC es e t
| ok = F.subst su (F.PImp (F.pAnd args) res)
| otherwise = F.PTrue
where
res = specTypeToResultRef e t
args = zipWith mkExpr (mkReft <$> ts) es
mkReft t = F.toReft $ Mb.fromMaybe mempty (stripRTypeBase t)
mkExpr (F.Reft (v, ev)) e = F.subst1 ev (v, e)
ok = okLen && okClass && okArgs
okLen = length xs == length xs
okClass = all (F.isTauto . snd) cls
okArgs = all okArg ts
okArg (RVar _ _) = True
okArg t@(RApp _ _ _ _) = F.isTauto (t{rt_reft = mempty})
okArg _ = False
su = F.mkSubst $ zip xs es
(cls, nocls) = L.partition ((if allowTC then isEmbeddedClass else isClassType).snd) $ zip (ty_binds trep) (ty_args trep)
:: ([(F.Symbol, SpecType)], [(F.Symbol, SpecType)])
(xs, ts) = unzip nocls :: ([F.Symbol], [SpecType])
trep = toRTypeRep t
specTypeToResultRef :: F.Expr -> SpecType -> F.Expr
specTypeToResultRef e t
= mkExpr $ F.toReft $ Mb.fromMaybe mempty (stripRTypeBase $ ty_res trep)
where
mkExpr (F.Reft (v, ev)) = F.subst1 ev (v, e)
trep = toRTypeRep t