\begin{code}
module TcBinds ( tcLocalBinds, tcTopBinds,
tcHsBootSigs, tcPolyBinds,
- PragFun, tcSpecPrags, mkPragFun,
+ PragFun, tcSpecPrags, tcVectDecls, mkPragFun,
TcSigInfo(..), SigFun, mkSigFun,
badBootDeclErr ) where
import TcPat
import TcMType
import TcType
-import RnBinds( misplacedSigErr )
import Coercion
import TysPrim
import Id
import Name
import NameSet
import NameEnv
-import VarSet
import SrcLoc
import Bag
+import ListSetOps
import ErrUtils
import Digraph
import Maybes
import Outputable
import FastString
-import Data.List( partition )
import Control.Monad
#include "HsVersions.h"
tcPolyBinds top_lvl sig_fn prag_fn rec_group rec_tc bind_list
= setSrcSpan loc $
recoverM (recoveryCode binder_names sig_fn) $ do
- -- Set up main recoer; take advantage of any type sigs
+ -- Set up main recover; take advantage of any type sigs
{ traceTc "------------------------------------------------" empty
; traceTc "Bindings for" (ppr binder_names)
+ -- Instantiate the polytypes of any binders that have signatures
+ -- (as determined by sig_fn), returning a TcSigInfo for each
; tc_sig_fn <- tcInstSigs sig_fn binder_names
; dflags <- getDOpts
; return (binds, poly_ids) }
where
binder_names = collectHsBindListBinders bind_list
- loc = getLoc (head bind_list)
- -- TODO: location a bit awkward, but the mbinds have been
- -- dependency analysed and may no longer be adjacent
+ loc = foldr1 combineSrcSpans (map getLoc bind_list)
+ -- The mbinds have been dependency analysed and
+ -- may no longer be adjacent; so find the narrowest
+ -- span that includes them all
------------------
tcPolyNoGen
-- it binds a single variable,
-- it has a signature,
tcPolyCheck sig@(TcSigInfo { sig_id = id, sig_tvs = tvs, sig_scoped = scoped
- , sig_theta = theta, sig_loc = loc })
+ , sig_theta = theta, sig_tau = tau })
prag_fn rec_tc bind_list
= do { ev_vars <- newEvVars theta
-
- ; let skol_info = SigSkol (FunSigCtxt (idName id))
+ ; let skol_info = SigSkol (FunSigCtxt (idName id)) (mkPhiTy theta tau)
; (ev_binds, (binds', [mono_info]))
<- checkConstraints skol_info tvs ev_vars $
tcExtendTyVarEnv2 (scoped `zip` mkTyVarTys tvs) $
; export <- mkExport prag_fn tvs theta mono_info
+ ; loc <- getSrcSpanM
; let (_, poly_id, _, _) = export
abs_bind = L loc $ AbsBinds
{ abs_tvs = tvs
-- dependencies based on type signatures
-> [LHsBind Name]
-> TcM (LHsBinds TcId, [TcId])
-tcPolyInfer top_lvl mono sig_fn prag_fn rec_tc bind_list
+tcPolyInfer top_lvl mono tc_sig_fn prag_fn rec_tc bind_list
= do { ((binds', mono_infos), wanted)
<- captureConstraints $
- tcMonoBinds sig_fn LetLclBndr rec_tc bind_list
+ tcMonoBinds tc_sig_fn LetLclBndr rec_tc bind_list
; unifyCtxts [sig | (_, Just sig, _) <- mono_infos]
- ; let get_tvs | isTopLevel top_lvl = tyVarsOfType
- | otherwise = exactTyVarsOfType
- -- See Note [Silly type synonym] in TcType
- tau_tvs = foldr (unionVarSet . get_tvs . getMonoType) emptyVarSet mono_infos
-
- ; (qtvs, givens, ev_binds) <- simplifyInfer mono tau_tvs wanted
+ ; let name_taus = [(name, idType mono_id) | (name, _, mono_id) <- mono_infos]
+ ; (qtvs, givens, ev_binds) <- simplifyInfer top_lvl mono name_taus wanted
; exports <- mapM (mkExport prag_fn qtvs (map evVarPred givens))
mono_infos
-- for the selector Id, but the poly_id is something like $cop
= addErrCtxt (spec_ctxt prag) $
do { spec_ty <- tcHsSigType sig_ctxt hs_ty
- ; checkTc (isOverloadedTy poly_ty)
- (ptext (sLit "Discarding pragma for non-overloaded function") <+> quotes (ppr poly_id))
- ; wrap <- tcSubType origin skol_info (idType poly_id) spec_ty
+ ; warnIf (not (isOverloadedTy poly_ty || isInlinePragma inl))
+ (ptext (sLit "SPECIALISE pragma for non-overloaded function") <+> quotes (ppr poly_id))
+ -- Note [SPECIALISE pragmas]
+ ; wrap <- tcSubType origin sig_ctxt (idType poly_id) spec_ty
; return (SpecPrag poly_id wrap inl) }
where
name = idName poly_id
poly_ty = idType poly_id
origin = SpecPragOrigin name
sig_ctxt = FunSigCtxt name
- skol_info = SigSkol sig_ctxt
spec_ctxt prag = hang (ptext (sLit "In the SPECIALISE pragma")) 2 (ppr prag)
tcSpec _ prag = pprPanic "tcSpec" (ppr prag)
--------------
tcImpPrags :: [LSig Name] -> TcM [LTcSpecPrag]
+-- SPECIALISE pragamas for imported things
tcImpPrags prags
= do { this_mod <- getModule
- ; let is_imp prag
- = case sigName prag of
- Nothing -> False
- Just name -> not (nameIsLocalOrFrom this_mod name)
- (spec_prags, others) = partition isSpecLSig $
- filter is_imp prags
- ; mapM_ misplacedSigErr others
- -- Messy that this misplaced-sig error comes here
- -- but the others come from the renamer
- ; mapAndRecoverM (wrapLocM tcImpSpec) spec_prags }
-
-tcImpSpec :: Sig Name -> TcM TcSpecPrag
-tcImpSpec prag@(SpecSig (L _ name) _ _)
+ ; dflags <- getDOpts
+ ; if (not_specialising dflags) then
+ return []
+ else
+ mapAndRecoverM (wrapLocM tcImpSpec)
+ [L loc (name,prag) | (L loc prag@(SpecSig (L _ name) _ _)) <- prags
+ , not (nameIsLocalOrFrom this_mod name) ] }
+ where
+ -- Ignore SPECIALISE pragmas for imported things
+ -- when we aren't specialising, or when we aren't generating
+ -- code. The latter happens when Haddocking the base library;
+ -- we don't wnat complaints about lack of INLINABLE pragmas
+ not_specialising dflags
+ | not (dopt Opt_Specialise dflags) = True
+ | otherwise = case hscTarget dflags of
+ HscNothing -> True
+ HscInterpreted -> True
+ _other -> False
+
+tcImpSpec :: (Name, Sig Name) -> TcM TcSpecPrag
+tcImpSpec (name, prag)
= do { id <- tcLookupId name
- ; checkTc (isInlinePragma (idInlinePragma id))
- (impSpecErr name)
+ ; unless (isAnyInlinePragma (idInlinePragma id))
+ (addWarnTc (impSpecErr name))
; tcSpec id prag }
-tcImpSpec p = pprPanic "tcImpSpec" (ppr p)
impSpecErr :: Name -> SDoc
impSpecErr name
= hang (ptext (sLit "You cannot SPECIALISE") <+> quotes (ppr name))
- 2 (ptext (sLit "because its definition has no INLINE/INLINABLE pragma"))
+ 2 (vcat [ ptext (sLit "because its definition has no INLINE/INLINABLE pragma")
+ , parens $ sep
+ [ ptext (sLit "or its defining module") <+> quotes (ppr mod)
+ , ptext (sLit "was compiled without -O")]])
+ where
+ mod = nameModule name
+
+--------------
+tcVectDecls :: [LVectDecl Name] -> TcM ([LVectDecl TcId])
+tcVectDecls decls
+ = do { decls' <- mapM (wrapLocM tcVect) decls
+ ; let ids = map lvectDeclName decls'
+ dups = findDupsEq (==) ids
+ ; mapM_ reportVectDups dups
+ ; traceTcConstraints "End of tcVectDecls"
+ ; return decls'
+ }
+ where
+ reportVectDups (first:_second:_more)
+ = addErrAt (getSrcSpan first) $
+ ptext (sLit "Duplicate vectorisation declarations for") <+> ppr first
+ reportVectDups _ = return ()
+
+--------------
+tcVect :: VectDecl Name -> TcM (VectDecl TcId)
+-- We can't typecheck the expression of a vectorisation declaration against the vectorised type
+-- of the original definition as this requires internals of the vectoriser not available during
+-- type checking. Instead, we infer the type of the expression and leave it to the vectoriser
+-- to check the compatibility of the Core types.
+tcVect (HsVect name Nothing)
+ = addErrCtxt (vectCtxt name) $
+ do { id <- wrapLocM tcLookupId name
+ ; return $ HsVect id Nothing
+ }
+tcVect (HsVect name@(L loc _) (Just rhs))
+ = addErrCtxt (vectCtxt name) $
+ do { _id <- wrapLocM tcLookupId name -- need to ensure that the name is already defined
+
+ -- turn the vectorisation declaration into a single non-recursive binding
+ ; let bind = L loc $ mkFunBind name [mkSimpleMatch [] rhs]
+ sigFun = const Nothing
+ pragFun = mkPragFun [] (unitBag bind)
+
+ -- perform type inference (including generalisation)
+ ; (binds, [id']) <- tcPolyInfer TopLevel False sigFun pragFun NonRecursive [bind]
+
+ ; traceTc "tcVect inferred type" $ ppr (varType id')
+ ; traceTc "tcVect bindings" $ ppr binds
+
+ -- add all bindings, including the type variable and dictionary bindings produced by type
+ -- generalisation to the right-hand side of the vectorisation declaration
+ ; let [AbsBinds tvs evs _ evBinds actualBinds] = (map unLoc . bagToList) binds
+ ; let [bind'] = bagToList actualBinds
+ MatchGroup
+ [L _ (Match _ _ (GRHSs [L _ (GRHS _ rhs')] _))]
+ _ = (fun_matches . unLoc) bind'
+ rhsWrapped = mkHsLams tvs evs (mkHsDictLet evBinds rhs')
+
+ -- We return the type-checked 'Id', to propagate the inferred signature
+ -- to the vectoriser - see "Note [Typechecked vectorisation pragmas]" in HsDecls
+ ; return $ HsVect (L loc id') (Just rhsWrapped)
+ }
+tcVect (HsNoVect name)
+ = addErrCtxt (vectCtxt name) $
+ do { id <- wrapLocM tcLookupId name
+ ; return $ HsNoVect id
+ }
+
+vectCtxt :: Located Name -> SDoc
+vectCtxt name = ptext (sLit "When checking the vectorisation declaration for") <+> ppr name
--------------
-- If typechecking the binds fails, then return with each
forall_a_a = mkForAllTy openAlphaTyVar (mkTyVarTy openAlphaTyVar)
\end{code}
+Note [SPECIALISE pragmas]
+~~~~~~~~~~~~~~~~~~~~~~~~~
+There is no point in a SPECIALISE pragma for a non-overloaded function:
+ reverse :: [a] -> [a]
+ {-# SPECIALISE reverse :: [Int] -> [Int] #-}
+
+But SPECIALISE INLINE *can* make sense for GADTS:
+ data Arr e where
+ ArrInt :: !Int -> ByteArray# -> Arr Int
+ ArrPair :: !Int -> Arr e1 -> Arr e2 -> Arr (e1, e2)
+
+ (!:) :: Arr e -> Int -> e
+ {-# SPECIALISE INLINE (!:) :: Arr Int -> Int -> Int #-}
+ {-# SPECIALISE INLINE (!:) :: Arr (a, b) -> Int -> (a, b) #-}
+ (ArrInt _ ba) !: (I# i) = I# (indexIntArray# ba i)
+ (ArrPair _ a1 a2) !: i = (a1 !: i, a2 !: i)
+
+When (!:) is specialised it becomes non-recursive, and can usefully
+be inlined. Scary! So we only warn for SPECIALISE *without* INLINE
+for a non-overloaded function.
%************************************************************************
%* *
-- Type signature (if any), and
-- the monomorphic bound things
-getMonoType :: MonoBindInfo -> TcTauType
-getMonoType (_,_,mono_id) = idType mono_id
-
tcLhs :: TcSigFun -> LetBndrSpec -> HsBind Name -> TcM TcMonoBind
tcLhs sig_fn no_gen (FunBind { fun_id = L nm_loc name, fun_infix = inf, fun_matches = matches })
| Just sig <- sig_fn name
-- where F is a type function and (F a ~ [a])
-- Then unification might succeed with a coercion. But it's much
-- much simpler to require that such signatures have identical contexts
- checkTc (all isIdentityCoI cois)
+ checkTc (all isReflCo cois)
(ptext (sLit "Mutually dependent functions have syntactically distinct contexts"))
}
\end{code}
| Just (scoped_tvs, loc) <- sig_fn name
= do { poly_id <- tcLookupId name -- Cannot fail; the poly ids are put into
-- scope when starting the binding group
- ; (tvs, theta, tau) <- tcInstSigType use_skols name (idType poly_id)
+ ; let poly_ty = idType poly_id
+ ; (tvs, theta, tau) <- if use_skols
+ then tcInstType tcInstSkolTyVars poly_ty
+ else tcInstType tcInstSigTyVars poly_ty
; let sig = TcSigInfo { sig_id = poly_id
, sig_scoped = scoped_tvs
, sig_tvs = tvs, sig_theta = theta, sig_tau = tau
decideGeneralisationPlan
:: DynFlags -> TopLevelFlag -> [Name] -> [LHsBind Name] -> TcSigFun -> GeneralisationPlan
decideGeneralisationPlan dflags top_lvl _bndrs binds sig_fn
+ | bang_pat_binds = NoGen
| mono_pat_binds = NoGen
| Just sig <- one_funbind_with_sig binds = if null (sig_tvs sig) && null (sig_theta sig)
then NoGen -- Optimise common case
| otherwise = InferGen mono_restriction
where
- mono_pat_binds = xopt Opt_MonoPatBinds dflags
+ bang_pat_binds = any (isBangHsBind . unLoc) binds
+ -- Bang patterns must not be polymorphic,
+ -- because we are going to force them
+ -- See Trac #4498
+
+ mono_pat_binds = xopt Opt_MonoPatBinds dflags
&& any (is_pat_bind . unLoc) binds
mono_restriction = xopt Opt_MonomorphismRestriction dflags
; checkTc (isNonRec rec_group)
(strictBindErr "Recursive" unlifted binds)
; checkTc (isSingleton binds)
- (strictBindErr "Multiple" unlifted binds)
+ (strictBindErr "Multiple" unlifted binds)
-- This should be a checkTc, not a warnTc, but as of GHC 6.11
-- the versions of alex and happy available have non-conforming
-- templates, so the GHC build fails if it's an error:
; warnUnlifted <- doptM Opt_WarnLazyUnliftedBindings
- ; warnTc (warnUnlifted && not bang_pat)
+ ; warnTc (warnUnlifted && not bang_pat && lifted_pat)
+ -- No outer bang, but it's a compound pattern
+ -- E.g (I# x#) = blah
+ -- Warn about this, but not about
+ -- x# = 4# +# 1#
+ -- (# a, b #) = ...
(unliftedMustBeBang binds) }
| otherwise
= return ()
where
- unlifted = any is_unlifted poly_ids
- bang_pat = any (isBangHsBind . unLoc) binds
+ unlifted = any is_unlifted poly_ids
+ bang_pat = any (isBangHsBind . unLoc) binds
+ lifted_pat = any (isLiftedPatBind . unLoc) binds
is_unlifted id = case tcSplitForAllTys (idType id) of
(_, rho) -> isUnLiftedType rho
unliftedMustBeBang :: [LHsBind Name] -> SDoc
unliftedMustBeBang binds
- = hang (text "Bindings containing unlifted types should use an outermost bang pattern:")
+ = hang (text "Pattern bindings containing unlifted types should use an outermost bang pattern:")
2 (pprBindList binds)
strictBindErr :: String -> Bool -> [LHsBind Name] -> SDoc
projects / ghc-hetmet.git / blobdiff