dsHsBind auto_scc rest (AbsBinds [] [] exports binds)
= do { core_prs <- ds_lhs_binds NoSccs binds
; let env = mkABEnv exports
- ar_env = mkArityEnv binds
do_one (lcl_id, rhs)
| Just (_, gbl_id, _, spec_prags) <- lookupVarEnv env lcl_id
- = WARN( not (null spec_prags), ppr gbl_id $$ ppr spec_prags ) -- Not overloaded
- makeCorePair gbl_id (lookupArity ar_env lcl_id)
- (addAutoScc auto_scc gbl_id rhs)
+ = WARN( hasSpecPrags spec_prags, pprTcSpecPrags gbl_id spec_prags ) -- Not overloaded
+ makeCorePair gbl_id False 0 (addAutoScc auto_scc gbl_id rhs)
| otherwise = (lcl_id, rhs)
where
fvs = exprSomeFreeVars (`elemVarSet` bndrs) rhs
- ar_env = mkArityEnv binds
env = mkABEnv exports
-
mk_lg_bind lcl_id gbl_id tyvars
= NonRec (setIdInfo lcl_id vanillaIdInfo)
-- Nuke the IdInfo so that no old unfoldings
do_one lg_binds (lcl_id, rhs)
| Just (id_tvs, gbl_id, _, spec_prags) <- lookupVarEnv env lcl_id
- = WARN( not (null spec_prags), ppr gbl_id $$ ppr spec_prags ) -- Not overloaded
+ = WARN( hasSpecPrags spec_prags, pprTcSpecPrags gbl_id spec_prags ) -- Not overloaded
(let rhs' = addAutoScc auto_scc gbl_id $
mkLams id_tvs $
mkLets [ NonRec tv (Type (lookupVarEnv_NF arby_env tv))
| tv <- tyvars, not (tv `elem` id_tvs)] $
add_lets lg_binds rhs
in return (mk_lg_bind lcl_id gbl_id id_tvs,
- makeCorePair gbl_id (lookupArity ar_env lcl_id) rhs'))
+ makeCorePair gbl_id False 0 rhs'))
| otherwise
= do { non_exp_gbl_id <- newUniqueId lcl_id (mkForAllTys tyvars (idType lcl_id))
; return (mk_lg_bind lcl_id non_exp_gbl_id tyvars,
= ASSERT( all (`elem` tyvars) all_tyvars )
do { core_prs <- ds_lhs_binds NoSccs binds
- ; let -- Always treat the binds as recursive, because the typechecker
- -- makes rather mixed-up dictionary bindings
+ ; let -- Always treat the binds as recursive, because the
+ -- typechecker makes rather mixed-up dictionary bindings
core_bind = Rec core_prs
- inl_arity = lookupArity (mkArityEnv binds) local
; (spec_binds, rules) <- dsSpecs all_tyvars dicts tyvars global
- local inl_arity core_bind prags
+ local core_bind prags
; let global' = addIdSpecialisations global rules
rhs = addAutoScc auto_scc global $
mkLams tyvars $ mkLams dicts $ Let core_bind (Var local)
- main_bind = makeCorePair global' (inl_arity + dictArity dicts) rhs
+ main_bind = makeCorePair global' (isDefaultMethod prags)
+ (dictArity dicts) rhs
; return (main_bind : spec_binds ++ rest) }
dsHsBind auto_scc rest (AbsBinds all_tyvars dicts exports binds)
= do { core_prs <- ds_lhs_binds NoSccs binds
; let env = mkABEnv exports
- ar_env = mkArityEnv binds
do_one (lcl_id,rhs) | Just (_, gbl_id, _, _prags) <- lookupVarEnv env lcl_id
= (lcl_id, addAutoScc auto_scc gbl_id rhs)
| otherwise = (lcl_id,rhs)
; locals' <- newSysLocalsDs (map substitute local_tys)
; tup_id <- newSysLocalDs (substitute tup_ty)
; (spec_binds, rules) <- dsSpecs all_tyvars dicts tyvars global local
- (lookupArity ar_env local) core_bind
+ core_bind
spec_prags
; let global' = addIdSpecialisations global rules
rhs = mkLams tyvars $ mkLams dicts $
(concat export_binds_s ++ rest)) }
------------------------
-makeCorePair :: Id-> Arity -> CoreExpr -> (Id, CoreExpr)
-makeCorePair gbl_id arity rhs
- | isInlinePragma (idInlinePragma gbl_id)
+makeCorePair :: Id -> Bool -> Arity -> CoreExpr -> (Id, CoreExpr)
+makeCorePair gbl_id is_default_method dict_arity rhs
+ | is_default_method -- Default methods are *always* inlined
+ = (gbl_id `setIdUnfolding` mkCompulsoryUnfolding rhs, rhs)
+
+ | not (isInlinePragma inline_prag)
+ = (gbl_id, rhs)
+
+ | Just arity <- inlinePragmaSat inline_prag
-- Add an Unfolding for an INLINE (but not for NOINLINE)
-- And eta-expand the RHS; see Note [Eta-expanding INLINE things]
- = (gbl_id `setIdUnfolding` mkInlineRule InlSat rhs arity,
+ = (gbl_id `setIdUnfolding` mkInlineRule rhs (Just (dict_arity + arity)),
+ -- NB: The arity in the InlineRule takes account of the dictionaries
etaExpand arity rhs)
+
| otherwise
- = (gbl_id, rhs)
+ = (gbl_id `setIdUnfolding` mkInlineRule rhs Nothing, rhs)
+ where
+ inline_prag = idInlinePragma gbl_id
+
+dictArity :: [Var] -> Arity
+-- Don't count coercion variables in arity
+dictArity dicts = count isId dicts
+
------------------------
-type AbsBindEnv = VarEnv ([TyVar], Id, Id, [LSpecPrag])
+type AbsBindEnv = VarEnv ([TyVar], Id, Id, TcSpecPrags)
-- Maps the "lcl_id" for an AbsBind to
-- its "gbl_id" and associated pragmas, if any
-mkABEnv :: [([TyVar], Id, Id, [LSpecPrag])] -> AbsBindEnv
+mkABEnv :: [([TyVar], Id, Id, TcSpecPrags)] -> AbsBindEnv
-- Takes the exports of a AbsBinds, and returns a mapping
-- lcl_id -> (tyvars, gbl_id, lcl_id, prags)
mkABEnv exports = mkVarEnv [ (lcl_id, export) | export@(_, _, lcl_id, _) <- exports]
-
-mkArityEnv :: LHsBinds Id -> IdEnv Arity
- -- Maps a local to the arity of its definition
-mkArityEnv binds = foldrBag (plusVarEnv . lhsBindArity) emptyVarEnv binds
-
-lhsBindArity :: LHsBind Id -> IdEnv Arity
-lhsBindArity (L _ (FunBind { fun_id = id, fun_matches = ms }))
- = unitVarEnv (unLoc id) (matchGroupArity ms)
-lhsBindArity (L _ (AbsBinds { abs_exports = exports
- , abs_dicts = dicts
- , abs_binds = binds }))
- = mkVarEnv [ (gbl, lookupArity ar_env lcl + n_val_dicts)
- | (_, gbl, lcl, _) <- exports]
- where -- See Note [Nested arities]
- ar_env = mkArityEnv binds
- n_val_dicts = dictArity dicts
-
-lhsBindArity _ = emptyVarEnv -- PatBind/VarBind
-
-dictArity :: [Var] -> Arity
--- Don't count coercion variables in arity
-dictArity dicts = count isId dicts
-
-lookupArity :: IdEnv Arity -> Id -> Arity
-lookupArity ar_env id = lookupVarEnv ar_env id `orElse` 0
\end{code}
Note [Eta-expanding INLINE things]
It might be better to have just one level of AbsBinds, but that requires more
thought!
+Note [Implementing SPECIALISE pragmas]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Example:
+ f :: (Eq a, Ix b) => a -> b -> Bool
+ {-# SPECIALISE f :: (Ix p, Ix q) => Int -> (p,q) -> Bool #-}
+
+From this the typechecker generates
+
+ AbsBinds [ab] [d1,d2] [([ab], f, f_mono, prags)] binds
+
+ SpecPrag (wrap_fn :: forall a b. (Eq a, Ix b) => XXX
+ -> forall p q. (Ix p, Ix q) => XXX[ Int/a, (p,q)/b ])
+
+Note that wrap_fn can transform *any* function with the right type prefix
+ forall ab. (Eq a, Ix b) => <blah>
+regardless of <blah>. It's sort of polymorphic in <blah>. This is
+useful: we use the same wrapper to transform each of the class ops, as
+well as the dict.
+
+From these we generate:
+
+ Rule: forall p, q, (dp:Ix p), (dq:Ix q).
+ f Int (p,q) dInt ($dfInPair dp dq) = f_spec p q dp dq
+
+ Spec bind: f_spec = wrap_fn (/\ab \d1 d2. Let binds in f_mono)
+
+Note that
+
+ * The LHS of the rule may mention dictionary *expressions* (eg
+ $dfIxPair dp dq), and that is essential because the dp, dq are
+ needed on the RHS.
+
+ * The RHS of f_spec has a *copy* of 'binds', so that it can fully
+ specialise it.
\begin{code}
------------------------
dsSpecs :: [TyVar] -> [DictId] -> [TyVar]
- -> Id -> Id -> Arity -- Global, local, arity of local
- -> CoreBind -> [LSpecPrag]
+ -> Id -> Id -- Global, local
+ -> CoreBind -> TcSpecPrags
-> DsM ( [(Id,CoreExpr)] -- Binding for specialised Ids
, [CoreRule] ) -- Rules for the Global Ids
--- Example:
--- f :: (Eq a, Ix b) => a -> b -> b
--- {-# SPECIALISE f :: Ix b => Int -> b -> b #-}
---
--- AbsBinds [ab] [d1,d2] [([ab], f, f_mono, prags)] binds
---
--- SpecPrag (/\b.\(d:Ix b). f Int b dInt d)
--- (forall b. Ix b => Int -> b -> b)
---
--- Rule: forall b,(d:Ix b). f Int b dInt d = f_spec b d
---
--- Spec bind: f_spec = Let f = /\ab \(d1:Eq a)(d2:Ix b). let binds in f_mono
--- /\b.\(d:Ix b). in f Int b dInt d
--- The idea is that f occurs just once, so it'll be
--- inlined and specialised
---
--- Given SpecPrag (/\as.\ds. f es) t, we have
--- the defn f_spec as ds = let-nonrec f = /\fas\fds. let f_mono = <f-rhs> in f_mono
--- in f es
--- and the RULE forall as, ds. f es = f_spec as ds
---
--- It is *possible* that 'es' does not mention all of the dictionaries 'ds'
--- (a bit silly, because then the
-
-dsSpecs all_tvs dicts tvs poly_id mono_id inl_arity mono_bind prags
- = do { pairs <- mapMaybeM spec_one prags
- ; let (spec_binds_s, rules) = unzip pairs
- ; return (concat spec_binds_s, rules) }
+-- See Note [Implementing SPECIALISE pragmas]
+dsSpecs all_tvs dicts tvs poly_id mono_id mono_bind prags
+ = case prags of
+ IsDefaultMethod -> return ([], [])
+ SpecPrags sps -> do { pairs <- mapMaybeM spec_one sps
+ ; let (spec_binds_s, rules) = unzip pairs
+ ; return (concat spec_binds_s, rules) }
where
- spec_one :: LSpecPrag -> DsM (Maybe ([(Id,CoreExpr)], CoreRule))
+ spec_one :: Located TcSpecPrag -> DsM (Maybe ([(Id,CoreExpr)], CoreRule))
spec_one (L loc (SpecPrag spec_co spec_inl))
= putSrcSpanDs loc $
do { let poly_name = idName poly_id
bs | not (null bs) -> do { warnDs (dead_msg bs); return Nothing }
| otherwise -> do
- { (spec_unf, unf_pairs) <- specUnfolding wrap_fn (idUnfolding poly_id)
+ { (spec_unf, unf_pairs) <- specUnfolding wrap_fn (realIdUnfolding poly_id)
; let f_body = fix_up (Let mono_bind (Var mono_id))
spec_ty = exprType ds_spec_expr
-- Get the INLINE pragma from SPECIALISE declaration, or,
-- failing that, from the original Id
- spec_id_arity = inl_arity + count isDictId bndrs
-
extra_dict_bndrs = [ localiseId d -- See Note [Constant rule dicts]
- | d <- varSetElems (exprFreeVars ds_spec_expr)
- , isDictId d]
+ | d <- varSetElems (exprFreeVars ds_spec_expr)
+ , isDictId d]
-- Note [Const rule dicts]
rule = mkLocalRule (mkFastString ("SPEC " ++ showSDoc (ppr poly_name)))
(mkVarApps (Var spec_id) bndrs)
spec_rhs = wrap_fn (mkLams (tvs ++ dicts) f_body)
- spec_pair = makeCorePair spec_id spec_id_arity spec_rhs
+ spec_pair = makeCorePair spec_id False (dictArity bndrs) spec_rhs
; return (Just (spec_pair : unf_pairs, rule))
} } } }
projects / ghc-hetmet.git / blobdiff