- primitive operations
\begin{code}
-{-# OPTIONS -fno-warn-missing-signatures #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
--- <http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings>
--- for details
-
module MkId (
mkDictFunId, mkDefaultMethodId,
mkDictSelId,
import Id
import Var ( Var, TyVar, mkCoVar, mkExportedLocalVar )
import IdInfo
-import NewDemand
+import Demand
import CoreSyn
import Unique
import PrelNames
data instance T [a] where
T1 :: forall b. b -> T [Maybe b]
-Hence
- Co7T a :: T [a] ~ :R7T a
-Now we want
+Hence we translate to
-- Wrapper
$WT1 :: forall b. b -> T [Maybe b]
-- Worker
T1 :: forall c b. (c ~ Maybe b) => b -> :R7T c
+ -- Coercion from family type to representation type
+ Co7T a :: T [a] ~ :R7T a
+
\begin{code}
mkDataConIds :: Name -> Name -> DataCon -> DataConIds
mkDataConIds wrap_name wkr_name data_con
| isNewTyCon tycon -- Newtype, only has a worker
= DCIds Nothing nt_work_id
- | any isMarkedStrict all_strict_marks -- Algebraic, needs wrapper
- || not (null eq_spec) -- NB: LoadIface.ifaceDeclSubBndrs
- || isFamInstTyCon tycon -- depends on this test
+ | any isBanged all_strict_marks -- Algebraic, needs wrapper
+ || not (null eq_spec) -- NB: LoadIface.ifaceDeclSubBndrs
+ || isFamInstTyCon tycon -- depends on this test
= DCIds (Just alg_wrap_id) wrk_id
| otherwise -- Algebraic, no wrapper
wkr_arity = dataConRepArity data_con
wkr_info = noCafIdInfo
`setArityInfo` wkr_arity
- `setAllStrictnessInfo` Just wkr_sig
+ `setStrictnessInfo` Just wkr_sig
`setUnfoldingInfo` evaldUnfolding -- Record that it's evaluated,
-- even if arity = 0
-- It's important to specify the arity, so that partial
-- applications are treated as values
`setUnfoldingInfo` wrap_unf
- `setAllStrictnessInfo` Just wrap_sig
+ `setStrictnessInfo` Just wrap_sig
all_strict_marks = dataConExStricts data_con ++ dataConStrictMarks data_con
wrap_sig = mkStrictSig (mkTopDmdType arg_dmds cpr_info)
arg_dmds = map mk_dmd all_strict_marks
- mk_dmd str | isMarkedStrict str = evalDmd
- | otherwise = lazyDmd
+ mk_dmd str | isBanged str = evalDmd
+ | otherwise = lazyDmd
-- The Cpr info can be important inside INLINE rhss, where the
-- wrapper constructor isn't inlined.
-- And the argument strictness can be important too; we
-- ...(let w = C x in ...(w p q)...)...
-- we want to see that w is strict in its two arguments
- wrap_unf = mkImplicitUnfolding $ Note InlineMe $
- mkLams wrap_tvs $
+ wrap_unf = mkInlineRule wrap_rhs (Just (length dict_args + length id_args))
+ wrap_rhs = mkLams wrap_tvs $
mkLams eq_args $
mkLams dict_args $ mkLams id_args $
foldr mk_case con_app
in (y:ys,j)
mk_case
- :: (Id, StrictnessMark) -- Arg, strictness
+ :: (Id, HsBang) -- Arg, strictness
-> (Int -> [Id] -> CoreExpr) -- Body
-> Int -- Next rep arg id
-> [Id] -- Rep args so far, reversed
-> CoreExpr
mk_case (arg,strict) body i rep_args
= case strict of
- NotMarkedStrict -> body i (arg:rep_args)
- MarkedStrict
- | isUnLiftedType (idType arg) -> body i (arg:rep_args)
- | otherwise ->
- Case (Var arg) arg res_ty [(DEFAULT,[], body i (arg:rep_args))]
-
- MarkedUnboxed
- -> unboxProduct i (Var arg) (idType arg) the_body
+ HsNoBang -> body i (arg:rep_args)
+ HsUnpack -> unboxProduct i (Var arg) (idType arg) the_body
where
the_body i con_args = body i (reverse con_args ++ rep_args)
+ _other -- HsUnpackFailed and HsStrict
+ | isUnLiftedType (idType arg) -> body i (arg:rep_args)
+ | otherwise -> Case (Var arg) arg res_ty
+ [(DEFAULT,[], body i (arg:rep_args))]
mAX_CPR_SIZE :: Arity
mAX_CPR_SIZE = 10
-- by the caller. So doing CPR for them may in fact make
-- things worse.
+mkLocals :: Int -> [Type] -> ([Id], Int)
mkLocals i tys = (zipWith mkTemplateLocal [i..i+n-1] tys, i+n)
where
n = length tys
-- But it's type must expose the representation of the dictionary
-- to get (say) C a -> (a -> a)
- info = noCafIdInfo
- `setArityInfo` 1
- `setAllStrictnessInfo` Just strict_sig
- `setUnfoldingInfo` (if no_unf then noUnfolding
- else mkImplicitUnfolding rhs)
-
- -- We no longer use 'must-inline' on record selectors. They'll
- -- inline like crazy if they scrutinise a constructor
+ base_info = noCafIdInfo
+ `setArityInfo` 1
+ `setStrictnessInfo` Just strict_sig
+ `setUnfoldingInfo` (if no_unf then noUnfolding
+ else mkImplicitUnfolding rhs)
+ -- In module where class op is defined, we must add
+ -- the unfolding, even though it'll never be inlined
+ -- becuase we use that to generate a top-level binding
+ -- for the ClassOp
+
+ info = base_info `setSpecInfo` mkSpecInfo [rule]
+ `setInlinePragInfo` neverInlinePragma
+ -- Add a magic BuiltinRule, and never inline it
+ -- so that the rule is always available to fire.
+ -- See Note [ClassOp/DFun selection] in TcInstDcls
+
+ n_ty_args = length tyvars
+
+ -- This is the built-in rule that goes
+ -- op (dfT d1 d2) ---> opT d1 d2
+ rule = BuiltinRule { ru_name = fsLit "Class op " `appendFS`
+ occNameFS (getOccName name)
+ , ru_fn = name
+ , ru_nargs = n_ty_args + 1
+ , ru_try = dictSelRule index n_ty_args }
-- The strictness signature is of the form U(AAAVAAAA) -> T
-- where the V depends on which item we are selecting
-- It's worth giving one, so that absence info etc is generated
-- even if the selector isn't inlined
strict_sig = mkStrictSig (mkTopDmdType [arg_dmd] TopRes)
- arg_dmd | isNewTyCon tycon = evalDmd
- | otherwise = Eval (Prod [ if the_arg_id == id then evalDmd else Abs
- | id <- arg_ids ])
+ arg_dmd | new_tycon = evalDmd
+ | otherwise = Eval (Prod [ if the_arg_id == id then evalDmd else Abs
+ | id <- arg_ids ])
tycon = classTyCon clas
+ new_tycon = isNewTyCon tycon
[data_con] = tyConDataCons tycon
tyvars = dataConUnivTyVars data_con
arg_tys = {- ASSERT( isVanillaDataCon data_con ) -} dataConRepArgTys data_con
eq_theta = dataConEqTheta data_con
- the_arg_id = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` arg_ids) name
+ index = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` [0..]) name
+ the_arg_id = arg_ids !! index
pred = mkClassPred clas (mkTyVarTys tyvars)
- dict_id = mkTemplateLocal 1 $ mkPredTy pred
- (eq_ids,n) = mkCoVarLocals 2 $ mkPredTys eq_theta
+ dict_id = mkTemplateLocal 1 $ mkPredTy pred
+ (eq_ids,n) = mkCoVarLocals 2 $ mkPredTys eq_theta
arg_ids = mkTemplateLocalsNum n arg_tys
mkCoVarLocals i [] = ([],i)
in (y:ys,j)
rhs = mkLams tyvars (Lam dict_id rhs_body)
- rhs_body | isNewTyCon tycon = unwrapNewTypeBody tycon (map mkTyVarTy tyvars) (Var dict_id)
- | otherwise = Case (Var dict_id) dict_id (idType the_arg_id)
- [(DataAlt data_con, eq_ids ++ arg_ids, Var the_arg_id)]
+ rhs_body | new_tycon = unwrapNewTypeBody tycon (map mkTyVarTy tyvars) (Var dict_id)
+ | otherwise = Case (Var dict_id) dict_id (idType the_arg_id)
+ [(DataAlt data_con, eq_ids ++ arg_ids, Var the_arg_id)]
+
+dictSelRule :: Int -> Arity -> IdUnfoldingFun -> [CoreExpr] -> Maybe CoreExpr
+-- Oh, very clever
+-- op_i t1..tk (df s1..sn d1..dm) = op_i_helper s1..sn d1..dm
+-- op_i t1..tk (D t1..tk op1 ... opm) = opi
+--
+-- NB: the data constructor has the same number of type args as the class op
+
+dictSelRule index n_ty_args id_unf args
+ | (dict_arg : _) <- drop n_ty_args args
+ , Just (_, _, val_args) <- exprIsConApp_maybe id_unf dict_arg
+ = Just (val_args !! index)
+ | otherwise
+ = Nothing
\end{code}
info = noCafIdInfo
`setSpecInfo` mkSpecInfo (primOpRules prim_op name)
`setArityInfo` arity
- `setAllStrictnessInfo` Just strict_sig
+ `setStrictnessInfo` Just strict_sig
-- For each ccall we manufacture a separate CCallOpId, giving it
-- a fresh unique, a type that is correct for this particular ccall,
info = noCafIdInfo
`setArityInfo` arity
- `setAllStrictnessInfo` Just strict_sig
+ `setStrictnessInfo` Just strict_sig
(_, tau) = tcSplitForAllTys ty
(arg_tys, _) = tcSplitFunTys tau
mkBreakPointOpId uniq mod ix = mkTickBox' uniq mod ix ty
where ty = mkSigmaTy [openAlphaTyVar] [] openAlphaTy
+mkTickBox' :: Unique -> Module -> TickBoxId -> Type -> Id
mkTickBox' uniq mod ix ty = mkGlobalId (TickBoxOpId tickbox) name ty info
where
tickbox = TickBox mod ix
that they aren't discarded by the occurrence analyser.
\begin{code}
-mkDefaultMethodId dm_name ty = mkExportedLocalId dm_name ty
+mkDefaultMethodId :: Id -- Selector Id
+ -> Name -- Default method name
+ -> Id -- Default method Id
+mkDefaultMethodId sel_id dm_name = mkExportedLocalId dm_name (idType sel_id)
mkDictFunId :: Name -- Name to use for the dict fun;
-> [TyVar]
-> Id
mkDictFunId dfun_name inst_tyvars dfun_theta clas inst_tys
- = mkExportedLocalVar DFunId dfun_name dfun_ty vanillaIdInfo
+ = mkExportedLocalVar (DFunId is_nt) dfun_name dfun_ty vanillaIdInfo
where
+ is_nt = isNewTyCon (classTyCon clas)
dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys)
\end{code}
another gun with which to shoot yourself in the foot.
\begin{code}
+mkWiredInIdName :: Module -> FastString -> Unique -> Id -> Name
mkWiredInIdName mod fs uniq id
= mkWiredInName mod (mkOccNameFS varName fs) uniq (AnId id) UserSyntax
+unsafeCoerceName, nullAddrName, seqName, realWorldName :: Name
+lazyIdName, errorName, recSelErrorName, runtimeErrorName :: Name
+irrefutPatErrorName, recConErrorName, patErrorName :: Name
+nonExhaustiveGuardsErrorName, noMethodBindingErrorName :: Name
unsafeCoerceName = mkWiredInIdName gHC_PRIM (fsLit "unsafeCoerce#") unsafeCoerceIdKey unsafeCoerceId
nullAddrName = mkWiredInIdName gHC_PRIM (fsLit "nullAddr#") nullAddrIdKey nullAddrId
seqName = mkWiredInIdName gHC_PRIM (fsLit "seq") seqIdKey seqId
\begin{code}
------------------------------------------------
-- unsafeCoerce# :: forall a b. a -> b
+unsafeCoerceId :: Id
unsafeCoerceId
= pcMiscPrelId unsafeCoerceName ty info
where
info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
- ty = mkForAllTys [openAlphaTyVar,openBetaTyVar]
- (mkFunTy openAlphaTy openBetaTy)
- [x] = mkTemplateLocals [openAlphaTy]
- rhs = mkLams [openAlphaTyVar,openBetaTyVar,x] $
- Cast (Var x) (mkUnsafeCoercion openAlphaTy openBetaTy)
+ ty = mkForAllTys [argAlphaTyVar,openBetaTyVar]
+ (mkFunTy argAlphaTy openBetaTy)
+ [x] = mkTemplateLocals [argAlphaTy]
+ rhs = mkLams [argAlphaTyVar,openBetaTyVar,x] $
+ Cast (Var x) (mkUnsafeCoercion argAlphaTy openBetaTy)
------------------------------------------------
nullAddrId :: Id
seqId = pcMiscPrelId seqName ty info
where
info = noCafIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
+ `setSpecInfo` mkSpecInfo [seq_cast_rule]
ty = mkForAllTys [alphaTyVar,openBetaTyVar]
[x,y] = mkTemplateLocals [alphaTy, openBetaTy]
rhs = mkLams [alphaTyVar,openBetaTyVar,x,y] (Case (Var x) x openBetaTy [(DEFAULT, [], Var y)])
+ -- See Note [Built-in RULES for seq]
+ seq_cast_rule = BuiltinRule { ru_name = fsLit "seq of cast"
+ , ru_fn = seqName
+ , ru_nargs = 4
+ , ru_try = match_seq_of_cast
+ }
+
+match_seq_of_cast :: IdUnfoldingFun -> [CoreExpr] -> Maybe CoreExpr
+ -- See Note [Built-in RULES for seq]
+match_seq_of_cast _ [Type _, Type res_ty, Cast scrut co, expr]
+ = Just (Var seqId `mkApps` [Type (fst (coercionKind co)), Type res_ty,
+ scrut, expr])
+match_seq_of_cast _ _ = Nothing
+
------------------------------------------------
lazyId :: Id -- See Note [lazyId magic]
lazyId = pcMiscPrelId lazyIdName ty info
Note [seqId magic]
~~~~~~~~~~~~~~~~~~
-'seq' is special in several ways.
+'GHC.Prim.seq' is special in several ways.
a) Its second arg can have an unboxed type
x `seq` (v +# w)
c) It has quite a bit of desugaring magic.
See DsUtils.lhs Note [Desugaring seq (1)] and (2) and (3)
-d) There is some special rule handing: Note [RULES for seq]
+d) There is some special rule handing: Note [User-defined RULES for seq]
-Note [Rules for seq]
-~~~~~~~~~~~~~~~~~~~~
+Note [User-defined RULES for seq]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Roman found situations where he had
case (f n) of _ -> e
where he knew that f (which was strict in n) would terminate if n did.
done in Note [seqId magic] item (c) is *not* done on the LHS of a rule.
Or rather, we arrange to un-do it, in DsBinds.decomposeRuleLhs.
+Note [Built-in RULES for seq]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+We also have the following built-in rule for seq
+
+ seq (x `cast` co) y = seq x y
+
+This eliminates unnecessary casts and also allows other seq rules to
+match more often. Notably,
+
+ seq (f x `cast` co) y --> seq (f x) y
+
+and now a user-defined rule for seq (see Note [User-defined RULES for seq])
+may fire.
+
Note [lazyId magic]
~~~~~~~~~~~~~~~~~~~
This comes up in strictness analysis
\begin{code}
+realWorldPrimId :: Id
realWorldPrimId -- :: State# RealWorld
= pcMiscPrelId realWorldName realWorldStatePrimTy
(noCafIdInfo `setUnfoldingInfo` evaldUnfolding)
mkImpossibleExpr res_ty
= mkRuntimeErrorApp rUNTIME_ERROR_ID res_ty "Impossible case alternative"
+rEC_SEL_ERROR_ID, rUNTIME_ERROR_ID, iRREFUT_PAT_ERROR_ID, rEC_CON_ERROR_ID :: Id
+pAT_ERROR_ID, nO_METHOD_BINDING_ERROR_ID, nON_EXHAUSTIVE_GUARDS_ERROR_ID :: Id
rEC_SEL_ERROR_ID = mkRuntimeErrorId recSelErrorName
rUNTIME_ERROR_ID = mkRuntimeErrorId runtimeErrorName
iRREFUT_PAT_ERROR_ID = mkRuntimeErrorId irrefutPatErrorName
\end{code}
\begin{code}
+eRROR_ID :: Id
eRROR_ID = pc_bottoming_Id errorName errorTy
errorTy :: Type
pc_bottoming_Id name ty
= pcMiscPrelId name ty bottoming_info
where
- bottoming_info = vanillaIdInfo `setAllStrictnessInfo` Just strict_sig
+ bottoming_info = vanillaIdInfo `setStrictnessInfo` Just strict_sig
`setArityInfo` 1
-- Make arity and strictness agree
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