import Id
import Var ( Var, TyVar, mkCoVar, mkExportedLocalVar )
import IdInfo
-import NewDemand
+import Demand
import CoreSyn
import Unique
import PrelNames
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)
-- 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
- `setSpecInfo` mkSpecInfo [rule]
- `setInlinePragInfo` neverInlinePragma
+ base_info = noCafIdInfo
+ `setArityInfo` 1
+ `setStrictnessInfo` Just strict_sig
`setUnfoldingInfo` (if no_unf then noUnfolding
- else mkImplicitUnfolding rhs)
- -- Experimental: NOINLINE, so that their rule matches
-
- -- We no longer use 'must-inline' on record selectors. They'll
- -- inline like crazy if they scrutinise a constructor
+ 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 | new_tycon = base_info
+ -- For newtype dictionaries, just inline the class op
+ -- See Note [Single-method classes] in TcInstDcls
+ | otherwise = base_info
+ `setSpecInfo` mkSpecInfo [rule]
+ `setInlinePragInfo` neverInlinePragma
+ -- Otherwise 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
-- 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
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 -> [CoreExpr] -> Maybe CoreExpr
-- Oh, very clever
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
[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 :: [CoreExpr] -> Maybe CoreExpr -- Note [RULES for seq]
+match_seq_of_cast :: [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])
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.
-We also have the following builtin rule:
+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.
+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]
~~~~~~~~~~~~~~~~~~~
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
projects / ghc-hetmet.git / blobdiff