mkIfThenElse, mkAltExpr, mkPiType, mkPiTypes,
-- Taking expressions apart
- findDefault, findAlt, isDefaultAlt, mergeAlts,
+ findDefault, findAlt, isDefaultAlt, mergeAlts, trimConArgs,
-- Properties of expressions
exprType, coreAltType,
import FastString
import Maybes
import Util
+import Data.Word
+import Data.Bits
import GHC.Exts -- For `xori`
\end{code}
\begin{code}
exprType :: CoreExpr -> Type
-exprType (Var var) = idType var
-exprType (Lit lit) = literalType lit
-exprType (Let _ body) = exprType body
-exprType (Case _ _ ty alts) = ty
-exprType (Cast e co)
- = let (_, ty) = coercionKind co in ty
-exprType (Note other_note e) = exprType e
-exprType (Lam binder expr) = mkPiType binder (exprType expr)
+exprType (Var var) = idType var
+exprType (Lit lit) = literalType lit
+exprType (Let _ body) = exprType body
+exprType (Case _ _ ty alts) = ty
+exprType (Cast e co) = snd (coercionKind co)
+exprType (Note other_note e) = exprType e
+exprType (Lam binder expr) = mkPiType binder (exprType expr)
exprType e@(App _ _)
= case collectArgs e of
(fun, args) -> applyTypeToArgs e (exprType fun) args
= mkConApp con (map Type inst_tys ++ varsToCoreExprs args)
mkAltExpr (LitAlt lit) [] []
= Lit lit
+mkAltExpr (LitAlt _) _ _ = panic "mkAltExpr LitAlt"
+mkAltExpr DEFAULT _ _ = panic "mkAltExpr DEFAULT"
mkIfThenElse :: CoreExpr -> CoreExpr -> CoreExpr -> CoreExpr
mkIfThenElse guard then_expr else_expr
LT -> a1 : mergeAlts as1 (a2:as2)
EQ -> a1 : mergeAlts as1 as2 -- Discard a2
GT -> a2 : mergeAlts (a1:as1) as2
+
+
+---------------------------------
+trimConArgs :: AltCon -> [CoreArg] -> [CoreArg]
+-- Given case (C a b x y) of
+-- C b x y -> ...
+-- we want to drop the leading type argument of the scrutinee
+-- leaving the arguments to match agains the pattern
+
+trimConArgs DEFAULT args = ASSERT( null args ) []
+trimConArgs (LitAlt lit) args = ASSERT( null args ) []
+trimConArgs (DataAlt dc) args = dropList (dataConUnivTyVars dc) args
\end{code}
For unlifted argument types, we have to be careful:
C (f x :: Int#)
-Suppose (f x) diverges; then C (f x) is not a value. True, but
-this form is illegal (see the invariants in CoreSyn). Args of unboxed
+Suppose (f x) diverges; then C (f x) is not a value. However this can't
+happen: see CoreSyn Note [CoreSyn let/app invariant]. Args of unboxed
type must be ok-for-speculation (or trivial).
\begin{code}
-- There is at least one value argument
app_is_value (Var fun) args
- | isDataConWorkId fun -- Constructor apps are values
- || idArity fun > valArgCount args -- Under-applied function
- = check_args (idType fun) args
-app_is_value (App f a) as = app_is_value f (a:as)
-app_is_value other as = False
-
- -- 'check_args' checks that unlifted-type args
- -- are in fact guaranteed non-divergent
-check_args fun_ty [] = True
-check_args fun_ty (Type _ : args) = case splitForAllTy_maybe fun_ty of
- Just (_, ty) -> check_args ty args
-check_args fun_ty (arg : args)
- | isUnLiftedType arg_ty = exprOkForSpeculation arg
- | otherwise = check_args res_ty args
- where
- (arg_ty, res_ty) = splitFunTy fun_ty
+ = idArity fun > valArgCount args -- Under-applied function
+ || isDataConWorkId fun -- or data constructor
+app_is_value (Note n f) as = app_is_value f as
+app_is_value (Cast f _) as = app_is_value f as
+app_is_value (App f a) as = app_is_value f (a:as)
+app_is_value other as = False
\end{code}
\begin{code}
co_kind = substTy subst (mkPredTy eq_pred)
-- make value vars, instantiating types
- mk_id_var uniq fs ty = mkUserLocal (mkVarOccFS fs) uniq (substTy subst ty) noSrcLoc
+ mk_id_var uniq fs ty = mkUserLocal (mkVarOccFS fs) uniq (substTy subst ty) noSrcSpan
id_bndrs = zipWith3 mk_id_var id_uniqs id_fss arg_tys
exprIsConApp_maybe :: CoreExpr -> Maybe (DataCon, [CoreExpr])
-- We must be careful that \x.x and \y.y map to the same hash code,
-- (at least if we want the above invariant to be true)
-hashExpr e | hash < 0 = 77 -- Just in case we hit -maxInt
- | otherwise = hash
- where
- hash = abs (hash_expr (1,emptyVarEnv) e) -- Negative numbers kill UniqFM
+hashExpr e = fromIntegral (hash_expr (1,emptyVarEnv) e .&. 0x7fffffff)
+ -- UniqFM doesn't like negative Ints
type HashEnv = (Int, VarEnv Int) -- Hash code for bound variables
-hash_expr :: HashEnv -> CoreExpr -> Int
+hash_expr :: HashEnv -> CoreExpr -> Word32
+-- Word32, because we're expecting overflows here, and overflowing
+-- signed types just isn't cool. In C it's even undefined.
hash_expr env (Note _ e) = hash_expr env e
hash_expr env (Cast e co) = hash_expr env e
hash_expr env (Var v) = hashVar env v
-hash_expr env (Lit lit) = hashLiteral lit
+hash_expr env (Lit lit) = fromIntegral (hashLiteral lit)
hash_expr env (App f e) = hash_expr env f * fast_hash_expr env e
hash_expr env (Let (NonRec b r) e) = hash_expr (extend_env env b) e * fast_hash_expr env r
hash_expr env (Let (Rec ((b,r):_)) e) = hash_expr (extend_env env b) e
hash_expr env (Case e _ _ _) = hash_expr env e
hash_expr env (Lam b e) = hash_expr (extend_env env b) e
-hash_expr env (Type t) = fast_hash_type env t
+hash_expr env (Type t) = WARN(True, text "hash_expr: type") 1
+-- Shouldn't happen. Better to use WARN than trace, because trace
+-- prevents the CPR optimisation kicking in for hash_expr.
fast_hash_expr env (Var v) = hashVar env v
fast_hash_expr env (Type t) = fast_hash_type env t
-fast_hash_expr env (Lit lit) = hashLiteral lit
+fast_hash_expr env (Lit lit) = fromIntegral (hashLiteral lit)
fast_hash_expr env (Cast e co) = fast_hash_expr env e
fast_hash_expr env (Note n e) = fast_hash_expr env e
fast_hash_expr env (App f a) = fast_hash_expr env a -- A bit idiosyncratic ('a' not 'f')!
fast_hash_expr env other = 1
-fast_hash_type :: HashEnv -> Type -> Int
+fast_hash_type :: HashEnv -> Type -> Word32
fast_hash_type env ty
- | Just tv <- getTyVar_maybe ty = hashVar env tv
- | Just (tc,_) <- splitTyConApp_maybe ty = hashName (tyConName tc)
- | otherwise = 1
+ | Just tv <- getTyVar_maybe ty = hashVar env tv
+ | Just (tc,tys) <- splitTyConApp_maybe ty = let hash_tc = fromIntegral (hashName (tyConName tc))
+ in foldr (\t n -> fast_hash_type env t + n) hash_tc tys
+ | otherwise = 1
extend_env :: HashEnv -> Var -> (Int, VarEnv Int)
extend_env (n,env) b = (n+1, extendVarEnv env b n)
-hashVar :: HashEnv -> Var -> Int
-hashVar (_,env) v = lookupVarEnv env v `orElse` hashName (idName v)
+hashVar :: HashEnv -> Var -> Word32
+hashVar (_,env) v
+ = fromIntegral (lookupVarEnv env v `orElse` hashName (idName v))
\end{code}
%************************************************************************
projects / ghc-hetmet.git / blobdiff