A ``lint'' pass to check for Core correctness
\begin{code}
+{-# OPTIONS_GHC -w #-}
+-- 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/WorkingConventions#Warnings
+-- for details
+
module CoreLint (
lintCoreBindings,
lintUnfolding,
#include "HsVersions.h"
+import NewDemand
import CoreSyn
import CoreFVs
import CoreUtils
import VarEnv
import VarSet
import Name
+import Id
import PprCore
import ErrUtils
import SrcLoc
lint_binds binds = addInScopeVars (bindersOfBinds binds) $
mapM lint_bind binds
- lint_bind (Rec prs) = mapM_ (lintSingleBinding Recursive) prs
- lint_bind (NonRec bndr rhs) = lintSingleBinding NonRecursive (bndr,rhs)
+ lint_bind (Rec prs) = mapM_ (lintSingleBinding TopLevel Recursive) prs
+ lint_bind (NonRec bndr rhs) = lintSingleBinding TopLevel NonRecursive (bndr,rhs)
display bad_news
= vcat [ text ("*** Core Lint Errors: in result of " ++ whoDunnit ++ " ***"),
Check a core binding, returning the list of variables bound.
\begin{code}
-lintSingleBinding rec_flag (binder,rhs)
+lintSingleBinding top_lvl_flag rec_flag (binder,rhs)
= addLoc (RhsOf binder) $
-- Check the rhs
do { ty <- lintCoreExpr rhs
; checkL (not (isUnLiftedType binder_ty)
|| (isNonRec rec_flag && exprOkForSpeculation rhs))
(mkRhsPrimMsg binder rhs)
+ -- Check that if the binder is top-level or recursive, it's not demanded
+ ; checkL (not (isStrictId binder)
+ || (isNonRec rec_flag && not (isTopLevel top_lvl_flag)))
+ (mkStrictMsg binder)
-- Check whether binder's specialisations contain any out-of-scope variables
- ; mapM_ (checkBndrIdInScope binder) bndr_vars }
+ ; mapM_ (checkBndrIdInScope binder) bndr_vars
+
+ -- Check whether arity and demand type are consistent (only if demand analysis
+ -- already happened)
+ ; checkL (case maybeDmdTy of
+ Just (StrictSig dmd_ty) -> idArity binder >= dmdTypeDepth dmd_ty || exprIsTrivial rhs
+ Nothing -> True)
+ (mkArityMsg binder) }
-- We should check the unfolding, if any, but this is tricky because
- -- the unfolding is a SimplifiableCoreExpr. Give up for now.
- where
- binder_ty = idType binder
- bndr_vars = varSetElems (idFreeVars binder)
+ -- the unfolding is a SimplifiableCoreExpr. Give up for now.
+ where
+ binder_ty = idType binder
+ maybeDmdTy = idNewStrictness_maybe binder
+ bndr_vars = varSetElems (idFreeVars binder)
lintBinder var | isId var = lintIdBndr var $ \_ -> (return ())
| otherwise = return ()
\end{code}
= lintCoreExpr expr
lintCoreExpr (Let (NonRec bndr rhs) body)
- = do { lintSingleBinding NonRecursive (bndr,rhs)
+ = do { lintSingleBinding NotTopLevel NonRecursive (bndr,rhs)
; addLoc (BodyOfLetRec [bndr])
(lintAndScopeId bndr $ \_ -> (lintCoreExpr body)) }
lintCoreExpr (Let (Rec pairs) body)
= lintAndScopeIds bndrs $ \_ ->
- do { mapM (lintSingleBinding Recursive) pairs
+ do { mapM (lintSingleBinding NotTopLevel Recursive) pairs
; addLoc (BodyOfLetRec bndrs) (lintCoreExpr body) }
where
bndrs = map fst pairs
subtype of the required type, as one would expect.
\begin{code}
-lintCoreArgs :: Type -> [CoreArg] -> LintM Type
-lintCoreArg :: Type -> CoreArg -> LintM Type
+lintCoreArgs :: OutType -> [CoreArg] -> LintM OutType
+lintCoreArg :: OutType -> CoreArg -> LintM OutType
-- First argument has already had substitution applied to it
\end{code}
\begin{code}
-- Both args have had substitution applied
+lintTyApp :: OutType -> OutType -> LintM OutType
lintTyApp ty arg_ty
= case splitForAllTy_maybe ty of
Nothing -> addErrL (mkTyAppMsg ty arg_ty)
= addLoc (CaseAlt alt) $ do
{ -- First instantiate the universally quantified
-- type variables of the data constructor
- con_payload_ty <- lintCoreArgs (dataConRepType con) (map Type tycon_arg_tys)
+ -- We've already check
+ checkL (tycon == dataConTyCon con) (mkBadConMsg tycon con)
+ ; let con_payload_ty = applyTys (dataConRepType con) tycon_arg_tys
-- And now bring the new binders into scope
; lintBinders args $ \ args -> do
lintAndScopeId :: Var -> (Var -> LintM a) -> LintM a
lintAndScopeId id linterF
= do { ty <- lintTy (idType id)
- ; let id' = setIdType id ty
+ ; let id' = Var.setIdType id ty
; addInScopeVars [id'] $ (linterF id')
}
text "Scrutinee type:" <+> ppr scrut_ty,
hsep [ptext SLIT("Current TV subst"), ppr subst]]
-
mkNonDefltMsg e
= hang (text "Case expression with DEFAULT not at the beginnning") 4 (ppr e)
mkNonIncreasingAltsMsg e
nonExhaustiveAltsMsg e
= hang (text "Case expression with non-exhaustive alternatives") 4 (ppr e)
+mkBadConMsg :: TyCon -> DataCon -> Message
+mkBadConMsg tycon datacon
+ = vcat [
+ text "In a case alternative, data constructor isn't in scrutinee type:",
+ text "Scrutinee type constructor:" <+> ppr tycon,
+ text "Data con:" <+> ppr datacon
+ ]
+
mkBadPatMsg :: Type -> Type -> Message
mkBadPatMsg con_result_ty scrut_ty
= vcat [
hsep [ptext SLIT("Binder's type:"), ppr (idType binder)]
]
+mkStrictMsg :: Id -> Message
+mkStrictMsg binder
+ = vcat [hsep [ptext SLIT("Recursive or top-level binder has strict demand info:"),
+ ppr binder],
+ hsep [ptext SLIT("Binder's demand info:"), ppr (idNewDemandInfo binder)]
+ ]
+
+mkArityMsg :: Id -> Message
+mkArityMsg binder
+ = vcat [hsep [ptext SLIT("Demand type has "),
+ ppr (dmdTypeDepth dmd_ty),
+ ptext SLIT(" arguments, rhs has "),
+ ppr (idArity binder),
+ ptext SLIT("arguments, "),
+ ppr binder],
+ hsep [ptext SLIT("Binder's strictness signature:"), ppr dmd_ty]
+
+ ]
+ where (StrictSig dmd_ty) = idNewStrictness binder
+
mkUnboxedTupleMsg :: Id -> Message
mkUnboxedTupleMsg binder
= vcat [hsep [ptext SLIT("A variable has unboxed tuple type:"), ppr binder],
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