%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcIfaceSig]{Type checking of type signatures in interface files}
\begin{code}
-#include "HsVersions.h"
-
-module TcIfaceSig ( tcInterfaceSigs ) where
-
-import Ubiq
-
-import TcMonad
-import TcMonoType ( tcPolyType )
-
-import HsSyn ( Sig(..), PolyType )
-import RnHsSyn ( RenamedSig(..), RnName(..) )
+module TcIfaceSig ( tcInterfaceSigs,
+ tcCoreExpr,
+ tcCoreLamBndrs,
+ tcCoreBinds ) where
-import CmdLineOpts ( opt_CompilingPrelude )
-import Id ( mkImported )
---import Name ( Name(..) )
-import Pretty
-import Util ( panic )
+#include "HsVersions.h"
+import HsSyn ( CoreDecl(..), TyClDecl(..), HsTupCon(..) )
+import TcHsSyn ( TypecheckedCoreBind )
+import TcRnTypes
+import TcRnMonad
+import TcMonoType ( tcIfaceType, kcHsSigType )
+import TcEnv ( tcExtendTyVarEnv, tcExtendGlobalValEnv, tcLookupGlobalId,
+ tcLookupDataCon )
---import TcPragmas ( tcGenPragmas )
-import IdInfo ( noIdInfo )
-tcGenPragmas ty id ps = returnNF_Tc noIdInfo
+import RnHsSyn ( RenamedCoreDecl, RenamedTyClDecl )
+import HsCore
+import Literal ( Literal(..) )
+import CoreSyn
+import CoreUtils ( exprType )
+import CoreUnfold
+import CoreLint ( lintUnfolding )
+import WorkWrap ( mkWrapper )
+import Id ( Id, mkVanillaGlobal, mkLocalId )
+import MkId ( mkFCallId )
+import IdInfo
+import TyCon ( tyConDataCons, tyConTyVars )
+import DataCon ( DataCon, dataConWorkId, dataConExistentialTyVars, dataConArgTys )
+import Type ( mkTyVarTys, splitTyConApp )
+import TysWiredIn ( tupleCon )
+import Var ( mkTyVar, tyVarKind )
+import Name ( Name )
+import UniqSupply ( initUs_ )
+import Outputable
+import Util ( zipWithEqual, dropList, equalLength )
+import HscTypes ( typeEnvIds )
+import CmdLineOpts ( DynFlag(..) )
\end{code}
Ultimately, type signatures in interfaces will have pragmatic
signatures.
\begin{code}
-tcInterfaceSigs :: [RenamedSig] -> TcM s [Id]
-
-tcInterfaceSigs [] = returnTc []
-
-tcInterfaceSigs (Sig name@(RnName full_name) ty pragmas src_loc : sigs)
- = tcAddSrcLoc src_loc (
- tcPolyType ty `thenTc` \ sigma_ty ->
- fixTc ( \ rec_id ->
- tcGenPragmas (Just sigma_ty) rec_id pragmas
- `thenNF_Tc` \ id_info ->
- returnTc (mkImported full_name sigma_ty id_info)
- )) `thenTc` \ id ->
- tcInterfaceSigs sigs `thenTc` \ sigs' ->
- returnTc (id:sigs')
-
-
-tcInterfaceSigs (Sig odd_name _ _ src_loc : sigs)
- = case odd_name of
- WiredInId _ | opt_CompilingPrelude
- -> tcInterfaceSigs sigs
- _ -> tcAddSrcLoc src_loc $
- failTc (ifaceSigNameErr odd_name)
-
-ifaceSigNameErr name sty
- = ppHang (ppStr "Bad name in an interface type signature (a Prelude name?)")
- 4 (ppr sty name)
+tcInterfaceSigs :: [RenamedTyClDecl] -- Ignore non-sig-decls in these decls
+ -> TcM TcGblEnv
+
+-- May 2003:
+-- NOTE 1: careful about the side-effected EPS
+-- in the two tcExtendGlobalValueEnv calls
+-- NOTE 2: no point in tying the knot with fixM; all
+-- the important knot-tying comes via the PCS global variable
+
+tcInterfaceSigs decls =
+ zapEnv (fixM (tc_interface_sigs decls)) `thenM` \ (_,sig_ids) ->
+ -- The zapEnv dramatically trims the environment, solely
+ -- to plug the space leak that would otherwise be caused
+ -- by a rich environment bound into lots of lazy thunks
+ -- The thunks are the lazily-typechecked IdInfo of the
+ -- imported things.
+
+ tcExtendGlobalValEnv sig_ids getGblEnv `thenM` \ gbl_env ->
+ returnM gbl_env
+ -- We tie a knot so that the Ids read out of interfaces are in scope
+ -- when we read their pragmas.
+ -- What we rely on is that pragmas are typechecked lazily; if
+ -- any type errors are found (ie there's an inconsistency)
+ -- we silently discard the pragma
+ --
+ -- NOTE ALSO: the knot is in two parts:
+ -- * Ids defined in this module are added to the typechecker envt
+ -- which is knot-tied by the fixM.
+ -- * Imported Ids are side-effected into the PCS by the
+ -- tcExtendGlobalValueEnv, so they will be seen there provided
+ -- we don't look them up too early.
+ -- In both cases, we must defer lookups until after the knot is tied
+ --
+ -- We used to have a much bigger loop (in TcRnDriver), so that the
+ -- interface pragmas could mention variables bound in this module
+ -- (by mutual recn), but
+ -- (a) the knot is tiresomely big, and
+ -- (b) it black-holes when we have Template Haskell
+ --
+ -- For (b) consider: f = $(...h....)
+ -- where h is imported, and calls f via an hi-boot file.
+ -- This is bad! But it is not seen as a staging error, because h
+ -- is indeed imported. We don't want the type-checker to black-hole
+ -- when simplifying and compiling the splice!
+ --
+ -- Simple solution: discard any unfolding that mentions a variable
+ -- bound in this module (and hence not yet processed).
+ -- The discarding happens when forkM finds a type error.
+
+tc_interface_sigs decls ~(unf_env, _)
+ = sequenceM [do_one d | d@(IfaceSig {}) <- decls] `thenM` \ sig_ids ->
+ tcExtendGlobalValEnv sig_ids getGblEnv `thenM` \ gbl_env ->
+ returnM (gbl_env, sig_ids)
+ where
+ in_scope_vars = typeEnvIds (tcg_type_env unf_env)
+ -- When we have hi-boot files, an unfolding might refer to
+ -- something defined in this module, so we must build a
+ -- suitable in-scope set. This thunk will only be poked
+ -- if -dcore-lint is on.
+
+ do_one IfaceSig {tcdName = name, tcdType = ty,
+ tcdIdInfo = id_infos, tcdLoc = src_loc}
+ = addSrcLoc src_loc $
+ addErrCtxt (ifaceSigCtxt name) $
+ tcIfaceType ty `thenM` \ sigma_ty ->
+ tcIdInfo unf_env in_scope_vars name
+ sigma_ty id_infos `thenM` \ id_info ->
+ returnM (mkVanillaGlobal name sigma_ty id_info)
\end{code}
+
+\begin{code}
+tcIdInfo unf_env in_scope_vars name ty info_ins
+ = setGblEnv unf_env $
+ -- Use the knot-tied environment for the IdInfo
+ -- In particular: typechecking unfoldings and worker names
+ foldlM tcPrag init_info info_ins
+ where
+ -- Set the CgInfo to something sensible but uninformative before
+ -- we start; default assumption is that it has CAFs
+ init_info = vanillaIdInfo
+
+ tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
+ tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
+ tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
+ tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
+
+ tcPrag info (HsUnfold inline_prag expr)
+ = tcPragExpr name in_scope_vars expr `thenM` \ maybe_expr' ->
+ let
+ -- maybe_expr' doesn't get looked at if the unfolding
+ -- is never inspected; so the typecheck doesn't even happen
+ unfold_info = case maybe_expr' of
+ Nothing -> noUnfolding
+ Just expr' -> mkTopUnfolding expr'
+ in
+ returnM (info `setUnfoldingInfoLazily` unfold_info
+ `setInlinePragInfo` inline_prag)
+\end{code}
+
+\begin{code}
+tcWorkerInfo ty info wkr_name arity
+ = forkM doc (tcVar wkr_name) `thenM` \ maybe_wkr_id ->
+ -- Watch out! We can't pull on unf_env too eagerly!
+ -- Hence the forkM
+
+ -- We return without testing maybe_wkr_id, but as soon as info is
+ -- looked at we will test it. That's ok, because its outside the
+ -- knot; and there seems no big reason to further defer the
+ -- tcVar lookup. (Contrast with tcPragExpr, where postponing walking
+ -- over the unfolding until it's actually used does seem worth while.)
+ newUniqueSupply `thenM` \ us ->
+ returnM (case maybe_wkr_id of
+ Nothing -> info
+ Just wkr_id -> info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
+ `setWorkerInfo` HasWorker wkr_id arity)
+
+ where
+ doc = text "worker for" <+> ppr wkr_name
+
+ mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
+
+ -- We are relying here on strictness info always appearing
+ -- before worker info, fingers crossed ....
+ strict_sig = case newStrictnessInfo info of
+ Just sig -> sig
+ Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr_name)
+\end{code}
+
+For unfoldings we try to do the job lazily, so that we never type check
+an unfolding that isn't going to be looked at.
+
+\begin{code}
+tcPragExpr :: Name -> [Id] -> UfExpr Name -> TcM (Maybe CoreExpr)
+tcPragExpr name in_scope_vars expr
+ = forkM doc $
+ tcCoreExpr expr `thenM` \ core_expr' ->
+
+ -- Check for type consistency in the unfolding
+ ifOptM Opt_DoCoreLinting (
+ getSrcLocM `thenM` \ src_loc ->
+ case lintUnfolding src_loc in_scope_vars core_expr' of
+ Nothing -> returnM ()
+ Just fail_msg -> failWithTc ((doc <+> text "Failed Lint") $$ fail_msg)
+ ) `thenM_`
+
+ returnM core_expr'
+ where
+ doc = text "unfolding of" <+> ppr name
+\end{code}
+
+
+Variables in unfoldings
+~~~~~~~~~~~~~~~~~~~~~~~
+
+\begin{code}
+tcVar :: Name -> TcM Id
+ -- Inside here we use only the Global environment, even for locally bound variables.
+ -- Why? Because we know all the types and want to bind them to real Ids.
+tcVar name = tcLookupGlobalId name
+\end{code}
+
+UfCore expressions.
+
+\begin{code}
+tcCoreExpr :: UfExpr Name -> TcM CoreExpr
+
+tcCoreExpr (UfType ty)
+ = tcIfaceType ty `thenM` \ ty' ->
+ -- It might not be of kind type
+ returnM (Type ty')
+
+tcCoreExpr (UfVar name)
+ = tcVar name `thenM` \ id ->
+ returnM (Var id)
+
+tcCoreExpr (UfLit lit)
+ = returnM (Lit lit)
+
+-- The dreaded lit-lits are also similar, except here the type
+-- is read in explicitly rather than being implicit
+tcCoreExpr (UfLitLit lit ty)
+ = tcIfaceType ty `thenM` \ ty' ->
+ returnM (Lit (MachLitLit lit ty'))
+
+tcCoreExpr (UfFCall cc ty)
+ = tcIfaceType ty `thenM` \ ty' ->
+ newUnique `thenM` \ u ->
+ returnM (Var (mkFCallId u cc ty'))
+
+tcCoreExpr (UfTuple (HsTupCon boxity arity) args)
+ = mappM tcCoreExpr args `thenM` \ args' ->
+ let
+ -- Put the missing type arguments back in
+ con_args = map (Type . exprType) args' ++ args'
+ in
+ returnM (mkApps (Var con_id) con_args)
+ where
+ con_id = dataConWorkId (tupleCon boxity arity)
+
+
+tcCoreExpr (UfLam bndr body)
+ = tcCoreLamBndr bndr $ \ bndr' ->
+ tcCoreExpr body `thenM` \ body' ->
+ returnM (Lam bndr' body')
+
+tcCoreExpr (UfApp fun arg)
+ = tcCoreExpr fun `thenM` \ fun' ->
+ tcCoreExpr arg `thenM` \ arg' ->
+ returnM (App fun' arg')
+
+tcCoreExpr (UfCase scrut case_bndr alts)
+ = tcCoreExpr scrut `thenM` \ scrut' ->
+ let
+ scrut_ty = exprType scrut'
+ case_bndr' = mkLocalId case_bndr scrut_ty
+ in
+ tcExtendGlobalValEnv [case_bndr'] $
+ mappM (tcCoreAlt scrut_ty) alts `thenM` \ alts' ->
+ returnM (Case scrut' case_bndr' alts')
+
+tcCoreExpr (UfLet (UfNonRec bndr rhs) body)
+ = tcCoreExpr rhs `thenM` \ rhs' ->
+ tcCoreValBndr bndr $ \ bndr' ->
+ tcCoreExpr body `thenM` \ body' ->
+ returnM (Let (NonRec bndr' rhs') body')
+
+tcCoreExpr (UfLet (UfRec pairs) body)
+ = tcCoreValBndrs bndrs $ \ bndrs' ->
+ mappM tcCoreExpr rhss `thenM` \ rhss' ->
+ tcCoreExpr body `thenM` \ body' ->
+ returnM (Let (Rec (bndrs' `zip` rhss')) body')
+ where
+ (bndrs, rhss) = unzip pairs
+
+tcCoreExpr (UfNote note expr)
+ = tcCoreExpr expr `thenM` \ expr' ->
+ case note of
+ UfCoerce to_ty -> tcIfaceType to_ty `thenM` \ to_ty' ->
+ returnM (Note (Coerce to_ty'
+ (exprType expr')) expr')
+ UfInlineCall -> returnM (Note InlineCall expr')
+ UfInlineMe -> returnM (Note InlineMe expr')
+ UfSCC cc -> returnM (Note (SCC cc) expr')
+\end{code}
+
+\begin{code}
+tcCoreLamBndr (UfValBinder name ty) thing_inside
+ = tcIfaceType ty `thenM` \ ty' ->
+ let
+ id = mkLocalId name ty'
+ in
+ tcExtendGlobalValEnv [id] $
+ thing_inside id
+
+tcCoreLamBndr (UfTyBinder name kind) thing_inside
+ = let
+ tyvar = mkTyVar name kind
+ in
+ tcExtendTyVarEnv [tyvar] (thing_inside tyvar)
+
+tcCoreLamBndrs [] thing_inside = thing_inside []
+tcCoreLamBndrs (b:bs) thing_inside
+ = tcCoreLamBndr b $ \ b' ->
+ tcCoreLamBndrs bs $ \ bs' ->
+ thing_inside (b':bs')
+
+tcCoreValBndr (UfValBinder name ty) thing_inside
+ = tcIfaceType ty `thenM` \ ty' ->
+ let
+ id = mkLocalId name ty'
+ in
+ tcExtendGlobalValEnv [id] $
+ thing_inside id
+
+tcCoreValBndrs bndrs thing_inside -- Expect them all to be ValBinders
+ = mappM tcIfaceType tys `thenM` \ tys' ->
+ let
+ ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys'
+ in
+ tcExtendGlobalValEnv ids $
+ thing_inside ids
+ where
+ names = [name | UfValBinder name _ <- bndrs]
+ tys = [ty | UfValBinder _ ty <- bndrs]
+\end{code}
+
+\begin{code}
+tcCoreAlt scrut_ty (UfDefault, names, rhs)
+ = ASSERT( null names )
+ tcCoreExpr rhs `thenM` \ rhs' ->
+ returnM (DEFAULT, [], rhs')
+
+tcCoreAlt scrut_ty (UfLitAlt lit, names, rhs)
+ = ASSERT( null names )
+ tcCoreExpr rhs `thenM` \ rhs' ->
+ returnM (LitAlt lit, [], rhs')
+
+tcCoreAlt scrut_ty (UfLitLitAlt str ty, names, rhs)
+ = ASSERT( null names )
+ tcCoreExpr rhs `thenM` \ rhs' ->
+ tcIfaceType ty `thenM` \ ty' ->
+ returnM (LitAlt (MachLitLit str ty'), [], rhs')
+
+-- A case alternative is made quite a bit more complicated
+-- by the fact that we omit type annotations because we can
+-- work them out. True enough, but its not that easy!
+tcCoreAlt scrut_ty alt@(con, names, rhs)
+ = tcConAlt con `thenM` \ con ->
+ let
+ ex_tyvars = dataConExistentialTyVars con
+ (tycon, inst_tys) = splitTyConApp scrut_ty -- NB: not tcSplitTyConApp
+ -- We are looking at Core here
+ main_tyvars = tyConTyVars tycon
+ ex_tyvars' = [mkTyVar name (tyVarKind tv) | (name,tv) <- names `zip` ex_tyvars]
+ ex_tys' = mkTyVarTys ex_tyvars'
+ arg_tys = dataConArgTys con (inst_tys ++ ex_tys')
+ id_names = dropList ex_tyvars names
+ arg_ids
+#ifdef DEBUG
+ | not (equalLength id_names arg_tys)
+ = pprPanic "tcCoreAlts" (ppr (con, names, rhs) $$
+ (ppr main_tyvars <+> ppr ex_tyvars) $$
+ ppr arg_tys)
+ | otherwise
+#endif
+ = zipWithEqual "tcCoreAlts" mkLocalId id_names arg_tys
+ in
+ ASSERT( con `elem` tyConDataCons tycon && equalLength inst_tys main_tyvars )
+ tcExtendTyVarEnv ex_tyvars' $
+ tcExtendGlobalValEnv arg_ids $
+ tcCoreExpr rhs `thenM` \ rhs' ->
+ returnM (DataAlt con, ex_tyvars' ++ arg_ids, rhs')
+
+
+tcConAlt :: UfConAlt Name -> TcM DataCon
+tcConAlt (UfTupleAlt (HsTupCon boxity arity))
+ = returnM (tupleCon boxity arity)
+
+tcConAlt (UfDataAlt con_name) -- When reading interface files
+ -- the con_name will be the real name of
+ -- the data con
+ = tcLookupDataCon con_name
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{Core decls}
+%* *
+%************************************************************************
+
+
+\begin{code}
+tcCoreBinds :: [RenamedCoreDecl] -> TcM [TypecheckedCoreBind]
+-- We don't assume the bindings are in dependency order
+-- So first build the environment, then check the RHSs
+tcCoreBinds ls = mappM tcCoreBinder ls `thenM` \ bndrs ->
+ tcExtendGlobalValEnv bndrs $
+ mappM (tcCoreBind bndrs) ls
+
+tcCoreBinder (CoreDecl nm ty _ _)
+ = kcHsSigType ty `thenM_`
+ tcIfaceType ty `thenM` \ ty' ->
+ returnM (mkLocalId nm ty')
+
+tcCoreBind bndrs (CoreDecl nm _ rhs loc)
+ = tcVar nm `thenM` \ id ->
+ tcCoreExpr rhs `thenM` \ rhs' ->
+ let
+ mb_err = lintUnfolding loc bndrs rhs'
+ in
+ (case mb_err of
+ Just err -> addErr err
+ Nothing -> returnM ()) `thenM_`
+
+ returnM (id, rhs')
+\end{code}
+
+
+\begin{code}
+ifaceSigCtxt sig_name
+ = hsep [ptext SLIT("In an interface-file signature for"), ppr sig_name]
+\end{code}
+
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