-- And some particular Ids; see below for why they are wired in
wiredInIds,
- unsafeCoerceId, realWorldPrimId,
+ unsafeCoerceId, realWorldPrimId, voidArgId, nullAddrId,
eRROR_ID, eRROR_CSTRING_ID, rEC_SEL_ERROR_ID, pAT_ERROR_ID, rEC_CON_ERROR_ID,
rEC_UPD_ERROR_ID, iRREFUT_PAT_ERROR_ID, nON_EXHAUSTIVE_GUARDS_ERROR_ID,
nO_METHOD_BINDING_ERROR_ID, aBSENT_ERROR_ID, pAR_ERROR_ID
import BasicTypes ( Arity, StrictnessMark(..), isMarkedUnboxed, isMarkedStrict )
-import TysPrim ( openAlphaTyVars, alphaTyVar, alphaTy,
+import TysPrim ( openAlphaTyVars, alphaTyVar, alphaTy, betaTyVar, betaTy,
intPrimTy, realWorldStatePrimTy, addrPrimTy
)
import TysWiredIn ( charTy, mkListTy )
-import PrelRules ( primOpRule )
+import PrelRules ( primOpRules )
import Rules ( addRule )
import TcType ( Type, ThetaType, mkDictTy, mkPredTys, mkTyConApp,
mkTyVarTys, mkClassPred, tcEqPred,
tcSplitFunTys, tcSplitForAllTys, mkPredTy
)
import Module ( Module )
-import CoreUtils ( exprType, mkInlineMe )
+import CoreUtils ( exprType )
import CoreUnfold ( mkTopUnfolding, mkCompulsoryUnfolding, mkOtherCon )
-import Literal ( Literal(..) )
+import Literal ( Literal(..), nullAddrLit )
import TyCon ( TyCon, isNewTyCon, tyConTyVars, tyConDataCons,
tyConTheta, isProductTyCon, isDataTyCon, isRecursiveTyCon )
import Class ( Class, classTyCon, classTyVars, classSelIds )
import ForeignCall ( ForeignCall )
import DataCon ( DataCon,
dataConFieldLabels, dataConRepArity, dataConTyCon,
- dataConArgTys, dataConRepType, dataConRepStrictness,
+ dataConArgTys, dataConRepType,
dataConInstOrigArgTys,
dataConName, dataConTheta,
dataConSig, dataConStrictMarks, dataConId,
splitProductType
)
import Id ( idType, mkGlobalId, mkVanillaGlobal, mkSysLocal,
- mkLocalIdWithInfo, setIdNoDiscard,
mkTemplateLocals, mkTemplateLocalsNum,
mkTemplateLocal, idNewStrictness, idName
)
import IdInfo ( IdInfo, noCafNoTyGenIdInfo,
- exactArity, setUnfoldingInfo, setCprInfo,
- setArityInfo, setSpecInfo, setCgInfo,
- mkNewStrictnessInfo, setNewStrictnessInfo,
- GlobalIdDetails(..), CafInfo(..), CprInfo(..),
- CgInfo(..), setCgArity
+ setUnfoldingInfo,
+ setArityInfo, setSpecInfo, setCafInfo,
+ setAllStrictnessInfo,
+ GlobalIdDetails(..), CafInfo(..)
)
import NewDemand ( mkStrictSig, strictSigResInfo, DmdResult(..),
- mkTopDmdType, topDmd, evalDmd )
+ mkTopDmdType, topDmd, evalDmd, lazyDmd,
+ Demand(..), Demands(..) )
import FieldLabel ( mkFieldLabel, fieldLabelName,
firstFieldLabelTag, allFieldLabelTags, fieldLabelType
)
+import DmdAnal ( dmdAnalTopRhs )
import CoreSyn
import Unique ( mkBuiltinUnique )
import Maybes
import PrelNames
import Maybe ( isJust )
+import Util ( dropList, isSingleton )
import Outputable
import ListSetOps ( assoc, assocMaybe )
import UnicodeUtil ( stringToUtf8 )
--
-- [The interface file format now carry such information, but there's
-- no way yet of expressing at the definition site for these
- -- error-reporting
- -- functions that they have an 'open' result type. -- sof 1/99]
+ -- error-reporting functions that they have an 'open'
+ -- result type. -- sof 1/99]
aBSENT_ERROR_ID
, eRROR_ID
, rEC_CON_ERROR_ID
, rEC_UPD_ERROR_ID
- -- These three can't be defined in Haskell
+ -- These can't be defined in Haskell, but they have
+ -- perfectly reasonable unfoldings in Core
, realWorldPrimId
, unsafeCoerceId
+ , nullAddrId
, getTagId
+ , seqId
]
\end{code}
-- Makes the *worker* for the data constructor; that is, the function
-- that takes the reprsentation arguments and builds the constructor.
mkDataConId work_name data_con
- = id
+ = mkGlobalId (DataConId data_con) work_name (dataConRepType data_con) info
where
- id = mkGlobalId (DataConId data_con) work_name (dataConRepType data_con) info
info = noCafNoTyGenIdInfo
- `setCgArity` arity
`setArityInfo` arity
- `setNewStrictnessInfo` Just strict_sig
-
- arity = dataConRepArity data_con
- strict_sig = mkStrictSig id arity (mkTopDmdType (replicate arity topDmd) cpr_info)
+ `setAllStrictnessInfo` Just strict_sig
+
+ arity = dataConRepArity data_con
+
+ strict_sig = mkStrictSig (mkTopDmdType (replicate arity topDmd) cpr_info)
+ -- Notice that we do *not* say the worker is strict
+ -- even if the data constructor is declared strict
+ -- e.g. data T = MkT !(Int,Int)
+ -- Why? Because the *wrapper* is strict (and its unfolding has case
+ -- expresssions that do the evals) but the *worker* itself is not.
+ -- If we pretend it is strict then when we see
+ -- case x of y -> $wMkT y
+ -- the simplifier thinks that y is "sure to be evaluated" (because
+ -- $wMkT is strict) and drops the case. No, $wMkT is not strict.
+ --
+ -- When the simplifer sees a pattern
+ -- case e of MkT x -> ...
+ -- it uses the dataConRepStrictness of MkT to mark x as evaluated;
+ -- but that's fine... dataConRepStrictness comes from the data con
+ -- not from the worker Id.
tycon = dataConTyCon data_con
cpr_info | isProductTyCon tycon &&
\begin{code}
mkDataConWrapId data_con
- = wrap_id
+ = mkGlobalId (DataConWrapId data_con) (dataConName data_con) wrap_ty info
where
- wrap_id = mkGlobalId (DataConWrapId data_con) (dataConName data_con) wrap_ty info
work_id = dataConId data_con
info = noCafNoTyGenIdInfo
- `setUnfoldingInfo` mkTopUnfolding (mkInlineMe wrap_rhs)
- `setCgArity` arity
+ `setUnfoldingInfo` wrap_unf
-- The NoCaf-ness is set by noCafNoTyGenIdInfo
`setArityInfo` arity
-- It's important to specify the arity, so that partial
-- applications are treated as values
- `setNewStrictnessInfo` Just wrap_sig
+ `setAllStrictnessInfo` Just wrap_sig
- wrap_ty = mkForAllTys all_tyvars $
- mkFunTys all_arg_tys
- result_ty
+ wrap_ty = mkForAllTys all_tyvars (mkFunTys all_arg_tys result_ty)
+ wrap_sig = mkStrictSig (mkTopDmdType arg_dmds res_info)
res_info = strictSigResInfo (idNewStrictness work_id)
- wrap_sig = mkStrictSig wrap_id arity (mkTopDmdType (replicate arity topDmd) res_info)
+ arg_dmds = [Abs | d <- dict_args] ++ map mk_dmd strict_marks
+ mk_dmd str | isMarkedStrict str = evalDmd
+ | otherwise = lazyDmd
-- The Cpr info can be important inside INLINE rhss, where the
- -- wrapper constructor isn't inlined
- -- But we are sloppy about the argument demands, because we expect
- -- to inline the constructor very vigorously.
-
- wrap_rhs | isNewTyCon tycon
- = ASSERT( null ex_tyvars && null ex_dict_args && length orig_arg_tys == 1 )
+ -- wrapper constructor isn't inlined.
+ -- And the argument strictness can be important too; we
+ -- may not inline a contructor when it is partially applied.
+ -- For example:
+ -- data W = C !Int !Int !Int
+ -- ...(let w = C x in ...(w p q)...)...
+ -- we want to see that w is strict in its two arguments
+
+ wrap_unf | isNewTyCon tycon
+ = ASSERT( null ex_tyvars && null ex_dict_args && isSingleton orig_arg_tys )
-- No existentials on a newtype, but it can have a context
-- e.g. newtype Eq a => T a = MkT (...)
+ mkTopUnfolding $ Note InlineMe $
mkLams tyvars $ mkLams dict_args $ Lam id_arg1 $
- mkNewTypeBody tycon result_ty id_arg1
+ mkNewTypeBody tycon result_ty (Var id_arg1)
| null dict_args && not (any isMarkedStrict strict_marks)
- = Var work_id -- The common case. Not only is this efficient,
- -- but it also ensures that the wrapper is replaced
- -- by the worker even when there are no args.
- -- f (:) x
- -- becomes
- -- f $w: x
- -- This is really important in rule matching,
- -- (We could match on the wrappers,
- -- but that makes it less likely that rules will match
- -- when we bring bits of unfoldings together.)
+ = mkCompulsoryUnfolding (Var work_id)
+ -- The common case. Not only is this efficient,
+ -- but it also ensures that the wrapper is replaced
+ -- by the worker even when there are no args.
+ -- f (:) x
+ -- becomes
+ -- f $w: x
+ -- This is really important in rule matching,
+ -- (We could match on the wrappers,
+ -- but that makes it less likely that rules will match
+ -- when we bring bits of unfoldings together.)
--
-- NB: because of this special case, (map (:) ys) turns into
- -- (map $w: ys), and thence into (map (\x xs. $w: x xs) ys)
- -- in core-to-stg. The top-level defn for (:) is never used.
+ -- (map $w: ys). The top-level defn for (:) is never used.
-- This is somewhat of a bore, but I'm currently leaving it
-- as is, so that there still is a top level curried (:) for
-- the interpreter to call.
| otherwise
- = mkLams all_tyvars $ mkLams dict_args $
+ = mkTopUnfolding $ Note InlineMe $
+ mkLams all_tyvars $ mkLams dict_args $
mkLams ex_dict_args $ mkLams id_args $
foldr mk_case con_app
(zip (ex_dict_args++id_args) strict_marks) i3 []
mkFunTy data_ty field_tau
arity = 1 + n_dict_tys + n_field_dict_tys
- info = noCafNoTyGenIdInfo
- `setCgInfo` (CgInfo arity caf_info)
- `setArityInfo` arity
- `setUnfoldingInfo` unfolding
- -- ToDo: consider adding further IdInfo
- unfolding = mkTopUnfolding sel_rhs
+ (strict_sig, rhs_w_str) = dmdAnalTopRhs sel_rhs
+ -- Use the demand analyser to work out strictness.
+ -- With all this unpackery it's not easy!
+
+ info = noCafNoTyGenIdInfo
+ `setCafInfo` caf_info
+ `setArityInfo` arity
+ `setUnfoldingInfo` mkTopUnfolding rhs_w_str
+ `setAllStrictnessInfo` Just strict_sig
-- Allocate Ids. We do it a funny way round because field_dict_tys is
-- almost always empty. Also note that we use length_tycon_theta
mkLams dict_ids $ mkLams field_dict_ids $
Lam data_id $ sel_body
- sel_body | isNewTyCon tycon = mkNewTypeBody tycon field_tau data_id
+ sel_body | isNewTyCon tycon = mkNewTypeBody tycon field_tau (mk_result data_id)
| otherwise = Case (Var data_id) data_id (default_alt ++ the_alts)
+ mk_result result_id = mkVarApps (mkVarApps (Var result_id) field_tyvars) field_dict_ids
+ -- We pull the field lambdas to the top, so we need to
+ -- apply them in the body. For example:
+ -- data T = MkT { foo :: forall a. a->a }
+ --
+ -- foo :: forall a. T -> a -> a
+ -- foo = /\a. \t:T. case t of { MkT f -> f a }
+
mk_maybe_alt data_con
= case maybe_the_arg_id of
Nothing -> Nothing
Just the_arg_id -> Just (DataAlt data_con, real_args, mkLets binds body)
where
- body = mkVarApps (mkVarApps (Var the_arg_id) field_tyvars) field_dict_ids
+ body = mk_result the_arg_id
strict_marks = dataConStrictMarks data_con
(binds, real_args) = rebuildConArgs arg_ids strict_marks
(map mkBuiltinUnique [unpack_base..])
= splitProductType "rebuildConArgs" arg_ty
unpacked_args = zipWith (mkSysLocal SLIT("rb")) us con_arg_tys
- (binds, args') = rebuildConArgs args stricts (drop (length con_arg_tys) us)
+ (binds, args') = rebuildConArgs args stricts (dropList con_arg_tys us)
con_app = mkConApp pack_con (map Type tycon_args ++ map Var unpacked_args)
in
(NonRec arg con_app : binds, unpacked_args ++ args')
tag = assoc "MkId.mkDictSelId" (map idName (classSelIds clas) `zip` allFieldLabelTags) name
info = noCafNoTyGenIdInfo
- `setCgArity` 1
- `setArityInfo` 1
- `setUnfoldingInfo` unfolding
-
+ `setArityInfo` 1
+ `setUnfoldingInfo` mkTopUnfolding rhs
+ `setAllStrictnessInfo` Just strict_sig
+
-- We no longer use 'must-inline' on record selectors. They'll
-- inline like crazy if they scrutinise a constructor
- unfolding = mkTopUnfolding rhs
+ -- 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 ])
tyvars = classTyVars clas
(dict_id:arg_ids) = mkTemplateLocals (mkPredTy pred : arg_tys)
rhs | isNewTyCon tycon = mkLams tyvars $ Lam dict_id $
- mkNewTypeBody tycon (head arg_tys) dict_id
+ mkNewTypeBody tycon (head arg_tys) (Var dict_id)
| otherwise = mkLams tyvars $ Lam dict_id $
Case (Var dict_id) dict_id
[(DataAlt data_con, arg_ids, Var the_arg_id)]
-mkNewTypeBody tycon result_ty result_id
+mkNewTypeBody tycon result_ty result_expr
+ -- Adds a coerce where necessary
+ -- Used for both wrapping and unwrapping
| isRecursiveTyCon tycon -- Recursive case; use a coerce
- = Note (Coerce result_ty (idType result_id)) (Var result_id)
+ = Note (Coerce result_ty (exprType result_expr)) result_expr
| otherwise -- Normal case
- = Var result_id
+ = result_expr
\end{code}
mkPrimOpId prim_op
= id
where
- (tyvars,arg_tys,res_ty, arity, strict_info) = primOpSig prim_op
+ (tyvars,arg_tys,res_ty, arity, strict_sig) = primOpSig prim_op
ty = mkForAllTys tyvars (mkFunTys arg_tys res_ty)
name = mkPrimOpIdName prim_op
id = mkGlobalId (PrimOpId prim_op) name ty info
info = noCafNoTyGenIdInfo
`setSpecInfo` rules
- `setCgArity` arity
`setArityInfo` arity
- `setNewStrictnessInfo` Just (mkNewStrictnessInfo id arity strict_info NoCPRInfo)
- -- Until we modify the primop generation code
+ `setAllStrictnessInfo` Just strict_sig
- rules = maybe emptyCoreRules (addRule emptyCoreRules id)
- (primOpRule prim_op)
+ rules = foldl (addRule id) emptyCoreRules (primOpRules prim_op)
-- For each ccall we manufacture a separate CCallOpId, giving it
= ASSERT( isEmptyVarSet (tyVarsOfType ty) )
-- A CCallOpId should have no free type variables;
-- when doing substitutions won't substitute over it
- id
+ mkGlobalId (FCallId fcall) name ty info
where
- id = mkGlobalId (FCallId fcall) name ty info
occ_str = showSDocIface (braces (ppr fcall <+> ppr ty))
-- The "occurrence name" of a ccall is the full info about the
-- ccall; it is encoded, but may have embedded spaces etc!
name = mkFCallName uniq occ_str
info = noCafNoTyGenIdInfo
- `setCgArity` arity
`setArityInfo` arity
- `setNewStrictnessInfo` Just strict_sig
+ `setAllStrictnessInfo` Just strict_sig
(_, tau) = tcSplitForAllTys ty
(arg_tys, _) = tcSplitFunTys tau
arity = length arg_tys
- strict_sig = mkStrictSig id arity (mkTopDmdType (replicate arity evalDmd) TopRes)
+ strict_sig = mkStrictSig (mkTopDmdType (replicate arity evalDmd) TopRes)
\end{code}
%* *
%************************************************************************
+Important notes about dict funs and default methods
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Dict funs and default methods are *not* ImplicitIds. Their definition
+involves user-written code, so we can't figure out their strictness etc
+based on fixed info, as we can for constructors and record selectors (say).
+
+We build them as GlobalIds, but when in the module where they are
+bound, we turn the Id at the *binding site* into an exported LocalId.
+This ensures that they are taken to account by free-variable finding
+and dependency analysis (e.g. CoreFVs.exprFreeVars). The simplifier
+will propagate the LocalId to all occurrence sites.
+
+Why shouldn't they be bound as GlobalIds? Because, in particular, if
+they are globals, the specialiser floats dict uses above their defns,
+which prevents good simplifications happening. Also the strictness
+analyser treats a occurrence of a GlobalId as imported and assumes it
+contains strictness in its IdInfo, which isn't true if the thing is
+bound in the same module as the occurrence.
+
+It's OK for dfuns to be LocalIds, because we form the instance-env to
+pass on to the next module (md_insts) in CoreTidy, afer tidying
+and globalising the top-level Ids.
+
+BUT make sure they are *exported* LocalIds (setIdLocalExported) so
+that they aren't discarded by the occurrence analyser.
+
\begin{code}
-mkDefaultMethodId dm_name ty
- = mkVanillaGlobal dm_name ty noCafNoTyGenIdInfo
+mkDefaultMethodId dm_name ty = mkVanillaGlobal dm_name ty noCafNoTyGenIdInfo
mkDictFunId :: Name -- Name to use for the dict fun;
-> Class
-> Id
mkDictFunId dfun_name clas inst_tyvars inst_tys dfun_theta
- = setIdNoDiscard (mkLocalIdWithInfo dfun_name dfun_ty noCafNoTyGenIdInfo)
- -- NB: It's important that dict funs are *local* Ids
- -- This ensures that they are taken to account by free-variable finding
- -- and dependency analysis (e.g. CoreFVs.exprFreeVars).
- -- In particular, if they are globals, the
- -- specialiser floats dict uses above their defns, which prevents
- -- good simplifications happening.
- --
- -- It's OK for them to be locals, because we form the instance-env to
- -- pass on to the next module (md_insts) in CoreTidy, afer tdying
- -- and globalising the top-level Ids.
- --
- -- BUT Make sure it's an exported Id (setIdNoDiscard) so that it's not dropped!
+ = mkVanillaGlobal dfun_name dfun_ty noCafNoTyGenIdInfo
where
dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys)
%* *
%************************************************************************
-These two can't be defined in Haskell.
+These Ids can't be defined in Haskell. They could be defined in
+unfoldings in PrelGHC.hi-boot, but we'd have to ensure that they
+were definitely, definitely inlined, because there is no curried
+identifier for them. That's what mkCompulsoryUnfolding does.
+If we had a way to get a compulsory unfolding from an interface file,
+we could do that, but we don't right now.
unsafeCoerce# isn't so much a PrimOp as a phantom identifier, that
just gets expanded into a type coercion wherever it occurs. Hence we
another gun with which to shoot yourself in the foot.
\begin{code}
+-- unsafeCoerce# :: forall a b. a -> b
unsafeCoerceId
= pcMiscPrelId unsafeCoerceIdKey pREL_GHC SLIT("unsafeCoerce#") ty info
where
[x] = mkTemplateLocals [openAlphaTy]
rhs = mkLams [openAlphaTyVar,openBetaTyVar,x] $
Note (Coerce openBetaTy openAlphaTy) (Var x)
-\end{code}
+-- nullAddr# :: Addr#
+-- The reason is is here is because we don't provide
+-- a way to write this literal in Haskell.
+nullAddrId
+ = pcMiscPrelId nullAddrIdKey pREL_GHC SLIT("nullAddr#") addrPrimTy info
+ where
+ info = noCafNoTyGenIdInfo `setUnfoldingInfo`
+ mkCompulsoryUnfolding (Lit nullAddrLit)
+
+seqId
+ = pcMiscPrelId seqIdKey pREL_GHC SLIT("seq") ty info
+ where
+ info = noCafNoTyGenIdInfo `setUnfoldingInfo` mkCompulsoryUnfolding rhs
+
+
+ ty = mkForAllTys [alphaTyVar,betaTyVar]
+ (mkFunTy alphaTy (mkFunTy betaTy betaTy))
+ [x,y] = mkTemplateLocals [alphaTy, betaTy]
+ rhs = mkLams [alphaTyVar,betaTyVar,x,y] (Case (Var x) x [(DEFAULT, [], Var y)])
+\end{code}
@getTag#@ is another function which can't be defined in Haskell. It needs to
evaluate its argument and call the dataToTag# primitive.
@realWorld#@ used to be a magic literal, \tr{void#}. If things get
nasty as-is, change it back to a literal (@Literal@).
+voidArgId is a Local Id used simply as an argument in functions
+where we just want an arg to avoid having a thunk of unlifted type.
+E.g.
+ x = \ void :: State# RealWorld -> (# p, q #)
+
+This comes up in strictness analysis
+
\begin{code}
realWorldPrimId -- :: State# RealWorld
= pcMiscPrelId realWorldPrimIdKey pREL_GHC SLIT("realWorld#")
-- which in turn makes Simplify.interestingArg return True,
-- which in turn makes INLINE things applied to realWorld# likely
-- to be inlined
+
+voidArgId -- :: State# RealWorld
+ = mkSysLocal SLIT("void") voidArgIdKey realWorldStatePrimTy
\end{code}
-- will be in "the right place" to be in scope.
pc_bottoming_Id key mod name ty
- = id
+ = pcMiscPrelId key mod name ty bottoming_info
where
- id = pcMiscPrelId key mod name ty bottoming_info
- arity = 1
- strict_sig = mkStrictSig id arity (mkTopDmdType [evalDmd] BotRes)
- bottoming_info = noCafNoTyGenIdInfo `setNewStrictnessInfo` Just strict_sig
+ strict_sig = mkStrictSig (mkTopDmdType [evalDmd] BotRes)
+ bottoming_info = noCafNoTyGenIdInfo `setAllStrictnessInfo` Just strict_sig
-- these "bottom" out, no matter what their arguments
generic_ERROR_ID u n = pc_bottoming_Id u pREL_ERR n errorTy
projects / ghc-hetmet.git / blobdiff