%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
%************************************************************************
%* *
Convert a @CoreSyntax@ program to a @StgSyntax@ program.
-
\begin{code}
-#include "HsVersions.h"
-
module CoreToStg ( topCoreBindsToStg ) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
import CoreSyn -- input
import StgSyn -- output
-import Bag ( emptyBag, unitBag, unionBags, unionManyBags, bagToList )
import CoreUtils ( coreExprType )
-import CostCentre ( noCostCentre )
-import Id ( mkSysLocal, idType, isBottomingId,
- nullIdEnv, addOneToIdEnv, lookupIdEnv,
- IdEnv(..), GenId{-instance NamedThing-}
- )
-import Literal ( mkMachInt, Literal(..) )
-import Name ( isExported )
-import PrelVals ( unpackCStringId, unpackCString2Id,
- integerZeroId, integerPlusOneId,
- integerPlusTwoId, integerMinusOneId
+import SimplUtils ( findDefault )
+import CostCentre ( noCCS )
+import Id ( Id, mkSysLocal, idType,
+ externallyVisibleId, setIdUnique, idName
)
+import DataCon ( DataCon, dataConName, dataConId )
+import Name ( Name, nameModule, isLocallyDefinedName )
+import Module ( isDynamicModule )
+import Const ( Con(..), Literal, isLitLitLit )
+import VarEnv
+import Const ( Con(..), isWHNFCon, Literal(..) )
import PrimOp ( PrimOp(..) )
-import SpecUtils ( mkSpecialisedCon )
-import SrcLoc ( mkUnknownSrcLoc )
-import TyCon ( TyCon{-instance Uniquable-} )
-import Type ( maybeAppDataTyCon, getAppDataTyConExpandingDicts )
-import TysWiredIn ( stringTy )
-import Unique ( integerTyConKey, ratioTyConKey, Unique{-instance Eq-} )
+import Type ( isUnLiftedType, isUnboxedTupleType, Type )
+import TysPrim ( intPrimTy )
+import Unique ( Unique, Uniquable(..) )
import UniqSupply -- all of it, really
-import Util ( panic, assertPanic, pprTrace{-ToDo:rm-} )
-import Pretty--ToDo:rm
-import PprStyle--ToDo:rm
-import PprType --ToDo:rm
-import Outputable--ToDo:rm
-import PprEnv--ToDo:rm
-
-isLeakFreeType x y = False -- safe option; ToDo
+import Outputable
\end{code}
x = y t1 t2
where t1, t2 are types
-* We make the representation of NoRep literals explicit, and
- float their bindings to the top level
+* We don't pin on correct arities any more, because they can be mucked up
+ by the lambda lifter. In particular, the lambda lifter can take a local
+ letrec-bound variable and make it a lambda argument, which shouldn't have
+ an arity. So SetStgVarInfo sets arities now.
* We do *not* pin on the correct free/live var info; that's done later.
Instead we use bOGUS_LVS and _FVS as a placeholder.
-* We convert case x of {...; x' -> ...x'...}
- to
- case x of {...; _ -> ...x... }
-
- See notes in SimplCase.lhs, near simplDefault for the reasoning here.
+[Quite a bit of stuff that used to be here has moved
+ to tidyCorePgm (SimplCore.lhs) SLPJ Nov 96]
%************************************************************************
%* *
%************************************************************************
-Because we're going to come across ``boring'' bindings like
-\tr{let x = /\ tyvars -> y in ...}, we want to keep a small
-environment, so we can just replace all occurrences of \tr{x}
-with \tr{y}.
+March 98: We keep a small environment to give all locally bound
+Names new unique ids, since the code generator assumes that binders
+are unique across a module. (Simplifier doesn't maintain this
+invariant any longer.)
\begin{code}
-type StgEnv = IdEnv StgArg
+type StgEnv = IdEnv Id
+
+data StgFloatBind
+ = LetBind Id StgExpr
+ | CaseBind Id StgExpr
\end{code}
No free/live variable information is pinned on in this pass; it's added
\begin{code}
topCoreBindsToStg :: UniqSupply -- name supply
- -> [CoreBinding] -- input
+ -> [CoreBind] -- input
-> [StgBinding] -- output
topCoreBindsToStg us core_binds
- = case (initUs us (binds_to_stg nullIdEnv core_binds)) of
- (_, stuff) -> stuff
+ = initUs us (coreBindsToStg emptyVarEnv core_binds)
where
- binds_to_stg :: StgEnv -> [CoreBinding] -> UniqSM [StgBinding]
-
- binds_to_stg env [] = returnUs []
- binds_to_stg env (b:bs)
- = do_top_bind env b `thenUs` \ (new_b, new_env, float_binds) ->
- binds_to_stg new_env bs `thenUs` \ new_bs ->
- returnUs (bagToList float_binds ++ -- Literals
- new_b ++
- new_bs)
-
- do_top_bind env bind@(Rec pairs)
- = coreBindToStg env bind
-
- do_top_bind env bind@(NonRec var rhs)
- = coreBindToStg env bind `thenUs` \ (stg_binds, new_env, float_binds) ->
-{- TESTING:
- let
- ppr_blah xs = ppInterleave ppComma (map pp_x xs)
- pp_x (u,x) = ppBesides [pprUnique u, ppStr ": ", ppr PprDebug x]
- in
- pprTrace "do_top_bind:" (ppAbove (ppr PprDebug stg_binds) (ppr_blah (ufmToList new_env))) $
--}
- case stg_binds of
- [StgNonRec var (StgRhsClosure cc bi fvs u [] rhs_body)] ->
- -- Mega-special case; there's still a binding there
- -- no fvs (of course), *no args*, "let" rhs
- let
- (extra_float_binds, rhs_body') = seek_liftable [] rhs_body
- in
- returnUs (extra_float_binds ++
- [StgNonRec var (StgRhsClosure cc bi fvs u [] rhs_body')],
- new_env,
- float_binds)
-
- other -> returnUs (stg_binds, new_env, float_binds)
-
- --------------------
- -- HACK: look for very simple, obviously-liftable bindings
- -- that can come up to the top level; those that couldn't
- -- 'cause they were big-lambda constrained in the Core world.
-
- seek_liftable :: [StgBinding] -- accumulator...
- -> StgExpr -- look for top-lev liftables
- -> ([StgBinding], StgExpr) -- result
-
- seek_liftable acc expr@(StgLet inner_bind body)
- | is_liftable inner_bind
- = seek_liftable (inner_bind : acc) body
-
- seek_liftable acc other_expr = (reverse acc, other_expr) -- Finished
-
- --------------------
- is_liftable (StgNonRec binder (StgRhsClosure _ _ _ _ args body))
- = not (null args) -- it's manifestly a function...
- || isLeakFreeType [] (idType binder)
- || is_whnf body
- -- ToDo: use a decent manifestlyWHNF function for STG?
- where
- is_whnf (StgCon _ _ _) = True
- is_whnf (StgApp (StgVarArg v) _ _) = isBottomingId v
- is_whnf other = False
-
- is_liftable (StgRec [(_, StgRhsClosure _ _ _ _ args body)])
- = not (null args) -- it's manifestly a (recursive) function...
-
- is_liftable anything_else = False
+ coreBindsToStg :: StgEnv -> [CoreBind] -> UniqSM [StgBinding]
+
+ coreBindsToStg env [] = returnUs []
+ coreBindsToStg env (b:bs)
+ = coreBindToStg env b `thenUs` \ (new_b, new_env) ->
+ coreBindsToStg new_env bs `thenUs` \ new_bs ->
+ returnUs (new_b ++ new_bs)
\end{code}
%************************************************************************
\begin{code}
coreBindToStg :: StgEnv
- -> CoreBinding
+ -> CoreBind
-> UniqSM ([StgBinding], -- Empty or singleton
- StgEnv, -- New envt
- Bag StgBinding) -- Floats
+ StgEnv) -- Floats
coreBindToStg env (NonRec binder rhs)
- = coreRhsToStg env rhs `thenUs` \ (stg_rhs, rhs_binds) ->
-
- let
- -- Binds to return if RHS is trivial
- triv_binds = if isExported binder then
- [StgNonRec binder stg_rhs] -- Retain it
- else
- [] -- Discard it
- in
- case stg_rhs of
- StgRhsClosure cc bi fvs upd [] (StgApp atom [] lvs) ->
- -- Trivial RHS, so augment envt, and ditch the binding
- returnUs (triv_binds, new_env, rhs_binds)
- where
- new_env = addOneToIdEnv env binder atom
-
- StgRhsCon cc con_id [] ->
- -- Trivial RHS, so augment envt, and ditch the binding
- returnUs (triv_binds, new_env, rhs_binds)
- where
- new_env = addOneToIdEnv env binder (StgVarArg con_id)
-
- other -> -- Non-trivial RHS, so don't augment envt
- returnUs ([StgNonRec binder stg_rhs], env, rhs_binds)
+ = coreRhsToStg env rhs `thenUs` \ stg_rhs ->
+ newLocalId env binder `thenUs` \ (new_env, new_binder) ->
+ returnUs ([StgNonRec new_binder stg_rhs], new_env)
coreBindToStg env (Rec pairs)
- = -- NB: *** WE DO NOT CHECK FOR TRIV_BINDS in REC BIND ****
- -- (possibly ToDo)
- let
- (binders, rhss) = unzip pairs
- in
- mapAndUnzipUs (coreRhsToStg env) rhss `thenUs` \ (stg_rhss, rhs_binds) ->
- returnUs ([StgRec (binders `zip` stg_rhss)], env, unionManyBags rhs_binds)
+ = newLocalIds env binders `thenUs` \ (env', binders') ->
+ mapUs (coreRhsToStg env') rhss `thenUs` \ stg_rhss ->
+ returnUs ([StgRec (binders' `zip` stg_rhss)], env')
+ where
+ (binders, rhss) = unzip pairs
\end{code}
%************************************************************************
\begin{code}
-coreRhsToStg :: StgEnv -> CoreExpr -> UniqSM (StgRhs, Bag StgBinding)
+coreRhsToStg :: StgEnv -> CoreExpr -> UniqSM StgRhs
coreRhsToStg env core_rhs
- = coreExprToStg env core_rhs `thenUs` \ (stg_expr, stg_binds) ->
-
- let stg_rhs = case stg_expr of
- StgLet (StgNonRec var1 rhs) (StgApp (StgVarArg var2) [] _)
- | var1 == var2 -> rhs
- -- This curious stuff is to unravel what a lambda turns into
- -- We have to do it this way, rather than spot a lambda in the
- -- incoming rhs
+ = coreExprToStg env core_rhs `thenUs` \ stg_expr ->
+ returnUs (exprToRhs stg_expr)
+
+exprToRhs (StgLet (StgNonRec var1 rhs) (StgApp var2 []))
+ | var1 == var2
+ = rhs
+ -- This curious stuff is to unravel what a lambda turns into
+ -- We have to do it this way, rather than spot a lambda in the
+ -- incoming rhs. Why? Because trivial bindings might conceal
+ -- what the rhs is actually like.
+
+{-
+ We reject the following candidates for 'static constructor'dom:
+
+ - any dcon that takes a lit-lit as an arg.
+ - [Win32 DLLs only]: any dcon that is (or takes as arg)
+ that's living in a DLL.
+
+ These constraints are necessary to ensure that the code
+ generated in the end for the static constructors, which
+ live in the data segment, remain valid - i.e., it has to
+ be constant. For obvious reasons, that's hard to guarantee
+ with lit-lits. The second case of a constructor referring
+ to static closures hiding out in some DLL is an artifact
+ of the way Win32 DLLs handle global DLL variables. A (data)
+ symbol exported from a DLL has to be accessed through a
+ level of indirection at the site of use, so whereas
+
+ extern StgClosure y_closure;
+ extern StgClosure z_closure;
+ x = { ..., &y_closure, &z_closure };
+
+ is legal when the symbols are in scope at link-time, it is
+ not when y_closure is in a DLL. So, any potential static
+ closures that refers to stuff that's residing in a DLL
+ will be put in an (updateable) thunk instead.
+
+ An alternative strategy is to support the generation of
+ constructors (ala C++ static class constructors) which will
+ then be run at load time to fix up static closures.
+-}
+exprToRhs (StgCon (DataCon con) args _)
+ | not is_dynamic &&
+ all (not.is_lit_lit) args = StgRhsCon noCCS con args
+ where
+ is_dynamic = isDynCon con || any (isDynArg) args
+
+ is_lit_lit (StgVarArg _) = False
+ is_lit_lit (StgConArg x) =
+ case x of
+ Literal l -> isLitLitLit l
+ _ -> False
+
+exprToRhs expr
+ = StgRhsClosure noCCS -- No cost centre (ToDo?)
+ stgArgOcc -- safe
+ noSRT -- figure out later
+ bOGUS_FVs
+
+ Updatable -- Be pessimistic
+ []
+ expr
+
+isDynCon :: DataCon -> Bool
+isDynCon con = isDynName (dataConName con)
+
+isDynArg :: StgArg -> Bool
+isDynArg (StgVarArg v) = isDynName (idName v)
+isDynArg (StgConArg con) =
+ case con of
+ DataCon dc -> isDynCon dc
+ Literal l -> isLitLitLit l
+ _ -> False
+
+isDynName :: Name -> Bool
+isDynName nm =
+ not (isLocallyDefinedName nm) &&
+ isDynamicModule (nameModule nm)
- StgCon con args _ -> StgRhsCon noCostCentre con args
- other -> StgRhsClosure noCostCentre -- No cost centre (ToDo?)
- stgArgOcc -- safe
- bOGUS_FVs
- Updatable -- Be pessimistic
- []
- stg_expr
- in
- returnUs (stg_rhs, stg_binds)
\end{code}
%************************************************************************
%* *
-\subsection[coreToStg-lits]{Converting literals}
+\subsection[coreToStg-atoms{Converting atoms}
%* *
%************************************************************************
-Literals: the NoRep kind need to be de-no-rep'd.
-We always replace them with a simple variable, and float a suitable
-binding out to the top level.
-
-If an Integer is small enough (Haskell implementations must support
-Ints in the range $[-2^29+1, 2^29-1]$), wrap it up in @int2Integer@;
-otherwise, wrap with @litString2Integer@.
-
\begin{code}
-tARGET_MIN_INT, tARGET_MAX_INT :: Integer
-tARGET_MIN_INT = -536870912
-tARGET_MAX_INT = 536870912
+coreArgsToStg :: StgEnv -> [CoreArg] -> UniqSM ([StgFloatBind], [StgArg])
-litToStgArg :: Literal -> UniqSM (StgArg, Bag StgBinding)
+coreArgsToStg env []
+ = returnUs ([], [])
-litToStgArg (NoRepStr s)
- = newStgVar stringTy `thenUs` \ var ->
- let
- rhs = StgRhsClosure noCostCentre -- No cost centre (ToDo?)
- stgArgOcc -- safe
- bOGUS_FVs
- Updatable -- WAS: ReEntrant (see note below)
- [] -- No arguments
- val
-
--- We used not to update strings, so that they wouldn't clog up the heap,
--- but instead be unpacked each time. But on some programs that costs a lot
--- [eg hpg], so now we update them.
-
- val = if (any is_NUL (_UNPK_ s)) then -- must cater for NULs in literal string
- StgApp (StgVarArg unpackCString2Id)
- [StgLitArg (MachStr s),
- StgLitArg (mkMachInt (toInteger (_LENGTH_ s)))]
- bOGUS_LVs
- else
- StgApp (StgVarArg unpackCStringId)
- [StgLitArg (MachStr s)]
- bOGUS_LVs
- in
- returnUs (StgVarArg var, unitBag (StgNonRec var rhs))
- where
- is_NUL c = c == '\0'
+coreArgsToStg env (Type ty : as) -- Discard type arguments
+ = coreArgsToStg env as
-litToStgArg (NoRepInteger i integer_ty)
- -- extremely convenient to look out for a few very common
- -- Integer literals!
- | i == 0 = returnUs (StgVarArg integerZeroId, emptyBag)
- | i == 1 = returnUs (StgVarArg integerPlusOneId, emptyBag)
- | i == 2 = returnUs (StgVarArg integerPlusTwoId, emptyBag)
- | i == (-1) = returnUs (StgVarArg integerMinusOneId, emptyBag)
-
- | otherwise
- = newStgVar integer_ty `thenUs` \ var ->
- let
- rhs = StgRhsClosure noCostCentre -- No cost centre (ToDo?)
- stgArgOcc -- safe
- bOGUS_FVs
- Updatable -- Update an integer
- [] -- No arguments
- val
-
- val
- | i > tARGET_MIN_INT && i < tARGET_MAX_INT
- = -- Start from an Int
- StgPrim Int2IntegerOp [StgLitArg (mkMachInt i)] bOGUS_LVs
-
- | otherwise
- = -- Start from a string
- StgPrim Addr2IntegerOp [StgLitArg (MachStr (_PK_ (show i)))] bOGUS_LVs
- in
- returnUs (StgVarArg var, unitBag (StgNonRec var rhs))
-
-litToStgArg (NoRepRational r rational_ty)
- = --ASSERT(is_rational_ty)
- (if is_rational_ty then \x->x else pprTrace "litToStgArg:not rational?" (pprType PprDebug rational_ty)) $
- litToStgArg (NoRepInteger (numerator r) integer_ty) `thenUs` \ (num_atom, binds1) ->
- litToStgArg (NoRepInteger (denominator r) integer_ty) `thenUs` \ (denom_atom, binds2) ->
- newStgVar rational_ty `thenUs` \ var ->
- let
- rhs = StgRhsCon noCostCentre -- No cost centre (ToDo?)
- ratio_data_con -- Constructor
- [num_atom, denom_atom]
- in
- returnUs (StgVarArg var, binds1 `unionBags`
- binds2 `unionBags`
- unitBag (StgNonRec var rhs))
- where
- (is_rational_ty, ratio_data_con, integer_ty)
- = case (maybeAppDataTyCon rational_ty) of
- Just (tycon, [i_ty], [con])
- -> ASSERT(is_integer_ty i_ty)
- (uniqueOf tycon == ratioTyConKey, con, i_ty)
-
- _ -> (False, panic "ratio_data_con", panic "integer_ty")
-
- is_integer_ty ty
- = case (maybeAppDataTyCon ty) of
- Just (tycon, [], _) -> uniqueOf tycon == integerTyConKey
- _ -> False
-
-litToStgArg other_lit = returnUs (StgLitArg other_lit, emptyBag)
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection[coreToStg-atoms{Converting atoms}
-%* *
-%************************************************************************
-
-\begin{code}
-coreArgsToStg :: StgEnv -> [CoreArg] -> UniqSM ([Type], [StgArg], Bag StgBinding)
-
-coreArgsToStg env [] = returnUs ([], [], emptyBag)
coreArgsToStg env (a:as)
- = coreArgsToStg env as `thenUs` \ (tys, args, binds) ->
- do_arg a tys args binds
- where
- do_arg a trest vrest binds
- = case a of
- TyArg t -> returnUs (t:trest, vrest, binds)
- UsageArg u -> returnUs (trest, vrest, binds)
- VarArg v -> returnUs (trest, stgLookup env v : vrest, binds)
- LitArg i -> litToStgArg i `thenUs` \ (v, bs) ->
- returnUs (trest, v:vrest, bs `unionBags` binds)
-\end{code}
+ = coreArgToStg env a `thenUs` \ (bs1, a') ->
+ coreArgsToStg env as `thenUs` \ (bs2, as') ->
+ returnUs (bs1 ++ bs2, a' : as')
+
+-- This is where we arrange that a non-trivial argument is let-bound
+
+coreArgToStg :: StgEnv -> CoreArg -> UniqSM ([StgFloatBind], StgArg)
+
+coreArgToStg env arg
+ = coreExprToStgFloat env arg `thenUs` \ (binds, arg') ->
+ case (binds, arg') of
+ ([], StgCon con [] _) | isWHNFCon con -> returnUs ([], StgConArg con)
+ ([], StgApp v []) -> returnUs ([], StgVarArg v)
+
+ -- A non-trivial argument: we must let (or case-bind)
+ -- We don't do the case part here... we leave that to mkStgBinds
+
+ -- Further complication: if we're converting this binding into
+ -- a case, then try to avoid generating any case-of-case
+ -- expressions by pulling out the floats.
+ (_, other) ->
+ newStgVar ty `thenUs` \ v ->
+ if isUnLiftedType ty
+ then returnUs (binds ++ [CaseBind v arg'], StgVarArg v)
+ else returnUs ([LetBind v (mkStgBinds binds arg')], StgVarArg v)
+ where
+ ty = coreExprType arg
-There's not anything interesting we can ASSERT about \tr{var} if it
-isn't in the StgEnv. (WDP 94/06)
-\begin{code}
-stgLookup :: StgEnv -> Id -> StgArg
-
-stgLookup env var = case (lookupIdEnv env var) of
- Nothing -> StgVarArg var
- Just atom -> atom
\end{code}
+
%************************************************************************
%* *
\subsection[coreToStg-exprs]{Converting core expressions}
%************************************************************************
\begin{code}
-coreExprToStg :: StgEnv
- -> CoreExpr
- -> UniqSM (StgExpr, -- Result
- Bag StgBinding) -- Float these to top level
-\end{code}
-
-\begin{code}
-coreExprToStg env (Lit lit)
- = litToStgArg lit `thenUs` \ (atom, binds) ->
- returnUs (StgApp atom [] bOGUS_LVs, binds)
+coreExprToStg :: StgEnv -> CoreExpr -> UniqSM StgExpr
coreExprToStg env (Var var)
- = returnUs (StgApp (stgLookup env var) [] bOGUS_LVs, emptyBag)
+ = returnUs (StgApp (stgLookup env var) [])
-coreExprToStg env (Con con args)
- = coreArgsToStg env args `thenUs` \ (types, stg_atoms, stg_binds) ->
- let
- spec_con = mkSpecialisedCon con types
- in
- returnUs (StgCon spec_con stg_atoms bOGUS_LVs, stg_binds)
-
-coreExprToStg env (Prim op args)
- = coreArgsToStg env args `thenUs` \ (_, stg_atoms, stg_binds) ->
- returnUs (StgPrim op stg_atoms bOGUS_LVs, stg_binds)
\end{code}
%************************************************************************
\begin{code}
coreExprToStg env expr@(Lam _ _)
= let
- (_,_, binders, body) = collectBinders expr
+ (binders, body) = collectBinders expr
+ id_binders = filter isId binders
in
- coreExprToStg env body `thenUs` \ stuff@(stg_body, binds) ->
+ newLocalIds env id_binders `thenUs` \ (env', binders') ->
+ coreExprToStg env' body `thenUs` \ stg_body ->
- if null binders then -- it was all type/usage binders; tossed
- returnUs stuff
+ if null id_binders then -- it was all type/usage binders; tossed
+ returnUs stg_body
else
+ case stg_body of
+
+ -- if the body reduced to a lambda too...
+ (StgLet (StgNonRec var (StgRhsClosure cc bi srt fvs uf args body))
+ (StgApp var' []))
+ | var == var' ->
+ returnUs (StgLet (StgNonRec var
+ (StgRhsClosure noCCS
+ stgArgOcc
+ noSRT
+ bOGUS_FVs
+ ReEntrant
+ (binders' ++ args)
+ body))
+ (StgApp var []))
+
+ other ->
+
+ -- We must let-bind the lambda
newStgVar (coreExprType expr) `thenUs` \ var ->
returnUs
- (StgLet (StgNonRec var (StgRhsClosure noCostCentre
+ (StgLet (StgNonRec var (StgRhsClosure noCCS
stgArgOcc
+ noSRT
bOGUS_FVs
ReEntrant -- binders is non-empty
- binders
+ binders'
stg_body))
- (StgApp (StgVarArg var) [] bOGUS_LVs),
- binds)
+ (StgApp var []))
+\end{code}
+
+%************************************************************************
+%* *
+\subsubsection[coreToStg-let(rec)]{Let and letrec expressions}
+%* *
+%************************************************************************
+
+\begin{code}
+coreExprToStg env (Let bind body)
+ = coreBindToStg env bind `thenUs` \ (stg_binds, new_env) ->
+ coreExprToStg new_env body `thenUs` \ stg_body ->
+ returnUs (foldr StgLet stg_body stg_binds)
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsubsection[coreToStg-scc]{SCC expressions}
+%* *
+%************************************************************************
+
+Covert core @scc@ expression directly to STG @scc@ expression.
+\begin{code}
+coreExprToStg env (Note (SCC cc) expr)
+ = coreExprToStg env expr `thenUs` \ stg_expr ->
+ returnUs (StgSCC cc stg_expr)
+\end{code}
+
+\begin{code}
+coreExprToStg env (Note other_note expr) = coreExprToStg env expr
+\end{code}
+
+The rest are handled by coreExprStgFloat.
+
+\begin{code}
+coreExprToStg env expr
+ = coreExprToStgFloat env expr `thenUs` \ (binds,stg_expr) ->
+ returnUs (mkStgBinds binds stg_expr)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-coreExprToStg env expr@(App _ _)
+coreExprToStgFloat env expr@(App _ _)
= let
- (fun, _, _, args) = collectArgs expr
+ (fun,args) = collect_args expr []
in
- -- Deal with the arguments
- coreArgsToStg env args `thenUs` \ (_, stg_args, arg_binds) ->
+ coreArgsToStg env args `thenUs` \ (binds, stg_args) ->
-- Now deal with the function
- case fun of
- Var fun_id -> returnUs (StgApp (stgLookup env fun_id) stg_args bOGUS_LVs, arg_binds)
+ case (fun, stg_args) of
+ (Var fun_id, _) -> -- A function Id, so do an StgApp; it's ok if
+ -- there are no arguments.
+ returnUs (binds,
+ StgApp (stgLookup env fun_id) stg_args)
+
+ (non_var_fun, []) -> -- No value args, so recurse into the function
+ ASSERT( null binds )
+ coreExprToStg env non_var_fun `thenUs` \e ->
+ returnUs ([], e)
other -> -- A non-variable applied to things; better let-bind it.
newStgVar (coreExprType fun) `thenUs` \ fun_id ->
- coreExprToStg env fun `thenUs` \ (stg_fun, fun_binds) ->
+ coreExprToStg env fun `thenUs` \ (stg_fun) ->
let
- fun_rhs = StgRhsClosure noCostCentre -- No cost centre (ToDo?)
+ fun_rhs = StgRhsClosure noCCS -- No cost centre (ToDo?)
stgArgOcc
+ noSRT
bOGUS_FVs
SingleEntry -- Only entered once
[]
stg_fun
in
- returnUs (StgLet (StgNonRec fun_id fun_rhs)
- (StgApp (StgVarArg fun_id) stg_args bOGUS_LVs),
- arg_binds `unionBags` fun_binds)
-\end{code}
-
-%************************************************************************
-%* *
-\subsubsection[coreToStg-cases]{Case expressions}
-%* *
-%************************************************************************
-
-At this point, we *mangle* cases involving fork# and par# in the
-discriminant. The original templates for these primops (see
-@PrelVals.lhs@) constructed case expressions with boolean results
-solely to fool the strictness analyzer, the simplifier, and anyone
-else who might want to fool with the evaluation order. Now, we
-believe that once the translation to STG code is performed, our
-evaluation order is safe. Therefore, we convert expressions of the
-form:
-
- case par# e of
- True -> rhs
- False -> parError#
-
-to
-
- case par# e of
- _ -> rhs
-
-\begin{code}
-
-coreExprToStg env (Case discrim@(Prim op _) alts)
- | funnyParallelOp op
- = getUnique `thenUs` \ uniq ->
- coreExprToStg env discrim `thenUs` \ (stg_discrim, discrim_binds) ->
- alts_to_stg alts `thenUs` \ (stg_alts, alts_binds) ->
- returnUs (
- StgCase stg_discrim
- bOGUS_LVs
- bOGUS_LVs
- uniq
- stg_alts,
- discrim_binds `unionBags` alts_binds
- )
- where
- funnyParallelOp SeqOp = True
- funnyParallelOp ParOp = True
- funnyParallelOp ForkOp = True
- funnyParallelOp _ = False
-
- discrim_ty = coreExprType discrim
-
- alts_to_stg (PrimAlts _ (BindDefault binder rhs))
- = coreExprToStg env rhs `thenUs` \ (stg_rhs, rhs_binds) ->
- let
- stg_deflt = StgBindDefault binder False stg_rhs
- in
- returnUs (StgPrimAlts discrim_ty [] stg_deflt, rhs_binds)
-
--- OK, back to real life...
-
-coreExprToStg env (Case discrim alts)
- = coreExprToStg env discrim `thenUs` \ (stg_discrim, discrim_binds) ->
- alts_to_stg discrim alts `thenUs` \ (stg_alts, alts_binds) ->
- getUnique `thenUs` \ uniq ->
- returnUs (
- StgCase stg_discrim
- bOGUS_LVs
- bOGUS_LVs
- uniq
- stg_alts,
- discrim_binds `unionBags` alts_binds
- )
+ returnUs (binds,
+ StgLet (StgNonRec fun_id fun_rhs) $
+ StgApp fun_id stg_args)
where
- discrim_ty = coreExprType discrim
- (_, discrim_ty_args, _) = getAppDataTyConExpandingDicts discrim_ty
-
- alts_to_stg discrim (AlgAlts alts deflt)
- = default_to_stg discrim deflt `thenUs` \ (stg_deflt, deflt_binds) ->
- mapAndUnzipUs boxed_alt_to_stg alts `thenUs` \ (stg_alts, alts_binds) ->
- returnUs (StgAlgAlts discrim_ty stg_alts stg_deflt,
- deflt_binds `unionBags` unionManyBags alts_binds)
- where
- boxed_alt_to_stg (con, bs, rhs)
- = coreExprToStg env rhs `thenUs` \ (stg_rhs, rhs_binds) ->
- returnUs ((spec_con, bs, [ True | b <- bs ]{-bogus use mask-}, stg_rhs),
- rhs_binds)
- where
- spec_con = mkSpecialisedCon con discrim_ty_args
-
- alts_to_stg discrim (PrimAlts alts deflt)
- = default_to_stg discrim deflt `thenUs` \ (stg_deflt,deflt_binds) ->
- mapAndUnzipUs unboxed_alt_to_stg alts `thenUs` \ (stg_alts, alts_binds) ->
- returnUs (StgPrimAlts discrim_ty stg_alts stg_deflt,
- deflt_binds `unionBags` unionManyBags alts_binds)
- where
- unboxed_alt_to_stg (lit, rhs)
- = coreExprToStg env rhs `thenUs` \ (stg_rhs, rhs_binds) ->
- returnUs ((lit, stg_rhs), rhs_binds)
-
- default_to_stg discrim NoDefault
- = returnUs (StgNoDefault, emptyBag)
-
- default_to_stg discrim (BindDefault binder rhs)
- = coreExprToStg new_env rhs `thenUs` \ (stg_rhs, rhs_binds) ->
- returnUs (StgBindDefault binder True{-used? no it is lying-} stg_rhs,
- rhs_binds)
- where
- --
- -- We convert case x of {...; x' -> ...x'...}
- -- to
- -- case x of {...; _ -> ...x... }
- --
- -- See notes in SimplCase.lhs, near simplDefault for the reasoning.
- -- It's quite easily done: simply extend the environment to bind the
- -- default binder to the scrutinee.
- --
- new_env = case discrim of
- Var v -> addOneToIdEnv env binder (stgLookup env v)
- other -> env
+ -- Collect arguments
+ collect_args (App fun arg) args = collect_args fun (arg:args)
+ collect_args (Note (Coerce _ _) expr) args = collect_args expr args
+ collect_args (Note InlineCall expr) args = collect_args expr args
+ collect_args fun args = (fun, args)
\end{code}
%************************************************************************
%* *
-\subsubsection[coreToStg-let(rec)]{Let and letrec expressions}
+\subsubsection[coreToStg-con]{Constructors}
%* *
%************************************************************************
\begin{code}
-coreExprToStg env (Let bind body)
- = coreBindToStg env bind `thenUs` \ (stg_binds, new_env, float_binds1) ->
- coreExprToStg new_env body `thenUs` \ (stg_body, float_binds2) ->
- returnUs (mkStgLets stg_binds stg_body, float_binds1 `unionBags` float_binds2)
+coreExprToStgFloat env expr@(Con (PrimOp (CCallOp (Right _) a b c)) args)
+ = getUniqueUs `thenUs` \ u ->
+ coreArgsToStg env args `thenUs` \ (binds, stg_atoms) ->
+ let con' = PrimOp (CCallOp (Right u) a b c) in
+ returnUs (binds, StgCon con' stg_atoms (coreExprType expr))
+
+coreExprToStgFloat env expr@(Con con args)
+ = coreArgsToStg env args `thenUs` \ (binds, stg_atoms) ->
+ returnUs (binds, StgCon con stg_atoms (coreExprType expr))
\end{code}
-
%************************************************************************
%* *
-\subsubsection[coreToStg-scc]{SCC expressions}
+\subsubsection[coreToStg-cases]{Case expressions}
%* *
%************************************************************************
-Covert core @scc@ expression directly to STG @scc@ expression.
\begin{code}
-coreExprToStg env (SCC cc expr)
- = coreExprToStg env expr `thenUs` \ (stg_expr, binds) ->
- returnUs (StgSCC (coreExprType expr) cc stg_expr, binds)
+coreExprToStgFloat env expr@(Case scrut bndr alts)
+ = coreExprToStgFloat env scrut `thenUs` \ (binds, scrut') ->
+ newLocalId env bndr `thenUs` \ (env', bndr') ->
+ alts_to_stg env' (findDefault alts) `thenUs` \ alts' ->
+ returnUs (binds, mkStgCase scrut' bndr' alts')
+ where
+ scrut_ty = idType bndr
+ prim_case = isUnLiftedType scrut_ty && not (isUnboxedTupleType scrut_ty)
+
+ alts_to_stg env (alts, deflt)
+ | prim_case
+ = default_to_stg env deflt `thenUs` \ deflt' ->
+ mapUs (prim_alt_to_stg env) alts `thenUs` \ alts' ->
+ returnUs (StgPrimAlts scrut_ty alts' deflt')
+
+ | otherwise
+ = default_to_stg env deflt `thenUs` \ deflt' ->
+ mapUs (alg_alt_to_stg env) alts `thenUs` \ alts' ->
+ returnUs (StgAlgAlts scrut_ty alts' deflt')
+
+ alg_alt_to_stg env (DataCon con, bs, rhs)
+ = coreExprToStg env rhs `thenUs` \ stg_rhs ->
+ returnUs (con, filter isId bs, [ True | b <- bs ]{-bogus use mask-}, stg_rhs)
+ -- NB the filter isId. Some of the binders may be
+ -- existential type variables, which STG doesn't care about
+
+ prim_alt_to_stg env (Literal lit, args, rhs)
+ = ASSERT( null args )
+ coreExprToStg env rhs `thenUs` \ stg_rhs ->
+ returnUs (lit, stg_rhs)
+
+ default_to_stg env Nothing
+ = returnUs StgNoDefault
+
+ default_to_stg env (Just rhs)
+ = coreExprToStg env rhs `thenUs` \ stg_rhs ->
+ returnUs (StgBindDefault stg_rhs)
+ -- The binder is used for prim cases and not otherwise
+ -- (hack for old code gen)
\end{code}
\begin{code}
-coreExprToStg env (Coerce c ty expr)
- = coreExprToStg env expr -- `thenUs` \ (stg_expr, binds) ->
--- returnUs (StgSCC (coreExprType expr) cc stg_expr, binds)
+coreExprToStgFloat env expr
+ = coreExprToStg env expr `thenUs` \stg_expr ->
+ returnUs ([], stg_expr)
\end{code}
-
%************************************************************************
%* *
\subsection[coreToStg-misc]{Miscellaneous helping functions}
%* *
%************************************************************************
-Utilities.
+There's not anything interesting we can ASSERT about \tr{var} if it
+isn't in the StgEnv. (WDP 94/06)
+
+\begin{code}
+stgLookup :: StgEnv -> Id -> Id
+stgLookup env var = case (lookupVarEnv env var) of
+ Nothing -> var
+ Just var -> var
+\end{code}
Invent a fresh @Id@:
\begin{code}
newStgVar :: Type -> UniqSM Id
newStgVar ty
- = getUnique `thenUs` \ uniq ->
- returnUs (mkSysLocal SLIT("stg") uniq ty mkUnknownSrcLoc)
+ = getUniqueUs `thenUs` \ uniq ->
+ returnUs (mkSysLocal SLIT("stg") uniq ty)
+\end{code}
+
+\begin{code}
+newLocalId env id
+ | externallyVisibleId id
+ = returnUs (env, id)
+
+ | otherwise
+ = -- Local binder, give it a new unique Id.
+ getUniqueUs `thenUs` \ uniq ->
+ let
+ id' = setIdUnique id uniq
+ new_env = extendVarEnv env id id'
+ in
+ returnUs (new_env, id')
+
+newLocalIds :: StgEnv -> [Id] -> UniqSM (StgEnv, [Id])
+newLocalIds env []
+ = returnUs (env, [])
+newLocalIds env (b:bs)
+ = newLocalId env b `thenUs` \ (env', b') ->
+ newLocalIds env' bs `thenUs` \ (env'', bs') ->
+ returnUs (env'', b':bs')
\end{code}
+
\begin{code}
-mkStgLets :: [StgBinding]
- -> StgExpr -- body of let
- -> StgExpr
+mkStgBinds :: [StgFloatBind] -> StgExpr -> StgExpr
+mkStgBinds binds body = foldr mkStgBind body binds
+
+mkStgBind (CaseBind bndr rhs) body
+ | isUnLiftedType bndr_ty
+ = mkStgCase rhs bndr (StgPrimAlts bndr_ty [] (StgBindDefault body))
+ | otherwise
+ = mkStgCase rhs bndr (StgAlgAlts bndr_ty [] (StgBindDefault body))
+ where
+ bndr_ty = idType bndr
+
+mkStgBind (LetBind bndr rhs) body
+ | isUnboxedTupleType bndr_ty
+ = panic "mkStgBinds: unboxed tuple"
+ | isUnLiftedType bndr_ty
+ = mkStgCase rhs bndr (StgPrimAlts bndr_ty [] (StgBindDefault body))
+
+ | otherwise
+ = StgLet (StgNonRec bndr (exprToRhs rhs)) body
+ where
+ bndr_ty = idType bndr
-mkStgLets binds body = foldr StgLet body binds
+mkStgCase (StgLet bind expr) bndr alts
+ = StgLet bind (mkStgCase expr bndr alts)
+mkStgCase scrut bndr alts
+ = StgCase scrut bOGUS_LVs bOGUS_LVs bndr noSRT alts
\end{code}
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