Convert a @CoreSyntax@ program to a @StgSyntax@ program.
-
\begin{code}
#include "HsVersions.h"
module CoreToStg ( topCoreBindsToStg ) where
-import Ubiq{-uitous-}
+IMP_Ubiq(){-uitous-}
+IMPORT_1_3(Ratio(numerator,denominator))
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 Id ( mkSysLocal, idType, isBottomingId, addIdArity,
+ externallyVisibleId,
+ nullIdEnv, addOneToIdEnv, lookupIdEnv, growIdEnvList,
+ SYN_IE(IdEnv), GenId{-instance NamedThing-}
)
+import IdInfo ( ArityInfo, exactArity )
import Literal ( mkMachInt, Literal(..) )
-import Name ( isExported )
-import PrelInfo ( unpackCStringId, unpackCString2Id, stringTy,
- integerTy, rationalTy, ratioDataCon,
+import PrelVals ( unpackCStringId, unpackCString2Id,
integerZeroId, integerPlusOneId,
integerPlusTwoId, integerMinusOneId
)
import PrimOp ( PrimOp(..) )
import SpecUtils ( mkSpecialisedCon )
-import SrcLoc ( mkUnknownSrcLoc )
-import Type ( getAppDataTyCon )
+import SrcLoc ( noSrcLoc )
+import TyCon ( TyCon{-instance Uniquable-} )
+import Type ( maybeAppDataTyCon, getAppDataTyConExpandingDicts )
+import TysWiredIn ( stringTy )
+import Unique ( integerTyConKey, ratioTyConKey, Unique{-instance Eq-} )
import UniqSupply -- all of it, really
-import Util ( panic )
+import Util ( zipLazy, 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
\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 pin correct arities on each let(rec)-bound binder, and propagate them
+ to their uses. This is used
+ a) when emitting arity info into interface files
+ b) in the code generator, when deciding if a right-hand side
+ is a saturated application so we can generate a VAP closure.
+ (b) is rather untidy, but the easiest compromise was to propagate arities here.
* 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]
%************************************************************************
-> [StgBinding] -- output
topCoreBindsToStg us core_binds
- = case (initUs us (binds_to_stg nullIdEnv core_binds)) of
+ = case (initUs us (coreBindsToStg nullIdEnv core_binds)) of
(_, stuff) -> stuff
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
+ coreBindsToStg :: StgEnv -> [CoreBinding] -> UniqSM [StgBinding]
- is_liftable (StgRec [(_, StgRhsClosure _ _ _ _ args body)])
- = not (null args) -- it's manifestly a (recursive) function...
-
- is_liftable anything_else = False
+ 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}
%************************************************************************
coreBindToStg :: StgEnv
-> CoreBinding
-> 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) ->
-
+ = coreRhsToStg env rhs `thenUs` \ stg_rhs ->
let
-- Binds to return if RHS is trivial
- triv_binds = if isExported binder then
- [StgNonRec binder stg_rhs] -- Retain it
- else
- [] -- Discard it
+ triv_binds | externallyVisibleId binder = [StgNonRec binder stg_rhs] -- Retain it
+ | otherwise = [] -- 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)
+ returnUs (triv_binds, new_env)
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)
+ returnUs (triv_binds, new_env)
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)
+ returnUs ([StgNonRec binder_w_arity stg_rhs], new_env)
+ where
+ binder_w_arity = binder `addIdArity` (rhsArity stg_rhs)
+ new_env = addOneToIdEnv env binder (StgVarArg binder_w_arity)
+ -- new_env propagates the arity
coreBindToStg env (Rec pairs)
= -- NB: *** WE DO NOT CHECK FOR TRIV_BINDS in REC BIND ****
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)
+ mapUs (coreRhsToStg env) rhss `thenUs` \ stg_rhss ->
+ let
+ binders_w_arities = [ b `addIdArity` rhsArity rhs
+ | (b,rhs) <- binders `zip` stg_rhss]
+ in
+ returnUs ([StgRec (binders_w_arities `zip` stg_rhss)], env)
+
+rhsArity (StgRhsClosure _ _ _ _ args _) = exactArity (length args)
+rhsArity (StgRhsCon _ _ _) = exactArity 0
\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) ->
+ = coreExprToStg env core_rhs `thenUs` \ stg_expr ->
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
+ -- incoming rhs. Why? Because trivial bindings might conceal
+ -- what the rhs is actually like.
StgCon con args _ -> StgRhsCon noCostCentre con args
[]
stg_expr
in
- returnUs (stg_rhs, stg_binds)
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection[coreToStg-lits]{Converting literals}
-%* *
-%************************************************************************
-
-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
-
-litToStgArg :: Literal -> UniqSM (StgArg, Bag StgBinding)
-
-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'
-
-litToStgArg (NoRepInteger i)
- -- 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 integerTy `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)
- = litToStgArg (NoRepInteger (numerator r)) `thenUs` \ (num_atom, binds1) ->
- litToStgArg (NoRepInteger (denominator r)) `thenUs` \ (denom_atom, binds2) ->
- newStgVar rationalTy `thenUs` \ var ->
- let
- rhs = StgRhsCon noCostCentre -- No cost centre (ToDo?)
- ratioDataCon -- Constructor
- [num_atom, denom_atom]
- in
- returnUs (StgVarArg var, binds1 `unionBags`
- binds2 `unionBags`
- unitBag (StgNonRec var rhs))
-
-litToStgArg other_lit = returnUs (StgLitArg other_lit, emptyBag)
+ returnUs stg_rhs
\end{code}
%************************************************************************
\begin{code}
-coreArgsToStg :: StgEnv -> [CoreArg] -> UniqSM ([Type], [StgArg], Bag StgBinding)
+coreArgsToStg :: StgEnv -> [CoreArg] -> ([Type], [StgArg])
-coreArgsToStg env [] = returnUs ([], [], emptyBag)
+coreArgsToStg env [] = ([], [])
coreArgsToStg env (a:as)
- = coreArgsToStg env as `thenUs` \ (tys, args, binds) ->
- do_arg a tys args binds
+ = case a of
+ TyArg t -> (t:trest, vrest)
+ UsageArg u -> (trest, vrest)
+ VarArg v -> (trest, stgLookup env v : vrest)
+ LitArg l -> (trest, StgLitArg l : vrest)
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)
+ (trest,vrest) = coreArgsToStg env as
\end{code}
-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}
%************************************************************************
%* *
%************************************************************************
\begin{code}
-coreExprToStg :: StgEnv
- -> CoreExpr
- -> UniqSM (StgExpr, -- Result
- Bag StgBinding) -- Float these to top level
-\end{code}
+coreExprToStg :: StgEnv -> CoreExpr -> UniqSM StgExpr
-\begin{code}
coreExprToStg env (Lit lit)
- = litToStgArg lit `thenUs` \ (atom, binds) ->
- returnUs (StgApp atom [] bOGUS_LVs, binds)
+ = returnUs (StgApp (StgLitArg lit) [] bOGUS_LVs)
coreExprToStg env (Var var)
- = returnUs (StgApp (stgLookup env var) [] bOGUS_LVs, emptyBag)
+ = returnUs (StgApp (stgLookup env var) [] bOGUS_LVs)
coreExprToStg env (Con con args)
- = coreArgsToStg env args `thenUs` \ (types, stg_atoms, stg_binds) ->
- let
+ = let
+ (types, stg_atoms) = coreArgsToStg env args
spec_con = mkSpecialisedCon con types
in
- returnUs (StgCon spec_con stg_atoms bOGUS_LVs, stg_binds)
+ returnUs (StgCon spec_con stg_atoms bOGUS_LVs)
coreExprToStg env (Prim op args)
- = coreArgsToStg env args `thenUs` \ (_, stg_atoms, stg_binds) ->
- returnUs (StgPrim op stg_atoms bOGUS_LVs, stg_binds)
+ = let
+ (types, stg_atoms) = coreArgsToStg env args
+ in
+ returnUs (StgPrim op stg_atoms bOGUS_LVs)
\end{code}
%************************************************************************
= let
(_,_, binders, body) = collectBinders expr
in
- coreExprToStg env body `thenUs` \ (stg_body, binds) ->
- newStgVar (coreExprType expr) `thenUs` \ var ->
- returnUs
- (StgLet (StgNonRec var (StgRhsClosure noCostCentre
- stgArgOcc
- bOGUS_FVs
- ReEntrant -- binders is non-empty
- binders
- stg_body))
- (StgApp (StgVarArg var) [] bOGUS_LVs),
- binds)
+ coreExprToStg env body `thenUs` \ stg_body ->
+
+ if null binders then -- it was all type/usage binders; tossed
+ returnUs stg_body
+ else
+ newStgVar (coreExprType expr) `thenUs` \ var ->
+ returnUs
+ (StgLet (StgNonRec (var `addIdArity` exactArity (length binders))
+ (StgRhsClosure noCostCentre
+ stgArgOcc
+ bOGUS_FVs
+ ReEntrant -- binders is non-empty
+ binders
+ stg_body))
+ (StgApp (StgVarArg var) [] bOGUS_LVs))
\end{code}
%************************************************************************
\begin{code}
coreExprToStg env expr@(App _ _)
= let
- (fun, _, _, args) = collectArgs expr
+ (fun,args) = collect_args expr []
+ (_, stg_args) = coreArgsToStg env args
in
- -- Deal with the arguments
- coreArgsToStg env args `thenUs` \ (_, stg_args, arg_binds) ->
-
-- 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, args) of
+ (Var fun_id, _) -> -- A function Id, so do an StgApp; it's ok if
+ -- there are no arguments.
+ returnUs (StgApp (stgLookup env fun_id) stg_args bOGUS_LVs)
+
+ (non_var_fun, []) -> -- No value args, so recurse into the function
+ coreExprToStg env non_var_fun
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?)
stgArgOcc
stg_fun
in
returnUs (StgLet (StgNonRec fun_id fun_rhs)
- (StgApp (StgVarArg fun_id) stg_args bOGUS_LVs),
- arg_binds `unionBags` fun_binds)
+ (StgApp (StgVarArg fun_id) stg_args bOGUS_LVs))
+ where
+ -- Collect arguments, discarding type/usage applications
+ collect_args (App e (TyArg _)) args = collect_args e args
+ collect_args (App e (UsageArg _)) args = collect_args e args
+ collect_args (App fun arg) args = collect_args fun (arg:args)
+ collect_args fun args = (fun, args)
\end{code}
%************************************************************************
%* *
%************************************************************************
-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) ->
+ = coreExprToStg env discrim `thenUs` \ stg_discrim ->
+ alts_to_stg discrim alts `thenUs` \ stg_alts ->
getUnique `thenUs` \ uniq ->
returnUs (
StgCase stg_discrim
bOGUS_LVs
bOGUS_LVs
uniq
- stg_alts,
- discrim_binds `unionBags` alts_binds
+ stg_alts
)
where
discrim_ty = coreExprType discrim
- (_, discrim_ty_args, _) = getAppDataTyCon discrim_ty
+ (_, 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)
+ = default_to_stg discrim deflt `thenUs` \ stg_deflt ->
+ mapUs boxed_alt_to_stg alts `thenUs` \ stg_alts ->
+ returnUs (StgAlgAlts discrim_ty stg_alts stg_deflt)
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)
+ = coreExprToStg env rhs `thenUs` \ stg_rhs ->
+ returnUs (spec_con, bs, [ True | b <- bs ]{-bogus use mask-}, stg_rhs)
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)
+ = default_to_stg discrim deflt `thenUs` \ stg_deflt ->
+ mapUs unboxed_alt_to_stg alts `thenUs` \ stg_alts ->
+ returnUs (StgPrimAlts discrim_ty stg_alts stg_deflt)
where
unboxed_alt_to_stg (lit, rhs)
- = coreExprToStg env rhs `thenUs` \ (stg_rhs, rhs_binds) ->
- returnUs ((lit, stg_rhs), rhs_binds)
+ = coreExprToStg env rhs `thenUs` \ stg_rhs ->
+ returnUs (lit, stg_rhs)
default_to_stg discrim NoDefault
- = returnUs (StgNoDefault, emptyBag)
+ = returnUs StgNoDefault
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
+ = coreExprToStg env rhs `thenUs` \ stg_rhs ->
+ returnUs (StgBindDefault binder True{-used? no it is lying-} stg_rhs)
\end{code}
%************************************************************************
\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)
+ = coreBindToStg env bind `thenUs` \ (stg_binds, new_env) ->
+ coreExprToStg new_env body `thenUs` \ stg_body ->
+ returnUs (mkStgLets stg_binds stg_body)
\end{code}
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)
+ = coreExprToStg env expr `thenUs` \ stg_expr ->
+ returnUs (StgSCC (coreExprType expr) cc stg_expr)
+\end{code}
+
+\begin{code}
+coreExprToStg env (Coerce c ty expr) = coreExprToStg env expr
\end{code}
%* *
%************************************************************************
-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 -> StgArg
+stgLookup env var = case (lookupIdEnv env var) of
+ Nothing -> StgVarArg var
+ Just atom -> atom
+\end{code}
Invent a fresh @Id@:
\begin{code}
newStgVar :: Type -> UniqSM Id
newStgVar ty
= getUnique `thenUs` \ uniq ->
- returnUs (mkSysLocal SLIT("stg") uniq ty mkUnknownSrcLoc)
+ returnUs (mkSysLocal SLIT("stg") uniq ty noSrcLoc)
\end{code}
\begin{code}
projects / ghc-hetmet.git / blobdiff