%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[CgBindery]{Utility functions related to doing @CgBindings@}
\begin{code}
-#include "HsVersions.h"
-
module CgBindery (
- CgBindings(..), CgIdInfo(..){-dubiously concrete-},
- StableLoc, VolatileLoc, LambdaFormInfo{-re-exported-},
-
- maybeAStkLoc, maybeBStkLoc,
+ CgBindings, CgIdInfo,
+ StableLoc, VolatileLoc,
stableAmodeIdInfo, heapIdInfo, newTempAmodeAndIdInfo,
letNoEscapeIdInfo, idInfoToAmode,
+ addBindC, addBindsC,
+
nukeVolatileBinds,
+ nukeDeadBindings,
- bindNewToAStack, bindNewToBStack,
+ bindNewToStack, rebindToStack,
bindNewToNode, bindNewToReg, bindArgsToRegs,
---UNUSED: bindNewToSameAsOther,
bindNewToTemp, bindNewPrimToAmode,
- getAtomAmode, getAtomAmodes,
+ getArgAmode, getArgAmodes,
getCAddrModeAndInfo, getCAddrMode,
getCAddrModeIfVolatile, getVolatileRegs,
- rebindToAStack, rebindToBStack,
---UNUSED: rebindToTemp,
- -- and to make a self-sufficient interface...
- AbstractC, CAddrMode, HeapOffset, MagicId, CLabel, CgState,
- BasicLit, IdEnv(..), UniqFM,
- Id, Maybe, Unique, StgAtom, UniqSet(..)
+ buildLivenessMask, buildContLivenessMask
) where
-IMPORT_Trace -- ToDo: rm (debugging only)
-import Outputable
-import Unpretty
-import PprAbsC
+#include "HsVersions.h"
import AbsCSyn
import CgMonad
-import CgUsages ( getHpRelOffset, getSpARelOffset, getSpBRelOffset )
-import CLabelInfo ( mkClosureLabel, CLabel )
-import ClosureInfo
-import Id ( getIdKind, toplevelishId, isDataCon, Id )
-import IdEnv -- used to build CgBindings
-import Maybes ( catMaybes, Maybe(..) )
-import UniqSet -- ( setToList )
-import StgSyn
-import Util
+import CgUsages ( getHpRelOffset, getSpRelOffset, getRealSp )
+import CgStackery ( freeStackSlots )
+import CLabel ( mkClosureLabel,
+ mkBitmapLabel, pprCLabel )
+import ClosureInfo ( mkLFImported, mkLFArgument, LambdaFormInfo )
+import BitSet ( mkBS, emptyBS )
+import PrimRep ( isFollowableRep, getPrimRepSize )
+import Id ( Id, idPrimRep, idType )
+import Type ( typePrimRep )
+import VarEnv
+import VarSet ( varSetElems )
+import Literal ( Literal )
+import Maybes ( catMaybes, maybeToBool )
+import Name ( isLocalName, NamedThing(..) )
+#ifdef DEBUG
+import PprAbsC ( pprAmode )
+#endif
+import PrimRep ( PrimRep(..) )
+import StgSyn ( StgArg, StgLiveVars, GenStgArg(..), isStgTypeArg )
+import Unique ( Unique, Uniquable(..) )
+import UniqSet ( elementOfUniqSet )
+import Util ( zipWithEqual, sortLt )
+import Outputable
\end{code}
| VirNodeLoc VirtualHeapOffset -- Cts of offset indirect from Node
-- ie *(Node+offset)
+\end{code}
+
+@StableLoc@ encodes where an Id can be found, used by
+the @CgBindings@ environment in @CgBindery@.
+\begin{code}
data StableLoc
= NoStableLoc
- | VirAStkLoc VirtualSpAOffset
- | VirBStkLoc VirtualSpBOffset
- | LitLoc BasicLit
+ | VirStkLoc VirtualSpOffset
+ | LitLoc Literal
| StableAmodeLoc CAddrMode
-- these are so StableLoc can be abstract:
-maybeAStkLoc (VirAStkLoc offset) = Just offset
-maybeAStkLoc _ = Nothing
-
-maybeBStkLoc (VirBStkLoc offset) = Just offset
-maybeBStkLoc _ = Nothing
+maybeStkLoc (VirStkLoc offset) = Just offset
+maybeStkLoc _ = Nothing
\end{code}
%************************************************************************
heapIdInfo i offset lf_info = MkCgIdInfo i (VirHpLoc offset) NoStableLoc lf_info
tempIdInfo i uniq lf_info = MkCgIdInfo i (TempVarLoc uniq) NoStableLoc lf_info
-letNoEscapeIdInfo i spa spb lf_info
- = MkCgIdInfo i NoVolatileLoc (StableAmodeLoc (CJoinPoint spa spb)) lf_info
+letNoEscapeIdInfo i sp lf_info
+ = MkCgIdInfo i NoVolatileLoc (StableAmodeLoc (CJoinPoint sp)) lf_info
newTempAmodeAndIdInfo :: Id -> LambdaFormInfo -> (CAddrMode, CgIdInfo)
newTempAmodeAndIdInfo name lf_info
= (temp_amode, temp_idinfo)
where
- uniq = getTheUnique name
- temp_amode = CTemp uniq (getIdKind name)
+ uniq = getUnique name
+ temp_amode = CTemp uniq (idPrimRep name)
temp_idinfo = tempIdInfo name uniq lf_info
-idInfoToAmode :: PrimKind -> CgIdInfo -> FCode CAddrMode
+idInfoToAmode :: PrimRep -> CgIdInfo -> FCode CAddrMode
idInfoToAmode kind (MkCgIdInfo _ vol stab _) = idInfoPiecesToAmode kind vol stab
-idInfoPiecesToAmode :: PrimKind -> VolatileLoc -> StableLoc -> FCode CAddrMode
+idInfoPiecesToAmode :: PrimRep -> VolatileLoc -> StableLoc -> FCode CAddrMode
idInfoPiecesToAmode kind (TempVarLoc uniq) stable_loc = returnFC (CTemp uniq kind)
idInfoPiecesToAmode kind (RegLoc magic_id) stable_loc = returnFC (CReg magic_id)
idInfoPiecesToAmode kind NoVolatileLoc (StableAmodeLoc amode) = returnFC amode
idInfoPiecesToAmode kind (VirNodeLoc nd_off) stable_loc
- = returnFC (CVal (NodeRel nd_off) kind)
+ = returnFC (CVal (nodeRel nd_off) kind)
-- Virtual offsets from Node increase into the closures,
-- and so do Node-relative offsets (which we want in the CVal),
-- so there is no mucking about to do to the offset.
= getHpRelOffset hp_off `thenFC` \ rel_hp ->
returnFC (CAddr rel_hp)
-idInfoPiecesToAmode kind NoVolatileLoc (VirAStkLoc i)
- = getSpARelOffset i `thenFC` \ rel_spA ->
- returnFC (CVal rel_spA kind)
-
-idInfoPiecesToAmode kind NoVolatileLoc (VirBStkLoc i)
- = getSpBRelOffset i `thenFC` \ rel_spB ->
- returnFC (CVal rel_spB kind)
+idInfoPiecesToAmode kind NoVolatileLoc (VirStkLoc i)
+ = getSpRelOffset i `thenFC` \ rel_sp ->
+ returnFC (CVal rel_sp kind)
+#ifdef DEBUG
idInfoPiecesToAmode kind NoVolatileLoc NoStableLoc = panic "idInfoPiecesToAmode: no loc"
+#endif
+\end{code}
+
+%************************************************************************
+%* *
+\subsection[CgMonad-bindery]{Monad things for fiddling with @CgBindings@}
+%* *
+%************************************************************************
+
+There are three basic routines, for adding (@addBindC@), modifying
+(@modifyBindC@) and looking up (@lookupBindC@) bindings.
+
+A @Id@ is bound to a @(VolatileLoc, StableLoc)@ triple.
+The name should not already be bound. (nice ASSERT, eh?)
+
+\begin{code}
+addBindC :: Id -> CgIdInfo -> Code
+addBindC name stuff_to_bind = do
+ binds <- getBinds
+ setBinds $ extendVarEnv binds name stuff_to_bind
+
+addBindsC :: [(Id, CgIdInfo)] -> Code
+addBindsC new_bindings = do
+ binds <- getBinds
+ let new_binds = foldl (\ binds (name,info) -> extendVarEnv binds name info)
+ binds
+ new_bindings
+ setBinds new_binds
+
+modifyBindC :: Id -> (CgIdInfo -> CgIdInfo) -> Code
+modifyBindC name mangle_fn = do
+ binds <- getBinds
+ setBinds $ modifyVarEnv mangle_fn binds name
+
+lookupBindC :: Id -> FCode CgIdInfo
+lookupBindC name = do
+ static_binds <- getStaticBinds
+ local_binds <- getBinds
+ case (lookupVarEnv local_binds name) of
+ Nothing -> case (lookupVarEnv static_binds name) of
+ Nothing -> cgPanic (text "lookupBindC: no info for" <+> ppr name)
+ Just this -> return this
+ Just this -> return this
+
+cgPanic :: SDoc -> FCode a
+cgPanic doc = do
+ static_binds <- getStaticBinds
+ local_binds <- getBinds
+ srt <- getSRTLabel
+ pprPanic "cgPanic"
+ (vcat [doc,
+ ptext SLIT("static binds for:"),
+ vcat [ ppr i | (MkCgIdInfo i _ _ _) <- rngVarEnv static_binds ],
+ ptext SLIT("local binds for:"),
+ vcat [ ppr i | (MkCgIdInfo i _ _ _) <- rngVarEnv local_binds ],
+ ptext SLIT("SRT label") <+> pprCLabel srt
+ ])
\end{code}
%************************************************************************
\begin{code}
nukeVolatileBinds :: CgBindings -> CgBindings
nukeVolatileBinds binds
- = mkIdEnv (foldr keep_if_stable [] (rngIdEnv binds))
+ = mkVarEnv (foldr keep_if_stable [] (rngVarEnv binds))
where
keep_if_stable (MkCgIdInfo i _ NoStableLoc entry_info) acc = acc
keep_if_stable (MkCgIdInfo i _ stable_loc entry_info) acc
I {\em think} all looking-up is done through @getCAddrMode(s)@.
\begin{code}
-getCAddrModeAndInfo :: Id -> FCode (CAddrMode, LambdaFormInfo)
+getCAddrModeAndInfo :: Id -> FCode (Id, CAddrMode, LambdaFormInfo)
-getCAddrModeAndInfo name
- | not (isLocallyDefined name)
- = returnFC (global_amode, mkLFImported name)
+getCAddrModeAndInfo id
+ | not (isLocalName name)
+ = returnFC (id, global_amode, mkLFImported id)
+ -- deals with imported or locally defined but externally visible ids
+ -- (CoreTidy makes all these into global names).
- | isDataCon name
- = returnFC (global_amode, mkConLFInfo name)
-
- | otherwise = -- *might* be a nested defn: in any case, it's something whose
+ | otherwise = do -- *might* be a nested defn: in any case, it's something whose
-- definition we will know about...
- lookupBindC name `thenFC` \ (MkCgIdInfo _ volatile_loc stable_loc lf_info) ->
- idInfoPiecesToAmode kind volatile_loc stable_loc `thenFC` \ amode ->
- returnFC (amode, lf_info)
+ (MkCgIdInfo id' volatile_loc stable_loc lf_info) <- lookupBindC id
+ amode <- idInfoPiecesToAmode kind volatile_loc stable_loc
+ return (id', amode, lf_info)
where
+ name = getName id
global_amode = CLbl (mkClosureLabel name) kind
- kind = getIdKind name
+ kind = idPrimRep id
getCAddrMode :: Id -> FCode CAddrMode
-getCAddrMode name
- = getCAddrModeAndInfo name `thenFC` \ (amode, _) ->
- returnFC amode
+getCAddrMode name = do
+ (_, amode, _) <- getCAddrModeAndInfo name
+ return amode
\end{code}
\begin{code}
getCAddrModeIfVolatile :: Id -> FCode (Maybe CAddrMode)
getCAddrModeIfVolatile name
- | toplevelishId name = returnFC Nothing
- | otherwise
- = lookupBindC name `thenFC` \ ~(MkCgIdInfo _ volatile_loc stable_loc lf_info) ->
- case stable_loc of
- NoStableLoc -> -- Aha! So it is volatile!
- idInfoPiecesToAmode (getIdKind name) volatile_loc NoStableLoc `thenFC` \ amode ->
- returnFC (Just amode)
-
- a_stable_loc -> returnFC Nothing
+-- | toplevelishId name = returnFC Nothing
+-- | otherwise
+ = do
+ (MkCgIdInfo _ volatile_loc stable_loc lf_info) <- lookupBindC name
+ case stable_loc of
+ NoStableLoc -> do -- Aha! So it is volatile!
+ amode <- idInfoPiecesToAmode (idPrimRep name) volatile_loc NoStableLoc
+ return $ Just amode
+ a_stable_loc -> return Nothing
\end{code}
@getVolatileRegs@ gets a set of live variables, and returns a list of
forget the volatile one.
\begin{code}
-getVolatileRegs :: PlainStgLiveVars -> FCode [MagicId]
-
-getVolatileRegs vars
- = mapFCs snaffle_it (uniqSetToList vars) `thenFC` \ stuff ->
- returnFC (catMaybes stuff)
- where
- snaffle_it var
- = lookupBindC var `thenFC` \ (MkCgIdInfo _ volatile_loc stable_loc lf_info) ->
- let
- -- commoned-up code...
- consider_reg reg
- = if not (isVolatileReg reg) then
- -- Potentially dies across C calls
- -- For now, that's everything; we leave
- -- it to the save-macros to decide which
- -- regs *really* need to be saved.
- returnFC Nothing
- else
- case stable_loc of
- NoStableLoc -> returnFC (Just reg) -- got one!
- is_a_stable_loc ->
- -- has both volatile & stable locations;
- -- force it to rely on the stable location
- modifyBindC var nuke_vol_bind `thenC`
- returnFC Nothing
- in
- case volatile_loc of
- RegLoc reg -> consider_reg reg
- VirHpLoc _ -> consider_reg Hp
- VirNodeLoc _ -> consider_reg node
- non_reg_loc -> returnFC Nothing
-
- nuke_vol_bind (MkCgIdInfo i _ stable_loc lf_info)
- = MkCgIdInfo i NoVolatileLoc stable_loc lf_info
+getVolatileRegs :: StgLiveVars -> FCode [MagicId]
+
+getVolatileRegs vars = do
+ stuff <- mapFCs snaffle_it (varSetElems vars)
+ returnFC $ catMaybes stuff
+ where
+ snaffle_it var = do
+ (MkCgIdInfo _ volatile_loc stable_loc lf_info) <- lookupBindC var
+ let
+ -- commoned-up code...
+ consider_reg reg =
+ if not (isVolatileReg reg) then
+ -- Potentially dies across C calls
+ -- For now, that's everything; we leave
+ -- it to the save-macros to decide which
+ -- regs *really* need to be saved.
+ returnFC Nothing
+ else
+ case stable_loc of
+ NoStableLoc -> returnFC (Just reg) -- got one!
+ is_a_stable_loc -> do
+ -- has both volatile & stable locations;
+ -- force it to rely on the stable location
+ modifyBindC var nuke_vol_bind
+ return Nothing
+ in
+ case volatile_loc of
+ RegLoc reg -> consider_reg reg
+ VirHpLoc _ -> consider_reg Hp
+ VirNodeLoc _ -> consider_reg node
+ non_reg_loc -> returnFC Nothing
+
+ nuke_vol_bind (MkCgIdInfo i _ stable_loc lf_info)
+ = MkCgIdInfo i NoVolatileLoc stable_loc lf_info
\end{code}
\begin{code}
-getAtomAmodes :: [PlainStgAtom] -> FCode [CAddrMode]
-getAtomAmodes [] = returnFC []
-getAtomAmodes (atom:atoms)
- = getAtomAmode atom `thenFC` \ amode ->
- getAtomAmodes atoms `thenFC` \ amodes ->
- returnFC ( amode : amodes )
-
-getAtomAmode :: PlainStgAtom -> FCode CAddrMode
-
-getAtomAmode (StgVarAtom var) = getCAddrMode var
-getAtomAmode (StgLitAtom lit) = returnFC (CLit lit)
+getArgAmodes :: [StgArg] -> FCode [CAddrMode]
+getArgAmodes [] = returnFC []
+getArgAmodes (atom:atoms)
+ | isStgTypeArg atom
+ = getArgAmodes atoms
+ | otherwise = do
+ amode <- getArgAmode atom
+ amodes <- getArgAmodes atoms
+ return ( amode : amodes )
+
+getArgAmode :: StgArg -> FCode CAddrMode
+
+getArgAmode (StgVarArg var) = getCAddrMode var -- The common case
+getArgAmode (StgLitArg lit) = returnFC (CLit lit)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-bindNewToAStack :: (Id, VirtualSpAOffset) -> Code
-bindNewToAStack (name, offset)
- = addBindC name info
- where
- info = MkCgIdInfo name NoVolatileLoc (VirAStkLoc offset) mkLFArgument
-
-bindNewToBStack :: (Id, VirtualSpBOffset) -> Code
-bindNewToBStack (name, offset)
+bindNewToStack :: (Id, VirtualSpOffset) -> Code
+bindNewToStack (name, offset)
= addBindC name info
where
- info = MkCgIdInfo name NoVolatileLoc (VirBStkLoc offset) (panic "bindNewToBStack")
- -- B-stack things shouldn't need lambda-form info!
+ info = MkCgIdInfo name NoVolatileLoc (VirStkLoc offset) mkLFArgument
bindNewToNode :: Id -> VirtualHeapOffset -> LambdaFormInfo -> Code
bindNewToNode name offset lf_info
-- This is used only for things we don't know
-- anything about; values returned by a case statement,
-- for example.
- in
- addBindC name id_info `thenC`
- returnFC temp_amode
+ in do
+ addBindC name id_info
+ return temp_amode
bindNewToReg :: Id -> MagicId -> LambdaFormInfo -> Code
bindNewToReg name magic_id lf_info
where
info = MkCgIdInfo name (RegLoc magic_id) NoStableLoc lf_info
-bindNewToLit name lit
- = addBindC name info
- where
- info = MkCgIdInfo name NoVolatileLoc (LitLoc lit) (error "bindNewToLit")
-
bindArgsToRegs :: [Id] -> [MagicId] -> Code
bindArgsToRegs args regs
- = listCs (zipWith bind args regs)
- where
- arg `bind` reg = bindNewToReg arg reg mkLFArgument
-
-{- UNUSED:
-bindNewToSameAsOther :: Id -> PlainStgAtom -> Code
-bindNewToSameAsOther name (StgVarAtom old_name)
-#ifdef DEBUG
- | toplevelishId old_name = panic "bindNewToSameAsOther: global old name"
- | otherwise
-#endif
- = lookupBindC old_name `thenFC` \ old_stuff ->
- addBindC name old_stuff
-
-bindNewToSameAsOther name (StgLitAtom lit)
- = addBindC name info
+ = listCs (zipWithEqual "bindArgsToRegs" bind args regs)
where
- info = MkCgIdInfo name NoVolatileLoc (LitLoc lit) (panic "bindNewToSameAsOther")
--}
+ arg `bind` reg = bindNewToReg arg reg mkLFArgument
\end{code}
-@bindNewPrimToAmode@ works only for certain addressing modes, because
-those are the only ones we've needed so far!
+@bindNewPrimToAmode@ works only for certain addressing modes. Making
+this work for stack offsets is non-trivial (virt vs. real stack offset
+difficulties).
\begin{code}
bindNewPrimToAmode :: Id -> CAddrMode -> Code
-bindNewPrimToAmode name (CReg reg) = bindNewToReg name reg (panic "bindNewPrimToAmode")
- -- was: mkLFArgument
- -- LFinfo is irrelevant for primitives
+bindNewPrimToAmode name (CReg reg)
+ = bindNewToReg name reg (panic "bindNewPrimToAmode")
+
bindNewPrimToAmode name (CTemp uniq kind)
= addBindC name (tempIdInfo name uniq (panic "bindNewPrimToAmode"))
- -- LFinfo is irrelevant for primitives
-
-bindNewPrimToAmode name (CLit lit) = bindNewToLit name lit
-
-bindNewPrimToAmode name (CVal (SpBRel _ offset) _)
- = bindNewToBStack (name, offset)
-
-bindNewPrimToAmode name (CVal (NodeRel offset) _)
- = bindNewToNode name offset (panic "bindNewPrimToAmode node")
- -- See comment on idInfoPiecesToAmode for VirNodeLoc
#ifdef DEBUG
bindNewPrimToAmode name amode
- = panic ("bindNew...:"++(uppShow 80 (pprAmode PprDebug amode)))
+ = pprPanic "bindNew...:" (pprAmode amode)
#endif
\end{code}
\begin{code}
-rebindToAStack :: Id -> VirtualSpAOffset -> Code
-rebindToAStack name offset
+rebindToStack :: Id -> VirtualSpOffset -> Code
+rebindToStack name offset
= modifyBindC name replace_stable_fn
where
replace_stable_fn (MkCgIdInfo i vol stab einfo)
- = MkCgIdInfo i vol (VirAStkLoc offset) einfo
+ = MkCgIdInfo i vol (VirStkLoc offset) einfo
+\end{code}
-rebindToBStack :: Id -> VirtualSpBOffset -> Code
-rebindToBStack name offset
- = modifyBindC name replace_stable_fn
- where
- replace_stable_fn (MkCgIdInfo i vol stab einfo)
- = MkCgIdInfo i vol (VirBStkLoc offset) einfo
-
-{- UNUSED:
-rebindToTemp :: Id -> FCode CAddrMode
-rebindToTemp name
- = let
- (temp_amode, MkCgIdInfo _ new_vol _ _ {-LF info discarded-})
- = newTempAmodeAndIdInfo name (panic "rebindToTemp")
- in
- modifyBindC name (replace_volatile_fn new_vol) `thenC`
- returnFC temp_amode
- where
- replace_volatile_fn new_vol (MkCgIdInfo i vol stab einfo)
- = MkCgIdInfo i new_vol stab einfo
--}
+%************************************************************************
+%* *
+\subsection[CgBindery-liveness]{Build a liveness mask for the current stack}
+%* *
+%************************************************************************
+
+ToDo: remove the dependency on 32-bit words.
+
+There are four kinds of things on the stack:
+
+ - pointer variables (bound in the environment)
+ - non-pointer variables (boudn in the environment)
+ - free slots (recorded in the stack free list)
+ - non-pointer data slots (recorded in the stack free list)
+
+We build up a bitmap of non-pointer slots by looking down the
+environment for all the non-pointer variables, and merging this with
+the slots recorded in the stack free list.
+
+There's a bit of a hack here to do with update frames: since nothing
+is recorded in either the environment or the stack free list for an
+update frame, the code below defaults to assuming the slots taken up
+by an update frame contain pointers. Furthermore, update frames are
+always in slots 0-2 at the bottom of the stack. The bitmap will
+therefore end at slot 3, which is what we want (the update frame info
+pointer has its own bitmap to describe the update frame).
+
+\begin{code}
+buildLivenessMask
+ :: Unique -- unique for for large bitmap label
+ -> VirtualSpOffset -- offset from which the bitmap should start
+ -> FCode Liveness -- mask for free/unlifted slots
+
+buildLivenessMask uniq sp = ASSERT (all (>=0) rel_slots) do
+ -- find all unboxed stack-resident ids
+ binds <- getBinds
+ ((vsp, free, _, _), heap_usage) <- getUsage
+
+ let unboxed_slots =
+ [ (ofs, size) |
+ (MkCgIdInfo id _ (VirStkLoc ofs) _) <- rngVarEnv binds,
+ let rep = idPrimRep id; size = getPrimRepSize rep,
+ not (isFollowableRep rep),
+ size > 0
+ ]
+
+ -- flatten this list into a list of unboxed stack slots
+ let flatten_slots = sortLt (<)
+ (foldr (\(ofs,size) r -> [ofs-size+1 .. ofs] ++ r) []
+ unboxed_slots)
+
+ -- merge in the free slots
+ let all_slots = mergeSlots flatten_slots (map fst free) ++
+ if vsp < sp then [vsp+1 .. sp] else []
+
+ -- recalibrate the list to be sp-relative
+ let rel_slots = reverse (map (sp-) all_slots)
+
+ -- build the bitmap
+ let liveness_mask = listToLivenessMask rel_slots
+
+ livenessToAbsC uniq liveness_mask
+
+mergeSlots :: [Int] -> [Int] -> [Int]
+mergeSlots cs [] = cs
+mergeSlots [] ns = ns
+mergeSlots (c:cs) (n:ns)
+ = if c < n then
+ c : mergeSlots cs (n:ns)
+ else if c > n then
+ n : mergeSlots (c:cs) ns
+ else
+ panic ("mergeSlots: equal slots: " ++ show (c:cs) ++ show (n:ns))
+
+listToLivenessMask :: [Int] -> LivenessMask
+listToLivenessMask [] = []
+listToLivenessMask slots =
+ mkBS this : listToLivenessMask (map (\x -> x-32) rest)
+ where (this,rest) = span (<32) slots
+
+livenessToAbsC :: Unique -> LivenessMask -> FCode Liveness
+livenessToAbsC uniq mask =
+ absC (CBitmap lbl mask) `thenC`
+ returnFC (Liveness lbl mask)
+ where lbl = mkBitmapLabel uniq
+\end{code}
+
+In a continuation, we want a liveness mask that starts from just after
+the return address, which is on the stack at realSp.
+
+\begin{code}
+buildContLivenessMask
+ :: Unique
+ -> FCode Liveness
+buildContLivenessMask uniq = do
+ realSp <- getRealSp
+ buildLivenessMask uniq (realSp-1)
+\end{code}
+
+%************************************************************************
+%* *
+\subsection[CgMonad-deadslots]{Finding dead stack slots}
+%* *
+%************************************************************************
+
+nukeDeadBindings does the following:
+
+ - Removes all bindings from the environment other than those
+ for variables in the argument to nukeDeadBindings.
+ - Collects any stack slots so freed, and returns them to the stack free
+ list.
+ - Moves the virtual stack pointer to point to the topmost used
+ stack locations.
+
+You can have multi-word slots on the stack (where a Double# used to
+be, for instance); if dead, such a slot will be reported as *several*
+offsets (one per word).
+
+Probably *naughty* to look inside monad...
+
+\begin{code}
+nukeDeadBindings :: StgLiveVars -- All the *live* variables
+ -> Code
+nukeDeadBindings live_vars = do
+ binds <- getBinds
+ let (dead_stk_slots, bs') =
+ dead_slots live_vars
+ [] []
+ [ (i, b) | b@(MkCgIdInfo i _ _ _) <- rngVarEnv binds ]
+ let extra_free = sortLt (<) dead_stk_slots
+ setBinds $ mkVarEnv bs'
+ freeStackSlots extra_free
\end{code}
+Several boring auxiliary functions to do the dirty work.
+
+\begin{code}
+dead_slots :: StgLiveVars
+ -> [(Id,CgIdInfo)]
+ -> [VirtualSpOffset]
+ -> [(Id,CgIdInfo)]
+ -> ([VirtualSpOffset], [(Id,CgIdInfo)])
+
+-- dead_slots carries accumulating parameters for
+-- filtered bindings, dead slots
+dead_slots live_vars fbs ds []
+ = (ds, reverse fbs) -- Finished; rm the dups, if any
+
+dead_slots live_vars fbs ds ((v,i):bs)
+ | v `elementOfUniqSet` live_vars
+ = dead_slots live_vars ((v,i):fbs) ds bs
+ -- Live, so don't record it in dead slots
+ -- Instead keep it in the filtered bindings
+
+ | otherwise
+ = case i of
+ MkCgIdInfo _ _ stable_loc _
+ | is_stk_loc && size > 0 ->
+ dead_slots live_vars fbs ([offset-size+1 .. offset] ++ ds) bs
+ where
+ maybe_stk_loc = maybeStkLoc stable_loc
+ is_stk_loc = maybeToBool maybe_stk_loc
+ (Just offset) = maybe_stk_loc
+
+ _ -> dead_slots live_vars fbs ds bs
+ where
+
+ size :: Int
+ size = (getPrimRepSize . typePrimRep . idType) v
+
+\end{code}
projects / ghc-hetmet.git / blobdiff