%
-% (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 (
- SYN_IE(CgBindings), CgIdInfo(..){-dubiously concrete-},
+ CgBindings, CgIdInfo,
StableLoc, VolatileLoc,
- maybeAStkLoc, maybeBStkLoc,
+ cgIdInfoId, cgIdInfoArgRep, cgIdInfoLF,
- stableAmodeIdInfo, heapIdInfo, newTempAmodeAndIdInfo,
+ stableIdInfo, heapIdInfo,
letNoEscapeIdInfo, idInfoToAmode,
+ addBindC, addBindsC,
+
nukeVolatileBinds,
+ nukeDeadBindings,
+ getLiveStackSlots,
- bindNewToAStack, bindNewToBStack,
+ bindArgsToStack, rebindToStack,
bindNewToNode, bindNewToReg, bindArgsToRegs,
- bindNewToTemp, bindNewPrimToAmode,
- getArgAmode, getArgAmodes,
- getCAddrModeAndInfo, getCAddrMode,
+ bindNewToTemp,
+ getArgAmode, getArgAmodes,
+ getCgIdInfo,
getCAddrModeIfVolatile, getVolatileRegs,
- rebindToAStack, rebindToBStack
+ maybeLetNoEscape,
) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
-import AbsCSyn
import CgMonad
-
-import CgUsages ( getHpRelOffset, getSpARelOffset, getSpBRelOffset )
-import CLabel ( mkStaticClosureLabel, mkClosureLabel )
-import ClosureInfo ( mkLFImported, mkConLFInfo, mkLFArgument, LambdaFormInfo )
-import HeapOffs ( SYN_IE(VirtualHeapOffset),
- SYN_IE(VirtualSpAOffset), SYN_IE(VirtualSpBOffset)
- )
-import Id ( idPrimRep, toplevelishId,
- mkIdEnv, rngIdEnv, SYN_IE(IdEnv),
- idSetToList,
- GenId{-instance NamedThing-}, SYN_IE(Id)
- )
-import Literal ( Literal )
+import CgHeapery ( getHpRelOffset )
+import CgStackery ( freeStackSlots, getSpRelOffset )
+import CgUtils ( cgLit, cmmOffsetW )
+import CLabel ( mkClosureLabel, pprCLabel )
+import ClosureInfo ( mkLFImported, mkLFArgument, LambdaFormInfo )
+
+import Cmm
+import PprCmm ( {- instance Outputable -} )
+import SMRep ( CgRep(..), WordOff, isFollowableArg,
+ isVoidArg, cgRepSizeW, argMachRep,
+ idCgRep, typeCgRep )
+import Id ( Id, idName )
+import VarEnv
+import VarSet ( varSetElems )
+import Literal ( literalType )
import Maybes ( catMaybes )
-import Name ( isLocallyDefined, isWiredInName,
- Name{-instance NamedThing-}, NamedThing(..) )
-#ifdef DEBUG
-import PprAbsC ( pprAmode )
-#endif
-import Outputable ( PprStyle(..) )
-import Pretty ( Doc )
-import PrimRep ( PrimRep )
-import StgSyn ( SYN_IE(StgArg), SYN_IE(StgLiveVars), GenStgArg(..) )
-import Unique ( Unique )
-import UniqFM ( Uniquable(..) )
-import Util ( zipWithEqual, panic )
+import Name ( isExternalName )
+import StgSyn ( StgArg, StgLiveVars, GenStgArg(..), isStgTypeArg )
+import Unique ( Uniquable(..) )
+import UniqSet ( elementOfUniqSet )
+import Outputable
\end{code}
type CgBindings = IdEnv CgIdInfo
data CgIdInfo
- = MkCgIdInfo Id -- Id that this is the info for
- VolatileLoc
- StableLoc
- LambdaFormInfo
+ = CgIdInfo
+ { cg_id :: Id -- Id that this is the info for
+ -- Can differ from the Id at occurrence sites by
+ -- virtue of being externalised, for splittable C
+ , cg_rep :: CgRep
+ , cg_vol :: VolatileLoc
+ , cg_stb :: StableLoc
+ , cg_lf :: LambdaFormInfo }
+
+mkCgIdInfo id vol stb lf
+ = CgIdInfo { cg_id = id, cg_vol = vol, cg_stb = stb,
+ cg_lf = lf, cg_rep = idCgRep id }
+
+voidIdInfo id = CgIdInfo { cg_id = id, cg_vol = NoVolatileLoc
+ , cg_stb = VoidLoc, cg_lf = mkLFArgument id
+ , cg_rep = VoidArg }
+ -- Used just for VoidRep things
data VolatileLoc
= NoVolatileLoc
- | TempVarLoc Unique
-
- | RegLoc MagicId -- in one of the magic registers
- -- (probably {Int,Float,Char,etc}Reg
-
- | VirHpLoc VirtualHeapOffset -- Hp+offset (address of closure)
+ | RegLoc CmmReg -- In one of the registers (global or local)
+ | VirHpLoc VirtualHpOffset -- Hp+offset (address of closure)
+ | VirNodeLoc VirtualHpOffset -- Cts of offset indirect from Node
+ -- ie *(Node+offset)
+\end{code}
- | VirNodeLoc VirtualHeapOffset -- Cts of offset indirect from Node
- -- ie *(Node+offset)
+@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 Literal
- | StableAmodeLoc CAddrMode
--- these are so StableLoc can be abstract:
+ | VirStkLoc VirtualSpOffset -- The thing is held in this
+ -- stack slot
+
+ | VirStkLNE VirtualSpOffset -- A let-no-escape thing; the
+ -- value is this stack pointer
+ -- (as opposed to the contents of the slot)
-maybeAStkLoc (VirAStkLoc offset) = Just offset
-maybeAStkLoc _ = Nothing
+ | StableLoc CmmExpr
+ | VoidLoc -- Used only for VoidRep variables. They never need to
+ -- be saved, so it makes sense to treat treat them as
+ -- having a stable location
+\end{code}
-maybeBStkLoc (VirBStkLoc offset) = Just offset
-maybeBStkLoc _ = Nothing
+\begin{code}
+instance Outputable CgIdInfo where
+ ppr (CgIdInfo id rep vol stb lf)
+ = ppr id <+> ptext SLIT("-->") <+> vcat [ppr vol, ppr stb]
+
+instance Outputable VolatileLoc where
+ ppr NoVolatileLoc = empty
+ ppr (RegLoc r) = ptext SLIT("reg") <+> ppr r
+ ppr (VirHpLoc v) = ptext SLIT("vh") <+> ppr v
+ ppr (VirNodeLoc v) = ptext SLIT("vn") <+> ppr v
+
+instance Outputable StableLoc where
+ ppr NoStableLoc = empty
+ ppr VoidLoc = ptext SLIT("void")
+ ppr (VirStkLoc v) = ptext SLIT("vs") <+> ppr v
+ ppr (VirStkLNE v) = ptext SLIT("lne") <+> ppr v
+ ppr (StableLoc a) = ptext SLIT("amode") <+> ppr a
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-stableAmodeIdInfo i amode lf_info = MkCgIdInfo i NoVolatileLoc (StableAmodeLoc amode) lf_info
-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
-
-newTempAmodeAndIdInfo :: Id -> LambdaFormInfo -> (CAddrMode, CgIdInfo)
-
-newTempAmodeAndIdInfo name lf_info
- = (temp_amode, temp_idinfo)
+stableIdInfo id amode lf_info = mkCgIdInfo id NoVolatileLoc (StableLoc amode) lf_info
+heapIdInfo id offset lf_info = mkCgIdInfo id (VirHpLoc offset) NoStableLoc lf_info
+letNoEscapeIdInfo id sp lf_info = mkCgIdInfo id NoVolatileLoc (VirStkLNE sp) lf_info
+stackIdInfo id sp lf_info = mkCgIdInfo id NoVolatileLoc (VirStkLoc sp) lf_info
+nodeIdInfo id offset lf_info = mkCgIdInfo id (VirNodeLoc offset) NoStableLoc lf_info
+regIdInfo id reg lf_info = mkCgIdInfo id (RegLoc reg) NoStableLoc lf_info
+
+idInfoToAmode :: CgIdInfo -> FCode CmmExpr
+idInfoToAmode info
+ = case cg_vol info of {
+ RegLoc reg -> returnFC (CmmReg reg) ;
+ VirNodeLoc nd_off -> returnFC (CmmLoad (cmmOffsetW (CmmReg nodeReg) nd_off) mach_rep) ;
+ VirHpLoc hp_off -> getHpRelOffset hp_off ;
+ NoVolatileLoc ->
+
+ case cg_stb info of
+ StableLoc amode -> returnFC amode
+ VirStkLoc sp_off -> do { sp_rel <- getSpRelOffset sp_off
+ ; return (CmmLoad sp_rel mach_rep) }
+
+ VirStkLNE sp_off -> getSpRelOffset sp_off ;
+
+ VoidLoc -> return $ pprPanic "idInfoToAmode: void" (ppr (cg_id info))
+ -- We return a 'bottom' amode, rather than panicing now
+ -- In this way getArgAmode returns a pair of (VoidArg, bottom)
+ -- and that's exactly what we want
+
+ NoStableLoc -> pprPanic "idInfoToAmode: no loc" (ppr (cg_id info))
+ }
where
- uniq = uniqueOf name
- temp_amode = CTemp uniq (idPrimRep name)
- temp_idinfo = tempIdInfo name uniq lf_info
+ mach_rep = argMachRep (cg_rep info)
-idInfoToAmode :: PrimRep -> CgIdInfo -> FCode CAddrMode
-idInfoToAmode kind (MkCgIdInfo _ vol stab _) = idInfoPiecesToAmode kind vol stab
+cgIdInfoId :: CgIdInfo -> Id
+cgIdInfoId = cg_id
-idInfoPiecesToAmode :: PrimRep -> VolatileLoc -> StableLoc -> FCode CAddrMode
+cgIdInfoLF :: CgIdInfo -> LambdaFormInfo
+cgIdInfoLF = cg_lf
-idInfoPiecesToAmode kind (TempVarLoc uniq) stable_loc = returnFC (CTemp uniq kind)
-idInfoPiecesToAmode kind (RegLoc magic_id) stable_loc = returnFC (CReg magic_id)
+cgIdInfoArgRep :: CgIdInfo -> CgRep
+cgIdInfoArgRep = cg_rep
-idInfoPiecesToAmode kind NoVolatileLoc (LitLoc lit) = returnFC (CLit lit)
-idInfoPiecesToAmode kind NoVolatileLoc (StableAmodeLoc amode) = returnFC amode
-
-idInfoPiecesToAmode kind (VirNodeLoc nd_off) stable_loc
- = 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.
+maybeLetNoEscape (CgIdInfo { cg_stb = VirStkLNE sp_off }) = Just sp_off
+maybeLetNoEscape other = Nothing
+\end{code}
-idInfoPiecesToAmode kind (VirHpLoc hp_off) stable_loc
- = getHpRelOffset hp_off `thenFC` \ rel_hp ->
- returnFC (CAddr rel_hp)
+%************************************************************************
+%* *
+\subsection[CgMonad-bindery]{Monad things for fiddling with @CgBindings@}
+%* *
+%************************************************************************
-idInfoPiecesToAmode kind NoVolatileLoc (VirAStkLoc i)
- = getSpARelOffset i `thenFC` \ rel_spA ->
- returnFC (CVal rel_spA kind)
+.There are three basic routines, for adding (@addBindC@), modifying
+(@modifyBindC@) and looking up (@getCgIdInfo@) bindings.
-idInfoPiecesToAmode kind NoVolatileLoc (VirBStkLoc i)
- = getSpBRelOffset i `thenFC` \ rel_spB ->
- returnFC (CVal rel_spB kind)
+A @Id@ is bound to a @(VolatileLoc, StableLoc)@ triple.
+The name should not already be bound. (nice ASSERT, eh?)
-#ifdef DEBUG
-idInfoPiecesToAmode kind NoVolatileLoc NoStableLoc = panic "idInfoPiecesToAmode: no loc"
-#endif
+\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
+
+getCgIdInfo :: Id -> FCode CgIdInfo
+getCgIdInfo id
+ = do { -- Try local bindings first
+ ; local_binds <- getBinds
+ ; case lookupVarEnv local_binds id of {
+ Just info -> return info ;
+ Nothing -> do
+
+ { -- Try top-level bindings
+ static_binds <- getStaticBinds
+ ; case lookupVarEnv static_binds id of {
+ Just info -> return info ;
+ Nothing ->
+
+ -- Should be imported; make up a CgIdInfo for it
+ if isExternalName name then
+ return (stableIdInfo id ext_lbl (mkLFImported id))
+ else
+ if isVoidArg (idCgRep id) then
+ -- Void things are never in the environment
+ return (voidIdInfo id)
+ else
+ -- Bug
+ cgLookupPanic id
+ }}}}
+ where
+ name = idName id
+ ext_lbl = CmmLit (CmmLabel (mkClosureLabel name))
+
+cgLookupPanic :: Id -> FCode a
+cgLookupPanic id
+ = do static_binds <- getStaticBinds
+ local_binds <- getBinds
+ srt <- getSRTLabel
+ pprPanic "cgPanic"
+ (vcat [ppr id,
+ ptext SLIT("static binds for:"),
+ vcat [ ppr (cg_id info) | info <- rngVarEnv static_binds ],
+ ptext SLIT("local binds for:"),
+ vcat [ ppr (cg_id info) | info <- 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, MkCgIdInfo i NoVolatileLoc stable_loc entry_info) : acc
+ keep_if_stable (CgIdInfo { cg_stb = NoStableLoc }) acc = acc
+ keep_if_stable info acc
+ = (cg_id info, info { cg_vol = NoVolatileLoc }) : acc
\end{code}
%* *
%************************************************************************
-I {\em think} all looking-up is done through @getCAddrMode(s)@.
-
\begin{code}
-getCAddrModeAndInfo :: Id -> FCode (CAddrMode, LambdaFormInfo)
-
-getCAddrModeAndInfo id
- | not (isLocallyDefined name) || isWiredInName name
- {- Why the "isWiredInName"?
- Imagine you are compiling PrelBase.hs (a module that
- supplies some of the wired-in values). What can
- happen is that the compiler will inject calls to
- (e.g.) GHCbase.unpackPS, where-ever it likes -- it
- assumes those values are ubiquitously available.
- The main point is: it may inject calls to them earlier
- in GHCbase.hs than the actual definition...
- -}
- = returnFC (global_amode, mkLFImported id)
-
- | otherwise = -- *might* be a nested defn: in any case, it's something whose
- -- definition we will know about...
- lookupBindC id `thenFC` \ (MkCgIdInfo _ volatile_loc stable_loc lf_info) ->
- idInfoPiecesToAmode kind volatile_loc stable_loc `thenFC` \ amode ->
- returnFC (amode, lf_info)
- where
- name = getName id
- global_amode = CLbl (mkClosureLabel id) kind
- kind = idPrimRep id
-
-getCAddrMode :: Id -> FCode CAddrMode
-getCAddrMode name
- = getCAddrModeAndInfo name `thenFC` \ (amode, _) ->
- returnFC 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 (idPrimRep name) volatile_loc NoStableLoc `thenFC` \ amode ->
- returnFC (Just amode)
-
- a_stable_loc -> returnFC Nothing
+getCAddrModeIfVolatile :: Id -> FCode (Maybe CmmExpr)
+getCAddrModeIfVolatile id
+ = do { info <- getCgIdInfo id
+ ; case cg_stb info of
+ NoStableLoc -> do -- Aha! So it is volatile!
+ amode <- idInfoToAmode info
+ 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 :: StgLiveVars -> FCode [MagicId]
+getVolatileRegs :: StgLiveVars -> FCode [GlobalReg]
-getVolatileRegs vars
- = mapFCs snaffle_it (idSetToList vars) `thenFC` \ stuff ->
- returnFC (catMaybes stuff)
+getVolatileRegs vars = do
+ do { stuff <- mapFCs snaffle_it (varSetElems vars)
+ ; 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
+ snaffle_it var = do
+ { info <- getCgIdInfo var
+ ; let
+ -- commoned-up code...
+ consider_reg reg
+ = -- We assume that all regs can die across C calls
+ -- 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
+ case cg_stb info 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 }
+
+ ; case cg_vol info of
+ RegLoc (CmmGlobal reg) -> consider_reg reg
+ VirNodeLoc _ -> consider_reg node
+ other_loc -> returnFC Nothing -- Local registers
+ }
+
+ nuke_vol_bind info = info { cg_vol = NoVolatileLoc }
\end{code}
\begin{code}
-getArgAmodes :: [StgArg] -> FCode [CAddrMode]
+getArgAmode :: StgArg -> FCode (CgRep, CmmExpr)
+getArgAmode (StgVarArg var)
+ = do { info <- getCgIdInfo var
+ ; amode <- idInfoToAmode info
+ ; return (cgIdInfoArgRep info, amode ) }
+
+getArgAmode (StgLitArg lit)
+ = do { cmm_lit <- cgLit lit
+ ; return (typeCgRep (literalType lit), CmmLit cmm_lit) }
+
+getArgAmode (StgTypeArg _) = panic "getArgAmode: type arg"
+
+getArgAmodes :: [StgArg] -> FCode [(CgRep, CmmExpr)]
getArgAmodes [] = returnFC []
getArgAmodes (atom:atoms)
- = getArgAmode atom `thenFC` \ amode ->
- getArgAmodes atoms `thenFC` \ amodes ->
- returnFC ( amode : amodes )
-
-getArgAmode :: StgArg -> FCode CAddrMode
-
-getArgAmode (StgConArg var)
- {- Why does this case differ from StgVarArg?
- Because the program might look like this:
- data Foo a = Empty | Baz a
- f a x = let c = Empty! a
- in h c
- Now, when we go Core->Stg, we drop the type applications,
- so we can inline c, giving
- f x = h Empty
- Now we are referring to Empty as an argument (rather than in an STGCon),
- so we'll look it up with getCAddrMode. We want to return an amode for
- the static closure that we make for nullary constructors. But if we blindly
- go ahead with getCAddrMode we end up looking in the environment, and it ain't there!
-
- This special case used to be in getCAddrModeAndInfo, but it doesn't work there.
- Consider:
- f a x = Baz a x
- If the constructor Baz isn't inlined we simply want to treat it like any other
- identifier, with a top level definition. We don't want to spot that it's a constructor.
-
- In short
- StgApp con args
- and
- StgCon con args
- are treated differently; the former is a call to a bog standard function while the
- latter uses the specially-labelled, pre-defined info tables etc for the constructor.
-
- The way to think of this case in getArgAmode is that
- SApp f Empty
- is really
- App f (StgCon Empty [])
- -}
- = returnFC (CLbl (mkStaticClosureLabel var) (idPrimRep var))
-
-getArgAmode (StgVarArg var) = getCAddrMode var -- The common case
-
-getArgAmode (StgLitArg lit) = returnFC (CLit lit)
+ | isStgTypeArg atom = getArgAmodes atoms
+ | otherwise = do { amode <- getArgAmode atom
+ ; amodes <- getArgAmodes atoms
+ ; return ( amode : amodes ) }
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-bindNewToAStack :: (Id, VirtualSpAOffset) -> Code
-bindNewToAStack (name, offset)
- = addBindC name info
+bindArgsToStack :: [(Id, VirtualSpOffset)] -> Code
+bindArgsToStack args
+ = mapCs bind args
where
- info = MkCgIdInfo name NoVolatileLoc (VirAStkLoc offset) mkLFArgument
+ bind(id, offset) = addBindC id (stackIdInfo id offset (mkLFArgument id))
-bindNewToBStack :: (Id, VirtualSpBOffset) -> Code
-bindNewToBStack (name, offset)
- = addBindC name info
+bindArgsToRegs :: [(Id, GlobalReg)] -> Code
+bindArgsToRegs args
+ = mapCs bind args
where
- info = MkCgIdInfo name NoVolatileLoc (VirBStkLoc offset) (panic "bindNewToBStack")
- -- B-stack things shouldn't need lambda-form info!
+ bind (arg, reg) = bindNewToReg arg (CmmGlobal reg) (mkLFArgument arg)
-bindNewToNode :: Id -> VirtualHeapOffset -> LambdaFormInfo -> Code
-bindNewToNode name offset lf_info
- = addBindC name info
- where
- info = MkCgIdInfo name (VirNodeLoc offset) NoStableLoc lf_info
+bindNewToNode :: Id -> VirtualHpOffset -> LambdaFormInfo -> Code
+bindNewToNode id offset lf_info
+ = addBindC id (nodeIdInfo id offset lf_info)
-- Create a new temporary whose unique is that in the id,
-- bind the id to it, and return the addressing mode for the
-- temporary.
-bindNewToTemp :: Id -> FCode CAddrMode
-bindNewToTemp name
- = let (temp_amode, id_info) = newTempAmodeAndIdInfo name mkLFArgument
- -- 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
-
-bindNewToReg :: Id -> MagicId -> LambdaFormInfo -> Code
-bindNewToReg name magic_id lf_info
- = addBindC name info
+bindNewToTemp :: Id -> FCode CmmReg
+bindNewToTemp id
+ = do addBindC id (regIdInfo id temp_reg lf_info)
+ return temp_reg
where
- info = MkCgIdInfo name (RegLoc magic_id) NoStableLoc lf_info
+ uniq = getUnique id
+ temp_reg = CmmLocal (LocalReg uniq (argMachRep (idCgRep id)))
+ lf_info = mkLFArgument id -- Always used of things we
+ -- know nothing about
-bindNewToLit name lit
+bindNewToReg :: Id -> CmmReg -> LambdaFormInfo -> Code
+bindNewToReg name reg lf_info
= addBindC name info
where
- info = MkCgIdInfo name NoVolatileLoc (LitLoc lit) (error "bindNewToLit")
+ info = mkCgIdInfo name (RegLoc reg) NoStableLoc lf_info
+\end{code}
-bindArgsToRegs :: [Id] -> [MagicId] -> Code
-bindArgsToRegs args regs
- = listCs (zipWithEqual "bindArgsToRegs" bind args regs)
+\begin{code}
+rebindToStack :: Id -> VirtualSpOffset -> Code
+rebindToStack name offset
+ = modifyBindC name replace_stable_fn
where
- arg `bind` reg = bindNewToReg arg reg mkLFArgument
+ replace_stable_fn info = info { cg_stb = VirStkLoc offset }
\end{code}
-@bindNewPrimToAmode@ works only for certain addressing modes, because
-those are the only ones we've needed so far!
+%************************************************************************
+%* *
+\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}
-bindNewPrimToAmode :: Id -> CAddrMode -> Code
-bindNewPrimToAmode name (CReg reg) = bindNewToReg name reg (panic "bindNewPrimToAmode")
- -- was: mkLFArgument
- -- LFinfo is irrelevant for primitives
-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...:"++(show (pprAmode PprDebug amode)))
-#endif
+nukeDeadBindings :: StgLiveVars -- All the *live* variables
+ -> Code
+nukeDeadBindings live_vars = do
+ binds <- getBinds
+ let (dead_stk_slots, bs') =
+ dead_slots live_vars
+ [] []
+ [ (cg_id b, b) | b <- rngVarEnv binds ]
+ setBinds $ mkVarEnv bs'
+ freeStackSlots dead_stk_slots
\end{code}
+Several boring auxiliary functions to do the dirty work.
+
\begin{code}
-rebindToAStack :: Id -> VirtualSpAOffset -> Code
-rebindToAStack name offset
- = modifyBindC name replace_stable_fn
- where
- replace_stable_fn (MkCgIdInfo i vol stab einfo)
- = MkCgIdInfo i vol (VirAStkLoc offset) einfo
+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
-rebindToBStack :: Id -> VirtualSpBOffset -> Code
-rebindToBStack name offset
- = modifyBindC name replace_stable_fn
+ | otherwise
+ = case cg_stb i of
+ VirStkLoc offset
+ | size > 0
+ -> dead_slots live_vars fbs ([offset-size+1 .. offset] ++ ds) bs
+
+ _ -> dead_slots live_vars fbs ds bs
where
- replace_stable_fn (MkCgIdInfo i vol stab einfo)
- = MkCgIdInfo i vol (VirBStkLoc offset) einfo
+ size :: WordOff
+ size = cgRepSizeW (cg_rep i)
\end{code}
+\begin{code}
+getLiveStackSlots :: FCode [VirtualSpOffset]
+-- Return the offsets of slots in stack containig live pointers
+getLiveStackSlots
+ = do { binds <- getBinds
+ ; return [off | CgIdInfo { cg_stb = VirStkLoc off,
+ cg_rep = rep } <- rngVarEnv binds,
+ isFollowableArg rep] }
+\end{code}
projects / ghc-hetmet.git / blobdiff