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|
-----------------------------------------------------------------------------
--
-- Stg to C-- code generation: the binding environment
--
-- (c) The University of Glasgow 2004-2006
--
-----------------------------------------------------------------------------
{-# OPTIONS -fno-warn-tabs #-}
-- The above warning supression flag is a temporary kludge.
-- While working on this module you are encouraged to remove it and
-- detab the module (please do the detabbing in a separate patch). See
-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#TabsvsSpaces
-- for details
module StgCmmEnv (
CgIdInfo,
cgIdInfoId, cgIdInfoLF,
litIdInfo, lneIdInfo, rhsIdInfo, mkRhsInit,
idInfoToAmode,
NonVoid(..), isVoidId, nonVoidIds,
addBindC, addBindsC,
bindArgsToRegs, bindToReg, rebindToReg,
bindArgToReg, idToReg,
getArgAmode, getNonVoidArgAmodes,
getCgIdInfo,
maybeLetNoEscape,
) where
#include "HsVersions.h"
import TyCon
import StgCmmMonad
import StgCmmUtils
import StgCmmClosure
import CLabel
import DynFlags
import MkGraph
import BlockId
import CmmExpr
import CmmUtils
import FastString
import Id
import VarEnv
import Control.Monad
import Name
import StgSyn
import Outputable
-------------------------------------
-- Non-void types
-------------------------------------
-- We frequently need the invariant that an Id or a an argument
-- is of a non-void type. This type is a witness to the invariant.
newtype NonVoid a = NonVoid a
deriving (Eq, Show)
instance (Outputable a) => Outputable (NonVoid a) where
ppr (NonVoid a) = ppr a
isVoidId :: Id -> Bool
isVoidId = isVoidRep . idPrimRep
nonVoidIds :: [Id] -> [NonVoid Id]
nonVoidIds ids = [NonVoid id | id <- ids, not (isVoidRep (idPrimRep id))]
-------------------------------------
-- Manipulating CgIdInfo
-------------------------------------
mkCgIdInfo :: DynFlags -> Id -> LambdaFormInfo -> CmmExpr -> CgIdInfo
mkCgIdInfo dflags id lf expr
= CgIdInfo { cg_id = id, cg_lf = lf
, cg_loc = CmmLoc expr,
cg_tag = lfDynTag dflags lf }
litIdInfo :: DynFlags -> Id -> LambdaFormInfo -> CmmLit -> CgIdInfo
litIdInfo dflags id lf lit
= CgIdInfo { cg_id = id, cg_lf = lf
, cg_loc = CmmLoc (addDynTag dflags (CmmLit lit) tag)
, cg_tag = tag }
where
tag = lfDynTag dflags lf
lneIdInfo :: DynFlags -> Id -> [NonVoid Id] -> CgIdInfo
lneIdInfo dflags id regs
= CgIdInfo { cg_id = id, cg_lf = lf
, cg_loc = LneLoc blk_id (map (idToReg dflags) regs)
, cg_tag = lfDynTag dflags lf }
where
lf = mkLFLetNoEscape
blk_id = mkBlockId (idUnique id)
rhsIdInfo :: Id -> LambdaFormInfo -> FCode (CgIdInfo, LocalReg)
rhsIdInfo id lf_info
= do dflags <- getDynFlags
reg <- newTemp (gcWord dflags)
return (mkCgIdInfo dflags id lf_info (CmmReg (CmmLocal reg)), reg)
mkRhsInit :: DynFlags -> LocalReg -> LambdaFormInfo -> CmmExpr -> CmmAGraph
mkRhsInit dflags reg lf_info expr
= mkAssign (CmmLocal reg) (addDynTag dflags expr (lfDynTag dflags lf_info))
idInfoToAmode :: CgIdInfo -> CmmExpr
-- Returns a CmmExpr for the *tagged* pointer
idInfoToAmode (CgIdInfo { cg_loc = CmmLoc e }) = e
idInfoToAmode cg_info
= pprPanic "idInfoToAmode" (ppr (cg_id cg_info)) -- LneLoc
addDynTag :: DynFlags -> CmmExpr -> DynTag -> CmmExpr
-- A tag adds a byte offset to the pointer
addDynTag dflags expr tag = cmmOffsetB dflags expr tag
cgIdInfoId :: CgIdInfo -> Id
cgIdInfoId = cg_id
cgIdInfoLF :: CgIdInfo -> LambdaFormInfo
cgIdInfoLF = cg_lf
maybeLetNoEscape :: CgIdInfo -> Maybe (BlockId, [LocalReg])
maybeLetNoEscape (CgIdInfo { cg_loc = LneLoc blk_id args}) = Just (blk_id, args)
maybeLetNoEscape _other = Nothing
---------------------------------------------------------
-- The binding environment
--
-- There are three basic routines, for adding (addBindC),
-- modifying(modifyBindC) and looking up (getCgIdInfo) bindings.
---------------------------------------------------------
addBindC :: Id -> CgIdInfo -> FCode ()
addBindC name stuff_to_bind = do
binds <- getBinds
setBinds $ extendVarEnv binds name stuff_to_bind
addBindsC :: [CgIdInfo] -> FCode ()
addBindsC new_bindings = do
binds <- getBinds
let new_binds = foldl (\ binds info -> extendVarEnv binds (cg_id info) info)
binds
new_bindings
setBinds new_binds
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
let
name = idName id
in
if isExternalName name then do
let ext_lbl = CmmLabel (mkClosureLabel name $ idCafInfo id)
dflags <- getDynFlags
return (litIdInfo dflags id (mkLFImported id) ext_lbl)
else
-- Bug
cgLookupPanic id
}}}}
cgLookupPanic :: Id -> FCode a
cgLookupPanic id
= do static_binds <- getStaticBinds
local_binds <- getBinds
pprPanic "StgCmmEnv: variable not found"
(vcat [ppr id,
ptext (sLit "static binds for:"),
vcat [ ppr (cg_id info) | info <- varEnvElts static_binds ],
ptext (sLit "local binds for:"),
vcat [ ppr (cg_id info) | info <- varEnvElts local_binds ]
])
--------------------
getArgAmode :: NonVoid StgArg -> FCode CmmExpr
getArgAmode (NonVoid (StgVarArg var)) =
do { info <- getCgIdInfo var; return (idInfoToAmode info) }
getArgAmode (NonVoid (StgLitArg lit)) = liftM CmmLit $ cgLit lit
getNonVoidArgAmodes :: [StgArg] -> FCode [CmmExpr]
-- NB: Filters out void args,
-- so the result list may be shorter than the argument list
getNonVoidArgAmodes [] = return []
getNonVoidArgAmodes (arg:args)
| isVoidRep (argPrimRep arg) = getNonVoidArgAmodes args
| otherwise = do { amode <- getArgAmode (NonVoid arg)
; amodes <- getNonVoidArgAmodes args
; return ( amode : amodes ) }
------------------------------------------------------------------------
-- Interface functions for binding and re-binding names
------------------------------------------------------------------------
bindToReg :: NonVoid Id -> LambdaFormInfo -> FCode LocalReg
-- Bind an Id to a fresh LocalReg
bindToReg nvid@(NonVoid id) lf_info
= do dflags <- getDynFlags
let reg = idToReg dflags nvid
addBindC id (mkCgIdInfo dflags id lf_info (CmmReg (CmmLocal reg)))
return reg
rebindToReg :: NonVoid Id -> FCode LocalReg
-- Like bindToReg, but the Id is already in scope, so
-- get its LF info from the envt
rebindToReg nvid@(NonVoid id)
= do { info <- getCgIdInfo id
; bindToReg nvid (cgIdInfoLF info) }
bindArgToReg :: NonVoid Id -> FCode LocalReg
bindArgToReg nvid@(NonVoid id) = bindToReg nvid (mkLFArgument id)
bindArgsToRegs :: [NonVoid Id] -> FCode [LocalReg]
bindArgsToRegs args = mapM bindArgToReg args
idToReg :: DynFlags -> NonVoid Id -> LocalReg
-- Make a register from an Id, typically a function argument,
-- free variable, or case binder
--
-- We re-use the Unique from the Id to make it easier to see what is going on
--
-- By now the Ids should be uniquely named; else one would worry
-- about accidental collision
idToReg dflags (NonVoid id)
= LocalReg (idUnique id)
(case idPrimRep id of VoidRep -> pprPanic "idToReg" (ppr id)
_ -> primRepCmmType dflags (idPrimRep id))
|
