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|
-- | An architecture independent description of a register.
-- This needs to stay architecture independent because it is used
-- by NCGMonad and the register allocators, which are shared
-- by all architectures.
--
module Reg (
RegNo,
Reg(..),
regPair,
regSingle,
isRealReg, takeRealReg,
isVirtualReg, takeVirtualReg,
VirtualReg(..),
renameVirtualReg,
classOfVirtualReg,
getHiVirtualRegFromLo,
getHiVRegFromLo,
RealReg(..),
regNosOfRealReg,
realRegsAlias,
liftPatchFnToRegReg
)
where
import Outputable
import Unique
import RegClass
import Data.List
-- | An identifier for a primitive real machine register.
type RegNo
= Int
-- VirtualRegs are virtual registers. The register allocator will
-- eventually have to map them into RealRegs, or into spill slots.
--
-- VirtualRegs are allocated on the fly, usually to represent a single
-- value in the abstract assembly code (i.e. dynamic registers are
-- usually single assignment).
--
-- The single assignment restriction isn't necessary to get correct code,
-- although a better register allocation will result if single
-- assignment is used -- because the allocator maps a VirtualReg into
-- a single RealReg, even if the VirtualReg has multiple live ranges.
--
-- Virtual regs can be of either class, so that info is attached.
--
data VirtualReg
= VirtualRegI {-# UNPACK #-} !Unique
| VirtualRegHi {-# UNPACK #-} !Unique -- High part of 2-word register
| VirtualRegF {-# UNPACK #-} !Unique
| VirtualRegD {-# UNPACK #-} !Unique
| VirtualRegSSE {-# UNPACK #-} !Unique
deriving (Eq, Show)
-- This is laborious, but necessary. We can't derive Ord because
-- Unique doesn't have an Ord instance. Note nonDetCmpUnique in the
-- implementation. See Note [No Ord for Unique]
-- This is non-deterministic but we do not currently support deterministic
-- code-generation. See Note [Unique Determinism and code generation]
instance Ord VirtualReg where
compare (VirtualRegI a) (VirtualRegI b) = nonDetCmpUnique a b
compare (VirtualRegHi a) (VirtualRegHi b) = nonDetCmpUnique a b
compare (VirtualRegF a) (VirtualRegF b) = nonDetCmpUnique a b
compare (VirtualRegD a) (VirtualRegD b) = nonDetCmpUnique a b
compare (VirtualRegSSE a) (VirtualRegSSE b) = nonDetCmpUnique a b
compare VirtualRegI{} _ = LT
compare _ VirtualRegI{} = GT
compare VirtualRegHi{} _ = LT
compare _ VirtualRegHi{} = GT
compare VirtualRegF{} _ = LT
compare _ VirtualRegF{} = GT
compare VirtualRegD{} _ = LT
compare _ VirtualRegD{} = GT
instance Uniquable VirtualReg where
getUnique reg
= case reg of
VirtualRegI u -> u
VirtualRegHi u -> u
VirtualRegF u -> u
VirtualRegD u -> u
VirtualRegSSE u -> u
instance Outputable VirtualReg where
ppr reg
= case reg of
VirtualRegI u -> text "%vI_" <> pprUniqueAlways u
VirtualRegHi u -> text "%vHi_" <> pprUniqueAlways u
VirtualRegF u -> text "%vF_" <> pprUniqueAlways u
VirtualRegD u -> text "%vD_" <> pprUniqueAlways u
VirtualRegSSE u -> text "%vSSE_" <> pprUniqueAlways u
renameVirtualReg :: Unique -> VirtualReg -> VirtualReg
renameVirtualReg u r
= case r of
VirtualRegI _ -> VirtualRegI u
VirtualRegHi _ -> VirtualRegHi u
VirtualRegF _ -> VirtualRegF u
VirtualRegD _ -> VirtualRegD u
VirtualRegSSE _ -> VirtualRegSSE u
classOfVirtualReg :: VirtualReg -> RegClass
classOfVirtualReg vr
= case vr of
VirtualRegI{} -> RcInteger
VirtualRegHi{} -> RcInteger
VirtualRegF{} -> RcFloat
VirtualRegD{} -> RcDouble
VirtualRegSSE{} -> RcDoubleSSE
-- Determine the upper-half vreg for a 64-bit quantity on a 32-bit platform
-- when supplied with the vreg for the lower-half of the quantity.
-- (NB. Not reversible).
getHiVirtualRegFromLo :: VirtualReg -> VirtualReg
getHiVirtualRegFromLo reg
= case reg of
-- makes a pseudo-unique with tag 'H'
VirtualRegI u -> VirtualRegHi (newTagUnique u 'H')
_ -> panic "Reg.getHiVirtualRegFromLo"
getHiVRegFromLo :: Reg -> Reg
getHiVRegFromLo reg
= case reg of
RegVirtual vr -> RegVirtual (getHiVirtualRegFromLo vr)
RegReal _ -> panic "Reg.getHiVRegFromLo"
------------------------------------------------------------------------------------
-- | RealRegs are machine regs which are available for allocation, in
-- the usual way. We know what class they are, because that's part of
-- the processor's architecture.
--
-- RealRegPairs are pairs of real registers that are allocated together
-- to hold a larger value, such as with Double regs on SPARC.
--
data RealReg
= RealRegSingle {-# UNPACK #-} !RegNo
| RealRegPair {-# UNPACK #-} !RegNo {-# UNPACK #-} !RegNo
deriving (Eq, Show, Ord)
instance Uniquable RealReg where
getUnique reg
= case reg of
RealRegSingle i -> mkRegSingleUnique i
RealRegPair r1 r2 -> mkRegPairUnique (r1 * 65536 + r2)
instance Outputable RealReg where
ppr reg
= case reg of
RealRegSingle i -> text "%r" <> int i
RealRegPair r1 r2 -> text "%r(" <> int r1
<> vbar <> int r2 <> text ")"
regNosOfRealReg :: RealReg -> [RegNo]
regNosOfRealReg rr
= case rr of
RealRegSingle r1 -> [r1]
RealRegPair r1 r2 -> [r1, r2]
realRegsAlias :: RealReg -> RealReg -> Bool
realRegsAlias rr1 rr2
= not $ null $ intersect (regNosOfRealReg rr1) (regNosOfRealReg rr2)
--------------------------------------------------------------------------------
-- | A register, either virtual or real
data Reg
= RegVirtual !VirtualReg
| RegReal !RealReg
deriving (Eq, Ord)
regSingle :: RegNo -> Reg
regSingle regNo = RegReal $ RealRegSingle regNo
regPair :: RegNo -> RegNo -> Reg
regPair regNo1 regNo2 = RegReal $ RealRegPair regNo1 regNo2
-- We like to have Uniques for Reg so that we can make UniqFM and UniqSets
-- in the register allocator.
instance Uniquable Reg where
getUnique reg
= case reg of
RegVirtual vr -> getUnique vr
RegReal rr -> getUnique rr
-- | Print a reg in a generic manner
-- If you want the architecture specific names, then use the pprReg
-- function from the appropriate Ppr module.
instance Outputable Reg where
ppr reg
= case reg of
RegVirtual vr -> ppr vr
RegReal rr -> ppr rr
isRealReg :: Reg -> Bool
isRealReg reg
= case reg of
RegReal _ -> True
RegVirtual _ -> False
takeRealReg :: Reg -> Maybe RealReg
takeRealReg reg
= case reg of
RegReal rr -> Just rr
_ -> Nothing
isVirtualReg :: Reg -> Bool
isVirtualReg reg
= case reg of
RegReal _ -> False
RegVirtual _ -> True
takeVirtualReg :: Reg -> Maybe VirtualReg
takeVirtualReg reg
= case reg of
RegReal _ -> Nothing
RegVirtual vr -> Just vr
-- | The patch function supplied by the allocator maps VirtualReg to RealReg
-- regs, but sometimes we want to apply it to plain old Reg.
--
liftPatchFnToRegReg :: (VirtualReg -> RealReg) -> (Reg -> Reg)
liftPatchFnToRegReg patchF reg
= case reg of
RegVirtual vr -> RegReal (patchF vr)
RegReal _ -> reg
|
