{-# LANGUAGE RecordWildCards #-}

-- | Put common type definitions here to break recursive module dependencies.

module GHC.CmmToAsm.Reg.Linear.Base (
        BlockAssignment,
        lookupBlockAssignment,
        lookupFirstUsed,
        emptyBlockAssignment,
        updateBlockAssignment,

        Loc(..),
        regsOfLoc,

        -- for stats
        SpillReason(..),
        RegAllocStats(..),

        -- the allocator monad
        RA_State(..),
)

where

import GHC.Prelude

import GHC.CmmToAsm.Reg.Linear.StackMap
import GHC.CmmToAsm.Reg.Liveness
import GHC.CmmToAsm.Config
import GHC.Platform.Reg

import GHC.Utils.Outputable
import GHC.Types.Unique
import GHC.Types.Unique.FM
import GHC.Types.Unique.Supply
import GHC.Cmm.BlockId
import GHC.Cmm.Dataflow.Collections
import GHC.CmmToAsm.Reg.Utils

data ReadingOrWriting = Reading | Writing deriving (ReadingOrWriting -> ReadingOrWriting -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: ReadingOrWriting -> ReadingOrWriting -> Bool
$c/= :: ReadingOrWriting -> ReadingOrWriting -> Bool
== :: ReadingOrWriting -> ReadingOrWriting -> Bool
$c== :: ReadingOrWriting -> ReadingOrWriting -> Bool
Eq,Eq ReadingOrWriting
ReadingOrWriting -> ReadingOrWriting -> Bool
ReadingOrWriting -> ReadingOrWriting -> Ordering
ReadingOrWriting -> ReadingOrWriting -> ReadingOrWriting
forall a.
Eq a
-> (a -> a -> Ordering)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> a)
-> (a -> a -> a)
-> Ord a
min :: ReadingOrWriting -> ReadingOrWriting -> ReadingOrWriting
$cmin :: ReadingOrWriting -> ReadingOrWriting -> ReadingOrWriting
max :: ReadingOrWriting -> ReadingOrWriting -> ReadingOrWriting
$cmax :: ReadingOrWriting -> ReadingOrWriting -> ReadingOrWriting
>= :: ReadingOrWriting -> ReadingOrWriting -> Bool
$c>= :: ReadingOrWriting -> ReadingOrWriting -> Bool
> :: ReadingOrWriting -> ReadingOrWriting -> Bool
$c> :: ReadingOrWriting -> ReadingOrWriting -> Bool
<= :: ReadingOrWriting -> ReadingOrWriting -> Bool
$c<= :: ReadingOrWriting -> ReadingOrWriting -> Bool
< :: ReadingOrWriting -> ReadingOrWriting -> Bool
$c< :: ReadingOrWriting -> ReadingOrWriting -> Bool
compare :: ReadingOrWriting -> ReadingOrWriting -> Ordering
$ccompare :: ReadingOrWriting -> ReadingOrWriting -> Ordering
Ord)

-- | Used to store the register assignment on entry to a basic block.
--      We use this to handle join points, where multiple branch instructions
--      target a particular label. We have to insert fixup code to make
--      the register assignments from the different sources match up.
--
data BlockAssignment freeRegs
        = BlockAssignment { forall freeRegs.
BlockAssignment freeRegs -> BlockMap (freeRegs, RegMap Loc)
blockMap :: !(BlockMap (freeRegs, RegMap Loc))
                          , forall freeRegs.
BlockAssignment freeRegs -> UniqFM VirtualReg RealReg
firstUsed :: !(UniqFM VirtualReg RealReg) }

-- | Find the register mapping for a specific BlockId.
lookupBlockAssignment :: BlockId -> BlockAssignment freeRegs -> Maybe (freeRegs, RegMap Loc)
lookupBlockAssignment :: forall freeRegs.
BlockId -> BlockAssignment freeRegs -> Maybe (freeRegs, RegMap Loc)
lookupBlockAssignment BlockId
bid BlockAssignment freeRegs
ba = forall (map :: * -> *) a.
IsMap map =>
KeyOf map -> map a -> Maybe a
mapLookup BlockId
bid (forall freeRegs.
BlockAssignment freeRegs -> BlockMap (freeRegs, RegMap Loc)
blockMap BlockAssignment freeRegs
ba)

-- | Lookup which register a virtual register was first assigned to.
lookupFirstUsed :: VirtualReg -> BlockAssignment freeRegs -> Maybe RealReg
lookupFirstUsed :: forall freeRegs.
VirtualReg -> BlockAssignment freeRegs -> Maybe RealReg
lookupFirstUsed VirtualReg
vr BlockAssignment freeRegs
ba = forall key elt. Uniquable key => UniqFM key elt -> key -> Maybe elt
lookupUFM (forall freeRegs.
BlockAssignment freeRegs -> UniqFM VirtualReg RealReg
firstUsed BlockAssignment freeRegs
ba) VirtualReg
vr

-- | An initial empty 'BlockAssignment'
emptyBlockAssignment :: BlockAssignment freeRegs
emptyBlockAssignment :: forall freeRegs. BlockAssignment freeRegs
emptyBlockAssignment = forall freeRegs.
BlockMap (freeRegs, RegMap Loc)
-> UniqFM VirtualReg RealReg -> BlockAssignment freeRegs
BlockAssignment forall (map :: * -> *) a. IsMap map => map a
mapEmpty forall a. Monoid a => a
mempty

-- | Add new register mappings for a specific block.
updateBlockAssignment :: BlockId
  -> (freeRegs, RegMap Loc)
  -> BlockAssignment freeRegs
  -> BlockAssignment freeRegs
updateBlockAssignment :: forall freeRegs.
BlockId
-> (freeRegs, RegMap Loc)
-> BlockAssignment freeRegs
-> BlockAssignment freeRegs
updateBlockAssignment BlockId
dest (freeRegs
freeRegs, RegMap Loc
regMap) (BlockAssignment {BlockMap (freeRegs, RegMap Loc)
UniqFM VirtualReg RealReg
firstUsed :: UniqFM VirtualReg RealReg
blockMap :: BlockMap (freeRegs, RegMap Loc)
firstUsed :: forall freeRegs.
BlockAssignment freeRegs -> UniqFM VirtualReg RealReg
blockMap :: forall freeRegs.
BlockAssignment freeRegs -> BlockMap (freeRegs, RegMap Loc)
..}) =
  forall freeRegs.
BlockMap (freeRegs, RegMap Loc)
-> UniqFM VirtualReg RealReg -> BlockAssignment freeRegs
BlockAssignment (forall (map :: * -> *) a.
IsMap map =>
KeyOf map -> a -> map a -> map a
mapInsert BlockId
dest (freeRegs
freeRegs, RegMap Loc
regMap) BlockMap (freeRegs, RegMap Loc)
blockMap)
                  (forall elta eltb eltc key.
(elta -> eltb -> Maybe eltc)
-> (UniqFM key elta -> UniqFM key eltc)
-> (UniqFM key eltb -> UniqFM key eltc)
-> UniqFM key elta
-> UniqFM key eltb
-> UniqFM key eltc
mergeUFM RealReg -> Loc -> Maybe RealReg
combWithExisting forall a. a -> a
id (forall elt1 elt2 key.
(elt1 -> Maybe elt2) -> UniqFM key elt1 -> UniqFM key elt2
mapMaybeUFM Loc -> Maybe RealReg
fromLoc) (UniqFM VirtualReg RealReg
firstUsed) (forall elt. UniqFM Reg elt -> UniqFM VirtualReg elt
toVRegMap RegMap Loc
regMap))
  where
    -- The blocks are processed in dependency order, so if there's already an
    -- entry in the map then keep that assignment rather than writing the new
    -- assignment.
    combWithExisting :: RealReg -> Loc -> Maybe RealReg
    combWithExisting :: RealReg -> Loc -> Maybe RealReg
combWithExisting RealReg
old_reg Loc
_ = forall a. a -> Maybe a
Just forall a b. (a -> b) -> a -> b
$ RealReg
old_reg

    fromLoc :: Loc -> Maybe RealReg
    fromLoc :: Loc -> Maybe RealReg
fromLoc (InReg RealReg
rr) = forall a. a -> Maybe a
Just RealReg
rr
    fromLoc (InBoth RealReg
rr StackSlot
_) = forall a. a -> Maybe a
Just RealReg
rr
    fromLoc Loc
_ = forall a. Maybe a
Nothing


-- | Where a vreg is currently stored
--      A temporary can be marked as living in both a register and memory
--      (InBoth), for example if it was recently loaded from a spill location.
--      This makes it cheap to spill (no save instruction required), but we
--      have to be careful to turn this into InReg if the value in the
--      register is changed.

--      This is also useful when a temporary is about to be clobbered.  We
--      save it in a spill location, but mark it as InBoth because the current
--      instruction might still want to read it.
--
data Loc
        -- | vreg is in a register
        = InReg   !RealReg

        -- | vreg is held in a stack slot
        | InMem   {-# UNPACK #-}  !StackSlot


        -- | vreg is held in both a register and a stack slot
        | InBoth   !RealReg
                   {-# UNPACK #-} !StackSlot
        deriving (Loc -> Loc -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: Loc -> Loc -> Bool
$c/= :: Loc -> Loc -> Bool
== :: Loc -> Loc -> Bool
$c== :: Loc -> Loc -> Bool
Eq, StackSlot -> Loc -> ShowS
[Loc] -> ShowS
Loc -> String
forall a.
(StackSlot -> a -> ShowS)
-> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Loc] -> ShowS
$cshowList :: [Loc] -> ShowS
show :: Loc -> String
$cshow :: Loc -> String
showsPrec :: StackSlot -> Loc -> ShowS
$cshowsPrec :: StackSlot -> Loc -> ShowS
Show, Eq Loc
Loc -> Loc -> Bool
Loc -> Loc -> Ordering
Loc -> Loc -> Loc
forall a.
Eq a
-> (a -> a -> Ordering)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
-> (a -> a -> a)
-> (a -> a -> a)
-> Ord a
min :: Loc -> Loc -> Loc
$cmin :: Loc -> Loc -> Loc
max :: Loc -> Loc -> Loc
$cmax :: Loc -> Loc -> Loc
>= :: Loc -> Loc -> Bool
$c>= :: Loc -> Loc -> Bool
> :: Loc -> Loc -> Bool
$c> :: Loc -> Loc -> Bool
<= :: Loc -> Loc -> Bool
$c<= :: Loc -> Loc -> Bool
< :: Loc -> Loc -> Bool
$c< :: Loc -> Loc -> Bool
compare :: Loc -> Loc -> Ordering
$ccompare :: Loc -> Loc -> Ordering
Ord)

instance Outputable Loc where
        ppr :: Loc -> SDoc
ppr Loc
l = String -> SDoc
text (forall a. Show a => a -> String
show Loc
l)


-- | Get the reg numbers stored in this Loc.
regsOfLoc :: Loc -> [RealReg]
regsOfLoc :: Loc -> [RealReg]
regsOfLoc (InReg RealReg
r)    = [RealReg
r]
regsOfLoc (InBoth RealReg
r StackSlot
_) = [RealReg
r]
regsOfLoc (InMem StackSlot
_)    = []


-- | Reasons why instructions might be inserted by the spiller.
--      Used when generating stats for -ddrop-asm-stats.
--
data SpillReason
        -- | vreg was spilled to a slot so we could use its
        --      current hreg for another vreg
        = SpillAlloc    !Unique

        -- | vreg was moved because its hreg was clobbered
        | SpillClobber  !Unique

        -- | vreg was loaded from a spill slot
        | SpillLoad     !Unique

        -- | reg-reg move inserted during join to targets
        | SpillJoinRR   !Unique

        -- | reg-mem move inserted during join to targets
        | SpillJoinRM   !Unique


-- | Used to carry interesting stats out of the register allocator.
data RegAllocStats
        = RegAllocStats
        { RegAllocStats -> UniqFM Unique [StackSlot]
ra_spillInstrs        :: UniqFM Unique [Int] -- Keys are the uniques of regs
                                                       -- and taken from SpillReason
                                                       -- See Note [UniqFM and the register allocator]
        , RegAllocStats -> [(BlockId, BlockId, BlockId)]
ra_fixupList     :: [(BlockId,BlockId,BlockId)]
        -- ^ (from,fixup,to) : We inserted fixup code between from and to
        }


-- | The register allocator state
data RA_State freeRegs
        = RA_State

        {
        -- | the current mapping from basic blocks to
        --      the register assignments at the beginning of that block.
          forall freeRegs. RA_State freeRegs -> BlockAssignment freeRegs
ra_blockassig :: BlockAssignment freeRegs

        -- | free machine registers
        , forall freeRegs. RA_State freeRegs -> freeRegs
ra_freeregs   :: !freeRegs

        -- | assignment of temps to locations
        , forall freeRegs. RA_State freeRegs -> RegMap Loc
ra_assig      :: RegMap Loc

        -- | current stack delta
        , forall freeRegs. RA_State freeRegs -> StackSlot
ra_delta      :: Int

        -- | free stack slots for spilling
        , forall freeRegs. RA_State freeRegs -> StackMap
ra_stack      :: StackMap

        -- | unique supply for generating names for join point fixup blocks.
        , forall freeRegs. RA_State freeRegs -> UniqSupply
ra_us         :: UniqSupply

        -- | Record why things were spilled, for -ddrop-asm-stats.
        --      Just keep a list here instead of a map of regs -> reasons.
        --      We don't want to slow down the allocator if we're not going to emit the stats.
        , forall freeRegs. RA_State freeRegs -> [SpillReason]
ra_spills     :: [SpillReason]

        -- | Native code generator configuration
        , forall freeRegs. RA_State freeRegs -> NCGConfig
ra_config     :: !NCGConfig

        -- | (from,fixup,to) : We inserted fixup code between from and to
        , forall freeRegs. RA_State freeRegs -> [(BlockId, BlockId, BlockId)]
ra_fixups     :: [(BlockId,BlockId,BlockId)]

        }