RegAlloc.Liveness

ghc-7.0.4: The GHC API

RegAlloc.Liveness

Synopsis

- type RegSet = UniqSet Reg
- type RegMap a = UniqFM a
- emptyRegMap :: UniqFM a
- type BlockMap a = BlockEnv a
- emptyBlockMap :: BlockEnv a
- type LiveCmmTop instr = GenCmmTop CmmStatic LiveInfo [SCC (LiveBasicBlock instr)]
- data InstrSR instr
  - = Instr instr
  - | SPILL Reg Int
  - | RELOAD Int Reg
- data LiveInstr instr = LiveInstr (InstrSR instr) (Maybe Liveness)
- data Liveness = Liveness {
  - liveBorn :: RegSet
  - liveDieRead :: RegSet
  - liveDieWrite :: RegSet
  }
- data LiveInfo = LiveInfo [CmmStatic] (Maybe BlockId) (Maybe (BlockMap RegSet)) (Map BlockId (Set Int))
- type LiveBasicBlock instr = GenBasicBlock (LiveInstr instr)
- mapBlockTop :: (LiveBasicBlock instr -> LiveBasicBlock instr) -> LiveCmmTop instr -> LiveCmmTop instr
- mapBlockTopM :: Monad m => (LiveBasicBlock instr -> m (LiveBasicBlock instr)) -> LiveCmmTop instr -> m (LiveCmmTop instr)
- mapSCCM :: Monad m => (a -> m b) -> SCC a -> m (SCC b)
- mapGenBlockTop :: (GenBasicBlock i -> GenBasicBlock i) -> GenCmmTop d h (ListGraph i) -> GenCmmTop d h (ListGraph i)
- mapGenBlockTopM :: Monad m => (GenBasicBlock i -> m (GenBasicBlock i)) -> GenCmmTop d h (ListGraph i) -> m (GenCmmTop d h (ListGraph i))
- stripLive :: (Outputable instr, Instruction instr) => LiveCmmTop instr -> NatCmmTop instr
- stripLiveBlock :: Instruction instr => LiveBasicBlock instr -> NatBasicBlock instr
- slurpConflicts :: Instruction instr => LiveCmmTop instr -> (Bag (UniqSet Reg), Bag (Reg, Reg))
- slurpReloadCoalesce :: forall instr. Instruction instr => LiveCmmTop instr -> Bag (Reg, Reg)
- eraseDeltasLive :: Instruction instr => LiveCmmTop instr -> LiveCmmTop instr
- patchEraseLive :: Instruction instr => (Reg -> Reg) -> LiveCmmTop instr -> LiveCmmTop instr
- patchRegsLiveInstr :: Instruction instr => (Reg -> Reg) -> LiveInstr instr -> LiveInstr instr
- reverseBlocksInTops :: LiveCmmTop instr -> LiveCmmTop instr
- regLiveness :: (Outputable instr, Instruction instr) => LiveCmmTop instr -> UniqSM (LiveCmmTop instr)
- natCmmTopToLive :: Instruction instr => NatCmmTop instr -> LiveCmmTop instr

# Documentation

type RegSet = UniqSet Reg

type RegMap a = UniqFM a

emptyRegMap :: UniqFM a

type BlockMap a = BlockEnv a

emptyBlockMap :: BlockEnv a

type LiveCmmTop instr = GenCmmTop CmmStatic LiveInfo [SCC (LiveBasicBlock instr)]

A top level thing which carries liveness information.

data InstrSR instr

The register allocator also wants to use SPILL/RELOAD meta instructions, so we'll keep those here.

Constructors

Instr instr | A real machine instruction
SPILL Reg Int | spill this reg to a stack slot
RELOAD Int Reg | reload this reg from a stack slot

Instances

Outputable instr => Outputable (InstrSR instr) |
Instruction instr => Instruction (InstrSR instr) |

data LiveInstr instr

An instruction with liveness information.

Constructors

LiveInstr (InstrSR instr) (Maybe Liveness) |

Instances

Outputable instr => Outputable (LiveInstr instr) |

data Liveness

Liveness information. The regs which die are ones which are no longer live in the *next* instruction in this sequence. (NB. if the instruction is a jump, these registers might still be live at the jump target(s) - you have to check the liveness at the destination block to find out).

Constructors

Liveness | registers that died because they were clobbered by something.
Fields liveBorn :: RegSet registers born in this instruction (written to for first time). liveDieRead :: RegSet registers that died because they were read for the last time. liveDieWrite :: RegSet

data LiveInfo

Stash regs live on entry to each basic block in the info part of the cmm code.

Constructors

LiveInfo [CmmStatic] (Maybe BlockId) (Maybe (BlockMap RegSet)) (Map BlockId (Set Int)) |

Instances

Outputable LiveInfo |

type LiveBasicBlock instr = GenBasicBlock (LiveInstr instr)

A basic block with liveness information.

mapBlockTop :: (LiveBasicBlock instr -> LiveBasicBlock instr) -> LiveCmmTop instr -> LiveCmmTop instr

map a function across all the basic blocks in this code

mapBlockTopM :: Monad m => (LiveBasicBlock instr -> m (LiveBasicBlock instr)) -> LiveCmmTop instr -> m (LiveCmmTop instr)

map a function across all the basic blocks in this code (monadic version)

mapSCCM :: Monad m => (a -> m b) -> SCC a -> m (SCC b)

mapGenBlockTop :: (GenBasicBlock i -> GenBasicBlock i) -> GenCmmTop d h (ListGraph i) -> GenCmmTop d h (ListGraph i)

mapGenBlockTopM :: Monad m => (GenBasicBlock i -> m (GenBasicBlock i)) -> GenCmmTop d h (ListGraph i) -> m (GenCmmTop d h (ListGraph i))

map a function across all the basic blocks in this code (monadic version)

stripLive :: (Outputable instr, Instruction instr) => LiveCmmTop instr -> NatCmmTop instr

Strip away liveness information, yielding NatCmmTop

stripLiveBlock :: Instruction instr => LiveBasicBlock instr -> NatBasicBlock instr

Strip away liveness information from a basic block, and make real spill instructions out of SPILL, RELOAD pseudos along the way.

slurpConflicts :: Instruction instr => LiveCmmTop instr -> (Bag (UniqSet Reg), Bag (Reg, Reg))

Slurp out the list of register conflicts and reg-reg moves from this top level thing. Slurping of conflicts and moves is wrapped up together so we don't have to make two passes over the same code when we want to build the graph.

slurpReloadCoalesce :: forall instr. Instruction instr => LiveCmmTop instr -> Bag (Reg, Reg)

For spill/reloads

SPILL v1, slot1 ... RELOAD slot1, v2

If we can arrange that v1 and v2 are allocated to the same hreg it's more likely the spill/reload instrs can be cleaned and replaced by a nop reg-reg move.

eraseDeltasLive :: Instruction instr => LiveCmmTop instr -> LiveCmmTop instr

Erase Delta instructions.

patchEraseLive :: Instruction instr => (Reg -> Reg) -> LiveCmmTop instr -> LiveCmmTop instr

Patch the registers in this code according to this register mapping. also erase reg -> reg moves when the reg is the same. also erase reg -> reg moves when the destination dies in this instr.

patchRegsLiveInstr :: Instruction instr => (Reg -> Reg) -> LiveInstr instr -> LiveInstr instr

Patch registers in this LiveInstr, including the liveness information.

reverseBlocksInTops :: LiveCmmTop instr -> LiveCmmTop instr

If we've compute liveness info for this code already we have to reverse the SCCs in each top to get them back to the right order so we can do it again.

regLiveness :: (Outputable instr, Instruction instr) => LiveCmmTop instr -> UniqSM (LiveCmmTop instr)

natCmmTopToLive :: Instruction instr => NatCmmTop instr -> LiveCmmTop instr

Convert a NatCmmTop to a LiveCmmTop, with empty liveness information