ghc-7.0.1: The GHC API




type RegMap a = UniqFM aSource

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

A top level thing which carries liveness information.

data InstrSR instr Source

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


Instr instr

A real machine instruction


spill this reg to a stack slot


reload this reg from a stack slot


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

data LiveInstr instr Source

An instruction with liveness information.


LiveInstr (InstrSR instr) (Maybe Liveness) 


Outputable instr => Outputable (LiveInstr instr) 

data Liveness Source

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).



registers that died because they were clobbered by something.


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 Source

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


type LiveBasicBlock instr = GenBasicBlock (LiveInstr instr)Source

A basic block with liveness information.

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

map a function across all the basic blocks in this code

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

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

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

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

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

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

Strip away liveness information, yielding NatCmmTop

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

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))Source

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)Source

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 instrSource

Erase Delta instructions.

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

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 instrSource

Patch registers in this LiveInstr, including the liveness information.

reverseBlocksInTops :: LiveCmmTop instr -> LiveCmmTop instrSource

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)Source

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

Convert a NatCmmTop to a LiveCmmTop, with empty liveness information