GHC.CmmToAsm.Reg.Liveness · ghc-9.10.3

typetype RegSet = UniqSet Reg

typetype RegMap a = UniqFM Reg a

Map from some kind of register to a.

While we give the type for keys as Reg which is the common case sometimes we end up using VirtualReq or naked Uniques. See Note [UniqFM and the register allocator]

valueemptyRegMap :: RegMap a

#

typetype BlockMap a = LabelMap a

#

valuemapEmpty :: LabelMap v

#

typetype LiveCmmDecl statics instr = GenCmmDecl statics LiveInfo [SCC (LiveBasicBlock instr)]

#

A top level thing which carries liveness information.

datadata 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

Instances3Functor, Outputable, Instruction

Functor InstrSRDefined in ghc-9.10.3 · GHC.CmmToAsm.Reg.Liveness
Outputable instr => Outputable (InstrSR instr)Defined in ghc-9.10.3 · GHC.CmmToAsm.Reg.Liveness
Instruction instr => Instruction (InstrSR instr)Defined in ghc-9.10.3 · GHC.CmmToAsm.Reg.Liveness

datadata LiveInstr instr

#

An instruction with liveness information.

Constructors

LiveInstr (InstrSR instr) (Maybe Liveness)

Instances3Functor, OutputableP, Outputable

Functor LiveInstrDefined in ghc-9.10.3 · GHC.CmmToAsm.Reg.Liveness
OutputableP env instr => OutputableP env (LiveInstr instr)Defined in ghc-9.10.3 · GHC.CmmToAsm.Reg.Liveness
Outputable instr => Outputable (LiveInstr instr)Defined in ghc-9.10.3 · GHC.CmmToAsm.Reg.Liveness

datadata 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
- 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
  registers that died because they were clobbered by something.

datadata LiveInfo

#

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

Constructors

LiveInfo (LabelMap RawCmmStatics) [BlockId] (BlockMap RegSet) (BlockMap IntSet)

Instances1OutputableP

OutputableP Platform LiveInfoDefined in ghc-9.10.3 · GHC.CmmToAsm.Reg.Liveness

typetype LiveBasicBlock instr = GenBasicBlock (LiveInstr instr)

#

A basic block with liveness information.

valuemapBlockTop

:: LiveBasicBlock instr -> LiveBasicBlock instr
-> LiveCmmDecl statics instr
-> LiveCmmDecl statics instr

#

map a function across all the basic blocks in this code

valuemapBlockTopM

:: Monad m
=> LiveBasicBlock instr -> m (LiveBasicBlock instr)
-> LiveCmmDecl statics instr
-> m (LiveCmmDecl statics instr)

#

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

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

#

valuemapGenBlockTop

:: GenBasicBlock i -> GenBasicBlock i
-> GenCmmDecl d h (ListGraph i)
-> GenCmmDecl d h (ListGraph i)

#

valuemapGenBlockTopM

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

#

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

valuemapLiveCmmDecl

:: instr -> b
-> LiveCmmDecl statics instr
-> LiveCmmDecl statics b

#

Map over instruction type in LiveCmmDecl

valuepprLiveCmmDecl

:: (OutputableP Platform statics, Instruction instr)
=> Platform
-> LiveCmmDecl statics instr
-> SDoc

#

Pretty-print a LiveCmmDecl

valuestripLive

:: (OutputableP Platform statics, Instruction instr)
=> NCGConfig
-> LiveCmmDecl statics instr
-> NatCmmDecl statics instr

#

Strip away liveness information, yielding NatCmmDecl

valuestripLiveBlock

:: Instruction instr
=> NCGConfig
-> 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.

valueslurpConflicts

:: Instruction instr
=> LiveCmmDecl statics 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.

valueslurpReloadCoalesce

:: Instruction instr
=> LiveCmmDecl statics 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.

valueeraseDeltasLive

:: Instruction instr
=> LiveCmmDecl statics instr
-> LiveCmmDecl statics instr

#

Erase Delta instructions.

valuepatchEraseLive

:: Instruction instr
=> Reg -> Reg
-> LiveCmmDecl statics instr
-> LiveCmmDecl statics 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.

valuepatchRegsLiveInstr

:: Instruction instr
=> Reg -> Reg
-> LiveInstr instr
-> LiveInstr instr

#

Patch registers in this LiveInstr, including the liveness information.

valuereverseBlocksInTops

:: LiveCmmDecl statics instr
-> LiveCmmDecl statics 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.

valueregLiveness

:: Instruction instr
=> Platform
-> LiveCmmDecl statics instr
-> UniqSM (LiveCmmDecl statics instr)

#

valuecmmTopLiveness

:: Instruction instr
=> Maybe CFG
-> Platform
-> NatCmmDecl statics instr
-> UniqSM (LiveCmmDecl statics instr)

#

Convert a NatCmmDecl to a LiveCmmDecl, with liveness information