module GHC.CmmToAsm.Reg.Linear.FreeRegs (
    FR(..),
    maxSpillSlots
)
where

import GHC.Prelude

import GHC.Platform.Reg
import GHC.Platform.Reg.Class

import GHC.CmmToAsm.Config
import GHC.Utils.Panic
import GHC.Platform

-- -----------------------------------------------------------------------------
-- The free register set
-- This needs to be *efficient*
-- Here's an inefficient 'executable specification' of the FreeRegs data type:
--
--      type FreeRegs = [RegNo]
--      noFreeRegs = 0
--      releaseReg n f = if n `elem` f then f else (n : f)
--      initFreeRegs = allocatableRegs
--      getFreeRegs cls f = filter ( (==cls) . regClass . RealReg ) f
--      allocateReg f r = filter (/= r) f

import qualified GHC.CmmToAsm.Reg.Linear.PPC     as PPC
import qualified GHC.CmmToAsm.Reg.Linear.X86     as X86
import qualified GHC.CmmToAsm.Reg.Linear.X86_64  as X86_64
import qualified GHC.CmmToAsm.Reg.Linear.AArch64 as AArch64

import qualified GHC.CmmToAsm.PPC.Instr     as PPC.Instr
import qualified GHC.CmmToAsm.X86.Instr     as X86.Instr
import qualified GHC.CmmToAsm.AArch64.Instr as AArch64.Instr

class Show freeRegs => FR freeRegs where
    frAllocateReg :: Platform -> RealReg -> freeRegs -> freeRegs
    frGetFreeRegs :: Platform -> RegClass -> freeRegs -> [RealReg]
    frInitFreeRegs :: Platform -> freeRegs
    frReleaseReg :: Platform -> RealReg -> freeRegs -> freeRegs

instance FR X86.FreeRegs where
    frAllocateReg  = \_ -> X86.allocateReg
    frGetFreeRegs  = X86.getFreeRegs
    frInitFreeRegs = X86.initFreeRegs
    frReleaseReg   = \_ -> X86.releaseReg

instance FR X86_64.FreeRegs where
    frAllocateReg  = \_ -> X86_64.allocateReg
    frGetFreeRegs  = X86_64.getFreeRegs
    frInitFreeRegs = X86_64.initFreeRegs
    frReleaseReg   = \_ -> X86_64.releaseReg

instance FR PPC.FreeRegs where
    frAllocateReg  = \_ -> PPC.allocateReg
    frGetFreeRegs  = \_ -> PPC.getFreeRegs
    frInitFreeRegs = PPC.initFreeRegs
    frReleaseReg   = \_ -> PPC.releaseReg

instance FR AArch64.FreeRegs where
    frAllocateReg = \_ -> AArch64.allocateReg
    frGetFreeRegs = \_ -> AArch64.getFreeRegs
    frInitFreeRegs = AArch64.initFreeRegs
    frReleaseReg = \_ -> AArch64.releaseReg

maxSpillSlots :: NCGConfig -> Int
maxSpillSlots config = case platformArch (ncgPlatform config) of
   ArchX86       -> X86.Instr.maxSpillSlots config
   ArchX86_64    -> X86.Instr.maxSpillSlots config
   ArchPPC       -> PPC.Instr.maxSpillSlots config
   ArchS390X     -> panic "maxSpillSlots ArchS390X"
   ArchARM _ _ _ -> panic "maxSpillSlots ArchARM"
   ArchAArch64   -> AArch64.Instr.maxSpillSlots config
   ArchPPC_64 _  -> PPC.Instr.maxSpillSlots config
   ArchAlpha     -> panic "maxSpillSlots ArchAlpha"
   ArchMipseb    -> panic "maxSpillSlots ArchMipseb"
   ArchMipsel    -> panic "maxSpillSlots ArchMipsel"
   ArchRISCV64   -> panic "maxSpillSlots ArchRISCV64"
   ArchJavaScript-> panic "maxSpillSlots ArchJavaScript"
   ArchUnknown   -> panic "maxSpillSlots ArchUnknown"
