2 -- | A description of the register set of the X86.
3 -- This isn't used directly in GHC proper.
5 -- See RegArchBase.hs for the reference.
6 -- See MachRegs.hs for the actual trivColorable function used in GHC.
9 module RegAlloc.Graph.ArchX86 (
18 import RegAlloc.Graph.ArchBase (Reg(..), RegSub(..), RegClass(..))
22 -- | Determine the class of a register
23 classOfReg :: Reg -> RegClass
28 RegSub SubL16 _ -> ClassG16
29 RegSub SubL8 _ -> ClassG8
30 RegSub SubL8H _ -> ClassG8
33 -- | Determine all the regs that make up a certain class.
34 regsOfClass :: RegClass -> UniqSet Reg
38 -> mkUniqSet [ Reg ClassG32 i | i <- [0..7] ]
41 -> mkUniqSet [ RegSub SubL16 (Reg ClassG32 i) | i <- [0..7] ]
45 (mkUniqSet [ RegSub SubL8 (Reg ClassG32 i) | i <- [0..3] ])
46 (mkUniqSet [ RegSub SubL8H (Reg ClassG32 i) | i <- [0..3] ])
49 -> mkUniqSet [ Reg ClassF64 i | i <- [0..5] ]
52 -- | Determine the common name of a reg
53 -- returns Nothing if this reg is not part of the machine.
54 regName :: Reg -> Maybe String
58 | i <= 7 -> Just ([ "eax", "ebx", "ecx", "edx", "ebp", "esi", "edi", "esp" ] !! i)
60 RegSub SubL16 (Reg ClassG32 i)
61 | i <= 7 -> Just ([ "ax", "bx", "cx", "dx", "bp", "si", "di", "sp"] !! i)
63 RegSub SubL8 (Reg ClassG32 i)
64 | i <= 3 -> Just ([ "al", "bl", "cl", "dl"] !! i)
66 RegSub SubL8H (Reg ClassG32 i)
67 | i <= 3 -> Just ([ "ah", "bh", "ch", "dh"] !! i)
72 -- | Which regs alias what other regs
73 regAlias :: Reg -> UniqSet Reg
77 -- 32 bit regs alias all of the subregs
80 -- for eax, ebx, ecx, eds
82 -> mkUniqSet $ [ Reg ClassG32 i, RegSub SubL16 reg, RegSub SubL8 reg, RegSub SubL8H reg ]
84 -- for esi, edi, esp, ebp
86 -> mkUniqSet $ [ Reg ClassG32 i, RegSub SubL16 reg ]
89 -- 16 bit subregs alias the whole reg
90 RegSub SubL16 r@(Reg ClassG32 _)
93 -- 8 bit subregs alias the 32 and 16, but not the other 8 bit subreg
94 RegSub SubL8 r@(Reg ClassG32 _)
95 -> mkUniqSet $ [ r, RegSub SubL16 r, RegSub SubL8 r ]
97 RegSub SubL8H r@(Reg ClassG32 _)
98 -> mkUniqSet $ [ r, RegSub SubL16 r, RegSub SubL8H r ]
104 _ -> error "regAlias: invalid register"
107 -- | Optimised versions of RegColorBase.{worst, squeese} specific to x86
109 worst :: Int -> RegClass -> RegClass -> Int
110 worst n classN classC
128 ClassG32 -> min (n*2) 8
129 ClassG16 -> min (n*2) 8
138 squeese :: RegClass -> [(Int, RegClass)] -> Int
139 squeese classN countCs
140 = sum (map (\(i, classC) -> worst i classN classC) countCs)