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module GHC.Cmm.CallConv (
ParamLocation(..),
assignArgumentsPos,
assignStack,
realArgRegsCover
) where
import GhcPrelude
import GHC.Cmm.Expr
import GHC.Runtime.Heap.Layout
import GHC.Cmm (Convention(..))
import GHC.Cmm.Ppr () -- For Outputable instances
import DynFlags
import GHC.Platform
import Outputable
-- Calculate the 'GlobalReg' or stack locations for function call
-- parameters as used by the Cmm calling convention.
data ParamLocation
= RegisterParam GlobalReg
| StackParam ByteOff
instance Outputable ParamLocation where
ppr (RegisterParam g) = ppr g
ppr (StackParam p) = ppr p
-- |
-- Given a list of arguments, and a function that tells their types,
-- return a list showing where each argument is passed
--
assignArgumentsPos :: DynFlags
-> ByteOff -- stack offset to start with
-> Convention
-> (a -> CmmType) -- how to get a type from an arg
-> [a] -- args
-> (
ByteOff -- bytes of stack args
, [(a, ParamLocation)] -- args and locations
)
assignArgumentsPos dflags off conv arg_ty reps = (stk_off, assignments)
where
regs = case (reps, conv) of
(_, NativeNodeCall) -> getRegsWithNode dflags
(_, NativeDirectCall) -> getRegsWithoutNode dflags
([_], NativeReturn) -> allRegs dflags
(_, NativeReturn) -> getRegsWithNode dflags
-- GC calling convention *must* put values in registers
(_, GC) -> allRegs dflags
(_, Slow) -> nodeOnly
-- The calling conventions first assign arguments to registers,
-- then switch to the stack when we first run out of registers
-- (even if there are still available registers for args of a
-- different type). When returning an unboxed tuple, we also
-- separate the stack arguments by pointerhood.
(reg_assts, stk_args) = assign_regs [] reps regs
(stk_off, stk_assts) = assignStack dflags off arg_ty stk_args
assignments = reg_assts ++ stk_assts
assign_regs assts [] _ = (assts, [])
assign_regs assts (r:rs) regs | isVecType ty = vec
| isFloatType ty = float
| otherwise = int
where vec = case (w, regs) of
(W128, (vs, fs, ds, ls, s:ss))
| passVectorInReg W128 dflags -> k (RegisterParam (XmmReg s), (vs, fs, ds, ls, ss))
(W256, (vs, fs, ds, ls, s:ss))
| passVectorInReg W256 dflags -> k (RegisterParam (YmmReg s), (vs, fs, ds, ls, ss))
(W512, (vs, fs, ds, ls, s:ss))
| passVectorInReg W512 dflags -> k (RegisterParam (ZmmReg s), (vs, fs, ds, ls, ss))
_ -> (assts, (r:rs))
float = case (w, regs) of
(W32, (vs, fs, ds, ls, s:ss))
| passFloatInXmm -> k (RegisterParam (FloatReg s), (vs, fs, ds, ls, ss))
(W32, (vs, f:fs, ds, ls, ss))
| not passFloatInXmm -> k (RegisterParam f, (vs, fs, ds, ls, ss))
(W64, (vs, fs, ds, ls, s:ss))
| passFloatInXmm -> k (RegisterParam (DoubleReg s), (vs, fs, ds, ls, ss))
(W64, (vs, fs, d:ds, ls, ss))
| not passFloatInXmm -> k (RegisterParam d, (vs, fs, ds, ls, ss))
_ -> (assts, (r:rs))
int = case (w, regs) of
(W128, _) -> panic "W128 unsupported register type"
(_, (v:vs, fs, ds, ls, ss)) | widthInBits w <= widthInBits (wordWidth dflags)
-> k (RegisterParam (v gcp), (vs, fs, ds, ls, ss))
(_, (vs, fs, ds, l:ls, ss)) | widthInBits w > widthInBits (wordWidth dflags)
-> k (RegisterParam l, (vs, fs, ds, ls, ss))
_ -> (assts, (r:rs))
k (asst, regs') = assign_regs ((r, asst) : assts) rs regs'
ty = arg_ty r
w = typeWidth ty
gcp | isGcPtrType ty = VGcPtr
| otherwise = VNonGcPtr
passFloatInXmm = passFloatArgsInXmm dflags
passFloatArgsInXmm :: DynFlags -> Bool
passFloatArgsInXmm dflags = case platformArch (targetPlatform dflags) of
ArchX86_64 -> True
ArchX86 -> False
_ -> False
-- We used to spill vector registers to the stack since the LLVM backend didn't
-- support vector registers in its calling convention. However, this has now
-- been fixed. This function remains only as a convenient way to re-enable
-- spilling when debugging code generation.
passVectorInReg :: Width -> DynFlags -> Bool
passVectorInReg _ _ = True
assignStack :: DynFlags -> ByteOff -> (a -> CmmType) -> [a]
-> (
ByteOff -- bytes of stack args
, [(a, ParamLocation)] -- args and locations
)
assignStack dflags offset arg_ty args = assign_stk offset [] (reverse args)
where
assign_stk offset assts [] = (offset, assts)
assign_stk offset assts (r:rs)
= assign_stk off' ((r, StackParam off') : assts) rs
where w = typeWidth (arg_ty r)
off' = offset + size
-- Stack arguments always take a whole number of words, we never
-- pack them unlike constructor fields.
size = roundUpToWords dflags (widthInBytes w)
-----------------------------------------------------------------------------
-- Local information about the registers available
type AvailRegs = ( [VGcPtr -> GlobalReg] -- available vanilla regs.
, [GlobalReg] -- floats
, [GlobalReg] -- doubles
, [GlobalReg] -- longs (int64 and word64)
, [Int] -- XMM (floats and doubles)
)
-- Vanilla registers can contain pointers, Ints, Chars.
-- Floats and doubles have separate register supplies.
--
-- We take these register supplies from the *real* registers, i.e. those
-- that are guaranteed to map to machine registers.
getRegsWithoutNode, getRegsWithNode :: DynFlags -> AvailRegs
getRegsWithoutNode dflags =
( filter (\r -> r VGcPtr /= node) (realVanillaRegs dflags)
, realFloatRegs dflags
, realDoubleRegs dflags
, realLongRegs dflags
, realXmmRegNos dflags)
-- getRegsWithNode uses R1/node even if it isn't a register
getRegsWithNode dflags =
( if null (realVanillaRegs dflags)
then [VanillaReg 1]
else realVanillaRegs dflags
, realFloatRegs dflags
, realDoubleRegs dflags
, realLongRegs dflags
, realXmmRegNos dflags)
allFloatRegs, allDoubleRegs, allLongRegs :: DynFlags -> [GlobalReg]
allVanillaRegs :: DynFlags -> [VGcPtr -> GlobalReg]
allXmmRegs :: DynFlags -> [Int]
allVanillaRegs dflags = map VanillaReg $ regList (mAX_Vanilla_REG dflags)
allFloatRegs dflags = map FloatReg $ regList (mAX_Float_REG dflags)
allDoubleRegs dflags = map DoubleReg $ regList (mAX_Double_REG dflags)
allLongRegs dflags = map LongReg $ regList (mAX_Long_REG dflags)
allXmmRegs dflags = regList (mAX_XMM_REG dflags)
realFloatRegs, realDoubleRegs, realLongRegs :: DynFlags -> [GlobalReg]
realVanillaRegs :: DynFlags -> [VGcPtr -> GlobalReg]
realXmmRegNos :: DynFlags -> [Int]
realVanillaRegs dflags = map VanillaReg $ regList (mAX_Real_Vanilla_REG dflags)
realFloatRegs dflags = map FloatReg $ regList (mAX_Real_Float_REG dflags)
realDoubleRegs dflags = map DoubleReg $ regList (mAX_Real_Double_REG dflags)
realLongRegs dflags = map LongReg $ regList (mAX_Real_Long_REG dflags)
realXmmRegNos dflags
| isSse2Enabled dflags = regList (mAX_Real_XMM_REG dflags)
| otherwise = []
regList :: Int -> [Int]
regList n = [1 .. n]
allRegs :: DynFlags -> AvailRegs
allRegs dflags = (allVanillaRegs dflags,
allFloatRegs dflags,
allDoubleRegs dflags,
allLongRegs dflags,
allXmmRegs dflags)
nodeOnly :: AvailRegs
nodeOnly = ([VanillaReg 1], [], [], [], [])
-- This returns the set of global registers that *cover* the machine registers
-- used for argument passing. On platforms where registers can overlap---right
-- now just x86-64, where Float and Double registers overlap---passing this set
-- of registers is guaranteed to preserve the contents of all live registers. We
-- only use this functionality in hand-written C-- code in the RTS.
realArgRegsCover :: DynFlags -> [GlobalReg]
realArgRegsCover dflags
| passFloatArgsInXmm dflags = map ($VGcPtr) (realVanillaRegs dflags) ++
realLongRegs dflags ++
map XmmReg (realXmmRegNos dflags)
| otherwise = map ($VGcPtr) (realVanillaRegs dflags) ++
realFloatRegs dflags ++
realDoubleRegs dflags ++
realLongRegs dflags ++
map XmmReg (realXmmRegNos dflags)
|
