{-# LANGUAGE BangPatterns #-}

module GHC.Cmm.Pipeline (
  -- | Converts C-- with an implicit stack and native C-- calls into
  -- optimized, CPS converted and native-call-less C--.  The latter
  -- C-- can be used to generate assembly.
  cmmPipeline
) where

import GHC.Prelude

import GHC.Cmm
import GHC.Cmm.Config
import GHC.Cmm.ContFlowOpt
import GHC.Cmm.CommonBlockElim
import GHC.Cmm.Dataflow.Collections
import GHC.Cmm.Info.Build
import GHC.Cmm.Lint
import GHC.Cmm.LayoutStack
import GHC.Cmm.ProcPoint
import GHC.Cmm.Sink
import GHC.Cmm.Switch.Implement

import GHC.Types.Unique.Supply
import GHC.Driver.Session
import GHC.Driver.Config.Cmm
import GHC.Utils.Error
import GHC.Utils.Logger
import GHC.Driver.Env
import Control.Monad
import GHC.Utils.Outputable
import GHC.Platform
import Data.Either (partitionEithers)

-----------------------------------------------------------------------------
-- | Top level driver for C-- pipeline
-----------------------------------------------------------------------------

cmmPipeline
 :: HscEnv -- Compilation env including
           -- dynamic flags: -dcmm-lint -ddump-cmm-cps
 -> ModuleSRTInfo        -- Info about SRTs generated so far
 -> CmmGroup             -- Input C-- with Procedures
 -> IO (ModuleSRTInfo, CmmGroupSRTs) -- Output CPS transformed C--

cmmPipeline :: HscEnv
-> ModuleSRTInfo -> CmmGroup -> IO (ModuleSRTInfo, [CmmDeclSRTs])
cmmPipeline HscEnv
hsc_env ModuleSRTInfo
srtInfo CmmGroup
prog = do
  let logger :: Logger
logger    = HscEnv -> Logger
hsc_logger HscEnv
hsc_env
  let cmmConfig :: CmmConfig
cmmConfig = DynFlags -> CmmConfig
initCmmConfig (HscEnv -> DynFlags
hsc_dflags HscEnv
hsc_env)
  let forceRes :: (a, t a) -> ()
forceRes (a
info, t a
group) = a
info a -> () -> ()
forall a b. a -> b -> b
`seq` (a -> () -> ()) -> () -> t a -> ()
forall a b. (a -> b -> b) -> b -> t a -> b
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr a -> () -> ()
forall a b. a -> b -> b
seq () t a
group
  let platform :: Platform
platform = CmmConfig -> Platform
cmmPlatform CmmConfig
cmmConfig
  Logger
-> SDoc
-> ((ModuleSRTInfo, [CmmDeclSRTs]) -> ())
-> IO (ModuleSRTInfo, [CmmDeclSRTs])
-> IO (ModuleSRTInfo, [CmmDeclSRTs])
forall (m :: * -> *) a.
MonadIO m =>
Logger -> SDoc -> (a -> ()) -> m a -> m a
withTimingSilent Logger
logger (String -> SDoc
text String
"Cmm pipeline") (ModuleSRTInfo, [CmmDeclSRTs]) -> ()
forall {t :: * -> *} {a} {a}. Foldable t => (a, t a) -> ()
forceRes (IO (ModuleSRTInfo, [CmmDeclSRTs])
 -> IO (ModuleSRTInfo, [CmmDeclSRTs]))
-> IO (ModuleSRTInfo, [CmmDeclSRTs])
-> IO (ModuleSRTInfo, [CmmDeclSRTs])
forall a b. (a -> b) -> a -> b
$ do
     [Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)]
tops <- {-# SCC "tops" #-} (CmmDecl
 -> IO (Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)))
-> CmmGroup
-> IO [Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM (Logger
-> Platform
-> CmmConfig
-> CmmDecl
-> IO (Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl))
cpsTop Logger
logger Platform
platform CmmConfig
cmmConfig) CmmGroup
prog

     let ([(CAFEnv, CmmGroup)]
procs, [(Set CAFfyLabel, CmmDecl)]
data_) = [Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)]
-> ([(CAFEnv, CmmGroup)], [(Set CAFfyLabel, CmmDecl)])
forall a b. [Either a b] -> ([a], [b])
partitionEithers [Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)]
tops
     (ModuleSRTInfo
srtInfo, [CmmDeclSRTs]
cmms) <- {-# SCC "doSRTs" #-} CmmConfig
-> ModuleSRTInfo
-> [(CAFEnv, CmmGroup)]
-> [(Set CAFfyLabel, CmmDecl)]
-> IO (ModuleSRTInfo, [CmmDeclSRTs])
doSRTs CmmConfig
cmmConfig ModuleSRTInfo
srtInfo [(CAFEnv, CmmGroup)]
procs [(Set CAFfyLabel, CmmDecl)]
data_
     Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith Logger
logger DumpFlag
Opt_D_dump_cmm_cps String
"Post CPS Cmm" DumpFormat
FormatCMM (Platform -> [CmmDeclSRTs] -> SDoc
forall env a. OutputableP env a => env -> a -> SDoc
pdoc Platform
platform [CmmDeclSRTs]
cmms)

     (ModuleSRTInfo, [CmmDeclSRTs]) -> IO (ModuleSRTInfo, [CmmDeclSRTs])
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (ModuleSRTInfo
srtInfo, [CmmDeclSRTs]
cmms)


-- | The Cmm pipeline for a single 'CmmDecl'. Returns:
--
--   - in the case of a 'CmmProc': 'Left' of the resulting (possibly
--     proc-point-split) 'CmmDecl's and their 'CafEnv'. CAF analysis
--     necessarily happens *before* proc-point splitting, as described in Note
--     [SRTs].
--
--   - in the case of a `CmmData`, the unmodified 'CmmDecl' and a 'CAFSet' containing
cpsTop :: Logger -> Platform -> CmmConfig -> CmmDecl -> IO (Either (CAFEnv, [CmmDecl]) (CAFSet, CmmDecl))
cpsTop :: Logger
-> Platform
-> CmmConfig
-> CmmDecl
-> IO (Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl))
cpsTop Logger
_logger Platform
platform CmmConfig
_ p :: CmmDecl
p@(CmmData Section
_ GenCmmStatics 'False
statics) = Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)
-> IO (Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl))
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ((Set CAFfyLabel, CmmDecl)
-> Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)
forall a b. b -> Either a b
Right (Platform -> GenCmmStatics 'False -> Set CAFfyLabel
cafAnalData Platform
platform GenCmmStatics 'False
statics, CmmDecl
p))
cpsTop Logger
logger Platform
platform CmmConfig
cfg CmmDecl
proc =
    do
      ----------- Control-flow optimisations ----------------------------------

      -- The first round of control-flow optimisation speeds up the
      -- later passes by removing lots of empty blocks, so we do it
      -- even when optimisation isn't turned on.
      --
      CmmProc CmmTopInfo
h CLabel
l [GlobalReg]
v CmmGraph
g <- {-# SCC "cmmCfgOpts(1)" #-}
           CmmDecl -> IO CmmDecl
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (CmmDecl -> IO CmmDecl) -> CmmDecl -> IO CmmDecl
forall a b. (a -> b) -> a -> b
$ Bool -> CmmDecl -> CmmDecl
cmmCfgOptsProc Bool
splitting_proc_points CmmDecl
proc
      DumpFlag -> String -> CmmGraph -> IO ()
dump DumpFlag
Opt_D_dump_cmm_cfg String
"Post control-flow optimisations" CmmGraph
g

      let !TopInfo {stack_info :: CmmTopInfo -> CmmStackInfo
stack_info=StackInfo { arg_space :: CmmStackInfo -> ByteOff
arg_space = ByteOff
entry_off
                                         , do_layout :: CmmStackInfo -> Bool
do_layout = Bool
do_layout }} = CmmTopInfo
h

      ----------- Eliminate common blocks -------------------------------------
      CmmGraph
g <- {-# SCC "elimCommonBlocks" #-}
           Bool
-> (CmmGraph -> CmmGraph)
-> CmmGraph
-> DumpFlag
-> String
-> IO CmmGraph
condPass (CmmConfig -> Bool
cmmOptElimCommonBlks CmmConfig
cfg) CmmGraph -> CmmGraph
elimCommonBlocks CmmGraph
g
                         DumpFlag
Opt_D_dump_cmm_cbe String
"Post common block elimination"

      -- Any work storing block Labels must be performed _after_
      -- elimCommonBlocks

      ----------- Implement switches ------------------------------------------
      CmmGraph
g <- if CmmConfig -> Bool
cmmDoCmmSwitchPlans CmmConfig
cfg
             then {-# SCC "createSwitchPlans" #-}
                  UniqSM CmmGraph -> IO CmmGraph
forall a. UniqSM a -> IO a
runUniqSM (UniqSM CmmGraph -> IO CmmGraph) -> UniqSM CmmGraph -> IO CmmGraph
forall a b. (a -> b) -> a -> b
$ Platform -> CmmGraph -> UniqSM CmmGraph
cmmImplementSwitchPlans Platform
platform CmmGraph
g
             else CmmGraph -> IO CmmGraph
forall a. a -> IO a
forall (f :: * -> *) a. Applicative f => a -> f a
pure CmmGraph
g
      DumpFlag -> String -> CmmGraph -> IO ()
dump DumpFlag
Opt_D_dump_cmm_switch String
"Post switch plan" CmmGraph
g

      ----------- Proc points -------------------------------------------------
      let
        call_pps :: ProcPointSet -- LabelMap
        call_pps :: ProcPointSet
call_pps = {-# SCC "callProcPoints" #-} CmmGraph -> ProcPointSet
callProcPoints CmmGraph
g
      ProcPointSet
proc_points <-
         if Bool
splitting_proc_points
            then do
              ProcPointSet
pp <- {-# SCC "minimalProcPointSet" #-} UniqSM ProcPointSet -> IO ProcPointSet
forall a. UniqSM a -> IO a
runUniqSM (UniqSM ProcPointSet -> IO ProcPointSet)
-> UniqSM ProcPointSet -> IO ProcPointSet
forall a b. (a -> b) -> a -> b
$
                 Platform -> ProcPointSet -> CmmGraph -> UniqSM ProcPointSet
minimalProcPointSet Platform
platform ProcPointSet
call_pps CmmGraph
g
              Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith Logger
logger DumpFlag
Opt_D_dump_cmm_proc String
"Proc points"
                    DumpFormat
FormatCMM (Platform -> CLabel -> SDoc
forall env a. OutputableP env a => env -> a -> SDoc
pdoc Platform
platform CLabel
l SDoc -> SDoc -> SDoc
$$ ProcPointSet -> SDoc
forall a. Outputable a => a -> SDoc
ppr ProcPointSet
pp SDoc -> SDoc -> SDoc
$$ Platform -> CmmGraph -> SDoc
forall env a. OutputableP env a => env -> a -> SDoc
pdoc Platform
platform CmmGraph
g)
              ProcPointSet -> IO ProcPointSet
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ProcPointSet
pp
            else
              ProcPointSet -> IO ProcPointSet
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ProcPointSet
call_pps

      ----------- Layout the stack and manifest Sp ----------------------------
      (CmmGraph
g, LabelMap StackMap
stackmaps) <-
           {-# SCC "layoutStack" #-}
           if Bool
do_layout
              then UniqSM (CmmGraph, LabelMap StackMap)
-> IO (CmmGraph, LabelMap StackMap)
forall a. UniqSM a -> IO a
runUniqSM (UniqSM (CmmGraph, LabelMap StackMap)
 -> IO (CmmGraph, LabelMap StackMap))
-> UniqSM (CmmGraph, LabelMap StackMap)
-> IO (CmmGraph, LabelMap StackMap)
forall a b. (a -> b) -> a -> b
$ CmmConfig
-> ProcPointSet
-> ByteOff
-> CmmGraph
-> UniqSM (CmmGraph, LabelMap StackMap)
cmmLayoutStack CmmConfig
cfg ProcPointSet
proc_points ByteOff
entry_off CmmGraph
g
              else (CmmGraph, LabelMap StackMap) -> IO (CmmGraph, LabelMap StackMap)
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (CmmGraph
g, LabelMap StackMap
forall a. LabelMap a
forall (map :: * -> *) a. IsMap map => map a
mapEmpty)
      DumpFlag -> String -> CmmGraph -> IO ()
dump DumpFlag
Opt_D_dump_cmm_sp String
"Layout Stack" CmmGraph
g

      ----------- Sink and inline assignments  --------------------------------
      CmmGraph
g <- {-# SCC "sink" #-} -- See Note [Sinking after stack layout]
           Bool
-> (CmmGraph -> CmmGraph)
-> CmmGraph
-> DumpFlag
-> String
-> IO CmmGraph
condPass (CmmConfig -> Bool
cmmOptSink CmmConfig
cfg) (Platform -> CmmGraph -> CmmGraph
cmmSink Platform
platform) CmmGraph
g
                    DumpFlag
Opt_D_dump_cmm_sink String
"Sink assignments"

      ------------- CAF analysis ----------------------------------------------
      let cafEnv :: CAFEnv
cafEnv = {-# SCC "cafAnal" #-} Platform -> ProcPointSet -> CLabel -> CmmGraph -> CAFEnv
cafAnal Platform
platform ProcPointSet
call_pps CLabel
l CmmGraph
g
      Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith Logger
logger DumpFlag
Opt_D_dump_cmm_caf String
"CAFEnv" DumpFormat
FormatText (Platform -> CAFEnv -> SDoc
forall env a. OutputableP env a => env -> a -> SDoc
pdoc Platform
platform CAFEnv
cafEnv)

      CmmGroup
g <- if Bool
splitting_proc_points
           then do
             ------------- Split into separate procedures -----------------------
             let pp_map :: LabelMap Status
pp_map = {-# SCC "procPointAnalysis" #-}
                          ProcPointSet -> CmmGraph -> LabelMap Status
procPointAnalysis ProcPointSet
proc_points CmmGraph
g
             Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith Logger
logger DumpFlag
Opt_D_dump_cmm_procmap String
"procpoint map"
                DumpFormat
FormatCMM (LabelMap Status -> SDoc
forall a. Outputable a => a -> SDoc
ppr LabelMap Status
pp_map)
             CmmGroup
g <- {-# SCC "splitAtProcPoints" #-} UniqSM CmmGroup -> IO CmmGroup
forall a. UniqSM a -> IO a
runUniqSM (UniqSM CmmGroup -> IO CmmGroup) -> UniqSM CmmGroup -> IO CmmGroup
forall a b. (a -> b) -> a -> b
$
                  Platform
-> CLabel
-> ProcPointSet
-> ProcPointSet
-> LabelMap Status
-> CmmDecl
-> UniqSM CmmGroup
splitAtProcPoints Platform
platform CLabel
l ProcPointSet
call_pps ProcPointSet
proc_points LabelMap Status
pp_map
                                    (CmmTopInfo -> CLabel -> [GlobalReg] -> CmmGraph -> CmmDecl
forall d h g. h -> CLabel -> [GlobalReg] -> g -> GenCmmDecl d h g
CmmProc CmmTopInfo
h CLabel
l [GlobalReg]
v CmmGraph
g)
             DumpFlag -> String -> CmmGroup -> IO ()
dumps DumpFlag
Opt_D_dump_cmm_split String
"Post splitting" CmmGroup
g
             CmmGroup -> IO CmmGroup
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return CmmGroup
g
           else
             -- attach info tables to return points
             CmmGroup -> IO CmmGroup
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (CmmGroup -> IO CmmGroup) -> CmmGroup -> IO CmmGroup
forall a b. (a -> b) -> a -> b
$ [ProcPointSet -> CmmDecl -> CmmDecl
attachContInfoTables ProcPointSet
call_pps (CmmTopInfo -> CLabel -> [GlobalReg] -> CmmGraph -> CmmDecl
forall d h g. h -> CLabel -> [GlobalReg] -> g -> GenCmmDecl d h g
CmmProc CmmTopInfo
h CLabel
l [GlobalReg]
v CmmGraph
g)]

      ------------- Populate info tables with stack info -----------------
      CmmGroup
g <- {-# SCC "setInfoTableStackMap" #-}
           CmmGroup -> IO CmmGroup
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (CmmGroup -> IO CmmGroup) -> CmmGroup -> IO CmmGroup
forall a b. (a -> b) -> a -> b
$ (CmmDecl -> CmmDecl) -> CmmGroup -> CmmGroup
forall a b. (a -> b) -> [a] -> [b]
map (Platform -> LabelMap StackMap -> CmmDecl -> CmmDecl
setInfoTableStackMap Platform
platform LabelMap StackMap
stackmaps) CmmGroup
g
      DumpFlag -> String -> CmmGroup -> IO ()
dumps DumpFlag
Opt_D_dump_cmm_info String
"after setInfoTableStackMap" CmmGroup
g

      ----------- Control-flow optimisations -----------------------------
      CmmGroup
g <- {-# SCC "cmmCfgOpts(2)" #-}
           CmmGroup -> IO CmmGroup
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (CmmGroup -> IO CmmGroup) -> CmmGroup -> IO CmmGroup
forall a b. (a -> b) -> a -> b
$ if CmmConfig -> Bool
cmmOptControlFlow CmmConfig
cfg
                    then (CmmDecl -> CmmDecl) -> CmmGroup -> CmmGroup
forall a b. (a -> b) -> [a] -> [b]
map (Bool -> CmmDecl -> CmmDecl
cmmCfgOptsProc Bool
splitting_proc_points) CmmGroup
g
                    else CmmGroup
g
      CmmGroup
g <- CmmGroup -> IO CmmGroup
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ((CmmDecl -> CmmDecl) -> CmmGroup -> CmmGroup
forall a b. (a -> b) -> [a] -> [b]
map CmmDecl -> CmmDecl
removeUnreachableBlocksProc CmmGroup
g)
           -- See Note [unreachable blocks]
      DumpFlag -> String -> CmmGroup -> IO ()
dumps DumpFlag
Opt_D_dump_cmm_cfg String
"Post control-flow optimisations" CmmGroup
g

      Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)
-> IO (Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl))
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ((CAFEnv, CmmGroup)
-> Either (CAFEnv, CmmGroup) (Set CAFfyLabel, CmmDecl)
forall a b. a -> Either a b
Left (CAFEnv
cafEnv, CmmGroup
g))

  where dump :: DumpFlag -> String -> CmmGraph -> IO ()
dump = Logger
-> Platform -> Bool -> DumpFlag -> String -> CmmGraph -> IO ()
dumpGraph Logger
logger Platform
platform (CmmConfig -> Bool
cmmDoLinting CmmConfig
cfg)

        dumps :: DumpFlag -> String -> CmmGroup -> IO ()
dumps DumpFlag
flag String
name
           = (CmmDecl -> IO ()) -> CmmGroup -> IO ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith Logger
logger DumpFlag
flag String
name DumpFormat
FormatCMM (SDoc -> IO ()) -> (CmmDecl -> SDoc) -> CmmDecl -> IO ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Platform -> CmmDecl -> SDoc
forall env a. OutputableP env a => env -> a -> SDoc
pdoc Platform
platform)

        condPass :: Bool
-> (CmmGraph -> CmmGraph)
-> CmmGraph
-> DumpFlag
-> String
-> IO CmmGraph
condPass Bool
do_opt CmmGraph -> CmmGraph
pass CmmGraph
g DumpFlag
dumpflag String
dumpname =
            if Bool
do_opt
               then do
                    CmmGraph
g <- CmmGraph -> IO CmmGraph
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (CmmGraph -> IO CmmGraph) -> CmmGraph -> IO CmmGraph
forall a b. (a -> b) -> a -> b
$ CmmGraph -> CmmGraph
pass CmmGraph
g
                    DumpFlag -> String -> CmmGraph -> IO ()
dump DumpFlag
dumpflag String
dumpname CmmGraph
g
                    CmmGraph -> IO CmmGraph
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return CmmGraph
g
               else CmmGraph -> IO CmmGraph
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return CmmGraph
g

        -- we don't need to split proc points for the NCG, unless
        -- tablesNextToCode is off.  The latter is because we have no
        -- label to put on info tables for basic blocks that are not
        -- the entry point.
        splitting_proc_points :: Bool
splitting_proc_points = CmmConfig -> Bool
cmmSplitProcPoints CmmConfig
cfg

-- Note [Sinking after stack layout]
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- In the past we considered running sinking pass also before stack
-- layout, but after making some measurements we realized that:
--
--   a) running sinking only before stack layout produces slower
--      code than running sinking only before stack layout
--
--   b) running sinking both before and after stack layout produces
--      code that has the same performance as when running sinking
--      only after stack layout.
--
-- In other words sinking before stack layout doesn't buy as anything.
--
-- An interesting question is "why is it better to run sinking after
-- stack layout"? It seems that the major reason are stores and loads
-- generated by stack layout. Consider this code before stack layout:
--
--  c1E:
--      _c1C::P64 = R3;
--      _c1B::P64 = R2;
--      _c1A::P64 = R1;
--      I64[(young<c1D> + 8)] = c1D;
--      call stg_gc_noregs() returns to c1D, args: 8, res: 8, upd: 8;
--  c1D:
--      R3 = _c1C::P64;
--      R2 = _c1B::P64;
--      R1 = _c1A::P64;
--      call (P64[(old + 8)])(R3, R2, R1) args: 8, res: 0, upd: 8;
--
-- Stack layout pass will save all local variables live across a call
-- (_c1C, _c1B and _c1A in this example) on the stack just before
-- making a call and reload them from the stack after returning from a
-- call:
--
--  c1E:
--      _c1C::P64 = R3;
--      _c1B::P64 = R2;
--      _c1A::P64 = R1;
--      I64[Sp - 32] = c1D;
--      P64[Sp - 24] = _c1A::P64;
--      P64[Sp - 16] = _c1B::P64;
--      P64[Sp - 8] = _c1C::P64;
--      Sp = Sp - 32;
--      call stg_gc_noregs() returns to c1D, args: 8, res: 8, upd: 8;
--  c1D:
--      _c1A::P64 = P64[Sp + 8];
--      _c1B::P64 = P64[Sp + 16];
--      _c1C::P64 = P64[Sp + 24];
--      R3 = _c1C::P64;
--      R2 = _c1B::P64;
--      R1 = _c1A::P64;
--      Sp = Sp + 32;
--      call (P64[Sp])(R3, R2, R1) args: 8, res: 0, upd: 8;
--
-- If we don't run sinking pass after stack layout we are basically
-- left with such code. However, running sinking on this code can lead
-- to significant improvements:
--
--  c1E:
--      I64[Sp - 32] = c1D;
--      P64[Sp - 24] = R1;
--      P64[Sp - 16] = R2;
--      P64[Sp - 8] = R3;
--      Sp = Sp - 32;
--      call stg_gc_noregs() returns to c1D, args: 8, res: 8, upd: 8;
--  c1D:
--      R3 = P64[Sp + 24];
--      R2 = P64[Sp + 16];
--      R1 = P64[Sp + 8];
--      Sp = Sp + 32;
--      call (P64[Sp])(R3, R2, R1) args: 8, res: 0, upd: 8;
--
-- Now we only have 9 assignments instead of 15.
--
-- There is one case when running sinking before stack layout could
-- be beneficial. Consider this:
--
--   L1:
--      x = y
--      call f() returns L2
--   L2: ...x...y...
--
-- Since both x and y are live across a call to f, they will be stored
-- on the stack during stack layout and restored after the call:
--
--   L1:
--      x = y
--      P64[Sp - 24] = L2
--      P64[Sp - 16] = x
--      P64[Sp - 8]  = y
--      Sp = Sp - 24
--      call f() returns L2
--   L2:
--      y = P64[Sp + 16]
--      x = P64[Sp + 8]
--      Sp = Sp + 24
--      ...x...y...
--
-- However, if we run sinking before stack layout we would propagate x
-- to its usage place (both x and y must be local register for this to
-- be possible - global registers cannot be floated past a call):
--
--   L1:
--      x = y
--      call f() returns L2
--   L2: ...y...y...
--
-- Thus making x dead at the call to f(). If we ran stack layout now
-- we would generate less stores and loads:
--
--   L1:
--      x = y
--      P64[Sp - 16] = L2
--      P64[Sp - 8]  = y
--      Sp = Sp - 16
--      call f() returns L2
--   L2:
--      y = P64[Sp + 8]
--      Sp = Sp + 16
--      ...y...y...
--
-- But since we don't see any benefits from running sinking before stack
-- layout, this situation probably doesn't arise too often in practice.
--

{- Note [inconsistent-pic-reg]
   ~~~~~~~~~~~~~~~~~~~~~~~~~~~
On x86/Darwin, PIC is implemented by inserting a sequence like

    call 1f
 1: popl %reg

at the proc entry point, and then referring to labels as offsets from
%reg.  If we don't split proc points, then we could have many entry
points in a proc that would need this sequence, and each entry point
would then get a different value for %reg.  If there are any join
points, then at the join point we don't have a consistent value for
%reg, so we don't know how to refer to labels.

Hence, on x86/Darwin, we have to split proc points, and then each proc
point will get its own PIC initialisation sequence.

This isn't an issue on x86/ELF, where the sequence is

    call 1f
 1: popl %reg
    addl $_GLOBAL_OFFSET_TABLE_+(.-1b), %reg

so %reg always has a consistent value: the address of
_GLOBAL_OFFSET_TABLE_, regardless of which entry point we arrived via.

-}

{- Note [unreachable blocks]
   ~~~~~~~~~~~~~~~~~~~~~~~~~
The control-flow optimiser sometimes leaves unreachable blocks behind
containing junk code.  These aren't necessarily a problem, but
removing them is good because it might save time in the native code
generator later.

-}

runUniqSM :: UniqSM a -> IO a
runUniqSM :: forall a. UniqSM a -> IO a
runUniqSM UniqSM a
m = do
  UniqSupply
us <- Char -> IO UniqSupply
mkSplitUniqSupply Char
'u'
  a -> IO a
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return (UniqSupply -> UniqSM a -> a
forall a. UniqSupply -> UniqSM a -> a
initUs_ UniqSupply
us UniqSM a
m)


dumpGraph :: Logger -> Platform -> Bool -> DumpFlag -> String -> CmmGraph -> IO ()
dumpGraph :: Logger
-> Platform -> Bool -> DumpFlag -> String -> CmmGraph -> IO ()
dumpGraph Logger
logger Platform
platform Bool
do_linting DumpFlag
flag String
name CmmGraph
g = do
  Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when Bool
do_linting (IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ CmmGraph -> IO ()
do_lint CmmGraph
g
  Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith Logger
logger DumpFlag
flag String
name DumpFormat
FormatCMM (Platform -> CmmGraph -> SDoc
forall env a. OutputableP env a => env -> a -> SDoc
pdoc Platform
platform CmmGraph
g)
 where
  do_lint :: CmmGraph -> IO ()
do_lint CmmGraph
g = case Platform -> CmmGraph -> Maybe SDoc
cmmLintGraph Platform
platform CmmGraph
g of
                 Just SDoc
err -> do { Logger -> SDoc -> IO ()
fatalErrorMsg Logger
logger SDoc
err
                                ; Logger -> ByteOff -> IO ()
ghcExit Logger
logger ByteOff
1
                                }
                 Maybe SDoc
Nothing  -> () -> IO ()
forall a. a -> IO a
forall (m :: * -> *) a. Monad m => a -> m a
return ()

dumpWith :: Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith :: Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
dumpWith Logger
logger DumpFlag
flag String
txt DumpFormat
fmt SDoc
sdoc = do
  Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
putDumpFileMaybe Logger
logger DumpFlag
flag String
txt DumpFormat
fmt SDoc
sdoc
  Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Bool -> Bool
not (Logger -> DumpFlag -> Bool
logHasDumpFlag Logger
logger DumpFlag
flag)) (IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$
    -- If `-ddump-cmm-verbose -ddump-to-file` is specified,
    -- dump each Cmm pipeline stage output to a separate file.  #16930
    Bool -> IO () -> IO ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Logger -> DumpFlag -> Bool
logHasDumpFlag Logger
logger DumpFlag
Opt_D_dump_cmm_verbose)
      (IO () -> IO ()) -> IO () -> IO ()
forall a b. (a -> b) -> a -> b
$ Logger
-> PprStyle -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
logDumpFile Logger
logger (PrintUnqualified -> PprStyle
mkDumpStyle PrintUnqualified
alwaysQualify) DumpFlag
flag String
txt DumpFormat
fmt SDoc
sdoc
  Logger -> DumpFlag -> String -> DumpFormat -> SDoc -> IO ()
putDumpFileMaybe Logger
logger DumpFlag
Opt_D_dump_cmm_verbose_by_proc String
txt DumpFormat
fmt SDoc
sdoc