never executed always true always false

    1 module GHC.CmmToAsm.SPARC.ShortcutJump (
    2         JumpDest(..), getJumpDestBlockId,
    3         canShortcut,
    4         shortcutJump,
    5         shortcutStatics,
    6         shortBlockId
    7 )
    8 
    9 where
   10 
   11 import GHC.Prelude
   12 
   13 import GHC.CmmToAsm.SPARC.Instr
   14 import GHC.CmmToAsm.SPARC.Imm
   15 
   16 import GHC.Cmm.CLabel
   17 import GHC.Cmm.BlockId
   18 import GHC.Cmm
   19 
   20 import GHC.Utils.Panic
   21 import GHC.Utils.Outputable
   22 
   23 data JumpDest
   24         = DestBlockId BlockId
   25         | DestImm Imm
   26 
   27 -- Debug Instance
   28 instance Outputable JumpDest where
   29   ppr (DestBlockId bid) = text "blk:" <> ppr bid
   30   ppr (DestImm _bid)    = text "imm:?"
   31 
   32 getJumpDestBlockId :: JumpDest -> Maybe BlockId
   33 getJumpDestBlockId (DestBlockId bid) = Just bid
   34 getJumpDestBlockId _                 = Nothing
   35 
   36 
   37 canShortcut :: Instr -> Maybe JumpDest
   38 canShortcut _ = Nothing
   39 
   40 
   41 shortcutJump :: (BlockId -> Maybe JumpDest) -> Instr -> Instr
   42 shortcutJump _ other = other
   43 
   44 
   45 
   46 shortcutStatics :: (BlockId -> Maybe JumpDest) -> RawCmmStatics -> RawCmmStatics
   47 shortcutStatics fn (CmmStaticsRaw lbl statics)
   48   = CmmStaticsRaw lbl $ map (shortcutStatic fn) statics
   49   -- we need to get the jump tables, so apply the mapping to the entries
   50   -- of a CmmData too.
   51 
   52 shortcutLabel :: (BlockId -> Maybe JumpDest) -> CLabel -> CLabel
   53 shortcutLabel fn lab
   54   | Just blkId <- maybeLocalBlockLabel lab = shortBlockId fn blkId
   55   | otherwise                              = lab
   56 
   57 shortcutStatic :: (BlockId -> Maybe JumpDest) -> CmmStatic -> CmmStatic
   58 shortcutStatic fn (CmmStaticLit (CmmLabel lab))
   59         = CmmStaticLit (CmmLabel (shortcutLabel fn lab))
   60 shortcutStatic fn (CmmStaticLit (CmmLabelDiffOff lbl1 lbl2 off w))
   61         = CmmStaticLit (CmmLabelDiffOff (shortcutLabel fn lbl1) lbl2 off w)
   62 -- slightly dodgy, we're ignoring the second label, but this
   63 -- works with the way we use CmmLabelDiffOff for jump tables now.
   64 shortcutStatic _ other_static
   65         = other_static
   66 
   67 
   68 shortBlockId :: (BlockId -> Maybe JumpDest) -> BlockId -> CLabel
   69 shortBlockId fn blockid =
   70    case fn blockid of
   71       Nothing -> blockLbl blockid
   72       Just (DestBlockId blockid')  -> shortBlockId fn blockid'
   73       Just (DestImm (ImmCLbl lbl)) -> lbl
   74       _other -> panic "shortBlockId"