[project @ 2003-05-14 09:13:52 by simonmar]

[ghc-hetmet.git] / ghc / compiler / absCSyn / AbsCSyn.lhs

diff --git a/ghc/compiler/absCSyn/AbsCSyn.lhs b/ghc/compiler/absCSyn/AbsCSyn.lhs
index 6a3d0eb..2b8a0e4 100644 (file)
--- a/ghc/compiler/absCSyn/AbsCSyn.lhs
+++ b/ghc/compiler/absCSyn/AbsCSyn.lhs
@@ -1,7 +1,7 @@
 %
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-% $Id: AbsCSyn.lhs,v 1.51 2002/12/11 15:36:21 simonmar Exp $
+% $Id: AbsCSyn.lhs,v 1.52 2003/05/14 09:13:52 simonmar Exp $
 %
 \section[AbstractC]{Abstract C: the last stop before machine code}
 
@@ -51,7 +51,8 @@ import MachOp         ( MachOp(..) )
 import Unique           ( Unique )
 import StgSyn          ( StgOp )
 import TyCon           ( TyCon )
-import BitSet                          -- for liveness masks
+import Bitmap          ( Bitmap, mAX_SMALL_BITMAP_SIZE )
+import SMRep           ( StgWord, StgHalfWord )
 import FastTypes
 import FastString
 \end{code}
@@ -199,8 +200,15 @@ stored in a mixed type location.)
   | CSRT CLabel [CLabel]       -- SRT declarations: basically an array of 
                                -- pointers to static closures.
   
-  | CBitmap Liveness           -- A bitmap to be emitted if and only if
-                               -- it is larger than a target machine word.
+  | CBitmap Liveness           -- A "large" bitmap to be emitted
+
+  | CSRTDesc                   -- A "large" SRT descriptor (one that doesn't
+                               -- fit into the half-word bitmap in the itbl).
+       !CLabel                 -- Label for this SRT descriptor
+       !CLabel                 -- Pointer to the SRT
+       !Int                    -- Offset within the SRT
+       !Int                    -- Length
+       !Bitmap                 -- Bitmap
 
   | CClosureInfoAndCode
        ClosureInfo             -- Explains placement and layout of closure
@@ -236,7 +244,7 @@ stored in a mixed type location.)
 -- we add a label for the table, and expect only the 'offset/length' form
 
 data C_SRT = NoC_SRT
-          | C_SRT CLabel !Int{-offset-} !Int{-length-}
+          | C_SRT !CLabel !Int{-offset-} !StgHalfWord{-bitmap or escape-}
 
 needsSRT :: C_SRT -> Bool
 needsSRT NoC_SRT       = False
@@ -365,10 +373,6 @@ data CAddrMode
        !PrimRep        -- the kind of the result
        CExprMacro      -- the macro to generate a value
        [CAddrMode]     -- and its arguments
-
-  | CBytesPerWord      -- Word size, in bytes, on this platform
-                       -- required for: half-word loads (used in fishing tags
-                       -- out of info tables), and sizeofByteArray#.
 \end{code}
 
 Various C macros for values which are dependent on the back-end layout.
@@ -392,6 +396,9 @@ Convenience functions:
 mkIntCLit :: Int -> CAddrMode
 mkIntCLit i = CLit (mkMachInt (toInteger i))
 
+mkWordCLit :: StgWord -> CAddrMode
+mkWordCLit wd = CLit (MachWord (fromIntegral wd))
+
 mkCString :: FastString -> CAddrMode
 mkCString s = CLit (MachStr s)
 
@@ -449,16 +456,15 @@ vectors to indicate the state of the stack for the garbage collector.
 
 In the compiled program, liveness bitmaps that fit inside a single
 word (StgWord) are stored as a single word, while larger bitmaps are
-stored as a pointer to an array of words.  When we compile via C
-(especially when we bootstrap via HC files), we generate identical C
-code regardless of whether words are 32- or 64-bit on the target
-machine, by postponing the decision of how to store each liveness
-bitmap to C compilation time (or rather, C preprocessing time).
+stored as a pointer to an array of words. 
 
 \begin{code}
-type LivenessMask = [BitSet]
+data Liveness = Liveness CLabel !Int Bitmap
 
-data Liveness = Liveness CLabel !Int LivenessMask
+maybeLargeBitmap :: Liveness -> AbstractC
+maybeLargeBitmap liveness@(Liveness _ size _)
+  | size <= mAX_SMALL_BITMAP_SIZE = AbsCNop
+  | otherwise                     = CBitmap liveness
 \end{code}
 
 %************************************************************************