[project @ 2004-08-13 10:45:16 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..3c8a470 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 1.56 2003/11/17 14:47:53 simonmar Exp $
 %
 \section[AbstractC]{Abstract C: the last stop before machine code}
 
@@ -14,27 +14,7 @@ From @AbstractC@, one may convert to real C (for portability) or to
 raw assembler/machine code.
 
 \begin{code}
-module AbsCSyn {- (
-       -- export everything
-       AbstractC(..),
-       C_SRT(..)
-       CStmtMacro(..),
-       CExprMacro(..),
-       CAddrMode(..),
-       ReturnInfo(..),
-       mkAbstractCs, mkAbsCStmts, mkAlgAltsCSwitch,
-       mkIntCLit,
-       mkAbsCStmtList,
-       mkCCostCentre,
-
-       -- RegRelatives
-       RegRelative(..),
-
-       -- registers
-       MagicId(..), node, infoptr,
-       isVolatileReg,
-       CostRes(Cost)
-    )-} where
+module AbsCSyn where   -- export everything
 
 #include "HsVersions.h"
 
@@ -51,7 +31,8 @@ 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}
@@ -59,8 +40,6 @@ import FastString
 @AbstractC@ is a list of Abstract~C statements, but the data structure
 is tree-ish, for easier and more efficient putting-together.
 \begin{code}
-absCNop = AbsCNop
-
 data AbstractC
   = AbsCNop
   | AbsCStmts          AbstractC AbstractC
@@ -199,8 +178,15 @@ 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 +222,7 @@ 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 +351,6 @@ 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.
@@ -379,7 +361,6 @@ data CExprMacro
   = ENTRY_CODE
   | ARG_TAG                            -- stack argument tagging
   | GET_TAG                            -- get current constructor tag
-  | UPD_FRAME_UPDATEE
   | CCS_HDR
   | BYTE_ARR_CTS               -- used when passing a ByteArray# to a ccall
   | PTRS_ARR_CTS               -- similarly for an Array#
@@ -392,6 +373,9 @@ 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 +433,15 @@ 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}
 
 %************************************************************************
@@ -476,9 +459,6 @@ type HeapOffset = Int                       -- ToDo: remove
 
 type VirtualHeapOffset = HeapOffset
 type VirtualSpOffset   = Int
-
-type HpRelOffset       = HeapOffset
-type SpRelOffset       = Int
 \end{code}
 
 %************************************************************************