[project @ 2001-10-17 11:26:04 by simonpj]

-------------------------------------------
	nullAddr# fix for the HEAD
	-------------------------------------------

	*** DO NOT MERGE ***

nullAddr# is simply a name for (Lit nullAddrLit).  Up
to now it has been a PrimOp with the rather stange type
	nullAddr# :: Int# -> Addr#
which discards its argument.  (I think the problem with
nullary primops is to do with the top-level bindings in
PrelPrimOpWrappers.)   And there was a RULE in PrelRules
to rewrite
	nullAddr _ ==> nullAddrLit

It's excessive to make it a PrimOp.  We can just treat it
like unsafeCoerce#, which is made in MkId.lhs.   So I've
done that, and given it the more sensible type
	nullAddr# :: Addr#

I fixed all the occurrences I could find.

diff --git a/ghc/compiler/basicTypes/MkId.lhs b/ghc/compiler/basicTypes/MkId.lhs
index 0e45b8f..7fc7804 100644 (file)
--- a/ghc/compiler/basicTypes/MkId.lhs
+++ b/ghc/compiler/basicTypes/MkId.lhs
@@ -22,7 +22,7 @@ module MkId (
 
        -- And some particular Ids; see below for why they are wired in
        wiredInIds,
-       unsafeCoerceId, realWorldPrimId,
+       unsafeCoerceId, realWorldPrimId, nullAddrId,
        eRROR_ID, eRROR_CSTRING_ID, rEC_SEL_ERROR_ID, pAT_ERROR_ID, rEC_CON_ERROR_ID,
        rEC_UPD_ERROR_ID, iRREFUT_PAT_ERROR_ID, nON_EXHAUSTIVE_GUARDS_ERROR_ID,
        nO_METHOD_BINDING_ERROR_ID, aBSENT_ERROR_ID, pAR_ERROR_ID
@@ -47,7 +47,7 @@ import TcType         ( Type, ThetaType, mkDictTy, mkPredTys, mkTyConApp,
 import Module          ( Module )
 import CoreUtils       ( mkInlineMe )
 import CoreUnfold      ( mkTopUnfolding, mkCompulsoryUnfolding, mkOtherCon )
-import Literal         ( Literal(..) )
+import Literal         ( Literal(..), nullAddrLit )
 import TyCon           ( TyCon, isNewTyCon, tyConTyVars, tyConDataCons,
                           tyConTheta, isProductTyCon, isDataTyCon, isRecursiveTyCon )
 import Class           ( Class, classTyCon, classTyVars, classSelIds )
@@ -121,9 +121,11 @@ wiredInIds
     , rEC_CON_ERROR_ID
     , rEC_UPD_ERROR_ID
 
-       -- These three can't be defined in Haskell
+       -- These can't be defined in Haskell, but they have
+       -- perfectly reasonable unfoldings in Core
     , realWorldPrimId
     , unsafeCoerceId
+    , nullAddrId
     , getTagId
     , seqId
     ]
@@ -756,7 +758,7 @@ mkDictFunId dfun_name clas inst_tyvars inst_tys dfun_theta
 These Ids can't be defined in Haskell.  They could be defined in 
 unfoldings in PrelGHC.hi-boot, but we'd have to ensure that they
 were definitely, definitely inlined, because there is no curried
-identifier for them.  Thats what mkCompulsoryUnfolding does.
+identifier for them.  That's what mkCompulsoryUnfolding does.
 If we had a way to get a compulsory unfolding from an interface file,
 we could do that, but we don't right now.
 
@@ -782,6 +784,15 @@ unsafeCoerceId
     rhs = mkLams [openAlphaTyVar,openBetaTyVar,x] $
          Note (Coerce openBetaTy openAlphaTy) (Var x)
 
+-- nullAddr# :: Addr#
+-- The reason is is here is because we don't provide 
+-- a way to write this literal in Haskell.
+nullAddrId 
+  = pcMiscPrelId nullAddrIdKey pREL_GHC SLIT("nullAddr#") addrPrimTy info
+  where
+    info = noCafNoTyGenIdInfo `setUnfoldingInfo` 
+          mkCompulsoryUnfolding (Lit nullAddrLit)
+
 seqId
   = pcMiscPrelId seqIdKey pREL_GHC SLIT("seq") ty info
   where

diff --git a/ghc/compiler/prelude/PrelNames.lhs b/ghc/compiler/prelude/PrelNames.lhs
index 20384c2..ed4d031 100644 (file)
--- a/ghc/compiler/prelude/PrelNames.lhs
+++ b/ghc/compiler/prelude/PrelNames.lhs
@@ -846,6 +846,7 @@ timesIntegerIdKey         = mkPreludeMiscIdUnique 42
 printIdKey                   = mkPreludeMiscIdUnique 43
 failIOIdKey                  = mkPreludeMiscIdUnique 44
 unpackCStringListIdKey       = mkPreludeMiscIdUnique 45
+nullAddrIdKey                = mkPreludeMiscIdUnique 46
 \end{code}
 
 Certain class operations from Prelude classes.  They get their own

diff --git a/ghc/compiler/prelude/PrelRules.lhs b/ghc/compiler/prelude/PrelRules.lhs
index 9a1c493..c916e63 100644 (file)
--- a/ghc/compiler/prelude/PrelRules.lhs
+++ b/ghc/compiler/prelude/PrelRules.lhs
@@ -28,7 +28,7 @@ import Literal                ( Literal(..), isLitLitLit, mkMachInt, mkMachWord
                        , narrow8WordLit, narrow16WordLit, narrow32WordLit
                        , char2IntLit, int2CharLit
                        , float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit
-                       , nullAddrLit, float2DoubleLit, double2FloatLit
+                       , float2DoubleLit, double2FloatLit
                        )
 import PrimOp          ( PrimOp(..), primOpOcc )
 import TysWiredIn      ( trueDataConId, falseDataConId )
@@ -64,7 +64,6 @@ primOpRules op = primop_rule op
     -- ToDo:   something for integer-shift ops?
     --         NotOp
 
-    primop_rule AddrNullOp  = one_rule nullAddrRule    
     primop_rule SeqOp      = one_rule seqRule
     primop_rule TagToEnumOp = one_rule tagToEnumRule
     primop_rule DataToTagOp = one_rule dataToTagRule
@@ -349,10 +348,6 @@ mkFloatVal  f = Lit (convFloating (MachFloat  f))
 mkDoubleVal d = Lit (convFloating (MachDouble d))
 \end{code}
 
-\begin{code}
-nullAddrRule _ = Just(Lit nullAddrLit)
-\end{code}
-
                                                
 %************************************************************************
 %*                                                                     *

diff --git a/ghc/compiler/prelude/primops.txt.pp b/ghc/compiler/prelude/primops.txt.pp
index 3e78e47..7d6b000 100644 (file)
--- a/ghc/compiler/prelude/primops.txt.pp
+++ b/ghc/compiler/prelude/primops.txt.pp
@@ -1,5 +1,5 @@
 -----------------------------------------------------------------------
--- $Id: primops.txt.pp,v 1.7 2001/10/16 13:31:56 simonmar Exp $
+-- $Id: primops.txt.pp,v 1.8 2001/10/17 11:26:04 simonpj Exp $
 --
 -- Primitive Operations
 --
@@ -13,7 +13,7 @@
 --
 -- To add a new primop, you currently need to update the following files:
 --
---     - this file (ghc/compiler/prelude/primops.txt), which includes
+--     - this file (ghc/compiler/prelude/primops.txt.pp), which includes
 --       the type of the primop, and various other properties (its
 --       strictness attributes, whether it is defined as a macro
 --       or as out-of-line code, etc.)
@@ -934,12 +934,12 @@ primop  WriteByteArrayOp_Word64 "writeWord64Array#" GenPrimOp
 ------------------------------------------------------------------------
 section "Addr#"
        {Addr\# is an arbitrary machine address assumed to point outside
-        the garbage-collected heap.}
+        the garbage-collected heap.  
+
+        NB: {\tt nullAddr\#::Addr\#} is not a primop, but is defined in MkId.lhs.
+        It is the null address.}
 ------------------------------------------------------------------------
 
-primop  AddrNullOp "nullAddr#" GenPrimOp  Int# -> Addr#
-        {Returns null address. Argument is ignored (nullary primops 
-         don't quite work!)}
 primop  AddrAddOp "plusAddr#" GenPrimOp Addr# -> Int# -> Addr#
 primop  AddrSubOp "minusAddr#" GenPrimOp Addr# -> Addr# -> Int#
         {Result is meaningless if two Addr\#s are so far apart that their
@@ -1606,6 +1606,13 @@ primop  NewBCOOp "newBCO#" GenPrimOp
    out_of_line      = True
 
 ------------------------------------------------------------------------
+section "Coercion" 
+       {{\tt unsafeCoerce# :: a -> b} is not a primop, but is defined in MkId.lhs.}
+
+------------------------------------------------------------------------
+
+
+------------------------------------------------------------------------
 ---                                                                  ---
 ------------------------------------------------------------------------
 

diff --git a/ghc/lib/std/PrelGHC.hi-boot.pp b/ghc/lib/std/PrelGHC.hi-boot.pp
index 51850e0..5fc5008 100644 (file)
--- a/ghc/lib/std/PrelGHC.hi-boot.pp
+++ b/ghc/lib/std/PrelGHC.hi-boot.pp
@@ -52,7 +52,7 @@ __export PrelGHC
   isEmptyMVarzh
 
   -- Seq
-  seq
+  seq          -- Defined in MkId
 
   -- Parallel
   seqzh
@@ -136,7 +136,7 @@ __export PrelGHC
 #endif
 
   Addrzh
-  nullAddrzh
+  nullAddrzh   -- Defined in MkId
   plusAddrzh
   minusAddrzh
   remAddrzh
@@ -424,7 +424,7 @@ __export PrelGHC
   BCOzh
   mkApUpd0zh
 
-  unsafeCoercezh
+  unsafeCoercezh       -- Defined in MkId
   addrToHValuezh
 ;
 

diff --git a/ghc/lib/std/PrelPtr.lhs b/ghc/lib/std/PrelPtr.lhs
index cbf076c..ddff34e 100644 (file)
--- a/ghc/lib/std/PrelPtr.lhs
+++ b/ghc/lib/std/PrelPtr.lhs
@@ -1,5 +1,5 @@
 -----------------------------------------------------------------------------
--- $Id: PrelPtr.lhs,v 1.3 2001/08/17 17:18:54 apt Exp $
+-- $Id: PrelPtr.lhs,v 1.4 2001/10/17 11:26:04 simonpj Exp $
 -- 
 -- (c) 2000
 -- 
@@ -17,7 +17,7 @@ import PrelBase
 data Ptr a = Ptr Addr# deriving (Eq, Ord)
 
 nullPtr :: Ptr a
-nullPtr = Ptr (nullAddr# 0#)
+nullPtr = Ptr nullAddr#
 
 castPtr :: Ptr a -> Ptr b
 castPtr (Ptr addr) = Ptr addr
@@ -43,7 +43,7 @@ instance CReturnable (Ptr a)
 data FunPtr a = FunPtr Addr# deriving (Eq, Ord)
 
 nullFunPtr :: FunPtr a
-nullFunPtr = FunPtr (nullAddr# 0#)
+nullFunPtr = FunPtr nullAddr#
 
 castFunPtr :: FunPtr a -> FunPtr b
 castFunPtr (FunPtr addr) = FunPtr addr