[project @ 2003-01-24 13:56:45 by simonmar]

- Reverse the code for workers and wrappers for nullary constructors.
  For some reason it was the wrong way around, but the effects were
  harmless since they both evaluate to the same thing.

- When passing a nullary constructor as an argument, we should pass
  the name of the worker rather than the wrapper.  Again, this is
  mostly harmless, but it enables some small simplification in
  pushAtom.

- Rearrange/cleanup pushAtom.

diff --git a/ghc/compiler/ghci/ByteCodeGen.lhs b/ghc/compiler/ghci/ByteCodeGen.lhs
index 1c86210..d367bec 100644 (file)
--- a/ghc/compiler/ghci/ByteCodeGen.lhs
+++ b/ghc/compiler/ghci/ByteCodeGen.lhs
@@ -31,7 +31,7 @@ import Type           ( typePrimRep, isUnLiftedType, splitTyConApp_maybe,
                          isTyVarTy )
 import DataCon         ( DataCon, dataConTag, fIRST_TAG, dataConTyCon, 
                           isUnboxedTupleCon, isNullaryDataCon,
-                         dataConRepArity )
+                         dataConRepArity, dataConWorkId )
 import TyCon           ( tyConFamilySize, isDataTyCon, tyConDataCons,
                          isFunTyCon, isUnboxedTupleTyCon )
 import Class           ( Class, classTyCon )
@@ -239,15 +239,15 @@ schemeTopBind :: (Id, AnnExpr Id VarSet) -> BcM (ProtoBCO Name)
 
 
 schemeTopBind (id, rhs)
-  | Just data_con <- isDataConWrapId_maybe id,
+  | Just data_con <- isDataConId_maybe id,
     isNullaryDataCon data_con
-  =    -- Special case for the wrapper of a nullary data con.
-       -- It'll look like this:        Nil = /\a -> $wNil a
+  =    -- Special case for the worker of a nullary data con.
+       -- It'll look like this:        $wNil = /\a -> $wNil a
        -- If we feed it into schemeR, we'll get 
-       --      Nil = Nil
+       --      $wNil = $wNil
        -- because mkConAppCode treats nullary constructor applications
        -- by just re-using the single top-level definition.  So
-       -- for the wrapper itself, we must allocate it directly.
+       -- for the worker itself, we must allocate it directly.
     emitBc (mkProtoBCO (getName id) (toOL [PACK data_con 0, ENTER])
                        (Right rhs) 0 0 [{-no bitmap-}] False{-not alts-})
 
@@ -569,7 +569,7 @@ mkConAppCode :: Int -> Sequel -> BCEnv
 
 mkConAppCode orig_d s p con [] -- Nullary constructor
   = ASSERT( isNullaryDataCon con )
-    returnBc (unitOL (PUSH_G (getName con)))
+    returnBc (unitOL (PUSH_G (getName (dataConWorkId con))))
        -- Instead of doing a PACK, which would allocate a fresh
        -- copy of this constructor, use the single shared version.
        -- The name of the constructor is the name of its wrapper function
@@ -1085,8 +1085,8 @@ pushAtom d p (AnnVar v)
    | Just primop <- isPrimOpId_maybe v
    = returnBc (unitOL (PUSH_PRIMOP primop), 1)
 
-   | otherwise
-   = let
+   | Just d_v <- lookupBCEnv_maybe p v  -- v is a local variable
+   = returnBc (toOL (nOfThem sz (PUSH_L (d-d_v+sz-2))), sz)
         -- d - d_v                 the number of words between the TOS 
         --                         and the 1st slot of the object
         --
@@ -1097,19 +1097,13 @@ pushAtom d p (AnnVar v)
         --
         -- Having found the last slot, we proceed to copy the right number of
         -- slots on to the top of the stack.
-        --
-         result
-            = case lookupBCEnv_maybe p v of
-                 Just d_v -> (toOL (nOfThem sz (PUSH_L (d-d_v+sz-2))), sz)
-                 Nothing  -> ASSERT(sz == 1) (unitOL (PUSH_G nm), sz)
 
-         nm = case isDataConId_maybe v of
-                 Just c  -> getName c
-                 Nothing -> getName v
+    | otherwise  -- v must be a global variable
+    = ASSERT(sz == 1) 
+      returnBc (unitOL (PUSH_G (getName v)), sz)
 
-         sz   = idSizeW v
-     in
-         returnBc result
+    where
+         sz = idSizeW v
 
 
 pushAtom d p (AnnLit lit)