X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FsimplCore%2FSimplEnv.lhs;h=d9eea39ed69e7bb1d76820ee0af5e4e532dc9086;hb=46ff3d8caded776ab471d3682258147e42be8f14;hp=10b000357479c0ea67638e50a3fb917fb447d5ed;hpb=d2ce0f52d42edf32bb9f13796e6ba6edba8bd516;p=ghc-hetmet.git

diff --git a/compiler/simplCore/SimplEnv.lhs b/compiler/simplCore/SimplEnv.lhs
index 10b0003..d9eea39 100644
--- a/compiler/simplCore/SimplEnv.lhs
+++ b/compiler/simplCore/SimplEnv.lhs
@@ -1,5 +1,5 @@
 %
-% (c) The AQUA Project, Glasgow University, 1993-1998
+o% (c) The AQUA Project, Glasgow University, 1993-1998
 %
 \section[SimplMonad]{The simplifier Monad}
 
@@ -12,18 +12,14 @@ module SimplEnv (
 	-- The simplifier mode
 	setMode, getMode, updMode,
 
-	-- Switch checker
-	SwitchChecker, SwitchResult(..), getSwitchChecker, getSimplIntSwitch,
-	isAmongSimpl, intSwitchSet, switchIsOn,
-
-	setEnclosingCC, getEnclosingCC,
+        setEnclosingCC, getEnclosingCC,
 
 	-- Environments
 	SimplEnv(..), StaticEnv, pprSimplEnv,	-- Temp not abstract
 	mkSimplEnv, extendIdSubst, SimplEnv.extendTvSubst, 
 	zapSubstEnv, setSubstEnv, 
 	getInScope, setInScope, setInScopeSet, modifyInScope, addNewInScopeIds,
-	getSimplRules, inGentleMode,
+        getSimplRules,
 
 	SimplSR(..), mkContEx, substId, lookupRecBndr,
 
@@ -50,6 +46,8 @@ import VarEnv
 import VarSet
 import OrdList
 import Id
+import MkCore
+import TysWiredIn
 import qualified CoreSubst
 import qualified Type		( substTy, substTyVarBndr, substTyVar )
 import Type hiding		( substTy, substTyVarBndr, substTyVar )
@@ -106,8 +104,7 @@ data SimplEnv
      -- wrt the original expression
 
 	seMode 	    :: SimplifierMode,
-	seChkr      :: SwitchChecker,
-	seCC        :: CostCentreStack,	-- The enclosing CCS (when profiling)
+        seCC        :: CostCentreStack, -- The enclosing CCS (when profiling)
 
 	-- The current substitution
 	seTvSubst   :: TvSubstEnv,	-- InTyVar |--> OutType
@@ -131,7 +128,13 @@ pprSimplEnv :: SimplEnv -> SDoc
 -- Used for debugging; selective
 pprSimplEnv env
   = vcat [ptext (sLit "TvSubst:") <+> ppr (seTvSubst env),
- 	  ptext (sLit "IdSubst:") <+> ppr (seIdSubst env) ]
+ 	  ptext (sLit "IdSubst:") <+> ppr (seIdSubst env),
+          ptext (sLit "InScope:") <+> vcat (map ppr_one in_scope_vars)
+    ]
+  where
+   in_scope_vars = varEnvElts (getInScopeVars (seInScope env))
+   ppr_one v | isId v = ppr v <+> ppr (idUnfolding v)
+             | otherwise = ppr v
 
 type SimplIdSubst = IdEnv SimplSR	-- IdId |--> OutExpr
 	-- See Note [Extending the Subst] in CoreSubst
@@ -154,7 +157,8 @@ instance Outputable SimplSR where
 	-- keep uniq _ = uniq `elemUFM_Directly` fvs
 \end{code}
 
-
+Note [SimplEnv invariants]
+~~~~~~~~~~~~~~~~~~~~~~~~~~
 seInScope: 
 	The in-scope part of Subst includes *all* in-scope TyVars and Ids
 	The elements of the set may have better IdInfo than the
@@ -190,9 +194,8 @@ seIdSubst:
 * substId adds a binding (DoneId new_id) to the substitution if 
 	the Id's unique has changed
 
-
   Note, though that the substitution isn't necessarily extended
-  if the type changes.  Why not?  Because of the next point:
+  if the type of the Id changes.  Why not?  Because of the next point:
 
 * We *always, always* finish by looking up in the in-scope set 
   any variable that doesn't get a DoneEx or DoneVar hit in the substitution.
@@ -217,19 +220,40 @@ seIdSubst:
 
 
 \begin{code}
-mkSimplEnv :: SwitchChecker -> SimplifierMode -> SimplEnv
-mkSimplEnv switches mode
-  = SimplEnv { seChkr = switches, seCC = subsumedCCS, 
-	       seMode = mode, seInScope = emptyInScopeSet, 
-	       seFloats = emptyFloats,
-	       seTvSubst = emptyVarEnv, seIdSubst = emptyVarEnv }
+mkSimplEnv :: SimplifierMode -> SimplEnv
+mkSimplEnv mode
+  = SimplEnv { seCC = subsumedCCS
+             , seMode = mode
+             , seInScope = init_in_scope
+             , seFloats = emptyFloats
+             , seTvSubst = emptyVarEnv
+             , seIdSubst = emptyVarEnv }
 	-- The top level "enclosing CC" is "SUBSUMED".
 
----------------------
-getSwitchChecker :: SimplEnv -> SwitchChecker
-getSwitchChecker env = seChkr env
+init_in_scope :: InScopeSet
+init_in_scope = mkInScopeSet (unitVarSet (mkWildValBinder unitTy))
+              -- See Note [WildCard binders]
+\end{code}
 
----------------------
+Note [WildCard binders]
+~~~~~~~~~~~~~~~~~~~~~~~
+The program to be simplified may have wild binders
+    case e of wild { p -> ... }
+We want to *rename* them away, so that there are no
+occurrences of 'wild-id' (with wildCardKey).  The easy
+way to do that is to start of with a representative
+Id in the in-scope set
+
+There can be be *occurrences* of wild-id.  For example,
+MkCore.mkCoreApp transforms
+   e (a /# b)   -->   case (a /# b) of wild { DEFAULT -> e wild }
+This is ok provided 'wild' isn't free in 'e', and that's the delicate
+thing. Generally, you want to run the simplifier to get rid of the
+wild-ids before doing much else.
+
+It's a very dark corner of GHC.  Maybe it should be cleaned up.
+
+\begin{code}
 getMode :: SimplEnv -> SimplifierMode
 getMode env = seMode env
 
@@ -239,11 +263,6 @@ setMode mode env = env { seMode = mode }
 updMode :: (SimplifierMode -> SimplifierMode) -> SimplEnv -> SimplEnv
 updMode upd env = env { seMode = upd (seMode env) }
 
-inGentleMode :: SimplEnv -> Bool
-inGentleMode env = case seMode env of
-	                SimplGently {} -> True
-		        _other         -> False
-
 ---------------------
 getEnclosingCC :: SimplEnv -> CostCentreStack
 getEnclosingCC env = seCC env
@@ -397,7 +416,9 @@ addNonRec :: SimplEnv -> OutId -> OutExpr -> SimplEnv
 -- in-scope set (although it might also have been created with newId)
 -- but it may now have more IdInfo
 addNonRec env id rhs
-  = env { seFloats = seFloats env `addFlts` unitFloat (NonRec id rhs),
+  = id `seq`   -- This seq forces the Id, and hence its IdInfo,
+	       -- and hence any inner substitutions
+    env { seFloats = seFloats env `addFlts` unitFloat (NonRec id rhs),
 	  seInScope = extendInScopeSet (seInScope env) id }
 
 extendFloats :: SimplEnv -> OutBind -> SimplEnv
@@ -735,12 +756,14 @@ substIdType (SimplEnv { seInScope = in_scope,  seTvSubst = tv_env}) id
 ------------------
 substExpr :: SDoc -> SimplEnv -> CoreExpr -> CoreExpr
 substExpr doc env
-  = CoreSubst.substExprSC (text "SimplEnv.substExpr1" <+> doc) 
-                          (mkCoreSubst (text "SimplEnv.substExpr2" <+> doc) env) 
+  = CoreSubst.substExpr (text "SimplEnv.substExpr1" <+> doc) 
+                        (mkCoreSubst (text "SimplEnv.substExpr2" <+> doc) env) 
   -- Do *not* short-cut in the case of an empty substitution
-  -- See CoreSubst: Note [Extending the Subst]
+  -- See Note [SimplEnv invariants]
 
 substUnfolding :: SimplEnv -> Unfolding -> Unfolding
-substUnfolding env unf = CoreSubst.substUnfoldingSC (mkCoreSubst (text "subst-unfolding") env) unf
+substUnfolding env unf = CoreSubst.substUnfolding (mkCoreSubst (text "subst-unfolding") env) unf
+  -- Do *not* short-cut in the case of an empty substitution
+  -- See Note [SimplEnv invariants]
 \end{code}