Break out TyCon classifier into own module

[ghc-hetmet.git] / compiler / vectorise / Vectorise / Type / Classify.hs

diff --git a/compiler/vectorise/Vectorise/Type/Classify.hs b/compiler/vectorise/Vectorise/Type/Classify.hs
new file mode 100644 (file)
index 0000000..79cd035
--- /dev/null
+++ b/compiler/vectorise/Vectorise/Type/Classify.hs
@@ -0,0 +1,91 @@
+
+module Vectorise.Type.Classify
+       ( TyConGroup
+       , classifyTyCons
+       , tyConGroups)
+where
+import UniqSet
+import UniqFM
+import DataCon
+import TyCon
+import TypeRep
+import Type
+import Digraph
+import Outputable
+
+type TyConGroup = ([TyCon], UniqSet TyCon)
+
+-- | Split the given tycons into two sets depending on whether they have to be
+--   converted (first list) or not (second list). The first argument contains
+--   information about the conversion status of external tycons:
+--
+--   * tycons which have converted versions are mapped to True
+--   * tycons which are not changed by vectorisation are mapped to False
+--   * tycons which can't be converted are not elements of the map
+--
+classifyTyCons 
+       :: UniqFM Bool
+       -> [TyConGroup]
+       -> ([TyCon], [TyCon])
+
+classifyTyCons = classify [] []
+  where
+    classify conv keep _  [] = (conv, keep)
+    classify conv keep cs ((tcs, ds) : rs)
+      | can_convert && must_convert
+        = classify (tcs ++ conv) keep (cs `addListToUFM` [(tc,True) | tc <- tcs]) rs
+      | can_convert
+        = classify conv (tcs ++ keep) (cs `addListToUFM` [(tc,False) | tc <- tcs]) rs
+      | otherwise
+        = classify conv keep cs rs
+      where
+        refs = ds `delListFromUniqSet` tcs
+
+        can_convert  = isNullUFM (refs `minusUFM` cs) && all convertable tcs
+        must_convert = foldUFM (||) False (intersectUFM_C const cs refs)
+
+        convertable tc = isDataTyCon tc && all isVanillaDataCon (tyConDataCons tc)
+
+
+-- | Compute mutually recursive groups of tycons in topological order
+tyConGroups :: [TyCon] -> [TyConGroup]
+tyConGroups tcs = map mk_grp (stronglyConnCompFromEdgedVertices edges)
+  where
+    edges = [((tc, ds), tc, uniqSetToList ds) | tc <- tcs
+                                , let ds = tyConsOfTyCon tc]
+
+    mk_grp (AcyclicSCC (tc, ds)) = ([tc], ds)
+    mk_grp (CyclicSCC els)       = (tcs, unionManyUniqSets dss)
+      where
+        (tcs, dss) = unzip els
+
+
+-- | Collect the set of TyCons used by the representation of some data type.
+tyConsOfTyCon :: TyCon -> UniqSet TyCon
+tyConsOfTyCon
+  = tyConsOfTypes . concatMap dataConRepArgTys . tyConDataCons
+
+
+-- | Collect the set of TyCons that occur in these types.
+tyConsOfTypes :: [Type] -> UniqSet TyCon
+tyConsOfTypes = unionManyUniqSets . map tyConsOfType
+
+
+-- | Collect the set of TyCons that occur in this type.
+tyConsOfType :: Type -> UniqSet TyCon
+tyConsOfType ty
+  | Just ty' <- coreView ty    = tyConsOfType ty'
+tyConsOfType (TyVarTy _)       = emptyUniqSet
+tyConsOfType (TyConApp tc tys) = extend (tyConsOfTypes tys)
+  where
+    extend |  isUnLiftedTyCon tc
+           || isTupleTyCon   tc = id
+
+           | otherwise          = (`addOneToUniqSet` tc)
+
+tyConsOfType (AppTy a b)       = tyConsOfType a `unionUniqSets` tyConsOfType b
+tyConsOfType (FunTy a b)       = (tyConsOfType a `unionUniqSets` tyConsOfType b)
+                                 `addOneToUniqSet` funTyCon
+tyConsOfType (ForAllTy _ ty)   = tyConsOfType ty
+tyConsOfType other             = pprPanic "ClosureConv.tyConsOfType" $ ppr other
+