Remove ufmToList

This documents nondeterminism in code generation and removes
the nondeterministic ufmToList function. In the future someone
will have to use nonDetUFMToList (with proper explanation)
or pprUFMWithKeys.

2 files changed, 16 insertions, 6 deletions

diff --git a/compiler/utils/UniqDFM.hs b/compiler/utils/UniqDFM.hs
index 8ed1451eea..bbf6bb0bd8 100644
--- a/compiler/utils/UniqDFM.hs
+++ b/compiler/utils/UniqDFM.hs
@@ -66,7 +66,7 @@ import qualified Data.IntMap as M
 import Data.Data
 import Data.List (sortBy)
 import Data.Function (on)
-import UniqFM (UniqFM, listToUFM_Directly, ufmToList, ufmToIntMap)
+import UniqFM (UniqFM, listToUFM_Directly, nonDetUFMToList, ufmToIntMap)
 
 -- Note [Deterministic UniqFM]
 -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -372,7 +372,7 @@ instance Monoid (UniqDFM a) where
 -- This should not be used in commited code, provided for convenience to
 -- make ad-hoc conversions when developing
 alwaysUnsafeUfmToUdfm :: UniqFM elt -> UniqDFM elt
-alwaysUnsafeUfmToUdfm = listToUDFM_Directly . ufmToList
+alwaysUnsafeUfmToUdfm = listToUDFM_Directly . nonDetUFMToList
 
 -- Output-ery
 
diff --git a/compiler/utils/UniqFM.hs b/compiler/utils/UniqFM.hs
index f9832d5455..261dd1c622 100644
--- a/compiler/utils/UniqFM.hs
+++ b/compiler/utils/UniqFM.hs
@@ -64,8 +64,8 @@ module UniqFM (
         lookupWithDefaultUFM, lookupWithDefaultUFM_Directly,
         nonDetEltsUFM, eltsUFM, nonDetKeysUFM,
         ufmToSet_Directly,
-        nonDetUFMToList, ufmToList, ufmToIntMap,
-        pprUniqFM, pprUFM, pluralUFM
+        nonDetUFMToList, ufmToIntMap,
+        pprUniqFM, pprUFM, pprUFMWithKeys, pluralUFM
     ) where
 
 import Unique           ( Uniquable(..), Unique, getKey )
@@ -184,7 +184,6 @@ lookupWithDefaultUFM_Directly
                 :: UniqFM elt -> elt -> Unique -> elt
 eltsUFM         :: UniqFM elt -> [elt]
 ufmToSet_Directly :: UniqFM elt -> S.IntSet
-ufmToList       :: UniqFM elt -> [(Unique, elt)]
 
 {-
 ************************************************************************
@@ -286,7 +285,6 @@ lookupWithDefaultUFM (UFM m) v k = M.findWithDefault v (getKey $ getUnique k) m
 lookupWithDefaultUFM_Directly (UFM m) v u = M.findWithDefault v (getKey u) m
 eltsUFM (UFM m) = M.elems m
 ufmToSet_Directly (UFM m) = M.keysSet m
-ufmToList (UFM m) = map (\(k, v) -> (getUnique k, v)) $ M.toList m
 
 anyUFM :: (elt -> Bool) -> UniqFM elt -> Bool
 anyUFM p (UFM m) = M.fold ((||) . p) False m
@@ -357,6 +355,18 @@ pprUFM :: UniqFM a      -- ^ The things to be pretty printed
                         -- printed
 pprUFM ufm pp = pp (nonDetEltsUFM ufm)
 
+-- | Pretty-print a non-deterministic set.
+-- The order of variables is non-deterministic and for pretty-printing that
+-- shouldn't be a problem.
+-- Having this function helps contain the non-determinism created with
+-- nonDetUFMToList.
+pprUFMWithKeys
+       :: UniqFM a                -- ^ The things to be pretty printed
+       -> ([(Unique, a)] -> SDoc) -- ^ The pretty printing function to use on the elements
+       -> SDoc                    -- ^ 'SDoc' where the things have been pretty
+                                  -- printed
+pprUFMWithKeys ufm pp = pp (nonDetUFMToList ufm)
+
 -- | Determines the pluralisation suffix appropriate for the length of a set
 -- in the same way that plural from Outputable does for lists.
 pluralUFM :: UniqFM a -> SDoc