-- | Basic operations on graphs.
--
-{-# OPTIONS_GHC -w #-}
+{-# OPTIONS -w #-}
-- The above warning supression flag is a temporary kludge.
-- While working on this module you are encouraged to remove it and fix
-- any warnings in the module. See
--- http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings
+-- http://hackage.haskell.org/trac/ghc/wiki/CodingStyle#Warnings
-- for details
module GraphOps (
addCoalesce, delCoalesce,
addExclusion,
addPreference,
+ coalesceGraph,
+ coalesceNodes,
setColor,
- verify,
+ validateGraph,
slurpNodeConflictCount
)
where
= let Just node = lookupNode graph k
-- delete conflict edges from other nodes to this one.
- graph1 = foldl' (\g k1 -> delConflict k1 k g) graph
+ graph1 = foldl' (\g k1 -> let Just g' = delConflict k1 k g in g') graph
$ uniqSetToList (nodeConflicts node)
-- delete coalesce edge from other nodes to this one.
- graph2 = foldl' (\g k1 -> delCoalesce k1 k g) graph1
+ graph2 = foldl' (\g k1 -> let Just g' = delCoalesce k1 k g in g') graph1
$ uniqSetToList (nodeCoalesce node)
-- delete the node
in graph3
--- | Modify a node in the graph
+-- | Modify a node in the graph.
+-- returns Nothing if the node isn't present.
+--
modNode :: Uniquable k
=> (Node k cls color -> Node k cls color)
- -> k -> Graph k cls color -> Graph k cls color
+ -> k -> Graph k cls color -> Maybe (Graph k cls color)
modNode f k graph
- = case getNode graph k of
- Node{} -> graphMapModify
+ = case lookupNode graph k of
+ Just Node{}
+ -> Just
+ $ graphMapModify
(\fm -> let Just node = lookupUFM fm k
node' = f node
in addToUFM fm k node')
graph
+ Nothing -> Nothing
-- | Get the size of the graph, O(n)
size :: Uniquable k
-- | Delete a conflict edge. k1 -> k2
+-- returns Nothing if the node isn't in the graph
delConflict
:: Uniquable k
=> k -> k
- -> Graph k cls color -> Graph k cls color
+ -> Graph k cls color -> Maybe (Graph k cls color)
delConflict k1 k2
= modNode
delCoalesce
:: Uniquable k
=> k -> k
- -> Graph k cls color -> Graph k cls color
+ -> Graph k cls color -> Maybe (Graph k cls color)
delCoalesce k1 k2
= modNode (\node -> node { nodeCoalesce = delOneFromUniqSet (nodeCoalesce node) k2 })
(newNode u c) { nodePreference = [color] }
u
+
+-- | Do agressive coalescing on this graph.
+-- returns the new graph and the list of pairs of nodes that got coaleced together.
+-- for each pair, the resulting node will have the least key and be second in the pair.
+--
+coalesceGraph
+ :: (Uniquable k, Ord k, Eq cls, Outputable k)
+ => Graph k cls color
+ -> (Graph k cls color, [(k, k)])
+
+coalesceGraph graph
+ = let
+ -- find all the nodes that have coalescence edges
+ cNodes = filter (\node -> not $ isEmptyUniqSet (nodeCoalesce node))
+ $ eltsUFM $ graphMap graph
+
+ -- build a list of pairs of keys for node's we'll try and coalesce
+ -- every pair of nodes will appear twice in this list
+ -- ie [(k1, k2), (k2, k1) ... ]
+ -- This is ok, GrapOps.coalesceNodes handles this and it's convenient for
+ -- build a list of what nodes get coalesced together for later on.
+ --
+ cList = [ (nodeId node1, k2)
+ | node1 <- cNodes
+ , k2 <- uniqSetToList $ nodeCoalesce node1 ]
+
+ -- do the coalescing, returning the new graph and a list of pairs of keys
+ -- that got coalesced together.
+ (graph', mPairs)
+ = mapAccumL coalesceNodes graph cList
+
+ in (graph', catMaybes mPairs)
+
+
+-- | Coalesce this pair of nodes unconditionally / agressively.
+-- The resulting node is the one with the least key.
+--
+-- returns: Just the pair of keys if the nodes were coalesced
+-- the second element of the pair being the least one
+--
+-- Nothing if either of the nodes weren't in the graph
+
+coalesceNodes
+ :: (Uniquable k, Ord k, Eq cls, Outputable k)
+ => Graph k cls color
+ -> (k, k) -- ^ keys of the nodes to be coalesced
+ -> (Graph k cls color, Maybe (k, k))
+
+coalesceNodes graph (k1, k2)
+ | (kMin, kMax) <- if k1 < k2
+ then (k1, k2)
+ else (k2, k1)
+
+ -- nodes must be in the graph
+ , Just nMin <- lookupNode graph kMin
+ , Just nMax <- lookupNode graph kMax
+
+ -- can't coalesce conflicting nodes
+ , not $ elementOfUniqSet kMin (nodeConflicts nMax)
+ , not $ elementOfUniqSet kMax (nodeConflicts nMin)
+
+ = coalesceNodes' graph kMin kMax nMin nMax
+
+
+
+ -- one of the nodes wasn't in the graph anymore
+ | otherwise
+ = (graph, Nothing)
+
+coalesceNodes' graph kMin kMax nMin nMax
+
+ -- sanity checks
+ | nodeClass nMin /= nodeClass nMax
+ = error "GraphOps.coalesceNodes: can't coalesce nodes of different classes."
+
+ | not (isNothing (nodeColor nMin) && isNothing (nodeColor nMax))
+ = error "GraphOps.coalesceNodes: can't coalesce colored nodes."
+
+ ---
+ | otherwise
+ = let
+ -- the new node gets all the edges from its two components
+ node =
+ Node { nodeId = kMin
+ , nodeClass = nodeClass nMin
+ , nodeColor = Nothing
+
+ -- nodes don't conflict with themselves..
+ , nodeConflicts
+ = (unionUniqSets (nodeConflicts nMin) (nodeConflicts nMax))
+ `delOneFromUniqSet` kMin
+ `delOneFromUniqSet` kMax
+
+ , nodeExclusions = unionUniqSets (nodeExclusions nMin) (nodeExclusions nMax)
+ , nodePreference = nodePreference nMin ++ nodePreference nMax
+
+ -- nodes don't coalesce with themselves..
+ , nodeCoalesce
+ = (unionUniqSets (nodeCoalesce nMin) (nodeCoalesce nMax))
+ `delOneFromUniqSet` kMin
+ `delOneFromUniqSet` kMax
+ }
+
+ -- delete the old nodes from the graph and add the new one
+ graph' = addNode kMin node
+ $ delNode kMin
+ $ delNode kMax
+ $ graph
+
+ in (graph', Just (kMax, kMin))
+
--- | Verify the internal structure of a graph
+-- | validate the internal structure of a graph
-- all its edges should point to valid nodes
+-- if they don't then throw an error
--
-verify :: Uniquable k
- => Graph k cls color
- -> Bool
+validateGraph
+ :: (Uniquable k, Outputable k)
+ => SDoc
+ -> Graph k cls color
+ -> Graph k cls color
-verify graph
+validateGraph doc graph
= let edges = unionUniqSets
(unionManyUniqSets
(map nodeConflicts $ eltsUFM $ graphMap graph))
badEdges = minusUniqSet edges nodes
in if isEmptyUniqSet badEdges
- then True
- else False
+ then graph
+ else pprPanic "GraphOps.validateGraph"
+ ( text "-- bad edges"
+ $$ vcat (map ppr $ uniqSetToList badEdges)
+ $$ text "----------------------------"
+ $$ doc)
-- | Slurp out a map of how many nodes had a certain number of conflict neighbours
projects / ghc-hetmet.git / blobdiff