+{-# OPTIONS -fno-warn-missing-signatures #-}
-- | Graph Coloring.
-- This is a generic graph coloring library, abstracted over the type of
-- the node keys, nodes and colors.
--
-{-# OPTIONS -fno-warn-missing-signatures #-}
module GraphColor (
module GraphBase,
, Eq color, Eq cls, Ord k
, Outputable k, Outputable cls, Outputable color)
=> Bool -- ^ whether to do iterative coalescing
- -> Int -- ^ how many times coloring has been called so far
+ -> Int -- ^ how many times we've tried to color this graph so far.
-> UniqFM (UniqSet color) -- ^ map of (node class -> set of colors available for this class).
-> Triv k cls color -- ^ fn to decide whether a node is trivially colorable.
-> (Graph k cls color -> k) -- ^ fn to choose a node to potentially leave uncolored if nothing is trivially colorable.
colorGraph iterative spinCount colors triv spill graph0
= let
- -- If we're not doing iterative coalescing then just do a conservative
- -- coalescing stage at the front.
+ -- If we're not doing iterative coalescing then do an aggressive coalescing first time
+ -- around and then conservative coalescing for subsequent passes.
+ --
+ -- Aggressive coalescing is a quick way to get rid of many reg-reg moves. However, if
+ -- there is a lot of register pressure and we do it on every round then it can make the
+ -- graph less colorable and prevent the algorithm from converging in a sensible number
+ -- of cycles.
+ --
(graph_coalesced, kksCoalesce1)
- = if not iterative
- then coalesceGraph False triv graph0
- else (graph0, [])
+ = if iterative
+ then (graph0, [])
+ else if spinCount == 0
+ then coalesceGraph True triv graph0
+ else coalesceGraph False triv graph0
-- run the scanner to slurp out all the trivially colorable nodes
-- (and do coalescing if iterative coalescing is enabled)
-- with the provided triv function.
--
in if not $ null ksNoTriv
- then pprPanic "colorGraph: trivially colorable nodes didn't color!" empty
-{- ( empty
+ then pprPanic "colorGraph: trivially colorable nodes didn't color!" -- empty
+ ( empty
$$ text "ksTriv = " <> ppr ksTriv
$$ text "ksNoTriv = " <> ppr ksNoTriv
+ $$ text "colors = " <> ppr colors
$$ empty
- $$ dotGraph (\x -> text "white") triv graph1) -}
+ $$ dotGraph (\_ -> text "white") triv graph_triv)
else ( graph_prob
, mkUniqSet ksNoColor -- the nodes that didn't color (spills)
colorScan
:: ( Uniquable k, Uniquable cls, Uniquable color
, Ord k, Eq cls
- , Outputable k, Outputable color)
+ , Outputable k, Outputable cls)
=> Bool -- ^ whether to do iterative coalescing
-> Triv k cls color -- ^ fn to decide whether a node is trivially colorable
-> (Graph k cls color -> k) -- ^ fn to choose a node to potentially leave uncolored if nothing is trivially colorable.
-- if the graph is empty then we're done
| isNullUFM $ graphMap graph
- = (ksTriv, ksSpill, kksCoalesce)
+ = (ksTriv, ksSpill, reverse kksCoalesce)
-- Simplify:
-- Look for trivially colorable nodes.
-- go back to Simplify and see if this frees up more nodes to be trivially colorable.
(graph2, kksCoalesceFound @(_:_))
-> colorScan_spin iterative triv spill graph2
- ksTriv ksSpill (kksCoalesceFound ++ kksCoalesce)
+ ksTriv ksSpill (reverse kksCoalesceFound ++ kksCoalesce)
-- Freeze:
-- nothing could be coalesced (or was triv),
-- | Try to assign a color to all these nodes.
assignColors
- :: ( Uniquable k, Uniquable cls, Uniquable color, Eq color )
+ :: ( Uniquable k, Uniquable cls, Uniquable color
+ , Eq color, Outputable cls)
=> UniqFM (UniqSet color) -- ^ map of (node class -> set of colors available for this class).
-> Graph k cls color -- ^ the graph
-> [k] -- ^ nodes to assign a color to.
-- returns Nothing if no color can be assigned to this node.
--
selectColor
- :: ( Uniquable k, Uniquable cls, Uniquable color, Eq color)
+ :: ( Uniquable k, Uniquable cls, Uniquable color
+ , Eq color, Outputable cls)
=> UniqFM (UniqSet color) -- ^ map of (node class -> set of colors available for this class).
-> Graph k cls color -- ^ the graph
-> k -- ^ key of the node to select a color for.
Just node = lookupNode graph u
-- lookup the available colors for the class of this node.
- Just colors_avail
- = lookupUFM colors (nodeClass node)
+ colors_avail
+ = case lookupUFM colors (nodeClass node) of
+ Nothing -> pprPanic "selectColor: no colors available for class " (ppr (nodeClass node))
+ Just cs -> cs
-- find colors we can't use because they're already being used
-- by a node that conflicts with this one.
projects / ghc-hetmet.git / blobdiff