ghc-7.6.3: The GHC API

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GraphBase

Description

Types for the general graph colorer.

Synopsis

- type Triv k cls color = cls -> UniqSet k -> UniqSet color -> Bool
- data Graph k cls color = Graph {
  - graphMap :: UniqFM (Node k cls color)
  }
- initGraph :: Graph k cls color
- graphMapModify :: (UniqFM (Node k cls color) -> UniqFM (Node k cls color)) -> Graph k cls color -> Graph k cls color
- data Node k cls color = Node {
  - nodeId :: k
  - nodeClass :: cls
  - nodeColor :: Maybe color
  - nodeConflicts :: UniqSet k
  - nodeExclusions :: UniqSet color
  - nodePreference :: [color]
  - nodeCoalesce :: UniqSet k
  }
- newNode :: k -> cls -> Node k cls color

# Documentation

type Triv k cls color = cls -> UniqSet k -> UniqSet color -> Bool

A fn to check if a node is trivially colorable For graphs who's color classes are disjoint then a node is 'trivially colorable' when it has less neighbors and exclusions than available colors for that node.

For graph's who's color classes overlap, ie some colors alias other colors, then this can be a bit more tricky. There is a general way to calculate this, but it's likely be too slow for use in the code. The coloring algorithm takes a canned function which can be optimised by the user to be specific to the specific graph being colored.

for details, see A Generalised Algorithm for Graph-Coloring Register Allocation Smith, Ramsey, Holloway - PLDI 2004.

data Graph k cls color

The Interference graph. There used to be more fields, but they were turfed out in a previous revision. maybe we'll want more later..

Constructors

Graph |
Fields graphMap :: UniqFM (Node k cls color) All active nodes in the graph.

initGraph :: Graph k cls color

An empty graph.

graphMapModify :: (UniqFM (Node k cls color) -> UniqFM (Node k cls color)) -> Graph k cls color -> Graph k cls color

Modify the finite map holding the nodes in the graph.

data Node k cls color

Graph nodes. Represents a thing that can conflict with another thing. For the register allocater the nodes represent registers.

Constructors

Node |
Fields nodeId :: k A unique identifier for this node. nodeClass :: cls The class of this node, determines the set of colors that can be used. nodeColor :: Maybe color The color of this node, if any. nodeConflicts :: UniqSet k Neighbors which must be colored differently to this node. nodeExclusions :: UniqSet color Colors that cannot be used by this node. nodePreference :: [color] Colors that this node would prefer to be, in decending order. nodeCoalesce :: UniqSet k Neighbors that this node would like to be colored the same as.

newNode :: k -> cls -> Node k cls color

An empty node.