at.dms.kjc.sir.lowering.partition
Class RefactorSplitJoin

java.lang.Object
  at.dms.kjc.sir.lowering.partition.RefactorSplitJoin

public class RefactorSplitJoin
extends Object

Constructor Summary

RefactorSplitJoin()

Method Summary

static SIRStream	addDeepRectangularSyncPoints(SIRStream str) Returns new version of
static SIRSplitJoin	addHierarchicalChildren(SIRSplitJoin sj, PartitionGroup partition) Given a splitjoin
static SIRPipeline	addSyncPoints(SIRSplitJoin sj, PartitionGroup partition) Given that all of the children of
static SIRStream	convertToPipeline(SIRSplitJoin sj) Converts
static boolean	raiseSJChildren(SIRSplitJoin sj) Raises as many children of
static boolean	removeMatchingSyncPoints(SIRPipeline pipe) Does the opposite transformation of
static boolean	removeSyncPoints(SIRPipeline pipe) Removes all sync points that it can in a structued way in

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RefactorSplitJoin

public RefactorSplitJoin()

Method Detail

convertToPipeline

public static SIRStream convertToPipeline(SIRSplitJoin sj)

Converts

sj

to a pipeline, where the left-most children of the

sj

are the top-most elements of the pipeline. Initial input is passed through so that lower stages of the pipe can operate on it. Only works on splitjoins that have filters for children, that these filters have an integral pop/push ratio (this could possibly be lifted with more clever scheduling) and that have the same input and output type. Otherwise this returns the original

sj

. Note that this is an immutable method -- does not modify

sj

or its parent.

addHierarchicalChildren

public static SIRSplitJoin addHierarchicalChildren(SIRSplitJoin sj,
                                                   PartitionGroup partition)

Given a splitjoin

sj

and a partitioning

partition

of its children, returns a new splitjoin with each partition factored into its own child splitjoin. Note that this is an immutable method -- does not modify

sj

or its parent.

addDeepRectangularSyncPoints

public static SIRStream addDeepRectangularSyncPoints(SIRStream str)

Returns new version of

str

into one in which all splitjoins contained in any children are made rectangular and have synchronization after each child. Also mutates

str

.

addSyncPoints

public static SIRPipeline addSyncPoints(SIRSplitJoin sj,
                                        PartitionGroup partition)

Given that all of the children of

sj

are pipelines and that

partition

describes a partitioning for such a pipeline, re-arrange

sj

into a pipeline of several splitjoins, each of which has children corresponding to a segment of

partition

: | | . . / | \ / | \ | | | | | | | | | ===> \ | / | | | . \ | / / | \ . | | | | \ | / | . Note that this is an immutable method -- does not modify

sj

or its parent.

removeSyncPoints

public static boolean removeSyncPoints(SIRPipeline pipe)

Removes all sync points that it can in a structued way in

pipe

. Note that this might INCREASE the tile count because more joiners are introduced into the graph. If this is not desired, use only removeMatchingSyncPoints (below). Note that this method MUTATES its argument.

removeMatchingSyncPoints

public static boolean removeMatchingSyncPoints(SIRPipeline pipe)

Does the opposite transformation of

addSyncPoints

above. If any two adjacent children in

pipe

are splitjoins where the weights of the upstream joiner exactly match the weights of the downstream joiner, then the splitjoins can be combined into a single splitjoin. If this is the case, then

pipe

is mutated. This is intended only as a reverse routine for the above sync. addition. In particular, it doesn't deal with duplicate splitters or 1-way splitters, and it doesn't attempt to "duplicate" or "unroll" whole streams in order for synchronization to match up. This guarantees that the tile count is not increased by the procedure. Returns whether or not any change was made. Note that this method MUTATES its argument.

raiseSJChildren

public static boolean raiseSJChildren(SIRSplitJoin sj)

Raises as many children of

sj

as it can into

sj

, using helper functions below. Note that this method MUTATES its argument.