org.jikesrvm.compilers.opt.controlflow

Class YieldPoints

java.lang.Object

org.jikesrvm.compilers.opt.driver.CompilerPhase

org.jikesrvm.compilers.opt.controlflow.YieldPoints

public class YieldPoints
extends CompilerPhase

This class inserts yield points in

• 1) a method's prologue
• 2) loop headers
• 3) (optionally) method exits (epilogue, athrow)

Field Summary

Fields inherited from class org.jikesrvm.compilers.opt.driver.CompilerPhase

container

Constructor Summary

Constructors

Constructor and Description
YieldPoints()

Method Summary

Modifier and Type	Method and Description
String	getName() Return the name of this phase
CompilerPhase	newExecution(IR ir) This phase contains no per-compilation instance fields.
void	perform(IR ir) Insert yield points in method prologues, loop heads, and method exits
private void	prependYield(BasicBlock bb, Operator yp, int bcIndex, InlineSequence position) Add a YIELD instruction to the appropriate place for the basic block passed.
private void	processLoopNest(LSTNode n) Process all loop heads in a loop nest by inserting a backedge yieldpoint in each of them.

Methods inherited from class org.jikesrvm.compilers.opt.driver.CompilerPhase

dumpIR, dumpIR, getClassConstructor, getCompilerPhaseConstructor, getCompilerPhaseConstructor, performPhase, printingEnabled, reportAdditionalStats, setContainer, shouldPerform, verify

Methods inherited from class java.lang.Object

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

Constructor Detail

YieldPoints

public YieldPoints()

Method Detail

getName

public final String getName()

Return the name of this phase

Specified by:

getName in class CompilerPhase

Returns:

"Yield Point Insertion"

newExecution

public final CompilerPhase newExecution(IR ir)

This phase contains no per-compilation instance fields.

Overrides:

newExecution in class CompilerPhase

Parameters:

ir - the IR that is about to be passed to performPhase

Returns:

an opt compiler phase on which performPhase may be invoked.

perform

public final void perform(IR ir)

Insert yield points in method prologues, loop heads, and method exits

Specified by:

perform in class CompilerPhase

Parameters:

ir - the IR on which to apply the phase

processLoopNest

private void processLoopNest(LSTNode n)

Process all loop heads in a loop nest by inserting a backedge yieldpoint in each of them.

Parameters:

n - a loop node

prependYield

private void prependYield(BasicBlock bb,
                          Operator yp,
                          int bcIndex,
                          InlineSequence position)

Add a YIELD instruction to the appropriate place for the basic block passed.

Parameters:

bb - the basic block

yp - the yieldpoint operator to insert

bcIndex - the bcIndex of the yieldpoint

position - the source position of the yieldpoint