org.jikesrvm.compilers.opt.ssa

Class IndexPropagation

java.lang.Object

org.jikesrvm.compilers.opt.driver.CompilerPhase

org.jikesrvm.compilers.opt.ssa.IndexPropagation

public final class IndexPropagation
extends CompilerPhase

Perform index propagation (see Fink, Knobe & Sarkar, SAS 2000)

This analysis computes for each Array SSA variable A, the set of value numbers V(k) such that location A[k] is "available" at def A, and thus at all uses of A

We formulate this as a data flow problem as described in the paper.

This class relies on Array SSA form, global value numbering, and the dataflow equation solver framework.

TODO: This implementation is not terribly efficient. Speed it up.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
(package private) static class	IndexPropagation.ArrayCell An ArrayCell is a lattice cell for the index propagation problem, used in redundant load elimination for one-dimensional arrays.
(package private) static class	IndexPropagation.ObjectCell An ObjectCell is a lattice cell for the index propagation problem, used in redundant load elimination for fields.

Field Summary

Fields

Modifier and Type	Field and Description
private static Constructor<CompilerPhase>	constructor Constructor for this compiler phase
private static boolean	DEBUG Print verbose debugging messages?

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

container

Constructor Summary

Constructors

Constructor and Description
IndexPropagation()

Method Summary

Modifier and Type	Method and Description
Constructor<CompilerPhase>	getClassConstructor() Get a constructor object for this compiler phase
String	getName() Return the name of this compiler phase.
void	perform(IR ir) Perform the analysis.
boolean	shouldPerform(OptOptions options) This method determines if the phase should be run, based on the Options object it is passed.

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

dumpIR, dumpIR, getCompilerPhaseConstructor, getCompilerPhaseConstructor, newExecution, performPhase, printingEnabled, reportAdditionalStats, setContainer, verify

Methods inherited from class java.lang.Object

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

Field Detail

constructor

private static final Constructor<CompilerPhase> constructor

Constructor for this compiler phase

DEBUG

private static final boolean DEBUG

Print verbose debugging messages?

See Also:

Constant Field Values

Constructor Detail

IndexPropagation

public IndexPropagation()

Method Detail

getClassConstructor

public Constructor<CompilerPhase> getClassConstructor()

Get a constructor object for this compiler phase

Overrides:

getClassConstructor in class CompilerPhase

Returns:

compiler phase constructor

shouldPerform

public boolean shouldPerform(OptOptions options)

Description copied from class: CompilerPhase

This method determines if the phase should be run, based on the Options object it is passed. By default, phases are always performed. Subclasses should override this method if they only want to be performed conditionally.

Overrides:

shouldPerform in class CompilerPhase

Parameters:

options - the compiler options for the compilation

Returns:

true iff SSA is constructed on the HIR

getName

public String getName()

Return the name of this compiler phase.

Specified by:

getName in class CompilerPhase

Returns:

"Index Propagation"

perform

public void perform(IR ir)

Perform the analysis.

Pre-condition: The IR is in Array SSA form and global value numbers have been computed.

Specified by:

perform in class CompilerPhase

Parameters:

ir - the IR to optimize