org.graalvm.compiler.lir.ssa

Class SSAUtil

java.lang.Object

org.graalvm.compiler.lir.ssa.SSAUtil

public final class SSAUtil
extends Object

Utilities for working with Static-Single-Assignment LIR form.

Representation of PHIs

There is no explicit PHI LIRInstruction. Instead, they are implemented as parallel copy that span across a control-flow edge. The variables introduced by PHIs of a specific merge block are attached to the StandardOp.LabelOp of the block. The outgoing values from the predecessor are input to the StandardOp.BlockEndOp of the predecessor. Because there are no critical edges we know that the StandardOp.BlockEndOp of the predecessor has to be a StandardOp.JumpOp.

Example:

 B0 -> B1
   ...
   v0|i = ...
   JUMP ~[v0|i, int[0|0x0]] destination: B0 -> B1
 ________________________________________________

 B2 -> B1
   ...
   v1|i = ...
   v2|i = ...
   JUMP ~[v1|i, v2|i] destination: B2 -> B1
 ________________________________________________

 B1 <- B0,B2
   [v3|i, v4|i] = LABEL
   ...
 

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	SSAUtil.PhiValueVisitor

Constructor Summary

Constructors

Constructor and Description
SSAUtil()

Method Summary

Modifier and Type	Method and Description
static void	forEachPhiValuePair(LIR lir, AbstractBlockBase<?> merge, AbstractBlockBase<?> pred, SSAUtil.PhiValueVisitor visitor) Visits each phi value pair of an edge, i.e.
static int	indexOfValue(StandardOp.LabelOp label, Value value)
static StandardOp.LabelOp	phiIn(LIR lir, AbstractBlockBase<?> block)
static StandardOp.JumpOp	phiOut(LIR lir, AbstractBlockBase<?> block)
static int	phiOutIndex(LIR lir, AbstractBlockBase<?> block)
static void	removePhiIn(LIR lir, AbstractBlockBase<?> block)
static void	removePhiOut(LIR lir, AbstractBlockBase<?> block)
static void	verifyPhi(LIR lir, AbstractBlockBase<?> merge)
static boolean	verifySSAForm(LIR lir)

Methods inherited from class java.lang.Object

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

Constructor Detail

SSAUtil

public SSAUtil()

Method Detail

forEachPhiValuePair

public static void forEachPhiValuePair(LIR lir,
                                       AbstractBlockBase<?> merge,
                                       AbstractBlockBase<?> pred,
                                       SSAUtil.PhiValueVisitor visitor)

Visits each phi value pair of an edge, i.e. the outgoing value from the predecessor and the incoming value to the merge block.

phiOut

public static StandardOp.JumpOp phiOut(LIR lir,
                                       AbstractBlockBase<?> block)

phiOutIndex

public static int phiOutIndex(LIR lir,
                              AbstractBlockBase<?> block)

phiIn

public static StandardOp.LabelOp phiIn(LIR lir,
                                       AbstractBlockBase<?> block)

removePhiOut

public static void removePhiOut(LIR lir,
                                AbstractBlockBase<?> block)

removePhiIn

public static void removePhiIn(LIR lir,
                               AbstractBlockBase<?> block)

verifySSAForm

public static boolean verifySSAForm(LIR lir)

verifyPhi

public static void verifyPhi(LIR lir,
                             AbstractBlockBase<?> merge)

indexOfValue

public static int indexOfValue(StandardOp.LabelOp label,
                               Value value)