jdk.internal.jvmci.code

Class CalleeSaveLayout

java.lang.Object

jdk.internal.jvmci.code.CalleeSaveLayout

public class CalleeSaveLayout
extends Object

The callee save area (CSA) is a contiguous space in a stack frame used to save (and restore) the values of the caller's registers. This class describes the layout of a CSA in terms of its size, slot size and the callee save registers covered by the CSA.

Field Summary

Fields

Modifier and Type	Field and Description
int	frameOffsetToCSA The offset from the frame pointer to the CSA.
private Register[]	indexToReg
Register[]	registers The list of registers contained by this CSA.
private int[]	regNumToIndex Map from register numbers to slot indexes in the CSA.
int	size The size (in bytes) of the CSA.
int	slotSize The size (in bytes) of an indexable slot in the CSA.

Constructor Summary

Constructors

Constructor and Description
CalleeSaveLayout(TargetDescription target, int frameOffsetToCSA, int size, int slotSize, Register... registers) Creates a CSA layout.

Method Summary

Modifier and Type	Method and Description
boolean	contains(int reg) Determines if the CSA includes a slot for a given register.
int	indexOf(int reg) Gets the index of a given register in the CSA.
int	offsetOf(int reg) Gets the offset of a given register in the CSA.
int	offsetOf(Register reg) Gets the offset of a given register in the CSA.
Register	registerAt(int index) Gets the register whose slot in the CSA is at a given index.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

size

public final int size

The size (in bytes) of the CSA.

slotSize

public final int slotSize

The size (in bytes) of an indexable slot in the CSA.

regNumToIndex

private final int[] regNumToIndex

Map from register numbers to slot indexes in the CSA.

indexToReg

private final Register[] indexToReg

registers

public final Register[] registers

The list of registers contained by this CSA.

frameOffsetToCSA

public final int frameOffsetToCSA

The offset from the frame pointer to the CSA. If this is not known, then this field will have the value Integer.MAX_VALUE.

Constructor Detail

CalleeSaveLayout

public CalleeSaveLayout(TargetDescription target,
                        int frameOffsetToCSA,
                        int size,
                        int slotSize,
                        Register... registers)

Creates a CSA layout.

Parameters:

size - size (in bytes) of the CSA. If this is -1, then the CSA size will be computed from registers.

slotSize - the size (in bytes) of an indexable slot in the CSA

registers - the registers that can be saved in the CSA

Method Detail

offsetOf

public int offsetOf(int reg)

Gets the offset of a given register in the CSA.

Returns:

the offset (in bytes) of reg in the CSA

Throws:

IllegalArgumentException - if reg does not have a slot in the CSA

indexOf

public int indexOf(int reg)

Gets the index of a given register in the CSA.

Returns:

the index of reg in the CSA

Throws:

IllegalArgumentException - if reg does not have a slot in the CSA

offsetOf

public int offsetOf(Register reg)

Gets the offset of a given register in the CSA.

Returns:

the offset (in bytes) of reg in the CSA

Throws:

IllegalArgumentException - if reg does not have a slot in the CSA

contains

public boolean contains(int reg)

Determines if the CSA includes a slot for a given register.

Parameters:

reg - the register to test

Returns:

true if the CSA contains a slot for reg

registerAt

public Register registerAt(int index)

Gets the register whose slot in the CSA is at a given index.

Parameters:

index - an index of a slot in the CSA

Returns:

the register whose slot in the CSA is at index or null if index does not denote a slot in the CSA aligned with a register

toString

public String toString()

Overrides:

toString in class Object