Class LocalAccessor

java.lang.Object

com.oracle.truffle.api.bytecode.LocalAccessor

public final class LocalAccessor
extends Object

Operation parameter that allows an operation to get, set, and clear the value of a local.

To use a local accessor, declare a ConstantOperand on the operation. The corresponding builder method for the operation will take a BytecodeLocal argument for the local to be accessed. At run time, a LocalAccessor for the local will be supplied as a parameter to the operation.

Local accessors are useful to implement behaviour that cannot be implemented with the builtin local operations (like StoreLocal). For example, if an operation produces multiple outputs, it can write one of the outputs to a local using a local accessor. Prefer builtin operations when possible, since they automatically work with boxing elimination. Local accessors should be preferred over BytecodeNode helpers like BytecodeNode.getLocalValue(int, Frame, int), since the helpers use extra indirection.

All of the accessor methods take a bytecode node and the current frame. The bytecode node should be the current bytecode node and correspond to the root that declares the local; it should be compilation-final. The frame should contain the local.

Example usage:

@Operation
@ConstantOperand(type = LocalAccessor.class)
public static final class GetLocal {
    @Specialization
    public static Object perform(VirtualFrame frame,
                    LocalAccessor accessor,
                    @Bind BytecodeNode bytecodeNode) {
        return accessor.getObject(bytecodeNode, frame);
    }
}

Since:

24.2

Method Summary

Modifier and Type	Method	Description
void	clear(BytecodeNode bytecodeNode, VirtualFrame frame)	Clears the local from the frame.
static LocalAccessor	constantOf(BytecodeLocal local)	Obtains a LocalAccessor.
boolean	equals(Object obj)
boolean	getBoolean(BytecodeNode bytecodeNode, VirtualFrame frame)	Loads a boolean from the local.
byte	getByte(BytecodeNode bytecodeNode, VirtualFrame frame)	Loads a byte from the local.
double	getDouble(BytecodeNode bytecodeNode, VirtualFrame frame)	Loads a double from the local.
float	getFloat(BytecodeNode bytecodeNode, VirtualFrame frame)	Loads a float from the local.
int	getInt(BytecodeNode bytecodeNode, VirtualFrame frame)	Loads an int from the local.
Object	getLocalInfo(BytecodeNode bytecodeNode)	Returns the info associated with the local.
Object	getLocalName(BytecodeNode bytecodeNode)	Returns the name associated with the local.
long	getLong(BytecodeNode bytecodeNode, VirtualFrame frame)	Loads a long from the local.
Object	getObject(BytecodeNode bytecodeNode, VirtualFrame frame)	Loads an object from the local.
int	hashCode()
boolean	isCleared(BytecodeNode bytecodeNode, VirtualFrame frame)	Checks whether the local has been cleared (and a new value has not been set).
void	setBoolean(BytecodeNode bytecodeNode, VirtualFrame frame, boolean value)	Stores a short into the local.
void	setByte(BytecodeNode bytecodeNode, VirtualFrame frame, byte value)	Stores a byte into the local.
void	setDouble(BytecodeNode bytecodeNode, VirtualFrame frame, double value)	Stores a double into the local.
void	setFloat(BytecodeNode bytecodeNode, VirtualFrame frame, float value)	Stores a float into the local.
void	setInt(BytecodeNode bytecodeNode, VirtualFrame frame, int value)	Stores an int into the local.
void	setLong(BytecodeNode bytecodeNode, VirtualFrame frame, long value)	Stores a long into the local.
void	setObject(BytecodeNode bytecodeNode, VirtualFrame frame, Object value)	Stores an object into the local.
String	toString()	Returns a string representation of a LocalAccessor.

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Details

toString

public String toString()

Returns a string representation of a LocalAccessor.

Overrides:

toString in class Object

Since:

24.2

getObject

public Object getObject(BytecodeNode bytecodeNode,
 VirtualFrame frame)

Loads an object from the local.

Since:

24.2

getBoolean

public boolean getBoolean(BytecodeNode bytecodeNode,
 VirtualFrame frame)
                   throws UnexpectedResultException

Loads a boolean from the local.

Throws:

UnexpectedResultException

Since:

24.2

getByte

public byte getByte(BytecodeNode bytecodeNode,
 VirtualFrame frame)
             throws UnexpectedResultException

Loads a byte from the local.

Throws:

UnexpectedResultException

Since:

24.2

getInt

public int getInt(BytecodeNode bytecodeNode,
 VirtualFrame frame)
           throws UnexpectedResultException

Loads an int from the local.

Throws:

UnexpectedResultException

Since:

24.2

getLong

public long getLong(BytecodeNode bytecodeNode,
 VirtualFrame frame)
             throws UnexpectedResultException

Loads a long from the local.

Throws:

UnexpectedResultException

Since:

24.2

getFloat

public float getFloat(BytecodeNode bytecodeNode,
 VirtualFrame frame)
               throws UnexpectedResultException

Loads a float from the local.

Throws:

UnexpectedResultException

Since:

24.2

getDouble

public double getDouble(BytecodeNode bytecodeNode,
 VirtualFrame frame)
                 throws UnexpectedResultException

Loads a double from the local.

Throws:

UnexpectedResultException

Since:

24.2

setObject

public void setObject(BytecodeNode bytecodeNode,
 VirtualFrame frame,
 Object value)

Stores an object into the local.

Since:

24.2

setBoolean

public void setBoolean(BytecodeNode bytecodeNode,
 VirtualFrame frame,
 boolean value)

Stores a short into the local.

Since:

24.2

setByte

public void setByte(BytecodeNode bytecodeNode,
 VirtualFrame frame,
 byte value)

Stores a byte into the local.

Since:

24.2

setInt

public void setInt(BytecodeNode bytecodeNode,
 VirtualFrame frame,
 int value)

Stores an int into the local.

Since:

24.2

setLong

public void setLong(BytecodeNode bytecodeNode,
 VirtualFrame frame,
 long value)

Stores a long into the local.

Since:

24.2

setFloat

public void setFloat(BytecodeNode bytecodeNode,
 VirtualFrame frame,
 float value)

Stores a float into the local.

Since:

24.2

setDouble

public void setDouble(BytecodeNode bytecodeNode,
 VirtualFrame frame,
 double value)

Stores a double into the local.

Since:

24.2

clear

public void clear(BytecodeNode bytecodeNode,
 VirtualFrame frame)

Clears the local from the frame.

Clearing the slot marks the frame slot as illegal. An exception will be thrown if it is read before being set. Clearing does not insert a default local value, if specified.

Since:

24.2

isCleared

public boolean isCleared(BytecodeNode bytecodeNode,
 VirtualFrame frame)

Checks whether the local has been cleared (and a new value has not been set).

This method also returns true if a local has not been initialized and no default local value is specified.

Since:

24.2

getLocalName

public Object getLocalName(BytecodeNode bytecodeNode)

Returns the name associated with the local.

Since:

24.2

See Also:

• BytecodeNode.getLocalName(int, int)

getLocalInfo

public Object getLocalInfo(BytecodeNode bytecodeNode)

Returns the info associated with the local.

Since:

24.2

See Also:

• BytecodeNode.getLocalInfo(int, int)

constantOf

public static LocalAccessor constantOf(BytecodeLocal local)

Obtains a LocalAccessor. This method is invoked by the generated code and should not be called directly.

Since:

24.2

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object