Struct mmtk::vm::VMLocalMarkBitSpec

pub struct VMLocalMarkBitSpec(_);

Implementations

impl VMLocalMarkBitSpec

pub fn mark<VM: VMBinding>(&self, object: ObjectReference, ordering: Ordering)

Set the mark bit for the object to 1

pub fn is_marked<VM: VMBinding>( &self, object: ObjectReference, ordering: Ordering ) -> bool

Test if the mark bit for the object is set (1)

impl VMLocalMarkBitSpec

pub const LOG_NUM_BITS: usize = 0usize

pub const IS_GLOBAL: bool = false

pub const fn in_header(bit_offset: isize) -> Self

pub const fn side_first() -> Self

pub const fn side_after(spec: &MetadataSpec) -> Self

pub const fn as_spec(&self) -> &MetadataSpec

pub const fn num_bits(&self) -> usize

Methods from Deref<Target = MetadataSpec>

pub fn is_on_side(&self) -> bool

pub fn is_in_header(&self) -> bool

pub fn extract_side_spec(&self) -> &SideMetadataSpec

Extract SideMetadataSpec from a MetadataSpec. Panics if this is not side metadata.

pub unsafe fn load<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, mask: Option<T> ) -> T

A function to non-atomically load the specified metadata’s content. Returns the metadata value.

Arguments:

• object: is a reference to the target object.
• mask: is an optional mask value for the metadata. This value is used in cases like the forwarding pointer metadata, where some of the bits are reused by other metadata such as the forwarding bits.

Safety

This is a non-atomic load, thus not thread-safe.

pub fn load_atomic<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, mask: Option<T>, ordering: Ordering ) -> T

A function to atomically load the specified metadata’s content. Returns the metadata value.

Arguments:

• object: is a reference to the target object.
• mask: is an optional mask value for the metadata. This value is used in cases like the forwarding pointer metadata, where some of the bits are reused by other metadata such as the forwarding bits.
• atomic_ordering: is the ordering for the load operation.

pub unsafe fn store<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, val: T, mask: Option<T> )

A function to non-atomically store a value to the specified metadata.

Arguments:

• object: is a reference to the target object.
• val: is the new metadata value to be stored.
• mask: is an optional mask value for the metadata. This value is used in cases like the forwarding pointer metadata, where some of the bits are reused by other metadata such as the forwarding bits.

Safety

This is a non-atomic store, thus not thread-safe.

pub fn store_atomic<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, val: T, mask: Option<T>, ordering: Ordering )

A function to atomically store a value to the specified metadata.

Arguments:

• object: is a reference to the target object.
• val: is the new metadata value to be stored.
• mask: is an optional mask value for the metadata. This value is used in cases like the forwarding pointer metadata, where some of the bits are reused by other metadata such as the forwarding bits.
• ordering: is the ordering for the store operation.

pub fn compare_exchange_metadata<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, old_val: T, new_val: T, mask: Option<T>, success_order: Ordering, failure_order: Ordering ) -> Result<T, T>

A function to atomically compare-and-exchange the specified metadata’s content. Returns true if the operation is successful, and false otherwise.

Arguments:

• object: is a reference to the target object.
• old_val: is the expected current value of the metadata.
• new_val: is the new metadata value to be stored if the compare-and-exchange operation is successful.
• mask: is an optional mask value for the metadata. This value is used in cases like the forwarding pointer metadata, where some of the bits are reused by other metadata such as the forwarding bits.
• success_order: is the atomic ordering used if the operation is successful.
• failure_order: is the atomic ordering used if the operation fails.

pub fn fetch_add_metadata<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, val: T, order: Ordering ) -> T

A function to atomically perform an add operation on the specified metadata’s content. Returns the old metadata value.

Arguments:

• object: is a reference to the target object.
• val: is the value to be added to the current value of the metadata.
• order: is the atomic ordering of the fetch-and-add operation.

pub fn fetch_sub_metadata<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, val: T, order: Ordering ) -> T

A function to atomically perform a subtract operation on the specified metadata’s content. Returns the old metadata value.

Arguments:

• object: is a reference to the target object.
• val: is the value to be subtracted from the current value of the metadata.
• order: is the atomic ordering of the fetch-and-add operation.

pub fn fetch_and_metadata<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, val: T, order: Ordering ) -> T

A function to atomically perform a bit-and operation on the specified metadata’s content. Returns the old metadata value.

Arguments:

• object: is a reference to the target object.
• val: is the value to bit-and with the current value of the metadata.
• order: is the atomic ordering of the fetch-and-add operation.

pub fn fetch_or_metadata<VM: VMBinding, T: MetadataValue>( &self, object: ObjectReference, val: T, order: Ordering ) -> T

A function to atomically perform a bit-or operation on the specified metadata’s content. Returns the old metadata value.

Arguments:

• object: is a reference to the target object.
• val: is the value to bit-or with the current value of the metadata.
• order: is the atomic ordering of the fetch-and-add operation.

pub fn fetch_update_metadata<VM: VMBinding, T: MetadataValue, F: FnMut(T) -> Option<T> + Copy>( &self, object: ObjectReference, set_order: Ordering, fetch_order: Ordering, f: F ) -> Result<T, T>

A function to atomically perform an update operation on the specified metadata’s content. The semantics are the same as Rust’s fetch_update on atomic types. Returns a Result of Ok(previous_value) if the function returned Some(_), else Err(previous_value).

Arguments:

• object: is a reference to the target object.
• val: is the value to bit-or with the current value of the metadata.
• order: is the atomic ordering of the fetch-and-add operation.
• f: the update function. The function may be called multiple times.

Trait Implementations

impl Deref for VMLocalMarkBitSpec

type Target = MetadataSpec

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.