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|
use std::ptr::copy_nonoverlapping;
use crate::abi;
use crate::abi::RubyObjectAccess;
use crate::abi::MIN_OBJ_ALIGN;
use crate::abi::OBJREF_OFFSET;
use crate::Ruby;
use mmtk::util::constants::BITS_IN_BYTE;
use mmtk::util::copy::CopySemantics;
use mmtk::util::copy::GCWorkerCopyContext;
use mmtk::util::Address;
use mmtk::util::ObjectReference;
use mmtk::vm::*;
pub struct VMObjectModel {}
impl VMObjectModel {
const OBJREF_OFFSET: usize = abi::OBJREF_OFFSET;
}
impl ObjectModel<Ruby> for VMObjectModel {
const GLOBAL_LOG_BIT_SPEC: VMGlobalLogBitSpec = VMGlobalLogBitSpec::side_first();
// We overwrite the prepended word which were used to hold object sizes.
const LOCAL_FORWARDING_POINTER_SPEC: VMLocalForwardingPointerSpec =
VMLocalForwardingPointerSpec::in_header(-((OBJREF_OFFSET * BITS_IN_BYTE) as isize));
const LOCAL_FORWARDING_BITS_SPEC: VMLocalForwardingBitsSpec =
VMLocalForwardingBitsSpec::side_first();
const LOCAL_MARK_BIT_SPEC: VMLocalMarkBitSpec =
VMLocalMarkBitSpec::side_after(Self::LOCAL_FORWARDING_BITS_SPEC.as_spec());
const LOCAL_PINNING_BIT_SPEC: VMLocalPinningBitSpec =
VMLocalPinningBitSpec::side_after(Self::LOCAL_MARK_BIT_SPEC.as_spec());
const LOCAL_LOS_MARK_NURSERY_SPEC: VMLocalLOSMarkNurserySpec =
VMLocalLOSMarkNurserySpec::side_after(Self::LOCAL_PINNING_BIT_SPEC.as_spec());
const UNIFIED_OBJECT_REFERENCE_ADDRESS: bool = false;
const OBJECT_REF_OFFSET_LOWER_BOUND: isize = Self::OBJREF_OFFSET as isize;
const NEED_VO_BITS_DURING_TRACING: bool = true;
fn copy(
from: ObjectReference,
semantics: CopySemantics,
copy_context: &mut GCWorkerCopyContext<Ruby>,
) -> ObjectReference {
let from_acc = RubyObjectAccess::from_objref(from);
let from_start = from_acc.obj_start();
let object_size = from_acc.object_size();
let to_start = copy_context.alloc_copy(from, object_size, MIN_OBJ_ALIGN, 0, semantics);
debug_assert!(!to_start.is_zero());
let to_payload = to_start.add(OBJREF_OFFSET);
unsafe {
copy_nonoverlapping::<u8>(from_start.to_ptr(), to_start.to_mut_ptr(), object_size);
}
let to_obj = unsafe { ObjectReference::from_raw_address_unchecked(to_payload) };
copy_context.post_copy(to_obj, object_size, semantics);
trace!("Copied object from {} to {}", from, to_obj);
(crate::binding().upcalls().move_obj_during_marking)(from, to_obj);
#[cfg(feature = "clear_old_copy")]
{
trace!(
"Clearing old copy {} ({}-{})",
from,
from_start,
from_start + object_size
);
// For debug purpose, we clear the old copy so that if the Ruby VM reads from the old
// copy again, it will likely result in an error.
unsafe { std::ptr::write_bytes::<u8>(from_start.to_mut_ptr(), 0, object_size) }
}
to_obj
}
fn copy_to(_from: ObjectReference, _to: ObjectReference, _region: Address) -> Address {
unimplemented!(
"This function cannot be called because we do not support MarkCompact for Ruby."
)
}
fn get_reference_when_copied_to(_from: ObjectReference, _to: Address) -> ObjectReference {
unimplemented!(
"This function cannot be called because we do not support MarkCompact for Ruby."
)
}
fn get_current_size(object: ObjectReference) -> usize {
RubyObjectAccess::from_objref(object).object_size()
}
fn get_type_descriptor(_reference: ObjectReference) -> &'static [i8] {
todo!()
}
fn ref_to_object_start(object: ObjectReference) -> Address {
RubyObjectAccess::from_objref(object).obj_start()
}
fn ref_to_header(object: ObjectReference) -> Address {
RubyObjectAccess::from_objref(object).payload_addr()
}
fn get_size_when_copied(object: ObjectReference) -> usize {
Self::get_current_size(object)
}
fn get_align_when_copied(_object: ObjectReference) -> usize {
todo!()
}
fn get_align_offset_when_copied(_object: ObjectReference) -> usize {
todo!()
}
fn dump_object(_object: ObjectReference) {
todo!()
}
}
|
