Set the unlog bits for objects in the bootimage (#1168)

Author: k-sareen

Cargo.toml

@@ -88,6 +88,12 @@ mock_test = []
 # If a binding would need to trace/scan objects that is allocated and managed by the VM, `ActivePlan::vm_trace_object()` is an alternative.
 vm_space = []
 
+# Bulk set unlog bits for all objects inside the VM space. A binding can use
+# this in case they do not have a way to iterate through objects in the
+# bootimage to set the unlog bit. Note that this will set the unlog bit for
+# addresses that may not correspond to valid objects.
+set_unlog_bits_vm_space = []
+
 # A readonly space.
 # TODO: This is not properly implemented yet. We currently use an immortal space instead, and do not guarantee read-only semantics.
 ro_space = []

src/policy/vmspace.rs

@@ -9,6 +9,8 @@ use crate::util::heap::externalpageresource::{ExternalPageResource, ExternalPage
 use crate::util::heap::layout::vm_layout::BYTES_IN_CHUNK;
 use crate::util::heap::PageResource;
 use crate::util::metadata::mark_bit::MarkState;
+#[cfg(feature = "set_unlog_bits_vm_space")]
+use crate::util::metadata::MetadataSpec;
 use crate::util::opaque_pointer::*;
 use crate::util::ObjectReference;
 use crate::vm::{ObjectModel, VMBinding};
@@ -224,6 +226,15 @@ impl<VM: VMBinding> VMSpace<VM> {
             start: start.align_down(BYTES_IN_PAGE),
             end: end.align_up(BYTES_IN_PAGE),
         });
+
+        #[cfg(feature = "set_unlog_bits_vm_space")]
+        if self.common.needs_log_bit {
+            // Bulk set unlog bits for all addresses in the VM space. This ensures that any
+            // modification to the bootimage is logged
+            if let MetadataSpec::OnSide(side) = *VM::VMObjectModel::GLOBAL_LOG_BIT_SPEC {
+                side.bset_metadata(start, size);
+            }
+        }
     }
 
     pub fn prepare(&mut self) {