Update to MMTk core PR #949 (#36)

Updates to mmtk/mmtk-core#949

---------

Co-authored-by: mmtkgc-bot <[email protected]>

Author: qinsoon

mmtk/Cargo.lock

@@ -38,6 +38,7 @@ features = ["is_mmtk_object", "object_pinning"]
 # Uncomment one of the following lines to choose where to find mmtk-core.
 git = "https://github.com/mmtk/mmtk-core.git"  # Use mmtk-core from the official repository.
 #path = "../../mmtk-core"  # Use mmtk-core from a local repository.
+rev = "57af17fbfd94ff0df2cd3b1e504abe299ce4f0ab"
 
 [features]
 default = []

mmtk/Cargo.toml

@@ -7,15 +7,10 @@ use crate::Ruby;
 use mmtk::util::opaque_pointer::*;
 use mmtk::vm::ActivePlan;
 use mmtk::Mutator;
-use mmtk::Plan;
 
 pub struct VMActivePlan {}
 
 impl ActivePlan<Ruby> for VMActivePlan {
-    fn global() -> &'static dyn Plan<VM = Ruby> {
-        mmtk().get_plan()
-    }
-
     fn number_of_mutators() -> usize {
         (upcalls().number_of_mutators)()
     }

mmtk/src/active_plan.rs

@@ -208,11 +208,6 @@ pub extern "C" fn mmtk_is_mmtk_object(addr: Address) -> bool {
     memory_manager::is_mmtk_object(addr)
 }
 
-#[no_mangle]
-pub extern "C" fn mmtk_modify_check(object: ObjectReference) {
-    memory_manager::modify_check(mmtk(), object)
-}
-
 #[no_mangle]
 pub extern "C" fn mmtk_handle_user_collection_request(tls: VMMutatorThread) {
     memory_manager::handle_user_collection_request::<Ruby>(mmtk(), tls);