WIP

Author: qinsoon

mmtk/Cargo.toml

@@ -20,15 +20,16 @@ openjdk_version = "67d5d2b16aacb2ea948552fab2323ebd0abbe924"
 [dependencies]
 libc = "0.2"
 lazy_static = "1.1"
+log = {version = "0.4", features = ["max_level_trace", "release_max_level_off"] }
 # Be very careful to commit any changes to the following mmtk dependency, as our CI scripts (including mmtk-core CI)
 # rely on matching these lines to modify them: e.g. comment out the git dependency and use the local path.
 # These changes are safe:
 # - change branch
 # - change repo name
 # But other changes including adding/removing whitespaces in commented lines may break the CI.
-mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "dbd152b29ff54c3f028318e73ac182d681deda9a" }
+# mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "dbd152b29ff54c3f028318e73ac182d681deda9a" }
 # Uncomment the following to build locally
-# mmtk = { path = "../repos/mmtk-core" }
+mmtk = { path = "/home/yilin/Code/mmtk-core" }
 
 [features]
 default = []

mmtk/src/abi.rs

@@ -131,7 +131,7 @@ pub struct InstanceKlass {
     // #endif
     pub idnum_allocated_count: u16,
     pub init_state: u8,
-    pub reference_type: u8,
+    pub reference_type: ReferenceType,
     pub this_class_index: u16,
     // #if INCLUDE_JVMTI
     pub jvmti_cached_class_field_map: OpaquePointer, // JvmtiCachedClassFieldMap*
@@ -147,6 +147,18 @@ pub struct InstanceKlass {
     pub fields: OpaquePointer,                 // Array<u2>*
 }
 
+#[repr(u8)]
+#[derive(Copy, Clone, Debug)]
+#[allow(dead_code)]
+pub enum ReferenceType {
+    None,      // Regular class
+    Other,     // Subclass of java/lang/ref/Reference, but not subclass of one of the classes below
+    Soft,      // Subclass of java/lang/ref/SoftReference
+    Weak,      // Subclass of java/lang/ref/WeakReference
+    Final,     // Subclass of java/lang/ref/FinalReference
+    Phantom    // Subclass of java/lang/ref/PhantomReference
+}
+
 impl InstanceKlass {
     const HEADER_SIZE: usize = mem::size_of::<Self>() / BYTES_IN_WORD;
     const VTABLE_START_OFFSET: usize = Self::HEADER_SIZE * BYTES_IN_WORD;

mmtk/src/lib.rs

@@ -9,6 +9,8 @@ extern crate libc;
 extern crate mmtk;
 #[macro_use]
 extern crate lazy_static;
+#[macro_use]
+extern crate log;
 
 use std::ptr::null_mut;
 
@@ -83,7 +85,7 @@ pub struct OpenJDK_Upcalls {
     pub number_of_mutators: extern "C" fn() -> usize,
     pub schedule_finalizer: extern "C" fn(),
     pub prepare_for_roots_re_scanning: extern "C" fn(),
-    pub object_alignment: extern "C" fn() -> i32,
+    pub enqueue_reference: extern "C" fn(object: ObjectReference),
 }
 
 pub static mut UPCALLS: *const OpenJDK_Upcalls = null_mut();

mmtk/src/object_scanning.rs

@@ -111,11 +111,24 @@ impl OopIterate for TypeArrayKlass {
 impl OopIterate for InstanceRefKlass {
     #[inline]
     fn oop_iterate(&self, oop: Oop, closure: &mut impl TransitiveClosure) {
+        use crate::api::{add_weak_candidate, add_soft_candidate, add_phantom_candidate};
+        use crate::abi::*;
         self.instance_klass.oop_iterate(oop, closure);
-        let referent_addr = Self::referent_address(oop);
-        closure.process_edge(referent_addr);
-        let discovered_addr = Self::discovered_address(oop);
-        closure.process_edge(discovered_addr);
+
+        let reference = ObjectReference::from(oop);
+        let referent = unsafe { Self::referent_address(oop).load::<ObjectReference>() };
+        match self.instance_klass.reference_type {
+            ReferenceType::None => panic!("oop_iterate on InstanceRefKlass with reference_type as None"),
+            ReferenceType::Weak => add_weak_candidate(reference, referent),
+            ReferenceType::Soft => add_soft_candidate(reference, referent),
+            ReferenceType::Phantom => add_phantom_candidate(reference, referent),
+            _ => {
+                let referent_addr = Self::referent_address(oop);
+                closure.process_edge(referent_addr);
+                let discovered_addr = Self::discovered_address(oop);
+                closure.process_edge(discovered_addr);
+            }
+        }
     }
 }
 

mmtk/src/reference_glue.rs

@@ -1,23 +1,25 @@
 use crate::OpenJDK;
+use crate::abi::{InstanceRefKlass, Oop};
 use mmtk::util::opaque_pointer::VMWorkerThread;
 use mmtk::util::ObjectReference;
 use mmtk::vm::ReferenceGlue;
-use mmtk::TraceLocal;
+use mmtk::scheduler::ProcessEdgesWork;
+use crate::UPCALLS;
 
 pub struct VMReferenceGlue {}
 
 impl ReferenceGlue<OpenJDK> for VMReferenceGlue {
-    fn set_referent(_reff: ObjectReference, _referent: ObjectReference) {
-        unimplemented!()
+    fn set_referent(reff: ObjectReference, referent: ObjectReference) {
+        let oop = Oop::from(reff);
+        unsafe { InstanceRefKlass::referent_address(oop).store(referent) };
     }
-    fn get_referent(_object: ObjectReference) -> ObjectReference {
-        unimplemented!()
+    fn get_referent(object: ObjectReference) -> ObjectReference {
+        let oop = Oop::from(object);
+        unsafe { InstanceRefKlass::referent_address(oop).load::<ObjectReference>() }
     }
-    fn process_reference<T: TraceLocal>(
-        _trace: &mut T,
-        _reference: ObjectReference,
-        _tls: VMWorkerThread,
-    ) -> ObjectReference {
-        unimplemented!()
+    fn enqueue_reference(object: ObjectReference) {
+        unsafe {
+            ((*UPCALLS).enqueue_reference)(object);
+        }
     }
 }

openjdk/mmtk.h

@@ -144,6 +144,7 @@ typedef struct {
     size_t (*number_of_mutators)();
     void (*schedule_finalizer)();
     void (*prepare_for_roots_re_scanning)();
+    void (*enqueue_reference)(void* object);
 } OpenJDK_Upcalls;
 
 extern void openjdk_gc_init(OpenJDK_Upcalls *calls, size_t heap_size);

openjdk/mmtkUpcalls.cpp

@@ -319,6 +319,10 @@ static void mmtk_prepare_for_roots_re_scanning() {
 #endif
 }
 
+static void mmtk_enqueue_reference(void* object) {
+  printf("enqueue object: %p\n", object);
+}
+
 OpenJDK_Upcalls mmtk_upcalls = {
   mmtk_stop_all_mutators,
   mmtk_resume_mutators,
@@ -360,4 +364,5 @@ OpenJDK_Upcalls mmtk_upcalls = {
   mmtk_number_of_mutators,
   mmtk_schedule_finalizer,
   mmtk_prepare_for_roots_re_scanning,
+  mmtk_enqueue_reference,
 };