Add Java-specific constants from MMTk (#258)

Java-specific constants in MMTk are no longer public in
mmtk/mmtk-core#1026. This PR duplicates the
constants that are used in the binding.

---------

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

Author: qinsoon

mmtk/Cargo.lock

@@ -32,7 +32,7 @@ memoffset = "0.9.0"
 # - 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 = "39d237189fdfa22873eeb529f3e97b7578d9b246" }
+mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "b06619982f3cee271e453a555f48b613f3eba2f6" }
 # Uncomment the following to build locally
 # mmtk = { path = "../repos/mmtk-core" }
 

mmtk/Cargo.toml

@@ -11,6 +11,17 @@ use std::fmt;
 use std::sync::atomic::AtomicUsize;
 use std::{mem, slice};
 
+// These are some Java specific constants that were in MMTk.
+// As we plan to remove them from MMTk, they are moved here.
+// We could further investigae if we really need them in the OpenJDK binding.
+
+pub const LOG_BYTES_IN_INT: u8 = 2;
+pub const BYTES_IN_INT: usize = 1 << LOG_BYTES_IN_INT;
+pub const LOG_BYTES_IN_LONG: u8 = 3;
+pub const BYTES_IN_LONG: usize = 1 << LOG_BYTES_IN_LONG;
+pub const LOG_BITS_IN_LONG: u8 = LOG_BITS_IN_BYTE + LOG_BYTES_IN_LONG;
+pub const BITS_IN_LONG: usize = 1 << LOG_BITS_IN_LONG;
+
 #[repr(i32)]
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 #[allow(dead_code)]

mmtk/src/abi.rs

@@ -3,12 +3,10 @@ use std::{
     sync::atomic::{AtomicBool, AtomicUsize, Ordering},
 };
 
+use super::abi::LOG_BYTES_IN_INT;
 use atomic::Atomic;
 use mmtk::{
-    util::{
-        constants::{LOG_BYTES_IN_INT, LOG_BYTES_IN_WORD},
-        Address, ObjectReference,
-    },
+    util::{constants::LOG_BYTES_IN_WORD, Address, ObjectReference},
     vm::edge_shape::{Edge, MemorySlice},
 };