1 files changed, 161 insertions, 0 deletions
diff --git a/gc/mmtk/src/lib.rs b/gc/mmtk/src/lib.rs
new file mode 100644
index 0000000000..52dc782051
--- /dev/null
+++ b/gc/mmtk/src/lib.rs
@@ -0,0 +1,161 @@
+// Warn about unsafe operations in functions that are already marked as unsafe.
+// This will become default in Rust 2024 edition.
+#![warn(unsafe_op_in_unsafe_fn)]
+
+extern crate libc;
+extern crate mmtk;
+#[macro_use]
+extern crate log;
+extern crate probe;
+
+use std::collections::HashSet;
+use std::panic::PanicHookInfo;
+use std::sync::Mutex;
+use std::thread::ThreadId;
+
+use abi::RubyUpcalls;
+use binding::RubyBinding;
+use binding::RubyBindingFast;
+use binding::RubyConfiguration;
+use mmtk::vm::slot::SimpleSlot;
+use mmtk::vm::slot::UnimplementedMemorySlice;
+use mmtk::vm::VMBinding;
+use mmtk::MMTK;
+use once_cell::sync::OnceCell;
+
+pub mod abi;
+pub mod active_plan;
+pub mod api;
+pub mod binding;
+pub mod collection;
+pub mod heap;
+pub mod object_model;
+pub mod pinning_registry;
+pub mod reference_glue;
+pub mod scanning;
+pub mod utils;
+pub mod weak_proc;
+
+#[derive(Default)]
+pub struct Ruby;
+
+/// Ruby slot type, i.e. a slot that holds a VALUE.
+/// Currently we use SimpleSlot.
+/// It doesn't matter, becaues we have not started using slot-enqueuing, yet.
+pub type RubySlot = SimpleSlot;
+
+/// Ruby memory slice, i.e. an array of VALUEs.
+/// It is used by array-copy barriers which is supposed to perform bettern than copying array
+/// elements one by one.  At this moment, we just leave it unimplemented.
+pub type RubyMemorySlice = UnimplementedMemorySlice<RubySlot>;
+
+impl VMBinding for Ruby {
+    type VMObjectModel = object_model::VMObjectModel;
+    type VMScanning = scanning::VMScanning;
+    type VMCollection = collection::VMCollection;
+    type VMActivePlan = active_plan::VMActivePlan;
+    type VMReferenceGlue = reference_glue::VMReferenceGlue;
+
+    type VMSlot = RubySlot;
+    type VMMemorySlice = RubyMemorySlice;
+}
+
+/// The callback for mutator thread panic handler (which calls rb_bug to output
+/// debugging information such as the Ruby backtrace and memory maps).
+/// This is set before BINDING is set because mmtk_init could panic.
+pub static MUTATOR_THREAD_PANIC_HANDLER: OnceCell<extern "C" fn()> = OnceCell::new();
+
+/// The singleton object for the Ruby binding itself.
+pub static BINDING: OnceCell<RubyBinding> = OnceCell::new();
+
+/// Some data needs to be accessed fast.
+/// We sacrifice safety for speed using unsynchronized global variables.
+pub static mut BINDING_FAST: RubyBindingFast = RubyBindingFast::new();
+
+/// Some data needs to be accessed fast.
+pub static CONFIGURATION: RubyConfiguration = RubyConfiguration::new();
+
+pub fn binding<'b>() -> &'b RubyBinding {
+    BINDING
+        .get()
+        .expect("Attempt to use the binding before it is initialization")
+}
+
+pub fn mmtk() -> &'static MMTK<Ruby> {
+    binding().mmtk
+}
+
+pub fn upcalls() -> &'static RubyUpcalls {
+    binding().upcalls()
+}
+
+pub static GC_THREADS: OnceCell<Mutex<HashSet<ThreadId>>> = OnceCell::new();
+
+pub(crate) fn register_gc_thread(thread_id: ThreadId) {
+    let mut gc_threads = GC_THREADS.get().unwrap().lock().unwrap();
+    gc_threads.insert(thread_id);
+}
+
+pub(crate) fn unregister_gc_thread(thread_id: ThreadId) {
+    let mut gc_threads = GC_THREADS.get().unwrap().lock().unwrap();
+    gc_threads.remove(&thread_id);
+}
+
+pub(crate) fn is_gc_thread(thread_id: ThreadId) -> bool {
+    let gc_threads = GC_THREADS.get().unwrap().lock().unwrap();
+    gc_threads.contains(&thread_id)
+}
+
+fn handle_gc_thread_panic(panic_info: &PanicHookInfo) {
+    eprintln!("ERROR: An MMTk GC thread panicked.  This is a bug.");
+    eprintln!("{panic_info}");
+
+    let bt = std::backtrace::Backtrace::capture();
+    match bt.status() {
+        std::backtrace::BacktraceStatus::Unsupported => {
+            eprintln!("Backtrace is unsupported.")
+        }
+        std::backtrace::BacktraceStatus::Disabled => {
+            eprintln!("Backtrace is disabled.");
+            eprintln!("run with `RUST_BACKTRACE=1` environment variable to display a backtrace");
+        }
+        std::backtrace::BacktraceStatus::Captured => {
+            eprintln!("{bt}");
+        }
+        s => {
+            eprintln!("Unknown backtrace status: {s:?}");
+        }
+    }
+}
+
+pub(crate) fn set_panic_hook() {
+    if GC_THREADS.set(Default::default()).is_err() {
+        return;
+    }
+
+    let old_hook = std::panic::take_hook();
+
+    std::panic::set_hook(Box::new(move |panic_info| {
+        if is_gc_thread(std::thread::current().id()) {
+            handle_gc_thread_panic(panic_info);
+
+            (crate::binding().upcalls().gc_thread_panic_handler)();
+        } else {
+            old_hook(panic_info);
+            (crate::MUTATOR_THREAD_PANIC_HANDLER
+                .get()
+                .expect("MUTATOR_THREAD_PANIC_HANDLER is not set"))();
+        }
+    }));
+}
+
+/// This kind of assertion is enabled if either building in debug mode or the
+/// "extra_assert" feature is enabled.
+#[macro_export]
+macro_rules! extra_assert {
+    ($($arg:tt)*) => {
+        if std::cfg!(any(debug_assertions, feature = "extra_assert")) {
+            std::assert!($($arg)*);
+        }
+    };
+}