From d91b2034b7f5f8f138486019334d28feb722b1f5 Mon Sep 17 00:00:00 2001
From: Kunshan Wang <wks1986@gmail.com>
Date: Wed, 3 Apr 2024 07:47:19 +0800
Subject: [PATCH] Fix warnings with the stable Rust toolchain (#1099)

As getting a ref `&` of `static mut` variables will become a compilation
error in the Rust 2024 Edition, we use `unsafe { &*addr_of!(VM_LAYOUT)
}` to work around it. See: https://github.com/mmtk/mmtk-core/issues/1098

Changed the `static mut` in mock_test_doc_avoid_resolving_allocator.rs
to an ordinary local variable.

Initialize the thread-local variable `WORKER_ORDINAL` with a `const`
block. It avoids lazy initialization. We also bumped the `rust-version`
field in Cargo.toml to 1.71.1 because the semantics of the `const` block
in the `thread_local!` macro was undocumented in 1.70.0.
---
 Cargo.toml                                               | 2 +-
 rust-toolchain                                           | 2 +-
 src/policy/lockfreeimmortalspace.rs                      | 4 +++-
 src/scheduler/worker.rs                                  | 2 +-
 src/util/heap/layout/vm_layout.rs                        | 3 ++-
 .../mock_test_doc_avoid_resolving_allocator.rs           | 9 +++------
 6 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index e1f108df3f..0fc472534d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,7 @@ repository = "https://github.com/mmtk/mmtk-core"
 readme = "README.md"
 categories = ["memory-management"]
 keywords = ["gc", "garbage", "collection", "garbage-collection", "allocation"]
-rust-version = "1.70.0"
+rust-version = "1.71.1"
 build = "build.rs"
 
 [lib]
diff --git a/rust-toolchain b/rust-toolchain
index 68bc7ff2a8..79e15fd493 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-1.71.1
+1.77.0
diff --git a/src/policy/lockfreeimmortalspace.rs b/src/policy/lockfreeimmortalspace.rs
index e78f95e30a..9a077533ec 100644
--- a/src/policy/lockfreeimmortalspace.rs
+++ b/src/policy/lockfreeimmortalspace.rs
@@ -198,7 +198,9 @@ impl<VM: VMBinding> LockFreeImmortalSpace<VM> {
         // Create a VM request of fixed size
         let vmrequest = VMRequest::fixed_size(aligned_total_bytes);
         // Reserve the space
-        let VMRequest::Extent{ extent, top } = vmrequest else { unreachable!() };
+        let VMRequest::Extent { extent, top } = vmrequest else {
+            unreachable!()
+        };
         let start = args.heap.reserve(extent, top);
 
         let space = Self {
diff --git a/src/scheduler/worker.rs b/src/scheduler/worker.rs
index 1d850a7c1f..504b2f6b48 100644
--- a/src/scheduler/worker.rs
+++ b/src/scheduler/worker.rs
@@ -19,7 +19,7 @@ pub type ThreadId = usize;
 
 thread_local! {
     /// Current worker's ordinal
-    static WORKER_ORDINAL: Atomic<ThreadId> = Atomic::new(ThreadId::MAX);
+    static WORKER_ORDINAL: Atomic<ThreadId> = const { Atomic::new(ThreadId::MAX) };
 }
 
 /// Get current worker ordinal. Return `None` if the current thread is not a worker.
diff --git a/src/util/heap/layout/vm_layout.rs b/src/util/heap/layout/vm_layout.rs
index 598dbd8376..720237e6fb 100644
--- a/src/util/heap/layout/vm_layout.rs
+++ b/src/util/heap/layout/vm_layout.rs
@@ -1,5 +1,6 @@
 //! The module defines virutal memory layout parameters.
 
+use std::ptr::addr_of;
 use std::sync::atomic::AtomicBool;
 
 use atomic::Ordering;
@@ -192,5 +193,5 @@ pub fn vm_layout() -> &'static VMLayout {
     if cfg!(debug_assertions) {
         VM_LAYOUT_FETCHED.store(true, Ordering::SeqCst);
     }
-    unsafe { &VM_LAYOUT }
+    unsafe { &*addr_of!(VM_LAYOUT) }
 }
diff --git a/src/vm/tests/mock_tests/mock_test_doc_avoid_resolving_allocator.rs b/src/vm/tests/mock_tests/mock_test_doc_avoid_resolving_allocator.rs
index b7c50ddee0..3fb9d74140 100644
--- a/src/vm/tests/mock_tests/mock_test_doc_avoid_resolving_allocator.rs
+++ b/src/vm/tests/mock_tests/mock_test_doc_avoid_resolving_allocator.rs
@@ -18,7 +18,6 @@ pub fn acquire_typed_allocator() {
         || {
             let fixture = MMTKFixture::create();
             let tls_opaque_pointer = VMMutatorThread(VMThread(OpaquePointer::UNINITIALIZED));
-            static mut DEFAULT_ALLOCATOR_OFFSET: usize = 0;
 
             // ANCHOR: avoid_resolving_allocator
             // At boot time
@@ -26,17 +25,15 @@ pub fn acquire_typed_allocator() {
                 fixture.get_mmtk(),
                 AllocationSemantics::Default,
             );
-            unsafe {
-                DEFAULT_ALLOCATOR_OFFSET =
-                    crate::plan::Mutator::<MockVM>::get_allocator_base_offset(selector);
-            }
+            let default_allocator_offset =
+                crate::plan::Mutator::<MockVM>::get_allocator_base_offset(selector);
             let mutator = memory_manager::bind_mutator(fixture.get_mmtk(), tls_opaque_pointer);
 
             // At run time: allocate with the default semantics without resolving allocator
             let default_allocator: &mut BumpAllocator<MockVM> = {
                 let mutator_addr = Address::from_ref(&*mutator);
                 unsafe {
-                    (mutator_addr + DEFAULT_ALLOCATOR_OFFSET).as_mut_ref::<BumpAllocator<MockVM>>()
+                    (mutator_addr + default_allocator_offset).as_mut_ref::<BumpAllocator<MockVM>>()
                 }
             };
             let addr = default_allocator.alloc(8, 8, 0);