Auto merge of #18952 - jdm:no-leak-on-shutdown, r=nox

Do not trace Rust values when thread is shutting down.

This addresses a paint point when using debug-mozjs builds. jonco says that it is considered a leak when objects stored in side tables in a SpiderMonkey embedding are traced right before shutting down. This PR adds a per-thread flag that controls whether to run the Rust-side trace hooks, which is automatically toggled before the final GC occurs when destroying a JS runtime.

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #18948 and fix #18947.
- [x] These changes do not require tests because we don't use debug-mozjs on CI

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components/script/dom/bindings/refcounted.rs

@@ -35,7 +35,6 @@ use std::collections::hash_map::Entry::{Occupied, Vacant};
 use std::collections::hash_map::HashMap;
 use std::hash::Hash;
 use std::marker::PhantomData;
-use std::os;
 use std::rc::Rc;
 use std::sync::{Arc, Weak};
 use task::TaskOnce;
@@ -267,8 +266,7 @@ fn remove_nulls<K: Eq + Hash + Clone, V> (table: &mut HashMap<K, Weak<V>>) {
 
 /// A JSTraceDataOp for tracing reflectors held in LIVE_REFERENCES
 #[allow(unrooted_must_root)]
-pub unsafe extern "C" fn trace_refcounted_objects(tracer: *mut JSTracer,
-                                                  _data: *mut os::raw::c_void) {
+pub unsafe fn trace_refcounted_objects(tracer: *mut JSTracer) {
     info!("tracing live refcounted references");
     LIVE_REFERENCES.with(|ref r| {
         let r = r.borrow();

components/script/dom/dedicatedworkerglobalscope.rs

@@ -28,11 +28,10 @@ use ipc_channel::router::ROUTER;
 use js::jsapi::{HandleValue, JS_SetInterruptCallback};
 use js::jsapi::{JSAutoCompartment, JSContext, NullHandleValue};
 use js::jsval::UndefinedValue;
-use js::rust::Runtime;
 use msg::constellation_msg::TopLevelBrowsingContextId;
 use net_traits::{IpcSend, load_whole_resource};
 use net_traits::request::{CredentialsMode, Destination, RequestInit, Type as RequestType};
-use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, new_rt_and_cx};
+use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, new_rt_and_cx, Runtime};
 use script_runtime::ScriptThreadEventCategory::WorkerEvent;
 use script_traits::{TimerEvent, TimerSource, WorkerGlobalScopeInit, WorkerScriptLoadOrigin};
 use servo_rand::random;

components/script/dom/serviceworkerglobalscope.rs

@@ -22,10 +22,9 @@ use ipc_channel::ipc::{self, IpcSender, IpcReceiver};
 use ipc_channel::router::ROUTER;
 use js::jsapi::{JS_SetInterruptCallback, JSAutoCompartment, JSContext};
 use js::jsval::UndefinedValue;
-use js::rust::Runtime;
 use net_traits::{load_whole_resource, IpcSend, CustomResponseMediator};
 use net_traits::request::{CredentialsMode, Destination, RequestInit, Type as RequestType};
-use script_runtime::{CommonScriptMsg, ScriptChan, new_rt_and_cx};
+use script_runtime::{CommonScriptMsg, ScriptChan, new_rt_and_cx, Runtime};
 use script_traits::{TimerEvent, WorkerGlobalScopeInit, ScopeThings, ServiceWorkerMsg, WorkerScriptLoadOrigin};
 use servo_config::prefs::PREFS;
 use servo_rand::random;

components/script/dom/window.rs

@@ -57,7 +57,6 @@ use ipc_channel::router::ROUTER;
 use js::jsapi::{HandleObject, HandleValue, JSAutoCompartment, JSContext};
 use js::jsapi::{JS_GC, JS_GetRuntime};
 use js::jsval::UndefinedValue;
-use js::rust::Runtime;
 use layout_image::fetch_image_for_layout;
 use microtask::MicrotaskQueue;
 use msg::constellation_msg::{FrameType, PipelineId};
@@ -75,7 +74,7 @@ use script_layout_interface::reporter::CSSErrorReporter;
 use script_layout_interface::rpc::{ContentBoxResponse, ContentBoxesResponse, LayoutRPC};
 use script_layout_interface::rpc::{MarginStyleResponse, NodeScrollRootIdResponse};
 use script_layout_interface::rpc::{ResolvedStyleResponse, TextIndexResponse};
-use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, ScriptThreadEventCategory};
+use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, ScriptThreadEventCategory, Runtime};
 use script_thread::{ImageCacheMsg, MainThreadScriptChan, MainThreadScriptMsg};
 use script_thread::{ScriptThread, SendableMainThreadScriptChan};
 use script_traits::{ConstellationControlMsg, DocumentState, LoadData, MozBrowserEvent};

components/script/dom/workerglobalscope.rs

@@ -29,10 +29,9 @@ use ipc_channel::ipc::IpcSender;
 use js::jsapi::{HandleValue, JSAutoCompartment, JSContext, JSRuntime};
 use js::jsval::UndefinedValue;
 use js::panic::maybe_resume_unwind;
-use js::rust::Runtime;
 use net_traits::{IpcSend, load_whole_resource};
 use net_traits::request::{CredentialsMode, Destination, RequestInit as NetRequestInit, Type as RequestType};
-use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, get_reports};
+use script_runtime::{CommonScriptMsg, ScriptChan, ScriptPort, get_reports, Runtime};
 use script_traits::{TimerEvent, TimerEventId};
 use script_traits::WorkerGlobalScopeInit;
 use servo_url::{MutableOrigin, ServoUrl};

components/script/dom/worklet.rs

@@ -37,7 +37,6 @@ use js::jsapi::JSGCParamKey;
 use js::jsapi::JSTracer;
 use js::jsapi::JS_GC;
 use js::jsapi::JS_GetGCParameter;
-use js::rust::Runtime;
 use msg::constellation_msg::PipelineId;
 use net_traits::IpcSend;
 use net_traits::load_whole_resource;
@@ -46,6 +45,7 @@ use net_traits::request::RequestInit;
 use net_traits::request::RequestMode;
 use net_traits::request::Type as RequestType;
 use script_runtime::CommonScriptMsg;
+use script_runtime::Runtime;
 use script_runtime::ScriptThreadEventCategory;
 use script_runtime::new_rt_and_cx;
 use script_thread::{MainThreadScriptMsg, ScriptThread};