Bug 1782095 part 2 - Remove JSContext::freeLists_. r=jonco

We needed this to support off-thread atom allocation, but we no longer do that
since Stencil.

Depends on D153143

Differential Revision: https://phabricator.services.mozilla.com/D153144

js/src/gc/Allocator.cpp

@@ -349,7 +349,8 @@ template <typename T, AllowGC allowGC>
 T* GCRuntime::tryNewTenuredThing(JSContext* cx, AllocKind kind,
                                  size_t thingSize) {
   // Bump allocate in the arena's current free-list span.
-  auto* t = reinterpret_cast<T*>(cx->freeLists().allocate(kind));
+  Zone* zone = cx->zone();
+  auto* t = reinterpret_cast<T*>(zone->arenas.freeLists().allocate(kind));
   if (MOZ_UNLIKELY(!t)) {
     // Get the next available free list and allocate out of it. This may
     // acquire a new arena, which will lock the chunk list. If there are no
@@ -490,7 +491,7 @@ void GCRuntime::startBackgroundAllocTaskIfIdle() {
 
 /* static */
 TenuredCell* GCRuntime::refillFreeList(JSContext* cx, AllocKind thingKind) {
-  MOZ_ASSERT(cx->freeLists().isEmpty(thingKind));
+  MOZ_ASSERT(cx->zone()->arenas.freeLists().isEmpty(thingKind));
   MOZ_ASSERT(!cx->isHelperThreadContext());
 
   // It should not be possible to allocate on the main thread while we are
@@ -498,7 +499,8 @@ TenuredCell* GCRuntime::refillFreeList(JSContext* cx, AllocKind thingKind) {
   MOZ_ASSERT(!JS::RuntimeHeapIsBusy(), "allocating while under GC");
 
   return cx->zone()->arenas.refillFreeListAndAllocate(
-      cx->freeLists(), thingKind, ShouldCheckThresholds::CheckThresholds);
+      cx->zone()->arenas.freeLists(), thingKind,
+      ShouldCheckThresholds::CheckThresholds);
 }
 
 /* static */

js/src/vm/JSContext-inl.h

@@ -309,7 +309,6 @@ inline void JSContext::setZone(js::Zone* zone) {
   allocsThisZoneSinceMinorGC_ = 0;
 
   zone_ = zone;
-  freeLists_ = zone ? &zone_->arenas.freeLists() : nullptr;
 }
 
 inline void JSContext::enterRealmOf(JSObject* target) {

js/src/vm/JSContext.cpp

@@ -952,7 +952,6 @@ JSContext::JSContext(JSRuntime* runtime, const JS::ContextOptions& options)
       kind_(ContextKind::Uninitialized),
       nurserySuppressions_(this),
       options_(this, options),
-      freeLists_(this, nullptr),
       freeUnusedMemory(false),
       measuringExecutionTime_(this, false),
       jitActivation(this, nullptr),

js/src/vm/JSContext.h

@@ -179,9 +179,6 @@ struct JS_PUBLIC_API JSContext : public JS::RootingContext,
 
   js::ContextData<JS::ContextOptions> options_;
 
-  // Free lists for allocating in the current zone.
-  js::ContextData<js::gc::FreeLists*> freeLists_;
-
   // This is reset each time we switch zone, then added to the variable in the
   // zone when we switch away from it.  This would be a js::ThreadData but we
   // need to take its address.
@@ -250,11 +247,6 @@ struct JS_PUBLIC_API JSContext : public JS::RootingContext,
     return kind_ == js::ContextKind::HelperThread;
   }
 
-  js::gc::FreeLists& freeLists() {
-    MOZ_ASSERT(freeLists_);
-    return *freeLists_;
-  }
-
   template <typename T>
   bool isInsideCurrentZone(T thing) const {
     return thing->zoneFromAnyThread() == zone_;