[compiler] Perform MapRef's SupportsFastArray methods concurrently

We are safe to go through the native_contexts_list_ since we do it
through IsAnyInitialArrayPrototype which disallows the GC. Furthermore,
we read that list with an acquire load which guarantees that the fields
have been initialized.

Bug: v8:7790
Change-Id: I778d51f4ead44e472f842693a7e9ff577d6acfe3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2826541Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74086}

src/compiler/heap-refs.cc

@@ -2880,14 +2880,14 @@ bool MapRef::HasOnlyStablePrototypesWithFastElements(
 }
 
 bool MapRef::supports_fast_array_iteration() const {
-  if (data_->should_access_heap()) {
+  if (data_->should_access_heap() || FLAG_turbo_direct_heap_access) {
     return SupportsFastArrayIteration(broker()->isolate(), object());
   }
   return data()->AsMap()->supports_fast_array_iteration();
 }
 
 bool MapRef::supports_fast_array_resize() const {
-  if (data_->should_access_heap()) {
+  if (data_->should_access_heap() || FLAG_turbo_direct_heap_access) {
     return SupportsFastArrayResize(broker()->isolate(), object());
   }
   return data()->AsMap()->supports_fast_array_resize();

src/heap/heap.h

@@ -569,9 +569,12 @@ class Heap {
   V8_EXPORT_PRIVATE int NotifyContextDisposed(bool dependant_context);
 
   void set_native_contexts_list(Object object) {
-    native_contexts_list_ = object;
+    native_contexts_list_.store(object, std::memory_order_release);
+  }
+
+  Object native_contexts_list() const {
+    return native_contexts_list_.load(std::memory_order_acquire);
   }
-  Object native_contexts_list() const { return native_contexts_list_; }
 
   void set_allocation_sites_list(Object object) {
     allocation_sites_list_ = object;
@@ -2200,7 +2203,7 @@ class Heap {
 
   // Weak list heads, threaded through the objects.
   // List heads are initialized lazily and contain the undefined_value at start.
-  Object native_contexts_list_;
+  std::atomic<Object> native_contexts_list_;
   Object allocation_sites_list_;
   Object dirty_js_finalization_registries_list_;
   // Weak list tails.