Update FixedArray atomic accessor styles

Upcoming CLs will need atomic accessors for non-smi values. This CL
adds the full set of relaxed and acquire/release indexed accessors,
and I also take the opportunity to update the old
`synchronized_set(i, v)` style to `set(i, v, ReleaseStoreTag)`.

Bug: v8:7790
Change-Id: Ic4fa4ec52319ec943415f0e9ae515a00b04cbbc3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2717305
Auto-Submit: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72995}

src/objects/contexts-inl.h

@@ -31,11 +31,11 @@ OBJECT_CONSTRUCTORS_IMPL(ScriptContextTable, FixedArray)
 CAST_ACCESSOR(ScriptContextTable)
 
 int ScriptContextTable::synchronized_used() const {
-  return Smi::ToInt(synchronized_get(kUsedSlotIndex));
+  return Smi::ToInt(get(kUsedSlotIndex, kAcquireLoad));
 }
 
 void ScriptContextTable::synchronized_set_used(int used) {
-  synchronized_set(kUsedSlotIndex, Smi::FromInt(used));
+  set(kUsedSlotIndex, Smi::FromInt(used), kReleaseStore);
 }
 
 // static

src/objects/fixed-array-inl.h

@@ -123,21 +123,50 @@ void FixedArray::NoWriteBarrierSet(FixedArray array, int index, Object value) {
   RELAXED_WRITE_FIELD(array, offset, value);
 }
 
-Object FixedArray::synchronized_get(int index) const {
+Object FixedArray::get(int index, RelaxedLoadTag) const {
   IsolateRoot isolate = GetIsolateForPtrCompr(*this);
-  return synchronized_get(isolate, index);
+  return get(isolate, index);
 }
 
-Object FixedArray::synchronized_get(IsolateRoot isolate, int index) const {
+Object FixedArray::get(IsolateRoot isolate, int index, RelaxedLoadTag) const {
   DCHECK_LT(static_cast<unsigned>(index), static_cast<unsigned>(length()));
-  return ACQUIRE_READ_FIELD(*this, OffsetOfElementAt(index));
+  return RELAXED_READ_FIELD(*this, OffsetOfElementAt(index));
 }
 
-void FixedArray::synchronized_set(int index, Smi value) {
+void FixedArray::set(int index, Object value, RelaxedStoreTag,
+                     WriteBarrierMode mode) {
   DCHECK_NE(map(), GetReadOnlyRoots().fixed_cow_array_map());
   DCHECK_LT(static_cast<unsigned>(index), static_cast<unsigned>(length()));
+  RELAXED_WRITE_FIELD(*this, OffsetOfElementAt(index), value);
+  CONDITIONAL_WRITE_BARRIER(*this, OffsetOfElementAt(index), value, mode);
+}
+
+void FixedArray::set(int index, Smi value, RelaxedStoreTag tag) {
   DCHECK(Object(value).IsSmi());
+  set(index, value, tag, SKIP_WRITE_BARRIER);
+}
+
+Object FixedArray::get(int index, AcquireLoadTag) const {
+  IsolateRoot isolate = GetIsolateForPtrCompr(*this);
+  return get(isolate, index);
+}
+
+Object FixedArray::get(IsolateRoot isolate, int index, AcquireLoadTag) const {
+  DCHECK_LT(static_cast<unsigned>(index), static_cast<unsigned>(length()));
+  return ACQUIRE_READ_FIELD(*this, OffsetOfElementAt(index));
+}
+
+void FixedArray::set(int index, Object value, ReleaseStoreTag,
+                     WriteBarrierMode mode) {
+  DCHECK_NE(map(), GetReadOnlyRoots().fixed_cow_array_map());
+  DCHECK_LT(static_cast<unsigned>(index), static_cast<unsigned>(length()));
   RELEASE_WRITE_FIELD(*this, OffsetOfElementAt(index), value);
+  CONDITIONAL_WRITE_BARRIER(*this, OffsetOfElementAt(index), value, mode);
+}
+
+void FixedArray::set(int index, Smi value, ReleaseStoreTag tag) {
+  DCHECK(Object(value).IsSmi());
+  set(index, value, tag, SKIP_WRITE_BARRIER);
 }
 
 void FixedArray::set_undefined(int index) {

src/objects/fixed-array.h

@@ -111,12 +111,19 @@ class FixedArray
       Isolate* isolate, Handle<FixedArray> array, int index,
       Handle<Object> value);
 
-  // Synchronized setters and getters.
-  inline Object synchronized_get(int index) const;
-  inline Object synchronized_get(IsolateRoot isolate, int index) const;
-  // Currently only Smis are written with release semantics, hence we can avoid
-  // a write barrier.
-  inline void synchronized_set(int index, Smi value);
+  // Relaxed accessors.
+  inline Object get(int index, RelaxedLoadTag) const;
+  inline Object get(IsolateRoot isolate, int index, RelaxedLoadTag) const;
+  inline void set(int index, Object value, RelaxedStoreTag,
+                  WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
+  inline void set(int index, Smi value, RelaxedStoreTag);
+
+  // Acquire/release accessors.
+  inline Object get(int index, AcquireLoadTag) const;
+  inline Object get(IsolateRoot isolate, int index, AcquireLoadTag) const;
+  inline void set(int index, Object value, ReleaseStoreTag,
+                  WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
+  inline void set(int index, Smi value, ReleaseStoreTag);
 
   // Setter that uses write barrier.
   inline void set(int index, Object value);