Reland "[heap] Use std::unique_ptr for space_ array"

This is a reland of commit 6d342fa5

Original change's description:
> [heap] Use std::unique_ptr for space_ array
>
> Document ownership with using std::unique_ptr<Space> for the space_
> array.
>
> Bug: v8:13267
> Change-Id: I12861d97cd52d2a8cf9ceb43a2f90008be87b2a3
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3890913
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#83187}

Bug: v8:13267
Change-Id: Idb25a656c4ba571d23132aa5e07cb13957c90f0b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3899121Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83259}

src/heap/heap-inl.h

@@ -172,10 +172,10 @@ void Heap::SetPendingOptimizeForTestBytecode(Object hash_table) {
 
 PagedSpace* Heap::paged_space(int idx) {
   DCHECK(idx == OLD_SPACE || idx == CODE_SPACE || idx == MAP_SPACE);
-  return static_cast<PagedSpace*>(space_[idx]);
+  return static_cast<PagedSpace*>(space_[idx].get());
 }
 
-Space* Heap::space(int idx) { return space_[idx]; }
+Space* Heap::space(int idx) { return space_[idx].get(); }
 
 Address* Heap::NewSpaceAllocationTopAddress() {
   return new_space_ ? new_space_->allocation_top_address() : nullptr;

src/heap/heap.cc

@@ -5378,10 +5378,6 @@ void Heap::SetUp(LocalHeap* main_thread_local_heap) {
     concurrent_marking_.reset(new ConcurrentMarking(this, nullptr));
   }
 
-  for (int i = FIRST_SPACE; i <= LAST_SPACE; i++) {
-    space_[i] = nullptr;
-  }
-
   // Set up layout tracing callback.
   if (V8_UNLIKELY(v8_flags.trace_gc_heap_layout)) {
     v8::GCType gc_type = kGCTypeMarkSweepCompact;
@@ -5400,7 +5396,7 @@ void Heap::SetUpFromReadOnlyHeap(ReadOnlyHeap* ro_heap) {
   DCHECK_NOT_NULL(ro_heap);
   DCHECK_IMPLIES(read_only_space_ != nullptr,
                  read_only_space_ == ro_heap->read_only_space());
-  space_[RO_SPACE] = nullptr;
+  DCHECK_NULL(space_[RO_SPACE].get());
   read_only_space_ = ro_heap->read_only_space();
   heap_allocator_.SetReadOnlySpace(read_only_space_);
 }
@@ -5443,30 +5439,49 @@ void Heap::SetUpSpaces(LinearAllocationArea& new_allocation_info,
   const bool has_young_gen = !v8_flags.single_generation && !IsShared();
   if (has_young_gen) {
     if (v8_flags.minor_mc) {
-      space_[NEW_SPACE] = new_space_ =
-          new PagedNewSpace(this, initial_semispace_size_, max_semi_space_size_,
-                            new_allocation_info);
+      space_[NEW_SPACE] = std::make_unique<PagedNewSpace>(
+          this, initial_semispace_size_, max_semi_space_size_,
+          new_allocation_info);
     } else {
-      space_[NEW_SPACE] = new_space_ =
-          new SemiSpaceNewSpace(this, initial_semispace_size_,
-                                max_semi_space_size_, new_allocation_info);
+      space_[NEW_SPACE] = std::make_unique<SemiSpaceNewSpace>(
+          this, initial_semispace_size_, max_semi_space_size_,
+          new_allocation_info);
     }
-    space_[NEW_LO_SPACE] = new_lo_space_ =
-        new NewLargeObjectSpace(this, NewSpaceCapacity());
+    new_space_ = static_cast<NewSpace*>(space_[NEW_SPACE].get());
+
+    space_[NEW_LO_SPACE] =
+        std::make_unique<NewLargeObjectSpace>(this, NewSpaceCapacity());
+    new_lo_space_ =
+        static_cast<NewLargeObjectSpace*>(space_[NEW_LO_SPACE].get());
   }
-  space_[OLD_SPACE] = old_space_ = new OldSpace(this, old_allocation_info);
-  space_[CODE_SPACE] = code_space_ = new CodeSpace(this);
+
+  space_[OLD_SPACE] = std::make_unique<OldSpace>(this, old_allocation_info);
+  old_space_ = static_cast<OldSpace*>(space_[OLD_SPACE].get());
+
+  space_[CODE_SPACE] = std::make_unique<CodeSpace>(this);
+  code_space_ = static_cast<CodeSpace*>(space_[CODE_SPACE].get());
+
   if (v8_flags.use_map_space) {
-    space_[MAP_SPACE] = map_space_ = new MapSpace(this);
+    space_[MAP_SPACE] = std::make_unique<MapSpace>(this);
+    map_space_ = static_cast<MapSpace*>(space_[MAP_SPACE].get());
   }
+
   if (v8_flags.shared_space && isolate()->is_shared_space_isolate()) {
-    space_[SHARED_SPACE] = shared_space_ = new SharedSpace(this);
+    space_[SHARED_SPACE] = std::make_unique<SharedSpace>(this);
+    shared_space_ = static_cast<SharedSpace*>(space_[SHARED_SPACE].get());
   }
-  space_[LO_SPACE] = lo_space_ = new OldLargeObjectSpace(this);
-  space_[CODE_LO_SPACE] = code_lo_space_ = new CodeLargeObjectSpace(this);
+
+  space_[LO_SPACE] = std::make_unique<OldLargeObjectSpace>(this);
+  lo_space_ = static_cast<OldLargeObjectSpace*>(space_[LO_SPACE].get());
+
+  space_[CODE_LO_SPACE] = std::make_unique<CodeLargeObjectSpace>(this);
+  code_lo_space_ =
+      static_cast<CodeLargeObjectSpace*>(space_[CODE_LO_SPACE].get());
+
   if (v8_flags.shared_space && isolate()->is_shared_space_isolate()) {
-    space_[SHARED_LO_SPACE] = shared_lo_space_ =
-        new SharedLargeObjectSpace(this);
+    space_[SHARED_LO_SPACE] = std::make_unique<SharedLargeObjectSpace>(this);
+    shared_lo_space_ =
+        static_cast<SharedLargeObjectSpace*>(space_[SHARED_LO_SPACE].get());
   }
 
   for (int i = 0; i < static_cast<int>(v8::Isolate::kUseCounterFeatureCount);
@@ -5873,8 +5888,7 @@ void Heap::TearDown() {
         "Deletion of CODE_SPACE and CODE_LO_SPACE requires write access to "
         "Code page headers");
     for (int i = FIRST_MUTABLE_SPACE; i <= LAST_MUTABLE_SPACE; i++) {
-      delete space_[i];
-      space_[i] = nullptr;
+      space_[i].reset();
     }
   }
 

src/heap/heap.h

@@ -2210,7 +2210,7 @@ class Heap {
   std::unique_ptr<ConcurrentAllocator> shared_map_allocator_;
 
   // Map from the space id to the space.
-  Space* space_[LAST_SPACE + 1];
+  std::unique_ptr<Space> space_[LAST_SPACE + 1];
 
   LocalHeap* main_thread_local_heap_ = nullptr;