Reland "[heap] Remove FreeList when sealing RO_SPACE"

This is a reland of afd9493a

LSAN_IGNORE_OBJECTs for FreeListCategories are now removed.

Original change's description:
> [heap] Remove FreeList when sealing RO_SPACE
>
> This releases the FreeListCategories for each MemoryChunk when sealing
> the ReadOnlySpace and deletes the FreeList.
>
> Additionally this also calls
> ReleaseAllocatedMemoryNeededForWritableChunk for each MemoryChunk when
> sealing when pointer compression is enabled even if no memory is to be
> shared.
>
> Bug: v8:10454
> Change-Id: I45aec59f6d4fddedeb713e13095f58974cda279e
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2184292
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Commit-Queue: Dan Elphick <delphick@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#67598}

Bug: v8:10454
Change-Id: I08fcd122437c65c01af526fa8316d5c9e3ebeb3b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2184297
Commit-Queue: Dan Elphick <delphick@chromium.org>
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Auto-Submit: Dan Elphick <delphick@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67613}

src/heap/memory-chunk.h

@@ -354,6 +354,10 @@ class MemoryChunk : public BasicMemoryChunk {
     return &possibly_empty_buckets_;
   }
 
+  // Release memory allocated by the chunk, except that which is needed by
+  // read-only space chunks.
+  void ReleaseAllocatedMemoryNeededForWritableChunk();
+
  protected:
   static MemoryChunk* Initialize(Heap* heap, Address base, size_t size,
                                  Address area_start, Address area_end,
@@ -363,9 +367,6 @@ class MemoryChunk : public BasicMemoryChunk {
   // Release all memory allocated by the chunk. Should be called when memory
   // chunk is about to be freed.
   void ReleaseAllAllocatedMemory();
-  // Release memory allocated by the chunk, except that which is needed by
-  // read-only space chunks.
-  void ReleaseAllocatedMemoryNeededForWritableChunk();
 
   // Sets the requested page permissions only if the write unprotect counter
   // has reached 0.

src/heap/read-only-spaces.cc

@@ -71,13 +71,8 @@ void ReadOnlySpace::DetachPagesAndAddToArtifacts(
 
 void ReadOnlyPage::MakeHeaderRelocatable() {
   ReleaseAllocatedMemoryNeededForWritableChunk();
-  // Detached read-only space needs to have a valid marking bitmap and free list
-  // categories. Instruct Lsan to ignore them if required.
-  LSAN_IGNORE_OBJECT(categories_);
-  for (int i = kFirstCategory; i < owner()->free_list()->number_of_categories();
-       i++) {
-    LSAN_IGNORE_OBJECT(categories_[i]);
-  }
+  // Detached read-only space needs to have a valid marking bitmap. Instruct
+  // Lsan to ignore it if required.
   LSAN_IGNORE_OBJECT(marking_bitmap_);
   heap_ = nullptr;
   owner_ = nullptr;
@@ -153,8 +148,14 @@ void ReadOnlySpace::Seal(SealMode ro_mode) {
       memory_allocator->UnregisterMemory(p);
       static_cast<ReadOnlyPage*>(p)->MakeHeaderRelocatable();
     }
+  } else {
+    for (Page* p : *this) {
+      p->ReleaseAllocatedMemoryNeededForWritableChunk();
+    }
   }
 
+  free_list_.reset();
+
   SetPermissionsForPages(memory_allocator, PageAllocator::kRead);
 }
 

src/heap/spaces.cc

@@ -1248,14 +1248,14 @@ void MemoryChunk::ReleaseAllocatedMemoryNeededForWritableChunk() {
 
   if (local_tracker_ != nullptr) ReleaseLocalTracker();
   if (young_generation_bitmap_ != nullptr) ReleaseYoungGenerationBitmap();
-}
 
-void MemoryChunk::ReleaseAllAllocatedMemory() {
   if (!IsLargePage()) {
     Page* page = static_cast<Page*>(this);
     page->ReleaseFreeListCategories();
   }
+}
 
+void MemoryChunk::ReleaseAllAllocatedMemory() {
   ReleaseAllocatedMemoryNeededForWritableChunk();
   if (marking_bitmap_ != nullptr) ReleaseMarkingBitmap();
 }