| // Copyright 2016 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "third_party/blink/renderer/platform/heap/sparse_heap_bitmap.h" |
| |
| #include "third_party/blink/renderer/platform/heap/heap.h" |
| |
| namespace blink { |
| |
| // Return the subtree/bitmap that covers the |
| // [address, address + size) range. Null if there is none. |
| SparseHeapBitmap* SparseHeapBitmap::HasRange(Address address, size_t size) { |
| DCHECK(!(reinterpret_cast<uintptr_t>(address) & kPointerAlignmentMask)); |
| SparseHeapBitmap* bitmap = this; |
| while (bitmap) { |
| // Interval starts after, |m_right| handles. |
| if (address > bitmap->end()) { |
| bitmap = bitmap->right_.get(); |
| continue; |
| } |
| // Interval starts within, |bitmap| is included in the resulting range. |
| if (address >= bitmap->Base()) |
| break; |
| |
| Address right = address + size - 1; |
| // Interval starts before, but intersects with |bitmap|'s range. |
| if (right >= bitmap->Base()) |
| break; |
| |
| // Interval is before entirely, for |m_left| to handle. |
| bitmap = bitmap->left_.get(); |
| } |
| return bitmap; |
| } |
| |
| bool SparseHeapBitmap::IsSet(Address address) { |
| DCHECK(!(reinterpret_cast<uintptr_t>(address) & kPointerAlignmentMask)); |
| SparseHeapBitmap* bitmap = this; |
| while (bitmap) { |
| if (address > bitmap->end()) { |
| bitmap = bitmap->right_.get(); |
| continue; |
| } |
| if (address >= bitmap->Base()) { |
| if (bitmap->bitmap_) { |
| return bitmap->bitmap_->test((address - bitmap->Base()) >> |
| kPointerAlignmentInBits); |
| } |
| DCHECK(address == bitmap->Base()); |
| DCHECK_EQ(bitmap->size(), 1u); |
| return true; |
| } |
| bitmap = bitmap->left_.get(); |
| } |
| return false; |
| } |
| |
| void SparseHeapBitmap::Add(Address address) { |
| DCHECK(!(reinterpret_cast<uintptr_t>(address) & kPointerAlignmentMask)); |
| // |address| is beyond the maximum that this SparseHeapBitmap node can |
| // encompass. |
| if (address >= MaxEnd()) { |
| if (!right_) { |
| right_ = SparseHeapBitmap::Create(address); |
| return; |
| } |
| right_->Add(address); |
| return; |
| } |
| // Same on the other side. |
| if (address < MinStart()) { |
| if (!left_) { |
| left_ = SparseHeapBitmap::Create(address); |
| return; |
| } |
| left_->Add(address); |
| return; |
| } |
| if (address == Base()) |
| return; |
| // |address| can be encompassed by |this| by expanding its size. |
| if (address > Base()) { |
| if (!bitmap_) |
| CreateBitmap(); |
| bitmap_->set((address - Base()) >> kPointerAlignmentInBits); |
| return; |
| } |
| // Use |address| as the new base for this interval. |
| Address old_base = SwapBase(address); |
| CreateBitmap(); |
| bitmap_->set((old_base - address) >> kPointerAlignmentInBits); |
| } |
| |
| void SparseHeapBitmap::CreateBitmap() { |
| DCHECK(!bitmap_ && size() == 1); |
| bitmap_ = std::make_unique<std::bitset<kBitmapChunkSize>>(); |
| size_ = kBitmapChunkRange; |
| bitmap_->set(0); |
| } |
| |
| size_t SparseHeapBitmap::IntervalCount() const { |
| size_t count = 1; |
| if (left_) |
| count += left_->IntervalCount(); |
| if (right_) |
| count += right_->IntervalCount(); |
| return count; |
| } |
| |
| } // namespace blink |