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// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef RUNTIME_VM_VIRTUAL_MEMORY_COMPRESSED_H_
#define RUNTIME_VM_VIRTUAL_MEMORY_COMPRESSED_H_
#include "vm/globals.h"
#include "vm/heap/pages.h"
#include "vm/memory_region.h"
namespace dart {
#if defined(DART_COMPRESSED_POINTERS)
static constexpr intptr_t kCompressedHeapSize = 4 * GB;
static constexpr intptr_t kCompressedHeapAlignment = 4 * GB;
static constexpr intptr_t kCompressedHeapPageSize = kOldPageSize;
static constexpr intptr_t kCompressedHeapNumPages =
kCompressedHeapSize / kOldPageSize;
static constexpr intptr_t kCompressedHeapBitmapSize =
kCompressedHeapNumPages / 8;
#if !defined(HOST_OS_FUCHSIA)
#define DART_COMPRESSED_HEAP
#endif // !defined(HOST_OS_FUCHSIA)
#endif // defined(DART_COMPRESSED_POINTERS)
#if defined(DART_COMPRESSED_HEAP)
// Utilities for allocating memory within a contiguous region of memory, for use
// with compressed pointers.
class VirtualMemoryCompressedHeap : public AllStatic {
public:
// Initializes the compressed heap. The callee must allocate a region of
// kCompressedHeapSize bytes, aligned to kCompressedHeapSize.
static void Init(void* compressed_heap_region);
// Cleans up the compressed heap. The callee is responsible for freeing the
// region's memory.
static void Cleanup();
// Allocates a segment of the compressed heap with the given size. Returns a
// heap memory region if a large enough free segment can't be found.
static MemoryRegion Allocate(intptr_t size, intptr_t alignment);
// Frees a segment.
static void Free(void* address, intptr_t size);
// Returns whether the address is within the compressed heap.
static bool Contains(void* address);
// Returns a pointer to the compressed heap region.
static void* GetRegion();
private:
static bool IsPageUsed(uword page_id);
static void SetPageUsed(uword page_id);
static void ClearPageUsed(uword page_id);
static uword base_;
static uint8_t* pages_;
static uword minimum_free_page_id_;
static Mutex* mutex_;
};
#endif // defined(DART_COMPRESSED_HEAP)
} // namespace dart
#endif // RUNTIME_VM_VIRTUAL_MEMORY_COMPRESSED_H_