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// Copyright 2020 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef INCLUDE_CPPGC_INTERNAL_API_CONSTANTS_H_
#define INCLUDE_CPPGC_INTERNAL_API_CONSTANTS_H_
#include <cstddef>
#include <cstdint>
#include "v8config.h" // NOLINT(build/include_directory)
namespace cppgc {
namespace internal {
// Embedders should not rely on this code!
// Internal constants to avoid exposing internal types on the API surface.
namespace api_constants {
constexpr size_t kKB = 1024;
constexpr size_t kMB = kKB * 1024;
constexpr size_t kGB = kMB * 1024;
// Offset of the uint16_t bitfield from the payload contaning the
// in-construction bit. This is subtracted from the payload pointer to get
// to the right bitfield.
static constexpr size_t kFullyConstructedBitFieldOffsetFromPayload =
2 * sizeof(uint16_t);
// Mask for in-construction bit.
static constexpr uint16_t kFullyConstructedBitMask = uint16_t{1};
static constexpr size_t kPageSizeBits = 17;
static constexpr size_t kPageSize = size_t{1} << kPageSizeBits;
static constexpr size_t kLargeObjectSizeThreshold = kPageSize / 2;
#if defined(CPPGC_POINTER_COMPRESSION)
#if defined(CPPGC_ENABLE_LARGER_CAGE)
constexpr unsigned kPointerCompressionShift = 3;
#else // !defined(CPPGC_ENABLE_LARGER_CAGE)
constexpr unsigned kPointerCompressionShift = 1;
#endif // !defined(CPPGC_ENABLE_LARGER_CAGE)
#endif // !defined(CPPGC_POINTER_COMPRESSION)
#if defined(CPPGC_CAGED_HEAP)
constexpr size_t kCagedHeapDefaultReservationSize =
static_cast<size_t>(4) * kGB;
#if defined(CPPGC_POINTER_COMPRESSION)
constexpr size_t kCagedHeapMaxReservationSize =
size_t{1} << (31 + kPointerCompressionShift);
#else // !defined(CPPGC_POINTER_COMPRESSION)
constexpr size_t kCagedHeapMaxReservationSize =
kCagedHeapDefaultReservationSize;
#endif // !defined(CPPGC_POINTER_COMPRESSION)
constexpr size_t kCagedHeapReservationAlignment = kCagedHeapMaxReservationSize;
#endif // defined(CPPGC_CAGED_HEAP)
static constexpr size_t kDefaultAlignment = sizeof(void*);
// Maximum support alignment for a type as in `alignof(T)`.
static constexpr size_t kMaxSupportedAlignment = 2 * kDefaultAlignment;
// Granularity of heap allocations.
constexpr size_t kAllocationGranularity = sizeof(void*);
// Default cacheline size.
constexpr size_t kCachelineSize = 64;
} // namespace api_constants
} // namespace internal
} // namespace cppgc
#endif // INCLUDE_CPPGC_INTERNAL_API_CONSTANTS_H_
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