v8/include/cppgc/internal/api-constants.h
Anton Bikineev 22f80fc176 cppgc: Introduce heap object structure classes
This adds the following:
1) Heap object structure classes: RawHeap, BaseArena and BasePage.
   - freelist
   - linear allocation block
2) ObjectAllocator, a class responsible for object (and page) allocation.

The design doc with UML design: https://bit.ly/2VVTcqc

User defined arenas are followup.

Bug: chromium:1056170
Change-Id: I69a82974bd08e3cf3da90041b1628297cc890891
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2167392
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67425}
2020-04-28 10:21:11 +00:00

45 lines
1.4 KiB
C++

// 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 <stddef.h>
#include <stdint.h>
#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 {
// 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 size_t kFullyConstructedBitMask = size_t{1};
// Page constants used to align pointers to page begin.
static constexpr size_t kPageSize = size_t{1} << 17;
static constexpr size_t kPageAlignment = kPageSize;
static constexpr size_t kPageBaseMask = ~(kPageAlignment - 1);
static constexpr size_t kGuardPageSize = 4096;
// Offset of the Heap backref.
static constexpr size_t kHeapOffset = 0;
static constexpr size_t kLargeObjectSizeThreshold = kPageSize / 2;
} // namespace api_constants
} // namespace internal
} // namespace cppgc
#endif // INCLUDE_CPPGC_INTERNAL_API_CONSTANTS_H_