v8/include/cppgc/internal/api-constants.h
Anton Bikineev 62159ea316 cppgc: shared-cage: Remove heap-specific metadata from cage-header
The CL is a prerequisite for the shared cage. Instead of storing
state variables (is_incremental_marking_in_progress,
is_young_generation_enabled) in the cage metadata, the CL moves them to
HeapHandle. The HeapHandle pointer is now retrieved from page-headers.

To make sure that the write-barrier code is better optimized, the
HeapHandle definition is moved to internal/ headers. The part of
BasePage that contains HeapBase (i.e. HeapHandle) pointer is also
extracted and moved to the headers.

Bug: v8:12231
Change-Id: I44bf65d99a621d9548e4250386cf87476ca186ac
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3689730
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81005}
2022-06-08 16:13:53 +00:00

65 lines
1.9 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 <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 kPageSize = size_t{1} << 17;
#if defined(V8_TARGET_ARCH_ARM64) && defined(V8_OS_MACOS)
constexpr size_t kGuardPageSize = 0;
#else
constexpr size_t kGuardPageSize = 4096;
#endif
static constexpr size_t kLargeObjectSizeThreshold = kPageSize / 2;
#if defined(CPPGC_CAGED_HEAP)
constexpr size_t kCagedHeapReservationSize = static_cast<size_t>(4) * kGB;
constexpr size_t kCagedHeapReservationAlignment = kCagedHeapReservationSize;
constexpr size_t kCagedHeapNormalPageReservationSize =
kCagedHeapReservationSize / 2;
#endif
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*);
} // namespace api_constants
} // namespace internal
} // namespace cppgc
#endif // INCLUDE_CPPGC_INTERNAL_API_CONSTANTS_H_