v8/include/cppgc/internal/caged-heap.h
Anton Bikineev 411cd56db3 cppgc: Remove the 2GB split
The split is rudimental and now is not needed at all:
- as part of the shared-cage effort we added HeapHandle pointer to the
  BasePageHandle class (on the API side);
- for the value-full barrier we get HeapHandle from bitmasking the
  value;
- for the value-less barrier we get it from the callback provided by the
  caller.

The CL entirely removes the split and uses the single
BoundedPageAllocator. A minor note: the conservative stack scanning can
become sligthly more expensive.

Bug: chromium:1361582, chromium:1325007
Change-Id: I2a8aded3dd12037998f36341c68af8e23b0dcd88
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3899320
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83232}
2022-09-15 17:04:23 +00:00

62 lines
1.9 KiB
C++

// Copyright 2022 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_CAGED_HEAP_H_
#define INCLUDE_CPPGC_INTERNAL_CAGED_HEAP_H_
#include <climits>
#include <cstddef>
#include "cppgc/internal/api-constants.h"
#include "cppgc/internal/base-page-handle.h"
#include "v8config.h" // NOLINT(build/include_directory)
#if defined(CPPGC_CAGED_HEAP)
namespace cppgc {
namespace internal {
class V8_EXPORT CagedHeapBase {
public:
V8_INLINE static uintptr_t OffsetFromAddress(const void* address) {
return reinterpret_cast<uintptr_t>(address) &
(api_constants::kCagedHeapReservationAlignment - 1);
}
V8_INLINE static bool IsWithinCage(const void* address) {
CPPGC_DCHECK(g_heap_base_);
return (reinterpret_cast<uintptr_t>(address) &
~(api_constants::kCagedHeapReservationAlignment - 1)) ==
g_heap_base_;
}
V8_INLINE static bool AreWithinCage(const void* addr1, const void* addr2) {
#if defined(CPPGC_2GB_CAGE)
static constexpr size_t kHalfWordShift = sizeof(uint32_t) * CHAR_BIT - 1;
#else //! defined(CPPGC_2GB_CAGE)
static constexpr size_t kHalfWordShift = sizeof(uint32_t) * CHAR_BIT;
#endif //! defined(CPPGC_2GB_CAGE)
static_assert((static_cast<size_t>(1) << kHalfWordShift) ==
api_constants::kCagedHeapReservationSize);
CPPGC_DCHECK(g_heap_base_);
return !(((reinterpret_cast<uintptr_t>(addr1) ^ g_heap_base_) |
(reinterpret_cast<uintptr_t>(addr2) ^ g_heap_base_)) >>
kHalfWordShift);
}
V8_INLINE static uintptr_t GetBase() { return g_heap_base_; }
private:
friend class CagedHeap;
static uintptr_t g_heap_base_;
};
} // namespace internal
} // namespace cppgc
#endif // defined(CPPGC_CAGED_HEAP)
#endif // INCLUDE_CPPGC_INTERNAL_CAGED_HEAP_H_