v8/include/cppgc/internal/caged-heap.h
Anton Bikineev 897c5618aa cppgc: shared-cage: Introduce shared cage for all heaps
The CL does the following:
1) Globalizes CagedHeap for all HeapBases;
2) Adds the global variable representing the cage base;
3) Changes all write-barriers to use this global variable for value/slot
   checks;
4) Removes no longer needed functionality introduced in previous CLs.

Bug: v8:12231
Change-Id: I281a7b0bf67e349c988486fc2d43ec6d703fd292
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3688050
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81027}
2022-06-09 10:42:32 +00:00

80 lines
2.6 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) {
static constexpr size_t kHalfWordShift = sizeof(uint32_t) * CHAR_BIT;
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 bool IsWithinNormalPageReservation(void* address) {
return (reinterpret_cast<uintptr_t>(address) - g_heap_base_) <
api_constants::kCagedHeapNormalPageReservationSize;
}
V8_INLINE static bool IsWithinLargePageReservation(const void* ptr) {
CPPGC_DCHECK(g_heap_base_);
auto uptr = reinterpret_cast<uintptr_t>(ptr);
return (uptr >= g_heap_base_ +
api_constants::kCagedHeapNormalPageReservationSize) &&
(uptr < g_heap_base_ + api_constants::kCagedHeapReservationSize);
}
V8_INLINE static uintptr_t GetBase() { return g_heap_base_; }
V8_INLINE static BasePageHandle& LookupPageFromInnerPointer(void* ptr) {
if (V8_LIKELY(IsWithinNormalPageReservation(ptr)))
return *BasePageHandle::FromPayload(ptr);
else
return LookupLargePageFromInnerPointer(ptr);
}
private:
friend class CagedHeap;
static BasePageHandle& LookupLargePageFromInnerPointer(void* address);
static uintptr_t g_heap_base_;
};
} // namespace internal
} // namespace cppgc
#endif // defined(CPPGC_CAGED_HEAP)
#endif // INCLUDE_CPPGC_INTERNAL_CAGED_HEAP_H_