caged-heap-local-data.cc

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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.
 
#include "include/cppgc/internal/caged-heap-local-data.h"
 
#include <algorithm>
#include <type_traits>
 
#include "include/cppgc/platform.h"
#include "src/base/macros.h"
 
namespace cppgc {
namespace internal {
 
#if defined(CPPGC_YOUNG_GENERATION)
 
static_assert(
    std::is_trivially_default_constructible_v<AgeTable>,
    "To support lazy committing, AgeTable must be trivially constructible");
 
void AgeTable::SetAgeForRange(uintptr_t offset_begin, uintptr_t offset_end,
                              Age age,
                              AdjacentCardsPolicy adjacent_cards_policy) {
  // First, mark inner cards.
  const uintptr_t inner_card_offset_begin =
      RoundUp(offset_begin, kCardSizeInBytes);
  const uintptr_t outer_card_offset_end =
      RoundDown(offset_end, kCardSizeInBytes);
 
  for (auto inner_offset = inner_card_offset_begin;
       inner_offset < outer_card_offset_end; inner_offset += kCardSizeInBytes)
    SetAge(inner_offset, age);
 
  // If outer cards are not card-aligned and are not of the same age, mark them
  // as mixed.
  const auto set_age_for_outer_card =
      [this, age, adjacent_cards_policy](uintptr_t offset) {
        if (IsAligned(offset, kCardSizeInBytes)) return;
        if (adjacent_cards_policy == AdjacentCardsPolicy::kIgnore)
          SetAge(offset, age);
        else if (GetAge(offset) != age)
          SetAge(offset, AgeTable::Age::kMixed);
      };
 
  set_age_for_outer_card(offset_begin);
  set_age_for_outer_card(offset_end);
}
 
AgeTable::Age AgeTable::GetAgeForRange(uintptr_t offset_begin,
                                       uintptr_t offset_end) const {
  Age result = GetAge(offset_begin);
  for (auto offset = offset_begin + kCardSizeInBytes; offset < offset_end;
       offset += kCardSizeInBytes) {
    if (result != GetAge(offset)) result = Age::kMixed;
  }
  return result;
}
 
void AgeTable::ResetForTesting() {
  std::fill(&table_[0], &table_[CagedHeapBase::GetAgeTableSize()], Age::kOld);
}
 
#endif  // defined(CPPGC_YOUNG_GENERATION)
 
}  // namespace internal
}  // namespace cppgc