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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 "src/heap/cppgc/heap.h"
#include "include/cppgc/heap-consistency.h"
#include "src/heap/base/stack.h"
#include "src/heap/cppgc/garbage-collector.h"
#include "src/heap/cppgc/gc-invoker.h"
#include "src/heap/cppgc/heap-object-header.h"
#include "src/heap/cppgc/heap-visitor.h"
#include "src/heap/cppgc/marker.h"
#include "src/heap/cppgc/marking-verifier.h"
#include "src/heap/cppgc/prefinalizer-handler.h"
#include "src/heap/cppgc/stats-collector.h"
#include "src/heap/cppgc/sweeper.h"
namespace cppgc {
namespace {
void VerifyCustomSpaces(
const std::vector<std::unique_ptr<CustomSpaceBase>>& custom_spaces) {
// Ensures that user-provided custom spaces have indices that form a sequence
// starting at 0.
#ifdef DEBUG
for (size_t i = 0; i < custom_spaces.size(); ++i) {
DCHECK_EQ(i, custom_spaces[i]->GetCustomSpaceIndex().value);
}
#endif // DEBUG
}
} // namespace
std::unique_ptr<Heap> Heap::Create(std::shared_ptr<cppgc::Platform> platform,
cppgc::Heap::HeapOptions options) {
DCHECK(platform.get());
VerifyCustomSpaces(options.custom_spaces);
return std::make_unique<internal::Heap>(std::move(platform),
std::move(options));
}
void Heap::ForceGarbageCollectionSlow(const char* source, const char* reason,
Heap::StackState stack_state) {
internal::Heap::From(this)->CollectGarbage(
{internal::GarbageCollector::Config::CollectionType::kMajor, stack_state,
MarkingType::kAtomic, SweepingType::kAtomic,
internal::GarbageCollector::Config::FreeMemoryHandling::
kDiscardWherePossible,
internal::GarbageCollector::Config::IsForcedGC::kForced});
}
AllocationHandle& Heap::GetAllocationHandle() {
return internal::Heap::From(this)->object_allocator();
}
HeapHandle& Heap::GetHeapHandle() { return *internal::Heap::From(this); }
namespace internal {
namespace {
class Unmarker final : private HeapVisitor<Unmarker> {
friend class HeapVisitor<Unmarker>;
public:
explicit Unmarker(RawHeap& heap) { Traverse(heap); }
private:
bool VisitHeapObjectHeader(HeapObjectHeader& header) {
if (header.IsMarked()) header.Unmark();
return true;
}
};
void CheckConfig(Heap::Config config, Heap::MarkingType marking_support,
Heap::SweepingType sweeping_support) {
CHECK_WITH_MSG(
(config.collection_type != Heap::Config::CollectionType::kMinor) ||
(config.stack_state == Heap::Config::StackState::kNoHeapPointers),
"Minor GCs with stack is currently not supported");
CHECK_LE(static_cast<int>(config.marking_type),
static_cast<int>(marking_support));
CHECK_LE(static_cast<int>(config.sweeping_type),
static_cast<int>(sweeping_support));
}
} // namespace
Heap::Heap(std::shared_ptr<cppgc::Platform> platform,
cppgc::Heap::HeapOptions options)
: HeapBase(platform, options.custom_spaces, options.stack_support),
gc_invoker_(this, platform_.get(), options.stack_support),
growing_(&gc_invoker_, stats_collector_.get(),
options.resource_constraints, options.marking_support,
options.sweeping_support),
marking_support_(options.marking_support),
sweeping_support_(options.sweeping_support) {
CHECK_IMPLIES(options.marking_support != MarkingType::kAtomic,
platform_->GetForegroundTaskRunner());
CHECK_IMPLIES(options.sweeping_support != SweepingType::kAtomic,
platform_->GetForegroundTaskRunner());
}
Heap::~Heap() {
subtle::NoGarbageCollectionScope no_gc(*this);
// Finish already running GC if any, but don't finalize live objects.
sweeper_.FinishIfRunning();
}
void Heap::CollectGarbage(Config config) {
DCHECK_EQ(Config::MarkingType::kAtomic, config.marking_type);
CheckConfig(config, marking_support_, sweeping_support_);
if (in_no_gc_scope()) return;
config_ = config;
if (!IsMarking()) {
StartGarbageCollection(config);
}
DCHECK(IsMarking());
FinalizeGarbageCollection(config.stack_state);
}
void Heap::StartIncrementalGarbageCollection(Config config) {
DCHECK_NE(Config::MarkingType::kAtomic, config.marking_type);
DCHECK_NE(marking_support_, MarkingType::kAtomic);
CheckConfig(config, marking_support_, sweeping_support_);
if (IsMarking() || in_no_gc_scope()) return;
config_ = config;
StartGarbageCollection(config);
}
void Heap::FinalizeIncrementalGarbageCollectionIfRunning(Config config) {
DCHECK_NE(marking_support_, MarkingType::kAtomic);
CheckConfig(config, marking_support_, sweeping_support_);
if (!IsMarking()) return;
DCHECK(!in_no_gc_scope());
DCHECK_NE(Config::MarkingType::kAtomic, config_.marking_type);
config_ = config;
FinalizeGarbageCollection(config.stack_state);
}
void Heap::StartGarbageCollection(Config config) {
DCHECK(!IsMarking());
DCHECK(!in_no_gc_scope());
// Finish sweeping in case it is still running.
sweeper_.FinishIfRunning();
epoch_++;
#if defined(CPPGC_YOUNG_GENERATION)
if (config.collection_type == Config::CollectionType::kMajor)
Unmarker unmarker(raw_heap());
#endif
const Marker::MarkingConfig marking_config{
config.collection_type, config.stack_state, config.marking_type,
config.is_forced_gc};
marker_ = MarkerFactory::CreateAndStartMarking<Marker>(
AsBase(), platform_.get(), marking_config);
}
void Heap::FinalizeGarbageCollection(Config::StackState stack_state) {
DCHECK(IsMarking());
DCHECK(!in_no_gc_scope());
CHECK(!in_disallow_gc_scope());
config_.stack_state = stack_state;
if (override_stack_state_) {
config_.stack_state = *override_stack_state_;
}
SetStackEndOfCurrentGC(v8::base::Stack::GetCurrentStackPosition());
in_atomic_pause_ = true;
{
// This guards atomic pause marking, meaning that no internal method or
// external callbacks are allowed to allocate new objects.
cppgc::subtle::DisallowGarbageCollectionScope no_gc_scope(*this);
marker_->FinishMarking(config_.stack_state);
}
marker_.reset();
const size_t bytes_allocated_in_prefinalizers = ExecutePreFinalizers();
#if CPPGC_VERIFY_HEAP
MarkingVerifier verifier(*this);
verifier.Run(
config_.stack_state, stack_end_of_current_gc(),
stats_collector()->marked_bytes() + bytes_allocated_in_prefinalizers);
#endif // CPPGC_VERIFY_HEAP
#ifndef CPPGC_ALLOW_ALLOCATIONS_IN_PREFINALIZERS
DCHECK_EQ(0u, bytes_allocated_in_prefinalizers);
#endif
USE(bytes_allocated_in_prefinalizers);
subtle::NoGarbageCollectionScope no_gc(*this);
const Sweeper::SweepingConfig sweeping_config{
config_.sweeping_type,
Sweeper::SweepingConfig::CompactableSpaceHandling::kSweep,
config_.free_memory_handling};
sweeper_.Start(sweeping_config);
in_atomic_pause_ = false;
sweeper_.NotifyDoneIfNeeded();
}
void Heap::DisableHeapGrowingForTesting() { growing_.DisableForTesting(); }
void Heap::FinalizeIncrementalGarbageCollectionIfNeeded(
Config::StackState stack_state) {
StatsCollector::EnabledScope stats_scope(
stats_collector(), StatsCollector::kMarkIncrementalFinalize);
FinalizeGarbageCollection(stack_state);
}
void Heap::StartIncrementalGarbageCollectionForTesting() {
DCHECK(!IsMarking());
DCHECK(!in_no_gc_scope());
StartGarbageCollection({Config::CollectionType::kMajor,
Config::StackState::kNoHeapPointers,
Config::MarkingType::kIncrementalAndConcurrent,
Config::SweepingType::kIncrementalAndConcurrent});
}
void Heap::FinalizeIncrementalGarbageCollectionForTesting(
EmbedderStackState stack_state) {
DCHECK(!in_no_gc_scope());
DCHECK(IsMarking());
FinalizeGarbageCollection(stack_state);
sweeper_.FinishIfRunning();
}
} // namespace internal
} // namespace cppgc
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