blob: 7feea920a00bfc92d1355f0732ad7fd19892d8b0 [file] [log] [blame]
// Copyright 2013 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/profiler/heap-snapshot-generator.h"
#include <utility>
#include "src/api-inl.h"
#include "src/assembler-inl.h"
#include "src/conversions.h"
#include "src/debug/debug.h"
#include "src/global-handles.h"
#include "src/layout-descriptor.h"
#include "src/objects-body-descriptors.h"
#include "src/objects-inl.h"
#include "src/objects/allocation-site-inl.h"
#include "src/objects/api-callbacks.h"
#include "src/objects/cell-inl.h"
#include "src/objects/feedback-cell-inl.h"
#include "src/objects/hash-table-inl.h"
#include "src/objects/js-array-buffer-inl.h"
#include "src/objects/js-array-inl.h"
#include "src/objects/js-collection-inl.h"
#include "src/objects/js-generator-inl.h"
#include "src/objects/js-promise-inl.h"
#include "src/objects/js-regexp-inl.h"
#include "src/objects/literal-objects-inl.h"
#include "src/objects/slots-inl.h"
#include "src/objects/struct-inl.h"
#include "src/profiler/allocation-tracker.h"
#include "src/profiler/heap-profiler.h"
#include "src/profiler/heap-snapshot-generator-inl.h"
#include "src/prototype.h"
#include "src/transitions-inl.h"
#include "src/vector.h"
#include "src/visitors.h"
namespace v8 {
namespace internal {
HeapGraphEdge::HeapGraphEdge(Type type, const char* name, HeapEntry* from,
HeapEntry* to)
: bit_field_(TypeField::encode(type) |
FromIndexField::encode(from->index())),
to_entry_(to),
name_(name) {
DCHECK(type == kContextVariable
|| type == kProperty
|| type == kInternal
|| type == kShortcut
|| type == kWeak);
}
HeapGraphEdge::HeapGraphEdge(Type type, int index, HeapEntry* from,
HeapEntry* to)
: bit_field_(TypeField::encode(type) |
FromIndexField::encode(from->index())),
to_entry_(to),
index_(index) {
DCHECK(type == kElement || type == kHidden);
}
HeapEntry::HeapEntry(HeapSnapshot* snapshot, int index, Type type,
const char* name, SnapshotObjectId id, size_t self_size,
unsigned trace_node_id)
: type_(type),
index_(index),
children_count_(0),
self_size_(self_size),
snapshot_(snapshot),
name_(name),
id_(id),
trace_node_id_(trace_node_id) {
DCHECK_GE(index, 0);
}
void HeapEntry::SetNamedReference(HeapGraphEdge::Type type,
const char* name,
HeapEntry* entry) {
++children_count_;
snapshot_->edges().emplace_back(type, name, this, entry);
}
void HeapEntry::SetIndexedReference(HeapGraphEdge::Type type,
int index,
HeapEntry* entry) {
++children_count_;
snapshot_->edges().emplace_back(type, index, this, entry);
}
void HeapEntry::SetNamedAutoIndexReference(HeapGraphEdge::Type type,
const char* description,
HeapEntry* child,
StringsStorage* names) {
int index = children_count_ + 1;
const char* name = description
? names->GetFormatted("%d / %s", index, description)
: names->GetName(index);
SetNamedReference(type, name, child);
}
void HeapEntry::Print(
const char* prefix, const char* edge_name, int max_depth, int indent) {
STATIC_ASSERT(sizeof(unsigned) == sizeof(id()));
base::OS::Print("%6" PRIuS " @%6u %*c %s%s: ", self_size(), id(), indent, ' ',
prefix, edge_name);
if (type() != kString) {
base::OS::Print("%s %.40s\n", TypeAsString(), name_);
} else {
base::OS::Print("\"");
const char* c = name_;
while (*c && (c - name_) <= 40) {
if (*c != '\n')
base::OS::Print("%c", *c);
else
base::OS::Print("\\n");
++c;
}
base::OS::Print("\"\n");
}
if (--max_depth == 0) return;
for (auto i = children_begin(); i != children_end(); ++i) {
HeapGraphEdge& edge = **i;
const char* edge_prefix = "";
EmbeddedVector<char, 64> index;
const char* edge_name = index.start();
switch (edge.type()) {
case HeapGraphEdge::kContextVariable:
edge_prefix = "#";
edge_name = edge.name();
break;
case HeapGraphEdge::kElement:
SNPrintF(index, "%d", edge.index());
break;
case HeapGraphEdge::kInternal:
edge_prefix = "$";
edge_name = edge.name();
break;
case HeapGraphEdge::kProperty:
edge_name = edge.name();
break;
case HeapGraphEdge::kHidden:
edge_prefix = "$";
SNPrintF(index, "%d", edge.index());
break;
case HeapGraphEdge::kShortcut:
edge_prefix = "^";
edge_name = edge.name();
break;
case HeapGraphEdge::kWeak:
edge_prefix = "w";
edge_name = edge.name();
break;
default:
SNPrintF(index, "!!! unknown edge type: %d ", edge.type());
}
edge.to()->Print(edge_prefix, edge_name, max_depth, indent + 2);
}
}
const char* HeapEntry::TypeAsString() {
switch (type()) {
case kHidden: return "/hidden/";
case kObject: return "/object/";
case kClosure: return "/closure/";
case kString: return "/string/";
case kCode: return "/code/";
case kArray: return "/array/";
case kRegExp: return "/regexp/";
case kHeapNumber: return "/number/";
case kNative: return "/native/";
case kSynthetic: return "/synthetic/";
case kConsString: return "/concatenated string/";
case kSlicedString: return "/sliced string/";
case kSymbol: return "/symbol/";
case kBigInt:
return "/bigint/";
default: return "???";
}
}
HeapSnapshot::HeapSnapshot(HeapProfiler* profiler) : profiler_(profiler) {
// It is very important to keep objects that form a heap snapshot
// as small as possible. Check assumptions about data structure sizes.
STATIC_ASSERT((kSystemPointerSize == 4 && sizeof(HeapGraphEdge) == 12) ||
(kSystemPointerSize == 8 && sizeof(HeapGraphEdge) == 24));
STATIC_ASSERT((kSystemPointerSize == 4 && sizeof(HeapEntry) == 28) ||
(kSystemPointerSize == 8 && sizeof(HeapEntry) == 40));
memset(&gc_subroot_entries_, 0, sizeof(gc_subroot_entries_));
}
void HeapSnapshot::Delete() {
profiler_->RemoveSnapshot(this);
}
void HeapSnapshot::RememberLastJSObjectId() {
max_snapshot_js_object_id_ = profiler_->heap_object_map()->last_assigned_id();
}
void HeapSnapshot::AddSyntheticRootEntries() {
AddRootEntry();
AddGcRootsEntry();
SnapshotObjectId id = HeapObjectsMap::kGcRootsFirstSubrootId;
for (int root = 0; root < static_cast<int>(Root::kNumberOfRoots); root++) {
AddGcSubrootEntry(static_cast<Root>(root), id);
id += HeapObjectsMap::kObjectIdStep;
}
DCHECK_EQ(HeapObjectsMap::kFirstAvailableObjectId, id);
}
void HeapSnapshot::AddRootEntry() {
DCHECK_NULL(root_entry_);
DCHECK(entries_.empty()); // Root entry must be the first one.
root_entry_ = AddEntry(HeapEntry::kSynthetic, "",
HeapObjectsMap::kInternalRootObjectId, 0, 0);
DCHECK_EQ(1u, entries_.size());
DCHECK_EQ(root_entry_, &entries_.front());
}
void HeapSnapshot::AddGcRootsEntry() {
DCHECK_NULL(gc_roots_entry_);
gc_roots_entry_ = AddEntry(HeapEntry::kSynthetic, "(GC roots)",
HeapObjectsMap::kGcRootsObjectId, 0, 0);
}
void HeapSnapshot::AddGcSubrootEntry(Root root, SnapshotObjectId id) {
DCHECK_NULL(gc_subroot_entries_[static_cast<int>(root)]);
gc_subroot_entries_[static_cast<int>(root)] =
AddEntry(HeapEntry::kSynthetic, RootVisitor::RootName(root), id, 0, 0);
}
void HeapSnapshot::AddLocation(HeapEntry* entry, int scriptId, int line,
int col) {
locations_.emplace_back(entry->index(), scriptId, line, col);
}
HeapEntry* HeapSnapshot::AddEntry(HeapEntry::Type type,
const char* name,
SnapshotObjectId id,
size_t size,
unsigned trace_node_id) {
DCHECK(!is_complete());
entries_.emplace_back(this, static_cast<int>(entries_.size()), type, name, id,
size, trace_node_id);
return &entries_.back();
}
void HeapSnapshot::FillChildren() {
DCHECK(children().empty());
int children_index = 0;
for (HeapEntry& entry : entries()) {
children_index = entry.set_children_index(children_index);
}
DCHECK_EQ(edges().size(), static_cast<size_t>(children_index));
children().resize(edges().size());
for (HeapGraphEdge& edge : edges()) {
edge.from()->add_child(&edge);
}
}
HeapEntry* HeapSnapshot::GetEntryById(SnapshotObjectId id) {
if (entries_by_id_cache_.empty()) {
CHECK(is_complete());
entries_by_id_cache_.reserve(entries_.size());
for (HeapEntry& entry : entries_) {
entries_by_id_cache_.emplace(entry.id(), &entry);
}
}
auto it = entries_by_id_cache_.find(id);
return it != entries_by_id_cache_.end() ? it->second : nullptr;
}
void HeapSnapshot::Print(int max_depth) {
root()->Print("", "", max_depth, 0);
}
// We split IDs on evens for embedder objects (see
// HeapObjectsMap::GenerateId) and odds for native objects.
const SnapshotObjectId HeapObjectsMap::kInternalRootObjectId = 1;
const SnapshotObjectId HeapObjectsMap::kGcRootsObjectId =
HeapObjectsMap::kInternalRootObjectId + HeapObjectsMap::kObjectIdStep;
const SnapshotObjectId HeapObjectsMap::kGcRootsFirstSubrootId =
HeapObjectsMap::kGcRootsObjectId + HeapObjectsMap::kObjectIdStep;
const SnapshotObjectId HeapObjectsMap::kFirstAvailableObjectId =
HeapObjectsMap::kGcRootsFirstSubrootId +
static_cast<int>(Root::kNumberOfRoots) * HeapObjectsMap::kObjectIdStep;
HeapObjectsMap::HeapObjectsMap(Heap* heap)
: next_id_(kFirstAvailableObjectId), heap_(heap) {
// The dummy element at zero index is needed as entries_map_ cannot hold
// an entry with zero value. Otherwise it's impossible to tell if
// LookupOrInsert has added a new item or just returning exisiting one
// having the value of zero.
entries_.emplace_back(0, kNullAddress, 0, true);
}
bool HeapObjectsMap::MoveObject(Address from, Address to, int object_size) {
DCHECK_NE(kNullAddress, to);
DCHECK_NE(kNullAddress, from);
if (from == to) return false;
void* from_value = entries_map_.Remove(reinterpret_cast<void*>(from),
ComputeAddressHash(from));
if (from_value == nullptr) {
// It may occur that some untracked object moves to an address X and there
// is a tracked object at that address. In this case we should remove the
// entry as we know that the object has died.
void* to_value = entries_map_.Remove(reinterpret_cast<void*>(to),
ComputeAddressHash(to));
if (to_value != nullptr) {
int to_entry_info_index =
static_cast<int>(reinterpret_cast<intptr_t>(to_value));
entries_.at(to_entry_info_index).addr = kNullAddress;
}
} else {
base::HashMap::Entry* to_entry = entries_map_.LookupOrInsert(
reinterpret_cast<void*>(to), ComputeAddressHash(to));
if (to_entry->value != nullptr) {
// We found the existing entry with to address for an old object.
// Without this operation we will have two EntryInfo's with the same
// value in addr field. It is bad because later at RemoveDeadEntries
// one of this entry will be removed with the corresponding entries_map_
// entry.
int to_entry_info_index =
static_cast<int>(reinterpret_cast<intptr_t>(to_entry->value));
entries_.at(to_entry_info_index).addr = kNullAddress;
}
int from_entry_info_index =
static_cast<int>(reinterpret_cast<intptr_t>(from_value));
entries_.at(from_entry_info_index).addr = to;
// Size of an object can change during its life, so to keep information
// about the object in entries_ consistent, we have to adjust size when the
// object is migrated.
if (FLAG_heap_profiler_trace_objects) {
PrintF("Move object from %p to %p old size %6d new size %6d\n",
reinterpret_cast<void*>(from), reinterpret_cast<void*>(to),
entries_.at(from_entry_info_index).size, object_size);
}
entries_.at(from_entry_info_index).size = object_size;
to_entry->value = from_value;
}
return from_value != nullptr;
}
void HeapObjectsMap::UpdateObjectSize(Address addr, int size) {
FindOrAddEntry(addr, size, false);
}
SnapshotObjectId HeapObjectsMap::FindEntry(Address addr) {
base::HashMap::Entry* entry = entries_map_.Lookup(
reinterpret_cast<void*>(addr), ComputeAddressHash(addr));
if (entry == nullptr) return 0;
int entry_index = static_cast<int>(reinterpret_cast<intptr_t>(entry->value));
EntryInfo& entry_info = entries_.at(entry_index);
DCHECK(static_cast<uint32_t>(entries_.size()) > entries_map_.occupancy());
return entry_info.id;
}
SnapshotObjectId HeapObjectsMap::FindOrAddEntry(Address addr,
unsigned int size,
bool accessed) {
DCHECK(static_cast<uint32_t>(entries_.size()) > entries_map_.occupancy());
base::HashMap::Entry* entry = entries_map_.LookupOrInsert(
reinterpret_cast<void*>(addr), ComputeAddressHash(addr));
if (entry->value != nullptr) {
int entry_index =
static_cast<int>(reinterpret_cast<intptr_t>(entry->value));
EntryInfo& entry_info = entries_.at(entry_index);
entry_info.accessed = accessed;
if (FLAG_heap_profiler_trace_objects) {
PrintF("Update object size : %p with old size %d and new size %d\n",
reinterpret_cast<void*>(addr), entry_info.size, size);
}
entry_info.size = size;
return entry_info.id;
}
entry->value = reinterpret_cast<void*>(entries_.size());
SnapshotObjectId id = next_id_;
next_id_ += kObjectIdStep;
entries_.push_back(EntryInfo(id, addr, size, accessed));
DCHECK(static_cast<uint32_t>(entries_.size()) > entries_map_.occupancy());
return id;
}
void HeapObjectsMap::StopHeapObjectsTracking() { time_intervals_.clear(); }
void HeapObjectsMap::UpdateHeapObjectsMap() {
if (FLAG_heap_profiler_trace_objects) {
PrintF("Begin HeapObjectsMap::UpdateHeapObjectsMap. map has %d entries.\n",
entries_map_.occupancy());
}
heap_->PreciseCollectAllGarbage(Heap::kNoGCFlags,
GarbageCollectionReason::kHeapProfiler);
HeapIterator iterator(heap_);
for (HeapObject obj = iterator.next(); !obj.is_null();
obj = iterator.next()) {
FindOrAddEntry(obj->address(), obj->Size());
if (FLAG_heap_profiler_trace_objects) {
PrintF("Update object : %p %6d. Next address is %p\n",
reinterpret_cast<void*>(obj->address()), obj->Size(),
reinterpret_cast<void*>(obj->address() + obj->Size()));
}
}
RemoveDeadEntries();
if (FLAG_heap_profiler_trace_objects) {
PrintF("End HeapObjectsMap::UpdateHeapObjectsMap. map has %d entries.\n",
entries_map_.occupancy());
}
}
SnapshotObjectId HeapObjectsMap::PushHeapObjectsStats(OutputStream* stream,
int64_t* timestamp_us) {
UpdateHeapObjectsMap();
time_intervals_.emplace_back(next_id_);
int prefered_chunk_size = stream->GetChunkSize();
std::vector<v8::HeapStatsUpdate> stats_buffer;
DCHECK(!entries_.empty());
EntryInfo* entry_info = &entries_.front();
EntryInfo* end_entry_info = &entries_.back() + 1;
for (size_t time_interval_index = 0;
time_interval_index < time_intervals_.size(); ++time_interval_index) {
TimeInterval& time_interval = time_intervals_[time_interval_index];
SnapshotObjectId time_interval_id = time_interval.id;
uint32_t entries_size = 0;
EntryInfo* start_entry_info = entry_info;
while (entry_info < end_entry_info && entry_info->id < time_interval_id) {
entries_size += entry_info->size;
++entry_info;
}
uint32_t entries_count =
static_cast<uint32_t>(entry_info - start_entry_info);
if (time_interval.count != entries_count ||
time_interval.size != entries_size) {
stats_buffer.emplace_back(static_cast<uint32_t>(time_interval_index),
time_interval.count = entries_count,
time_interval.size = entries_size);
if (static_cast<int>(stats_buffer.size()) >= prefered_chunk_size) {
OutputStream::WriteResult result = stream->WriteHeapStatsChunk(
&stats_buffer.front(), static_cast<int>(stats_buffer.size()));
if (result == OutputStream::kAbort) return last_assigned_id();
stats_buffer.clear();
}
}
}
DCHECK(entry_info == end_entry_info);
if (!stats_buffer.empty()) {
OutputStream::WriteResult result = stream->WriteHeapStatsChunk(
&stats_buffer.front(), static_cast<int>(stats_buffer.size()));
if (result == OutputStream::kAbort) return last_assigned_id();
}
stream->EndOfStream();
if (timestamp_us) {
*timestamp_us =
(time_intervals_.back().timestamp - time_intervals_.front().timestamp)
.InMicroseconds();
}
return last_assigned_id();
}
void HeapObjectsMap::RemoveDeadEntries() {
DCHECK(entries_.size() > 0 && entries_.at(0).id == 0 &&
entries_.at(0).addr == kNullAddress);
size_t first_free_entry = 1;
for (size_t i = 1; i < entries_.size(); ++i) {
EntryInfo& entry_info = entries_.at(i);
if (entry_info.accessed) {
if (first_free_entry != i) {
entries_.at(first_free_entry) = entry_info;
}
entries_.at(first_free_entry).accessed = false;
base::HashMap::Entry* entry =
entries_map_.Lookup(reinterpret_cast<void*>(entry_info.addr),
ComputeAddressHash(entry_info.addr));
DCHECK(entry);
entry->value = reinterpret_cast<void*>(first_free_entry);
++first_free_entry;
} else {
if (entry_info.addr) {
entries_map_.Remove(reinterpret_cast<void*>(entry_info.addr),
ComputeAddressHash(entry_info.addr));
}
}
}
entries_.erase(entries_.begin() + first_free_entry, entries_.end());
DCHECK(static_cast<uint32_t>(entries_.size()) - 1 ==
entries_map_.occupancy());
}
V8HeapExplorer::V8HeapExplorer(HeapSnapshot* snapshot,
SnapshottingProgressReportingInterface* progress,
v8::HeapProfiler::ObjectNameResolver* resolver)
: heap_(snapshot->profiler()->heap_object_map()->heap()),
snapshot_(snapshot),
names_(snapshot_->profiler()->names()),
heap_object_map_(snapshot_->profiler()->heap_object_map()),
progress_(progress),
generator_(nullptr),
global_object_name_resolver_(resolver) {}
HeapEntry* V8HeapExplorer::AllocateEntry(HeapThing ptr) {
return AddEntry(HeapObject::cast(Object(reinterpret_cast<Address>(ptr))));
}
void V8HeapExplorer::ExtractLocation(HeapEntry* entry, HeapObject object) {
if (object->IsJSFunction()) {
JSFunction func = JSFunction::cast(object);
ExtractLocationForJSFunction(entry, func);
} else if (object->IsJSGeneratorObject()) {
JSGeneratorObject gen = JSGeneratorObject::cast(object);
ExtractLocationForJSFunction(entry, gen->function());
} else if (object->IsJSObject()) {
JSObject obj = JSObject::cast(object);
JSFunction maybe_constructor = GetConstructor(obj);
if (!maybe_constructor.is_null()) {
ExtractLocationForJSFunction(entry, maybe_constructor);
}
}
}
void V8HeapExplorer::ExtractLocationForJSFunction(HeapEntry* entry,
JSFunction func) {
if (!func->shared()->script()->IsScript()) return;
Script script = Script::cast(func->shared()->script());
int scriptId = script->id();
int start = func->shared()->StartPosition();
int line = script->GetLineNumber(start);
int col = script->GetColumnNumber(start);
snapshot_->AddLocation(entry, scriptId, line, col);
}
HeapEntry* V8HeapExplorer::AddEntry(HeapObject object) {
if (object->IsJSFunction()) {
JSFunction func = JSFunction::cast(object);
SharedFunctionInfo shared = func->shared();
const char* name = names_->GetName(shared->Name());
return AddEntry(object, HeapEntry::kClosure, name);
} else if (object->IsJSBoundFunction()) {
return AddEntry(object, HeapEntry::kClosure, "native_bind");
} else if (object->IsJSRegExp()) {
JSRegExp re = JSRegExp::cast(object);
return AddEntry(object,
HeapEntry::kRegExp,
names_->GetName(re->Pattern()));
} else if (object->IsJSObject()) {
const char* name = names_->GetName(
GetConstructorName(JSObject::cast(object)));
if (object->IsJSGlobalObject()) {
auto it = objects_tags_.find(JSGlobalObject::cast(object));
if (it != objects_tags_.end()) {
name = names_->GetFormatted("%s / %s", name, it->second);
}
}
return AddEntry(object, HeapEntry::kObject, name);
} else if (object->IsString()) {
String string = String::cast(object);
if (string->IsConsString()) {
return AddEntry(object, HeapEntry::kConsString, "(concatenated string)");
} else if (string->IsSlicedString()) {
return AddEntry(object, HeapEntry::kSlicedString, "(sliced string)");
} else {
return AddEntry(object, HeapEntry::kString,
names_->GetName(String::cast(object)));
}
} else if (object->IsSymbol()) {
if (Symbol::cast(object)->is_private())
return AddEntry(object, HeapEntry::kHidden, "private symbol");
else
return AddEntry(object, HeapEntry::kSymbol, "symbol");
} else if (object->IsBigInt()) {
return AddEntry(object, HeapEntry::kBigInt, "bigint");
} else if (object->IsCode()) {
return AddEntry(object, HeapEntry::kCode, "");
} else if (object->IsSharedFunctionInfo()) {
String name = SharedFunctionInfo::cast(object)->Name();
return AddEntry(object, HeapEntry::kCode, names_->GetName(name));
} else if (object->IsScript()) {
Object name = Script::cast(object)->name();
return AddEntry(
object, HeapEntry::kCode,
name->IsString() ? names_->GetName(String::cast(name)) : "");
} else if (object->IsNativeContext()) {
return AddEntry(object, HeapEntry::kHidden, "system / NativeContext");
} else if (object->IsContext()) {
return AddEntry(object, HeapEntry::kObject, "system / Context");
} else if (object->IsFixedArray() || object->IsFixedDoubleArray() ||
object->IsByteArray()) {
return AddEntry(object, HeapEntry::kArray, "");
} else if (object->IsHeapNumber()) {
return AddEntry(object, HeapEntry::kHeapNumber, "number");
}
return AddEntry(object, HeapEntry::kHidden, GetSystemEntryName(object));
}
HeapEntry* V8HeapExplorer::AddEntry(HeapObject object, HeapEntry::Type type,
const char* name) {
return AddEntry(object->address(), type, name, object->Size());
}
HeapEntry* V8HeapExplorer::AddEntry(Address address,
HeapEntry::Type type,
const char* name,
size_t size) {
SnapshotObjectId object_id = heap_object_map_->FindOrAddEntry(
address, static_cast<unsigned int>(size));
unsigned trace_node_id = 0;
if (AllocationTracker* allocation_tracker =
snapshot_->profiler()->allocation_tracker()) {
trace_node_id =
allocation_tracker->address_to_trace()->GetTraceNodeId(address);
}
return snapshot_->AddEntry(type, name, object_id, size, trace_node_id);
}
const char* V8HeapExplorer::GetSystemEntryName(HeapObject object) {
switch (object->map()->instance_type()) {
case MAP_TYPE:
switch (Map::cast(object)->instance_type()) {
#define MAKE_STRING_MAP_CASE(instance_type, size, name, Name) \
case instance_type: return "system / Map (" #Name ")";
STRING_TYPE_LIST(MAKE_STRING_MAP_CASE)
#undef MAKE_STRING_MAP_CASE
default: return "system / Map";
}
case CELL_TYPE: return "system / Cell";
case PROPERTY_CELL_TYPE: return "system / PropertyCell";
case FOREIGN_TYPE: return "system / Foreign";
case ODDBALL_TYPE: return "system / Oddball";
case ALLOCATION_SITE_TYPE:
return "system / AllocationSite";
#define MAKE_STRUCT_CASE(TYPE, Name, name) \
case TYPE: \
return "system / " #Name;
STRUCT_LIST(MAKE_STRUCT_CASE)
#undef MAKE_STRUCT_CASE
default: return "system";
}
}
int V8HeapExplorer::EstimateObjectsCount() {
HeapIterator it(heap_, HeapIterator::kFilterUnreachable);
int objects_count = 0;
while (!it.next().is_null()) ++objects_count;
return objects_count;
}
class IndexedReferencesExtractor : public ObjectVisitor {
public:
IndexedReferencesExtractor(V8HeapExplorer* generator, HeapObject parent_obj,
HeapEntry* parent)
: generator_(generator),
parent_obj_(parent_obj),
parent_start_(parent_obj_.RawMaybeWeakField(0)),
parent_end_(parent_obj_.RawMaybeWeakField(parent_obj_->Size())),
parent_(parent),
next_index_(0) {}
void VisitPointers(HeapObject host, ObjectSlot start,
ObjectSlot end) override {
VisitPointers(host, MaybeObjectSlot(start), MaybeObjectSlot(end));
}
void VisitPointers(HeapObject host, MaybeObjectSlot start,
MaybeObjectSlot end) override {
// [start,end) must be a sub-region of [parent_start_, parent_end), i.e.
// all the slots must point inside the object.
CHECK_LE(parent_start_, start);
CHECK_LE(end, parent_end_);
for (MaybeObjectSlot p = start; p < end; ++p) {
int field_index = static_cast<int>(p - parent_start_);
if (generator_->visited_fields_[field_index]) {
generator_->visited_fields_[field_index] = false;
continue;
}
HeapObject heap_object;
if ((*p)->GetHeapObject(&heap_object)) {
VisitHeapObjectImpl(heap_object, field_index);
}
}
}
void VisitCodeTarget(Code host, RelocInfo* rinfo) override {
Code target = Code::GetCodeFromTargetAddress(rinfo->target_address());
VisitHeapObjectImpl(target, -1);
}
void VisitEmbeddedPointer(Code host, RelocInfo* rinfo) override {
VisitHeapObjectImpl(rinfo->target_object(), -1);
}
private:
V8_INLINE void VisitHeapObjectImpl(HeapObject heap_object, int field_index) {
DCHECK_LE(-1, field_index);
// The last parameter {field_offset} is only used to check some well-known
// skipped references, so passing -1 * kTaggedSize for objects embedded
// into code is fine.
generator_->SetHiddenReference(parent_obj_, parent_, next_index_++,
heap_object, field_index * kTaggedSize);
}
V8HeapExplorer* generator_;
HeapObject parent_obj_;
MaybeObjectSlot parent_start_;
MaybeObjectSlot parent_end_;
HeapEntry* parent_;
int next_index_;
};
void V8HeapExplorer::ExtractReferences(HeapEntry* entry, HeapObject obj) {
if (obj->IsJSGlobalProxy()) {
ExtractJSGlobalProxyReferences(entry, JSGlobalProxy::cast(obj));
} else if (obj->IsJSArrayBuffer()) {
ExtractJSArrayBufferReferences(entry, JSArrayBuffer::cast(obj));
} else if (obj->IsJSObject()) {
if (obj->IsJSWeakSet()) {
ExtractJSWeakCollectionReferences(entry, JSWeakSet::cast(obj));
} else if (obj->IsJSWeakMap()) {
ExtractJSWeakCollectionReferences(entry, JSWeakMap::cast(obj));
} else if (obj->IsJSSet()) {
ExtractJSCollectionReferences(entry, JSSet::cast(obj));
} else if (obj->IsJSMap()) {
ExtractJSCollectionReferences(entry, JSMap::cast(obj));
} else if (obj->IsJSPromise()) {
ExtractJSPromiseReferences(entry, JSPromise::cast(obj));
} else if (obj->IsJSGeneratorObject()) {
ExtractJSGeneratorObjectReferences(entry, JSGeneratorObject::cast(obj));
}
ExtractJSObjectReferences(entry, JSObject::cast(obj));
} else if (obj->IsString()) {
ExtractStringReferences(entry, String::cast(obj));
} else if (obj->IsSymbol()) {
ExtractSymbolReferences(entry, Symbol::cast(obj));
} else if (obj->IsMap()) {
ExtractMapReferences(entry, Map::cast(obj));
} else if (obj->IsSharedFunctionInfo()) {
ExtractSharedFunctionInfoReferences(entry, SharedFunctionInfo::cast(obj));
} else if (obj->IsScript()) {
ExtractScriptReferences(entry, Script::cast(obj));
} else if (obj->IsAccessorInfo()) {
ExtractAccessorInfoReferences(entry, AccessorInfo::cast(obj));
} else if (obj->IsAccessorPair()) {
ExtractAccessorPairReferences(entry, AccessorPair::cast(obj));
} else if (obj->IsCode()) {
ExtractCodeReferences(entry, Code::cast(obj));
} else if (obj->IsCell()) {
ExtractCellReferences(entry, Cell::cast(obj));
} else if (obj->IsFeedbackCell()) {
ExtractFeedbackCellReferences(entry, FeedbackCell::cast(obj));
} else if (obj->IsPropertyCell()) {
ExtractPropertyCellReferences(entry, PropertyCell::cast(obj));
} else if (obj->IsAllocationSite()) {
ExtractAllocationSiteReferences(entry, AllocationSite::cast(obj));
} else if (obj->IsArrayBoilerplateDescription()) {
ExtractArrayBoilerplateDescriptionReferences(
entry, ArrayBoilerplateDescription::cast(obj));
} else if (obj->IsFeedbackVector()) {
ExtractFeedbackVectorReferences(entry, FeedbackVector::cast(obj));
} else if (obj->IsDescriptorArray()) {
ExtractDescriptorArrayReferences(entry, DescriptorArray::cast(obj));
} else if (obj->IsWeakFixedArray()) {
ExtractWeakArrayReferences(WeakFixedArray::kHeaderSize, entry,
WeakFixedArray::cast(obj));
} else if (obj->IsWeakArrayList()) {
ExtractWeakArrayReferences(WeakArrayList::kHeaderSize, entry,
WeakArrayList::cast(obj));
} else if (obj->IsContext()) {
ExtractContextReferences(entry, Context::cast(obj));
} else if (obj->IsEphemeronHashTable()) {
ExtractEphemeronHashTableReferences(entry, EphemeronHashTable::cast(obj));
} else if (obj->IsFixedArray()) {
ExtractFixedArrayReferences(entry, FixedArray::cast(obj));
}
}
void V8HeapExplorer::ExtractJSGlobalProxyReferences(HeapEntry* entry,
JSGlobalProxy proxy) {
SetInternalReference(entry, "native_context", proxy->native_context(),
JSGlobalProxy::kNativeContextOffset);
}
void V8HeapExplorer::ExtractJSObjectReferences(HeapEntry* entry,
JSObject js_obj) {
HeapObject obj = js_obj;
ExtractPropertyReferences(js_obj, entry);
ExtractElementReferences(js_obj, entry);
ExtractInternalReferences(js_obj, entry);
Isolate* isolate = Isolate::FromHeap(heap_);
PrototypeIterator iter(isolate, js_obj);
ReadOnlyRoots roots(isolate);
SetPropertyReference(entry, roots.proto_string(), iter.GetCurrent());
if (obj->IsJSBoundFunction()) {
JSBoundFunction js_fun = JSBoundFunction::cast(obj);
TagObject(js_fun->bound_arguments(), "(bound arguments)");
SetInternalReference(entry, "bindings", js_fun->bound_arguments(),
JSBoundFunction::kBoundArgumentsOffset);
SetInternalReference(entry, "bound_this", js_fun->bound_this(),
JSBoundFunction::kBoundThisOffset);
SetInternalReference(entry, "bound_function",
js_fun->bound_target_function(),
JSBoundFunction::kBoundTargetFunctionOffset);
FixedArray bindings = js_fun->bound_arguments();
for (int i = 0; i < bindings->length(); i++) {
const char* reference_name = names_->GetFormatted("bound_argument_%d", i);
SetNativeBindReference(entry, reference_name, bindings->get(i));
}
} else if (obj->IsJSFunction()) {
JSFunction js_fun = JSFunction::cast(js_obj);
if (js_fun->has_prototype_slot()) {
Object proto_or_map = js_fun->prototype_or_initial_map();
if (!proto_or_map->IsTheHole(isolate)) {
if (!proto_or_map->IsMap()) {
SetPropertyReference(entry, roots.prototype_string(), proto_or_map,
nullptr,
JSFunction::kPrototypeOrInitialMapOffset);
} else {
SetPropertyReference(entry, roots.prototype_string(),
js_fun->prototype());
SetInternalReference(entry, "initial_map", proto_or_map,
JSFunction::kPrototypeOrInitialMapOffset);
}
}
}
SharedFunctionInfo shared_info = js_fun->shared();
TagObject(js_fun->raw_feedback_cell(), "(function feedback cell)");
SetInternalReference(entry, "feedback_cell", js_fun->raw_feedback_cell(),
JSFunction::kFeedbackCellOffset);
TagObject(shared_info, "(shared function info)");
SetInternalReference(entry, "shared", shared_info,
JSFunction::kSharedFunctionInfoOffset);
TagObject(js_fun->context(), "(context)");
SetInternalReference(entry, "context", js_fun->context(),
JSFunction::kContextOffset);
SetInternalReference(entry, "code", js_fun->code(),
JSFunction::kCodeOffset);
} else if (obj->IsJSGlobalObject()) {
JSGlobalObject global_obj = JSGlobalObject::cast(obj);
SetInternalReference(entry, "native_context", global_obj->native_context(),
JSGlobalObject::kNativeContextOffset);
SetInternalReference(entry, "global_proxy", global_obj->global_proxy(),
JSGlobalObject::kGlobalProxyOffset);
STATIC_ASSERT(JSGlobalObject::kSize - JSObject::kHeaderSize ==
2 * kTaggedSize);
} else if (obj->IsJSArrayBufferView()) {
JSArrayBufferView view = JSArrayBufferView::cast(obj);
SetInternalReference(entry, "buffer", view->buffer(),
JSArrayBufferView::kBufferOffset);
}
TagObject(js_obj->raw_properties_or_hash(), "(object properties)");
SetInternalReference(entry, "properties", js_obj->raw_properties_or_hash(),
JSObject::kPropertiesOrHashOffset);
TagObject(js_obj->elements(), "(object elements)");
SetInternalReference(entry, "elements", js_obj->elements(),
JSObject::kElementsOffset);
}
void V8HeapExplorer::ExtractStringReferences(HeapEntry* entry, String string) {
if (string->IsConsString()) {
ConsString cs = ConsString::cast(string);
SetInternalReference(entry, "first", cs->first(), ConsString::kFirstOffset);
SetInternalReference(entry, "second", cs->second(),
ConsString::kSecondOffset);
} else if (string->IsSlicedString()) {
SlicedString ss = SlicedString::cast(string);
SetInternalReference(entry, "parent", ss->parent(),
SlicedString::kParentOffset);
} else if (string->IsThinString()) {
ThinString ts = ThinString::cast(string);
SetInternalReference(entry, "actual", ts->actual(),
ThinString::kActualOffset);
}
}
void V8HeapExplorer::ExtractSymbolReferences(HeapEntry* entry, Symbol symbol) {
SetInternalReference(entry, "name", symbol->name(), Symbol::kNameOffset);
}
void V8HeapExplorer::ExtractJSCollectionReferences(HeapEntry* entry,
JSCollection collection) {
SetInternalReference(entry, "table", collection->table(),
JSCollection::kTableOffset);
}
void V8HeapExplorer::ExtractJSWeakCollectionReferences(HeapEntry* entry,
JSWeakCollection obj) {
SetInternalReference(entry, "table", obj->table(),
JSWeakCollection::kTableOffset);
}
void V8HeapExplorer::ExtractEphemeronHashTableReferences(
HeapEntry* entry, EphemeronHashTable table) {
for (int i = 0, capacity = table->Capacity(); i < capacity; ++i) {
int key_index = EphemeronHashTable::EntryToIndex(i) +
EphemeronHashTable::kEntryKeyIndex;
int value_index = EphemeronHashTable::EntryToValueIndex(i);
Object key = table->get(key_index);
Object value = table->get(value_index);
SetWeakReference(entry, key_index, key,
table->OffsetOfElementAt(key_index));
SetWeakReference(entry, value_index, value,
table->OffsetOfElementAt(value_index));
HeapEntry* key_entry = GetEntry(key);
HeapEntry* value_entry = GetEntry(value);
if (key_entry && value_entry) {
const char* edge_name =
names_->GetFormatted("key %s in WeakMap", key_entry->name());
key_entry->SetNamedAutoIndexReference(HeapGraphEdge::kInternal, edge_name,
value_entry, names_);
}
}
}
// These static arrays are used to prevent excessive code-size in
// ExtractContextReferences below, which would happen if we called
// SetInternalReference for every native context field in a macro.
static const struct {
int index;
const char* name;
} native_context_names[] = {
#define CONTEXT_FIELD_INDEX_NAME(index, _, name) {Context::index, #name},
NATIVE_CONTEXT_FIELDS(CONTEXT_FIELD_INDEX_NAME)
#undef CONTEXT_FIELD_INDEX_NAME
};
void V8HeapExplorer::ExtractContextReferences(HeapEntry* entry,
Context context) {
if (!context->IsNativeContext() && context->is_declaration_context()) {
ScopeInfo scope_info = context->scope_info();
// Add context allocated locals.
int context_locals = scope_info->ContextLocalCount();
for (int i = 0; i < context_locals; ++i) {
String local_name = scope_info->ContextLocalName(i);
int idx = Context::MIN_CONTEXT_SLOTS + i;
SetContextReference(entry, local_name, context->get(idx),
Context::OffsetOfElementAt(idx));
}
if (scope_info->HasFunctionName()) {
String name = String::cast(scope_info->FunctionName());
int idx = scope_info->FunctionContextSlotIndex(name);
if (idx >= 0) {
SetContextReference(entry, name, context->get(idx),
Context::OffsetOfElementAt(idx));
}
}
}
SetInternalReference(
entry, "scope_info", context->get(Context::SCOPE_INFO_INDEX),
FixedArray::OffsetOfElementAt(Context::SCOPE_INFO_INDEX));
SetInternalReference(entry, "previous", context->get(Context::PREVIOUS_INDEX),
FixedArray::OffsetOfElementAt(Context::PREVIOUS_INDEX));
SetInternalReference(entry, "extension",
context->get(Context::EXTENSION_INDEX),
FixedArray::OffsetOfElementAt(Context::EXTENSION_INDEX));
SetInternalReference(
entry, "native_context", context->get(Context::NATIVE_CONTEXT_INDEX),
FixedArray::OffsetOfElementAt(Context::NATIVE_CONTEXT_INDEX));
if (context->IsNativeContext()) {
TagObject(context->normalized_map_cache(), "(context norm. map cache)");
TagObject(context->embedder_data(), "(context data)");
for (size_t i = 0; i < arraysize(native_context_names); i++) {
int index = native_context_names[i].index;
const char* name = native_context_names[i].name;
SetInternalReference(entry, name, context->get(index),
FixedArray::OffsetOfElementAt(index));
}
SetWeakReference(
entry, "optimized_code_list",
context->get(Context::OPTIMIZED_CODE_LIST),
FixedArray::OffsetOfElementAt(Context::OPTIMIZED_CODE_LIST));
SetWeakReference(
entry, "deoptimized_code_list",
context->get(Context::DEOPTIMIZED_CODE_LIST),
FixedArray::OffsetOfElementAt(Context::DEOPTIMIZED_CODE_LIST));
STATIC_ASSERT(Context::OPTIMIZED_CODE_LIST == Context::FIRST_WEAK_SLOT);
STATIC_ASSERT(Context::NEXT_CONTEXT_LINK + 1 ==
Context::NATIVE_CONTEXT_SLOTS);
STATIC_ASSERT(Context::FIRST_WEAK_SLOT + 3 ==
Context::NATIVE_CONTEXT_SLOTS);
}
}
void V8HeapExplorer::ExtractMapReferences(HeapEntry* entry, Map map) {
MaybeObject maybe_raw_transitions_or_prototype_info = map->raw_transitions();
HeapObject raw_transitions_or_prototype_info;
if (maybe_raw_transitions_or_prototype_info->GetHeapObjectIfWeak(
&raw_transitions_or_prototype_info)) {
DCHECK(raw_transitions_or_prototype_info->IsMap());
SetWeakReference(entry, "transition", raw_transitions_or_prototype_info,
Map::kTransitionsOrPrototypeInfoOffset);
} else if (maybe_raw_transitions_or_prototype_info->GetHeapObjectIfStrong(
&raw_transitions_or_prototype_info)) {
if (raw_transitions_or_prototype_info->IsTransitionArray()) {
TransitionArray transitions =
TransitionArray::cast(raw_transitions_or_prototype_info);
if (map->CanTransition() && transitions->HasPrototypeTransitions()) {
TagObject(transitions->GetPrototypeTransitions(),
"(prototype transitions)");
}
TagObject(transitions, "(transition array)");
SetInternalReference(entry, "transitions", transitions,
Map::kTransitionsOrPrototypeInfoOffset);
} else if (raw_transitions_or_prototype_info->IsTuple3() ||
raw_transitions_or_prototype_info->IsFixedArray()) {
TagObject(raw_transitions_or_prototype_info, "(transition)");
SetInternalReference(entry, "transition",
raw_transitions_or_prototype_info,
Map::kTransitionsOrPrototypeInfoOffset);
} else if (map->is_prototype_map()) {
TagObject(raw_transitions_or_prototype_info, "prototype_info");
SetInternalReference(entry, "prototype_info",
raw_transitions_or_prototype_info,
Map::kTransitionsOrPrototypeInfoOffset);
}
}
DescriptorArray descriptors = map->instance_descriptors();
TagObject(descriptors, "(map descriptors)");
SetInternalReference(entry, "descriptors", descriptors,
Map::kDescriptorsOffset);
SetInternalReference(entry, "prototype", map->prototype(),
Map::kPrototypeOffset);
if (FLAG_unbox_double_fields) {
SetInternalReference(entry, "layout_descriptor", map->layout_descriptor(),
Map::kLayoutDescriptorOffset);
}
Object constructor_or_backpointer = map->constructor_or_backpointer();
if (constructor_or_backpointer->IsMap()) {
TagObject(constructor_or_backpointer, "(back pointer)");
SetInternalReference(entry, "back_pointer", constructor_or_backpointer,
Map::kConstructorOrBackPointerOffset);
} else if (constructor_or_backpointer->IsFunctionTemplateInfo()) {
TagObject(constructor_or_backpointer, "(constructor function data)");
SetInternalReference(entry, "constructor_function_data",
constructor_or_backpointer,
Map::kConstructorOrBackPointerOffset);
} else {
SetInternalReference(entry, "constructor", constructor_or_backpointer,
Map::kConstructorOrBackPointerOffset);
}
TagObject(map->dependent_code(), "(dependent code)");
SetInternalReference(entry, "dependent_code", map->dependent_code(),
Map::kDependentCodeOffset);
}
void V8HeapExplorer::ExtractSharedFunctionInfoReferences(
HeapEntry* entry, SharedFunctionInfo shared) {
String shared_name = shared->DebugName();
const char* name = nullptr;
if (shared_name != ReadOnlyRoots(heap_).empty_string()) {
name = names_->GetName(shared_name);
TagObject(shared->GetCode(), names_->GetFormatted("(code for %s)", name));
} else {
TagObject(shared->GetCode(),
names_->GetFormatted(
"(%s code)", Code::Kind2String(shared->GetCode()->kind())));
}
if (shared->name_or_scope_info()->IsScopeInfo()) {
TagObject(shared->name_or_scope_info(), "(function scope info)");
}
SetInternalReference(entry, "name_or_scope_info",
shared->name_or_scope_info(),
SharedFunctionInfo::kNameOrScopeInfoOffset);
SetInternalReference(entry, "script_or_debug_info",
shared->script_or_debug_info(),
SharedFunctionInfo::kScriptOrDebugInfoOffset);
SetInternalReference(entry, "function_data", shared->function_data(),
SharedFunctionInfo::kFunctionDataOffset);
SetInternalReference(
entry, "raw_outer_scope_info_or_feedback_metadata",
shared->raw_outer_scope_info_or_feedback_metadata(),
SharedFunctionInfo::kOuterScopeInfoOrFeedbackMetadataOffset);
}
void V8HeapExplorer::ExtractScriptReferences(HeapEntry* entry, Script script) {
SetInternalReference(entry, "source", script->source(),
Script::kSourceOffset);
SetInternalReference(entry, "name", script->name(), Script::kNameOffset);
SetInternalReference(entry, "context_data", script->context_data(),
Script::kContextOffset);
TagObject(script->line_ends(), "(script line ends)");
SetInternalReference(entry, "line_ends", script->line_ends(),
Script::kLineEndsOffset);
}
void V8HeapExplorer::ExtractAccessorInfoReferences(HeapEntry* entry,
AccessorInfo accessor_info) {
SetInternalReference(entry, "name", accessor_info->name(),
AccessorInfo::kNameOffset);
SetInternalReference(entry, "expected_receiver_type",
accessor_info->expected_receiver_type(),
AccessorInfo::kExpectedReceiverTypeOffset);
SetInternalReference(entry, "getter", accessor_info->getter(),
AccessorInfo::kGetterOffset);
SetInternalReference(entry, "setter", accessor_info->setter(),
AccessorInfo::kSetterOffset);
SetInternalReference(entry, "data", accessor_info->data(),
AccessorInfo::kDataOffset);
}
void V8HeapExplorer::ExtractAccessorPairReferences(HeapEntry* entry,
AccessorPair accessors) {
SetInternalReference(entry, "getter", accessors->getter(),
AccessorPair::kGetterOffset);
SetInternalReference(entry, "setter", accessors->setter(),
AccessorPair::kSetterOffset);
}
void V8HeapExplorer::TagBuiltinCodeObject(Code code, const char* name) {
TagObject(code, names_->GetFormatted("(%s builtin)", name));
}
void V8HeapExplorer::ExtractCodeReferences(HeapEntry* entry, Code code) {
TagObject(code->relocation_info(), "(code relocation info)");
SetInternalReference(entry, "relocation_info", code->relocation_info(),
Code::kRelocationInfoOffset);
TagObject(code->deoptimization_data(), "(code deopt data)");
SetInternalReference(entry, "deoptimization_data",
code->deoptimization_data(),
Code::kDeoptimizationDataOffset);
TagObject(code->source_position_table(), "(source position table)");
SetInternalReference(entry, "source_position_table",
code->source_position_table(),
Code::kSourcePositionTableOffset);
}
void V8HeapExplorer::ExtractCellReferences(HeapEntry* entry, Cell cell) {
SetInternalReference(entry, "value", cell->value(), Cell::kValueOffset);
}
void V8HeapExplorer::ExtractFeedbackCellReferences(HeapEntry* entry,
FeedbackCell feedback_cell) {
TagObject(feedback_cell, "(feedback cell)");
SetInternalReference(entry, "value", feedback_cell->value(),
FeedbackCell::kValueOffset);
}
void V8HeapExplorer::ExtractPropertyCellReferences(HeapEntry* entry,
PropertyCell cell) {
SetInternalReference(entry, "value", cell->value(),
PropertyCell::kValueOffset);
TagObject(cell->dependent_code(), "(dependent code)");
SetInternalReference(entry, "dependent_code", cell->dependent_code(),
PropertyCell::kDependentCodeOffset);
}
void V8HeapExplorer::ExtractAllocationSiteReferences(HeapEntry* entry,
AllocationSite site) {
SetInternalReference(entry, "transition_info",
site->transition_info_or_boilerplate(),
AllocationSite::kTransitionInfoOrBoilerplateOffset);
SetInternalReference(entry, "nested_site", site->nested_site(),
AllocationSite::kNestedSiteOffset);
TagObject(site->dependent_code(), "(dependent code)");
SetInternalReference(entry, "dependent_code", site->dependent_code(),
AllocationSite::kDependentCodeOffset);
}
void V8HeapExplorer::ExtractArrayBoilerplateDescriptionReferences(
HeapEntry* entry, ArrayBoilerplateDescription value) {
SetInternalReference(entry, "constant_elements", value->constant_elements(),
ArrayBoilerplateDescription::kConstantElementsOffset);
}
class JSArrayBufferDataEntryAllocator : public HeapEntriesAllocator {
public:
JSArrayBufferDataEntryAllocator(size_t size, V8HeapExplorer* explorer)
: size_(size)
, explorer_(explorer) {
}
HeapEntry* AllocateEntry(HeapThing ptr) override {
return explorer_->AddEntry(reinterpret_cast<Address>(ptr),
HeapEntry::kNative, "system / JSArrayBufferData",
size_);
}
private:
size_t size_;
V8HeapExplorer* explorer_;
};
void V8HeapExplorer::ExtractJSArrayBufferReferences(HeapEntry* entry,
JSArrayBuffer buffer) {
// Setup a reference to a native memory backing_store object.
if (!buffer->backing_store()) return;
size_t data_size = buffer->byte_length();
JSArrayBufferDataEntryAllocator allocator(data_size, this);
HeapEntry* data_entry =
generator_->FindOrAddEntry(buffer->backing_store(), &allocator);
entry->SetNamedReference(HeapGraphEdge::kInternal, "backing_store",
data_entry);
}
void V8HeapExplorer::ExtractJSPromiseReferences(HeapEntry* entry,
JSPromise promise) {
SetInternalReference(entry, "reactions_or_result",
promise->reactions_or_result(),
JSPromise::kReactionsOrResultOffset);
}
void V8HeapExplorer::ExtractJSGeneratorObjectReferences(
HeapEntry* entry, JSGeneratorObject generator) {
SetInternalReference(entry, "function", generator->function(),
JSGeneratorObject::kFunctionOffset);
SetInternalReference(entry, "context", generator->context(),
JSGeneratorObject::kContextOffset);
SetInternalReference(entry, "receiver", generator->receiver(),
JSGeneratorObject::kReceiverOffset);
SetInternalReference(entry, "parameters_and_registers",
generator->parameters_and_registers(),
JSGeneratorObject::kParametersAndRegistersOffset);
}
void V8HeapExplorer::ExtractFixedArrayReferences(HeapEntry* entry,
FixedArray array) {
for (int i = 0, l = array->length(); i < l; ++i) {
DCHECK(!HasWeakHeapObjectTag(array->get(i)));
SetInternalReference(entry, i, array->get(i), array->OffsetOfElementAt(i));
}
}
void V8HeapExplorer::ExtractFeedbackVectorReferences(
HeapEntry* entry, FeedbackVector feedback_vector) {
MaybeObject code = feedback_vector->optimized_code_weak_or_smi();
HeapObject code_heap_object;
if (code->GetHeapObjectIfWeak(&code_heap_object)) {
SetWeakReference(entry, "optimized code", code_heap_object,
FeedbackVector::kOptimizedCodeOffset);
}
}
void V8HeapExplorer::ExtractDescriptorArrayReferences(HeapEntry* entry,
DescriptorArray array) {
SetInternalReference(entry, "enum_cache", array->enum_cache(),
DescriptorArray::kEnumCacheOffset);
MaybeObjectSlot start = MaybeObjectSlot(array->GetDescriptorSlot(0));
MaybeObjectSlot end = MaybeObjectSlot(
array->GetDescriptorSlot(array->number_of_all_descriptors()));
for (int i = 0; start + i < end; ++i) {
MaybeObjectSlot slot = start + i;
int offset = static_cast<int>(slot.address() - array->address());
MaybeObject object = *slot;
HeapObject heap_object;
if (object->GetHeapObjectIfWeak(&heap_object)) {
SetWeakReference(entry, i, heap_object, offset);
} else if (object->GetHeapObjectIfStrong(&heap_object)) {
SetInternalReference(entry, i, heap_object, offset);
}
}
}
template <typename T>
void V8HeapExplorer::ExtractWeakArrayReferences(int header_size,
HeapEntry* entry, T array) {
for (int i = 0; i < array->length(); ++i) {
MaybeObject object = array->Get(i);
HeapObject heap_object;
if (object->GetHeapObjectIfWeak(&heap_object)) {
SetWeakReference(entry, i, heap_object, header_size + i * kTaggedSize);
} else if (object->GetHeapObjectIfStrong(&heap_object)) {
SetInternalReference(entry, i, heap_object,
header_size + i * kTaggedSize);
}
}
}
void V8HeapExplorer::ExtractPropertyReferences(JSObject js_obj,
HeapEntry* entry) {
Isolate* isolate = js_obj->GetIsolate();
if (js_obj->HasFastProperties()) {
DescriptorArray descs = js_obj->map()->instance_descriptors();
int real_size = js_obj->map()->NumberOfOwnDescriptors();
for (int i = 0; i < real_size; i++) {
PropertyDetails details = descs->GetDetails(i);
switch (details.location()) {
case kField: {
Representation r = details.representation();
if (r.IsSmi() || r.IsDouble()) break;
Name k = descs->GetKey(i);
FieldIndex field_index = FieldIndex::ForDescriptor(js_obj->map(), i);
Object value = js_obj->RawFastPropertyAt(field_index);
int field_offset =
field_index.is_inobject() ? field_index.offset() : -1;
SetDataOrAccessorPropertyReference(details.kind(), entry, k, value,
nullptr, field_offset);
break;
}
case kDescriptor:
SetDataOrAccessorPropertyReference(details.kind(), entry,
descs->GetKey(i),
descs->GetStrongValue(i));
break;
}
}
} else if (js_obj->IsJSGlobalObject()) {
// We assume that global objects can only have slow properties.
GlobalDictionary dictionary =
JSGlobalObject::cast(js_obj)->global_dictionary();
int length = dictionary->Capacity();
ReadOnlyRoots roots(isolate);
for (int i = 0; i < length; ++i) {
if (!dictionary->IsKey(roots, dictionary->KeyAt(i))) continue;
PropertyCell cell = dictionary->CellAt(i);
Name name = cell->name();
Object value = cell->value();
PropertyDetails details = cell->property_details();
SetDataOrAccessorPropertyReference(details.kind(), entry, name, value);
}
} else {
NameDictionary dictionary = js_obj->property_dictionary();
int length = dictionary->Capacity();
ReadOnlyRoots roots(isolate);
for (int i = 0; i < length; ++i) {
Object k = dictionary->KeyAt(i);
if (!dictionary->IsKey(roots, k)) continue;
Object value = dictionary->ValueAt(i);
PropertyDetails details = dictionary->DetailsAt(i);
SetDataOrAccessorPropertyReference(details.kind(), entry, Name::cast(k),
value);
}
}
}
void V8HeapExplorer::ExtractAccessorPairProperty(HeapEntry* entry, Name key,
Object callback_obj,
int field_offset) {
if (!callback_obj->IsAccessorPair()) return;
AccessorPair accessors = AccessorPair::cast(callback_obj);
SetPropertyReference(entry, key, accessors, nullptr, field_offset);
Object getter = accessors->getter();
if (!getter->IsOddball()) {
SetPropertyReference(entry, key, getter, "get %s");
}
Object setter = accessors->setter();
if (!setter->IsOddball()) {
SetPropertyReference(entry, key, setter, "set %s");
}
}
void V8HeapExplorer::ExtractElementReferences(JSObject js_obj,
HeapEntry* entry) {
ReadOnlyRoots roots = js_obj->GetReadOnlyRoots();
if (js_obj->HasObjectElements()) {
FixedArray elements = FixedArray::cast(js_obj->elements());
int length = js_obj->IsJSArray()
? Smi::ToInt(JSArray::cast(js_obj)->length())
: elements->length();
for (int i = 0; i < length; ++i) {
if (!elements->get(i)->IsTheHole(roots)) {
SetElementReference(entry, i, elements->get(i));
}
}
} else if (js_obj->HasDictionaryElements()) {
NumberDictionary dictionary = js_obj->element_dictionary();
int length = dictionary->Capacity();
for (int i = 0; i < length; ++i) {
Object k = dictionary->KeyAt(i);
if (!dictionary->IsKey(roots, k)) continue;
DCHECK(k->IsNumber());
uint32_t index = static_cast<uint32_t>(k->Number());
SetElementReference(entry, index, dictionary->ValueAt(i));
}
}
}
void V8HeapExplorer::ExtractInternalReferences(JSObject js_obj,
HeapEntry* entry) {
int length = js_obj->GetEmbedderFieldCount();
for (int i = 0; i < length; ++i) {
Object o = js_obj->GetEmbedderField(i);
SetInternalReference(entry, i, o, js_obj->GetEmbedderFieldOffset(i));
}
}
JSFunction V8HeapExplorer::GetConstructor(JSReceiver receiver) {
Isolate* isolate = receiver->GetIsolate();
DisallowHeapAllocation no_gc;
HandleScope scope(isolate);
MaybeHandle<JSFunction> maybe_constructor =
JSReceiver::GetConstructor(handle(receiver, isolate));
if (maybe_constructor.is_null()) return JSFunction();
return *maybe_constructor.ToHandleChecked();
}
String V8HeapExplorer::GetConstructorName(JSObject object) {
Isolate* isolate = object->GetIsolate();
if (object->IsJSFunction()) return ReadOnlyRoots(isolate).closure_string();
DisallowHeapAllocation no_gc;
HandleScope scope(isolate);
return *JSReceiver::GetConstructorName(handle(object, isolate));
}
HeapEntry* V8HeapExplorer::GetEntry(Object obj) {
return obj->IsHeapObject() ? generator_->FindOrAddEntry(
reinterpret_cast<void*>(obj.ptr()), this)
: nullptr;
}
class RootsReferencesExtractor : public RootVisitor {
public:
explicit RootsReferencesExtractor(V8HeapExplorer* explorer)
: explorer_(explorer), visiting_weak_roots_(false) {}
void SetVisitingWeakRoots() { visiting_weak_roots_ = true; }
void VisitRootPointer(Root root, const char* description,
FullObjectSlot object) override {
if (root == Root::kBuiltins) {
explorer_->TagBuiltinCodeObject(Code::cast(*object), description);
}
explorer_->SetGcSubrootReference(root, description, visiting_weak_roots_,
*object);
}
void VisitRootPointers(Root root, const char* description,
FullObjectSlot start, FullObjectSlot end) override {
for (FullObjectSlot p = start; p < end; ++p) {
VisitRootPointer(root, description, p);
}
}
private:
V8HeapExplorer* explorer_;
bool visiting_weak_roots_;
};
bool V8HeapExplorer::IterateAndExtractReferences(
HeapSnapshotGenerator* generator) {
generator_ = generator;
// Create references to the synthetic roots.
SetRootGcRootsReference();
for (int root = 0; root < static_cast<int>(Root::kNumberOfRoots); root++) {
SetGcRootsReference(static_cast<Root>(root));
}
// Make sure builtin code objects get their builtin tags
// first. Otherwise a particular JSFunction object could set
// its custom name to a generic builtin.
RootsReferencesExtractor extractor(this);
ReadOnlyRoots(heap_).Iterate(&extractor);
heap_->IterateRoots(&extractor, VISIT_ONLY_STRONG);
extractor.SetVisitingWeakRoots();
heap_->IterateWeakGlobalHandles(&extractor);
bool interrupted = false;
HeapIterator iterator(heap_, HeapIterator::kFilterUnreachable);
// Heap iteration with filtering must be finished in any case.
for (HeapObject obj = iterator.next(); !obj.is_null();
obj = iterator.next(), progress_->ProgressStep()) {
if (interrupted) continue;
size_t max_pointer = obj->Size() / kTaggedSize;
if (max_pointer > visited_fields_.size()) {
// Clear the current bits.
std::vector<bool>().swap(visited_fields_);
// Reallocate to right size.
visited_fields_.resize(max_pointer, false);
}
HeapEntry* entry = GetEntry(obj);
ExtractReferences(entry, obj);
SetInternalReference(entry, "map", obj->map(), HeapObject::kMapOffset);
// Extract unvisited fields as hidden references and restore tags
// of visited fields.
IndexedReferencesExtractor refs_extractor(this, obj, entry);
obj->Iterate(&refs_extractor);
// Ensure visited_fields_ doesn't leak to the next object.
for (size_t i = 0; i < max_pointer; ++i) {
DCHECK(!visited_fields_[i]);
}
// Extract location for specific object types
ExtractLocation(entry, obj);
if (!progress_->ProgressReport(false)) interrupted = true;
}
generator_ = nullptr;
return interrupted ? false : progress_->ProgressReport(true);
}
bool V8HeapExplorer::IsEssentialObject(Object object) {
ReadOnlyRoots roots(heap_);
return object->IsHeapObject() && !object->IsOddball() &&
object != roots.empty_byte_array() &&
object != roots.empty_fixed_array() &&
object != roots.empty_weak_fixed_array() &&
object != roots.empty_descriptor_array() &&
object != roots.fixed_array_map() && object != roots.cell_map() &&
object != roots.global_property_cell_map() &&
object != roots.shared_function_info_map() &&
object != roots.free_space_map() &&
object != roots.one_pointer_filler_map() &&
object != roots.two_pointer_filler_map();
}
bool V8HeapExplorer::IsEssentialHiddenReference(Object parent,
int field_offset) {
if (parent->IsAllocationSite() &&
field_offset == AllocationSite::kWeakNextOffset)
return false;
if (parent->IsCodeDataContainer() &&
field_offset == CodeDataContainer::kNextCodeLinkOffset)
return false;
if (parent->IsContext() &&
field_offset == Context::OffsetOfElementAt(Context::NEXT_CONTEXT_LINK))
return false;
return true;
}
void V8HeapExplorer::SetContextReference(HeapEntry* parent_entry,
String reference_name,
Object child_obj, int field_offset) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
parent_entry->SetNamedReference(HeapGraphEdge::kContextVariable,
names_->GetName(reference_name), child_entry);
MarkVisitedField(field_offset);
}
void V8HeapExplorer::MarkVisitedField(int offset) {
if (offset < 0) return;
int index = offset / kTaggedSize;
DCHECK(!visited_fields_[index]);
visited_fields_[index] = true;
}
void V8HeapExplorer::SetNativeBindReference(HeapEntry* parent_entry,
const char* reference_name,
Object child_obj) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
parent_entry->SetNamedReference(HeapGraphEdge::kShortcut, reference_name,
child_entry);
}
void V8HeapExplorer::SetElementReference(HeapEntry* parent_entry, int index,
Object child_obj) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
parent_entry->SetIndexedReference(HeapGraphEdge::kElement, index,
child_entry);
}
void V8HeapExplorer::SetInternalReference(HeapEntry* parent_entry,
const char* reference_name,
Object child_obj, int field_offset) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
parent_entry->SetNamedReference(HeapGraphEdge::kInternal, reference_name,
child_entry);
}
MarkVisitedField(field_offset);
}
void V8HeapExplorer::SetInternalReference(HeapEntry* parent_entry, int index,
Object child_obj, int field_offset) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
parent_entry->SetNamedReference(HeapGraphEdge::kInternal,
names_->GetName(index), child_entry);
}
MarkVisitedField(field_offset);
}
void V8HeapExplorer::SetHiddenReference(HeapObject parent_obj,
HeapEntry* parent_entry, int index,
Object child_obj, int field_offset) {
DCHECK_EQ(parent_entry, GetEntry(parent_obj));
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry != nullptr && IsEssentialObject(child_obj) &&
IsEssentialHiddenReference(parent_obj, field_offset)) {
parent_entry->SetIndexedReference(HeapGraphEdge::kHidden, index,
child_entry);
}
}
void V8HeapExplorer::SetWeakReference(HeapEntry* parent_entry,
const char* reference_name,
Object child_obj, int field_offset) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
parent_entry->SetNamedReference(HeapGraphEdge::kWeak, reference_name,
child_entry);
}
MarkVisitedField(field_offset);
}
void V8HeapExplorer::SetWeakReference(HeapEntry* parent_entry, int index,
Object child_obj, int field_offset) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
parent_entry->SetNamedReference(
HeapGraphEdge::kWeak, names_->GetFormatted("%d", index), child_entry);
}
MarkVisitedField(field_offset);
}
void V8HeapExplorer::SetDataOrAccessorPropertyReference(
PropertyKind kind, HeapEntry* parent_entry, Name reference_name,
Object child_obj, const char* name_format_string, int field_offset) {
if (kind == kAccessor) {
ExtractAccessorPairProperty(parent_entry, reference_name, child_obj,
field_offset);
} else {
SetPropertyReference(parent_entry, reference_name, child_obj,
name_format_string, field_offset);
}
}
void V8HeapExplorer::SetPropertyReference(HeapEntry* parent_entry,
Name reference_name, Object child_obj,
const char* name_format_string,
int field_offset) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
HeapGraphEdge::Type type =
reference_name->IsSymbol() || String::cast(reference_name)->length() > 0
? HeapGraphEdge::kProperty
: HeapGraphEdge::kInternal;
const char* name =
name_format_string != nullptr && reference_name->IsString()
? names_->GetFormatted(
name_format_string,
String::cast(reference_name)
->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL)
.get())
: names_->GetName(reference_name);
parent_entry->SetNamedReference(type, name, child_entry);
MarkVisitedField(field_offset);
}
void V8HeapExplorer::SetRootGcRootsReference() {
snapshot_->root()->SetIndexedAutoIndexReference(HeapGraphEdge::kElement,
snapshot_->gc_roots());
}
void V8HeapExplorer::SetUserGlobalReference(Object child_obj) {
HeapEntry* child_entry = GetEntry(child_obj);
DCHECK_NOT_NULL(child_entry);
snapshot_->root()->SetNamedAutoIndexReference(HeapGraphEdge::kShortcut,
nullptr, child_entry, names_);
}
void V8HeapExplorer::SetGcRootsReference(Root root) {
snapshot_->gc_roots()->SetIndexedAutoIndexReference(
HeapGraphEdge::kElement, snapshot_->gc_subroot(root));
}
void V8HeapExplorer::SetGcSubrootReference(Root root, const char* description,
bool is_weak, Object child_obj) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
const char* name = GetStrongGcSubrootName(child_obj);
HeapGraphEdge::Type edge_type =
is_weak ? HeapGraphEdge::kWeak : HeapGraphEdge::kInternal;
if (name != nullptr) {
snapshot_->gc_subroot(root)->SetNamedReference(edge_type, name,
child_entry);
} else {
snapshot_->gc_subroot(root)->SetNamedAutoIndexReference(
edge_type, description, child_entry, names_);
}
// For full heap snapshots we do not emit user roots but rather rely on
// regular GC roots to retain objects.
if (FLAG_raw_heap_snapshots) return;
// Add a shortcut to JS global object reference at snapshot root.
// That allows the user to easily find global objects. They are
// also used as starting points in distance calculations.
if (is_weak || !child_obj->IsNativeContext()) return;
JSGlobalObject global = Context::cast(child_obj)->global_object();
if (!global->IsJSGlobalObject()) return;
if (!user_roots_.insert(global).second) return;
SetUserGlobalReference(global);
}
const char* V8HeapExplorer::GetStrongGcSubrootName(Object object) {
if (strong_gc_subroot_names_.empty()) {
Isolate* isolate = Isolate::FromHeap(heap_);
for (RootIndex root_index = RootIndex::kFirstStrongOrReadOnlyRoot;
root_index <= RootIndex::kLastStrongOrReadOnlyRoot; ++root_index) {
const char* name = RootsTable::name(root_index);
strong_gc_subroot_names_.emplace(isolate->root(root_index), name);
}
CHECK(!strong_gc_subroot_names_.empty());
}
auto it = strong_gc_subroot_names_.find(object);
return it != strong_gc_subroot_names_.end() ? it->second : nullptr;
}
void V8HeapExplorer::TagObject(Object obj, const char* tag) {
if (IsEssentialObject(obj)) {
HeapEntry* entry = GetEntry(obj);
if (entry->name()[0] == '\0') {
entry->set_name(tag);
}
}
}
class GlobalObjectsEnumerator : public RootVisitor {
public:
void VisitRootPointers(Root root, const char* description,
FullObjectSlot start, FullObjectSlot end) override {
for (FullObjectSlot p = start; p < end; ++p) {
if (!(*p)->IsNativeContext()) continue;
JSObject proxy = Context::cast(*p)->global_proxy();
if (!proxy->IsJSGlobalProxy()) continue;
Object global = proxy->map()->prototype();
if (!global->IsJSGlobalObject()) continue;
objects_.push_back(Handle<JSGlobalObject>(JSGlobalObject::cast(global),
proxy->GetIsolate()));
}
}
int count() const { return static_cast<int>(objects_.size()); }
Handle<JSGlobalObject>& at(int i) { return objects_[i]; }
private:
std::vector<Handle<JSGlobalObject>> objects_;
};
// Modifies heap. Must not be run during heap traversal.
void V8HeapExplorer::TagGlobalObjects() {
Isolate* isolate = Isolate::FromHeap(heap_);
HandleScope scope(isolate);
GlobalObjectsEnumerator enumerator;
isolate->global_handles()->IterateAllRoots(&enumerator);
std::vector<const char*> urls(enumerator.count());
for (int i = 0, l = enumerator.count(); i < l; ++i) {
urls[i] = global_object_name_resolver_
? global_object_name_resolver_->GetName(Utils::ToLocal(
Handle<JSObject>::cast(enumerator.at(i))))
: nullptr;
}
DisallowHeapAllocation no_allocation;
for (int i = 0, l = enumerator.count(); i < l; ++i) {
if (urls[i]) objects_tags_.emplace(*enumerator.at(i), urls[i]);
}
}
class EmbedderGraphImpl : public EmbedderGraph {
public:
struct Edge {
Node* from;
Node* to;
const char* name;
};
class V8NodeImpl : public Node {
public:
explicit V8NodeImpl(Object object) : object_(object) {}
Object GetObject() { return object_; }
// Node overrides.
bool IsEmbedderNode() override { return false; }
const char* Name() override {
// The name should be retrieved via GetObject().
UNREACHABLE();
return "";
}
size_t SizeInBytes() override {
// The size should be retrieved via GetObject().
UNREACHABLE();
return 0;
}
private:
Object object_;
};
Node* V8Node(const v8::Local<v8::Value>& value) final {
Handle<Object> object = v8::Utils::OpenHandle(*value);
DCHECK(!object.is_null());
return AddNode(std::unique_ptr<Node>(new V8NodeImpl(*object)));
}
Node* AddNode(std::unique_ptr<Node> node) final {
Node* result = node.get();
nodes_.push_back(std::move(node));
return result;
}
void AddEdge(Node* from, Node* to, const char* name) final {
edges_.push_back({from, to, name});
}
const std::vector<std::unique_ptr<Node>>& nodes() { return nodes_; }
const std::vector<Edge>& edges() { return edges_; }
private:
std::vector<std::unique_ptr<Node>> nodes_;
std::vector<Edge> edges_;
};
class EmbedderGraphEntriesAllocator : public HeapEntriesAllocator {
public:
explicit EmbedderGraphEntriesAllocator(HeapSnapshot* snapshot)
: snapshot_(snapshot),
names_(snapshot_->profiler()->names()),
heap_object_map_(snapshot_->profiler()->heap_object_map()) {}
HeapEntry* AllocateEntry(HeapThing ptr) override;
private:
HeapSnapshot* snapshot_;
StringsStorage* names_;
HeapObjectsMap* heap_object_map_;
};
namespace {
const char* EmbedderGraphNodeName(StringsStorage* names,
EmbedderGraphImpl::Node* node) {
const char* prefix = node->NamePrefix();
return prefix ? names->GetFormatted("%s %s", prefix, node->Name())
: names->GetCopy(node->Name());
}
HeapEntry::Type EmbedderGraphNodeType(EmbedderGraphImpl::Node* node) {
return node->IsRootNode() ? HeapEntry::kSynthetic : HeapEntry::kNative;
}
// Merges the names of an embedder node and its wrapper node.
// If the wrapper node name contains a tag suffix (part after '/') then the
// result is the embedder node name concatenated with the tag suffix.
// Otherwise, the result is the embedder node name.
const char* MergeNames(StringsStorage* names, const char* embedder_name,
const char* wrapper_name) {
const char* suffix = strchr(wrapper_name, '/');
return suffix ? names->GetFormatted("%s %s", embedder_name, suffix)
: embedder_name;
}
} // anonymous namespace
HeapEntry* EmbedderGraphEntriesAllocator::AllocateEntry(HeapThing ptr) {
EmbedderGraphImpl::Node* node =
reinterpret_cast<EmbedderGraphImpl::Node*>(ptr);
DCHECK(node->IsEmbedderNode());
size_t size = node->SizeInBytes();
return snapshot_->AddEntry(
EmbedderGraphNodeType(node), EmbedderGraphNodeName(names_, node),
static_cast<SnapshotObjectId>(reinterpret_cast<uintptr_t>(node) << 1),
static_cast<int>(size), 0);
}
NativeObjectsExplorer::NativeObjectsExplorer(
HeapSnapshot* snapshot, SnapshottingProgressReportingInterface* progress)
: isolate_(
Isolate::FromHeap(snapshot->profiler()->heap_object_map()->heap())),
snapshot_(snapshot),
names_(snapshot_->profiler()->names()),
embedder_graph_entries_allocator_(
new EmbedderGraphEntriesAllocator(snapshot)) {}
HeapEntry* NativeObjectsExplorer::EntryForEmbedderGraphNode(
EmbedderGraphImpl::Node* node) {
EmbedderGraphImpl::Node* wrapper = node->WrapperNode();
if (wrapper) {
node = wrapper;
}
if (node->IsEmbedderNode()) {
return generator_->FindOrAddEntry(node,
embedder_graph_entries_allocator_.get());
} else {
EmbedderGraphImpl::V8NodeImpl* v8_node =
static_cast<EmbedderGraphImpl::V8NodeImpl*>(node);
Object object = v8_node->GetObject();
if (object->IsSmi()) return nullptr;
return generator_->FindEntry(
reinterpret_cast<void*>(Object::cast(object).ptr()));
}
}
bool NativeObjectsExplorer::IterateAndExtractReferences(
HeapSnapshotGenerator* generator) {
generator_ = generator;
if (FLAG_heap_profiler_use_embedder_graph &&
snapshot_->profiler()->HasBuildEmbedderGraphCallback()) {
v8::HandleScope scope(reinterpret_cast<v8::Isolate*>(isolate_));
DisallowHeapAllocation no_allocation;
EmbedderGraphImpl graph;
snapshot_->profiler()->BuildEmbedderGraph(isolate_, &graph);
for (const auto& node : graph.nodes()) {
if (node->IsRootNode()) {
snapshot_->root()->SetIndexedAutoIndexReference(
HeapGraphEdge::kElement, EntryForEmbedderGraphNode(node.get()));
}
// Adjust the name and the type of the V8 wrapper node.
auto wrapper = node->WrapperNode();
if (wrapper) {
HeapEntry* wrapper_entry = EntryForEmbedderGraphNode(wrapper);
wrapper_entry->set_name(
MergeNames(names_, EmbedderGraphNodeName(names_, node.get()),
wrapper_entry->name()));
wrapper_entry->set_type(EmbedderGraphNodeType(node.get()));
}
}
// Fill edges of the graph.
for (const auto& edge : graph.edges()) {
HeapEntry* from = EntryForEmbedderGraphNode(edge.from);
// |from| and |to| can be nullptr if the corresponding node is a V8 node
// pointing to a Smi.
if (!from) continue;
HeapEntry* to = EntryForEmbedderGraphNode(edge.to);
if (!to) continue;
if (edge.name == nullptr) {
from->SetIndexedAutoIndexReference(HeapGraphEdge::kElement, to);
} else {
from->SetNamedReference(HeapGraphEdge::kInternal, edge.name, to);
}
}
}
generator_ = nullptr;
return true;
}
HeapSnapshotGenerator::HeapSnapshotGenerator(
HeapSnapshot* snapshot,
v8::ActivityControl* control,
v8::HeapProfiler::ObjectNameResolver* resolver,
Heap* heap)
: snapshot_(snapshot),
control_(control),
v8_heap_explorer_(snapshot_, this, resolver),
dom_explorer_(snapshot_, this),
heap_(heap) {
}
namespace {
class NullContextScope {
public:
explicit NullContextScope(Isolate* isolate)
: isolate_(isolate), prev_(isolate->context()) {
isolate_->set_context(Context());
}
~NullContextScope() { isolate_->set_context(prev_); }
private:
Isolate* isolate_;
Context prev_;
};
} // namespace
bool HeapSnapshotGenerator::GenerateSnapshot() {
v8_heap_explorer_.TagGlobalObjects();
// TODO(1562) Profiler assumes that any object that is in the heap after
// full GC is reachable from the root when computing dominators.
// This is not true for weakly reachable objects.
// As a temporary solution we call GC twice.
heap_->PreciseCollectAllGarbage(Heap::kNoGCFlags,
GarbageCollectionReason::kHeapProfiler);
heap_->PreciseCollectAllGarbage(Heap::kNoGCFlags,
GarbageCollectionReason::kHeapProfiler);
NullContextScope null_context_scope(Isolate::FromHeap(heap_));
#ifdef VERIFY_HEAP
Heap* debug_heap = heap_;
if (FLAG_verify_heap) {
debug_heap->Verify();
}
#endif
InitProgressCounter();
#ifdef VERIFY_HEAP
if (FLAG_verify_heap) {
debug_heap->Verify();
}
#endif
snapshot_->AddSyntheticRootEntries();
if (!FillReferences()) return false;
snapshot_->FillChildren();
snapshot_->RememberLastJSObjectId();
progress_counter_ = progress_total_;
if (!ProgressReport(true)) return false;
return true;
}
void HeapSnapshotGenerator::ProgressStep() {
++progress_counter_;
}
bool HeapSnapshotGenerator::ProgressReport(bool force) {
const int kProgressReportGranularity = 10000;
if (control_ != nullptr &&
(force || progress_counter_ % kProgressReportGranularity == 0)) {
return control_->ReportProgressValue(progress_counter_, progress_total_) ==
v8::ActivityControl::kContinue;
}
return true;
}
void HeapSnapshotGenerator::InitProgressCounter() {
if (control_ == nullptr) return;
// The +1 ensures that intermediate ProgressReport calls will never signal
// that the work is finished (i.e. progress_counter_ == progress_total_).
// Only the forced ProgressReport() at the end of GenerateSnapshot()
// should signal that the work is finished because signalling finished twice
// breaks the DevTools frontend.
progress_total_ = v8_heap_explorer_.EstimateObjectsCount() + 1;
progress_counter_ = 0;
}
bool HeapSnapshotGenerator::FillReferences() {
return v8_heap_explorer_.IterateAndExtractReferences(this) &&
dom_explorer_.IterateAndExtractReferences(this);
}
template<int bytes> struct MaxDecimalDigitsIn;
template<> struct MaxDecimalDigitsIn<4> {
static const int kSigned = 11;
static const int kUnsigned = 10;
};
template<> struct MaxDecimalDigitsIn<8> {
static const int kSigned = 20;
static const int kUnsigned = 20;
};
class OutputStreamWriter {
public:
explicit OutputStreamWriter(v8::OutputStream* stream)
: stream_(stream),
chunk_size_(stream->GetChunkSize()),
chunk_(chunk_size_),
chunk_pos_(0),
aborted_(false) {
DCHECK_GT(chunk_size_, 0);
}
bool aborted() { return aborted_; }
void AddCharacter(char c) {
DCHECK_NE(c, '\0');
DCHECK(chunk_pos_ < chunk_size_);
chunk_[chunk_pos_++] = c;
MaybeWriteChunk();
}
void AddString(const char* s) {
AddSubstring(s, StrLength(s));
}
void AddSubstring(const char* s, int n) {
if (n <= 0) return;
DCHECK(static_cast<size_t>(n) <= strlen(s));
const char* s_end = s + n;
while (s < s_end) {
int s_chunk_size =
Min(chunk_size_ - chunk_pos_, static_cast<int>(s_end - s));
DCHECK_GT(s_chunk_size, 0);
MemCopy(chunk_.start() + chunk_pos_, s, s_chunk_size);
s += s_chunk_size;
chunk_pos_ += s_chunk_size;
MaybeWriteChunk();
}
}
void AddNumber(unsigned n) { AddNumberImpl<unsigned>(n, "%u"); }
void Finalize() {
if (aborted_) return;
DCHECK(chunk_pos_ < chunk_size_);
if (chunk_pos_ != 0) {
WriteChunk();
}
stream_->EndOfStream();
}
private:
template<typename T>
void AddNumberImpl(T n, const char* format) {
// Buffer for the longest value plus trailing \0
static const int kMaxNumberSize =
MaxDecimalDigitsIn<sizeof(T)>::kUnsigned + 1;
if (chunk_size_ - chunk_pos_ >= kMaxNumberSize) {
int result = SNPrintF(
chunk_.SubVector(chunk_pos_, chunk_size_), format, n);
DCHECK_NE(result, -1);
chunk_pos_ += result;
MaybeWriteChunk();
} else {
EmbeddedVector<char, kMaxNumberSize> buffer;
int result = SNPrintF(buffer, format, n);
USE(result);
DCHECK_NE(result, -1);
AddString(buffer.start());
}
}
void MaybeWriteChunk() {
DCHECK(chunk_pos_ <= chunk_size_);
if (chunk_pos_ == chunk_size_) {
WriteChunk();
}
}
void WriteChunk() {
if (aborted_) return;
if (stream_->WriteAsciiChunk(chunk_.start(), chunk_pos_) ==
v8::OutputStream::kAbort) aborted_ = true;
chunk_pos_ = 0;
}
v8::OutputStream* stream_;
int chunk_size_;
ScopedVector<char> chunk_;
int chunk_pos_;
bool aborted_;
};
// type, name|index, to_node.
const int HeapSnapshotJSONSerializer::kEdgeFieldsCount = 3;
// type, name, id, self_size, edge_count, trace_node_id.
const int HeapSnapshotJSONSerializer::kNodeFieldsCount = 6;
void HeapSnapshotJSONSerializer::Serialize(v8::OutputStream* stream) {
if (AllocationTracker* allocation_tracker =
snapshot_->profiler()->allocation_tracker()) {
allocation_tracker->PrepareForSerialization();
}
DCHECK_NULL(writer_);
writer_ = new OutputStreamWriter(stream);
SerializeImpl();
delete writer_;
writer_ = nullptr;
}
void HeapSnapshotJSONSerializer::SerializeImpl() {
DCHECK_EQ(0, snapshot_->root()->index());
writer_->AddCharacter('{');
writer_->AddString("\"snapshot\":{");
SerializeSnapshot();
if (writer_->aborted()) return;
writer_->AddString("},\n");
writer_->AddString("\"nodes\":[");
SerializeNodes();
if (writer_->aborted()) return;
writer_->AddString("],\n");
writer_->AddString("\"edges\":[");
SerializeEdges();
if (writer_->aborted()) return;
writer_->AddString("],\n");
writer_->AddString("\"trace_function_infos\":[");
SerializeTraceNodeInfos();
if (writer_->aborted()) return;
writer_->AddString("],\n");
writer_->AddString("\"trace_tree\":[");
SerializeTraceTree();
if (writer_->aborted()) return;
writer_->AddString("],\n");
writer_->AddString("\"samples\":[");
SerializeSamples();
if (writer_->aborted()) return;
writer_->AddString("],\n");
writer_->AddString("\"locations\":[");
SerializeLocations();
if (writer_->aborted()) return;
writer_->AddString("],\n");
writer_->AddString("\"strings\":[");
SerializeStrings();
if (writer_->aborted()) return;
writer_->AddCharacter(']');
writer_->AddCharacter('}');
writer_->Finalize();
}
int HeapSnapshotJSONSerializer::GetStringId(const char* s) {
base::HashMap::Entry* cache_entry =
strings_.LookupOrInsert(const_cast<char*>(s), StringHash(s));
if (cache_entry->value == nullptr) {
cache_entry->value = reinterpret_cast<void*>(next_string_id_++);
}
return static_cast<int>(reinterpret_cast<intptr_t>(cache_entry->value));
}
namespace {
template<size_t size> struct ToUnsigned;
template<> struct ToUnsigned<4> {
typedef uint32_t Type;
};
template<> struct ToUnsigned<8> {
typedef uint64_t Type;
};
} // namespace
template<typename T>
static int utoa_impl(T value, const Vector<char>& buffer, int buffer_pos) {
STATIC_ASSERT(static_cast<T>(-1) > 0); // Check that T is unsigned
int number_of_digits = 0;
T t = value;
do {
++number_of_digits;
} while (t /= 10);
buffer_pos += number_of_digits;
int result = buffer_pos;
do {
int last_digit = static_cast<int>(value % 10);
buffer[--buffer_pos] = '0' + last_digit;
value /= 10;
} while (value);
return result;
}
template<typename T>
static int utoa(T value, const Vector<char>& buffer, int buffer_pos) {
typename ToUnsigned<sizeof(value)>::Type unsigned_value = value;
STATIC_ASSERT(sizeof(value) == sizeof(unsigned_value));
return utoa_impl(unsigned_value, buffer, buffer_pos);
}
void HeapSnapshotJSONSerializer::SerializeEdge(HeapGraphEdge* edge,
bool first_edge) {
// The buffer needs space for 3 unsigned ints, 3 commas, \n and \0
static const int kBufferSize =
MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned * 3 + 3 + 2; // NOLINT
EmbeddedVector<char, kBufferSize> buffer;
int edge_name_or_index = edge->type() == HeapGraphEdge::kElement
|| edge->type() == HeapGraphEdge::kHidden
? edge->index() : GetStringId(edge->name());
int buffer_pos = 0;
if (!first_edge) {
buffer[buffer_pos++] = ',';
}
buffer_pos = utoa(edge->type(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(edge_name_or_index, buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(to_node_index(edge->to()), buffer, buffer_pos);
buffer[buffer_pos++] = '\n';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.start());
}
void HeapSnapshotJSONSerializer::SerializeEdges() {
std::vector<HeapGraphEdge*>& edges = snapshot_->children();
for (size_t i = 0; i < edges.size(); ++i) {
DCHECK(i == 0 ||
edges[i - 1]->from()->index() <= edges[i]->from()->index());
SerializeEdge(edges[i], i == 0);
if (writer_->aborted()) return;
}
}
void HeapSnapshotJSONSerializer::SerializeNode(const HeapEntry* entry) {
// The buffer needs space for 4 unsigned ints, 1 size_t, 5 commas, \n and \0
static const int kBufferSize =
5 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned // NOLINT
+ MaxDecimalDigitsIn<sizeof(size_t)>::kUnsigned // NOLINT
+ 6 + 1 + 1;
EmbeddedVector<char, kBufferSize> buffer;
int buffer_pos = 0;
if (to_node_index(entry) != 0) {
buffer[buffer_pos++] = ',';
}
buffer_pos = utoa(entry->type(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(GetStringId(entry->name()), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(entry->id(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(entry->self_size(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(entry->children_count(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(entry->trace_node_id(), buffer, buffer_pos);
buffer[buffer_pos++] = '\n';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.start());
}
void HeapSnapshotJSONSerializer::SerializeNodes() {
const std::deque<HeapEntry>& entries = snapshot_->entries();
for (const HeapEntry& entry : entries) {
SerializeNode(&entry);
if (writer_->aborted()) return;
}
}
void HeapSnapshotJSONSerializer::SerializeSnapshot() {
writer_->AddString("\"meta\":");
// The object describing node serialization layout.
// We use a set of macros to improve readability.
// clang-format off
#define JSON_A(s) "[" s "]"
#define JSON_O(s) "{" s "}"
#define JSON_S(s) "\"" s "\""
writer_->AddString(JSON_O(
JSON_S("node_fields") ":" JSON_A(
JSON_S("type") ","
JSON_S("name") ","
JSON_S("id") ","
JSON_S("self_size") ","
JSON_S("edge_count") ","
JSON_S("trace_node_id")) ","
JSON_S("node_types") ":" JSON_A(
JSON_A(
JSON_S("hidden") ","
JSON_S("array") ","
JSON_S("string") ","
JSON_S("object") ","
JSON_S("code") ","
JSON_S("closure") ","
JSON_S("regexp") ","
JSON_S("number") ","
JSON_S("native") ","
JSON_S("synthetic") ","
JSON_S("concatenated string") ","
JSON_S("sliced string") ","
JSON_S("symbol") ","
JSON_S("bigint")) ","
JSON_S("string") ","
JSON_S("number") ","
JSON_S("number") ","
JSON_S("number") ","
JSON_S("number") ","
JSON_S("number")) ","