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cobalt / cobalt / ac9ac065c5083565917b15e7a672a79599f2f00b / . / src / v8 / src / profiler / heap-snapshot-generator.cc
blob: 8cacc20d8b8846d012e71d14521bd1834e2fd6e7 [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.h"
#include "src/code-stubs.h"
#include "src/conversions.h"
#include "src/debug/debug.h"
#include "src/layout-descriptor.h"
#include "src/objects-body-descriptors.h"
#include "src/objects-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.h"
#include "src/visitors.h"
#if V8_OS_STARBOARD
#include "src/poems.h"
#endif
namespace v8 {
namespace internal {
HeapGraphEdge::HeapGraphEdge(Type type, const char* name, int from, int to)
: bit_field_(TypeField::encode(type) | FromIndexField::encode(from)),
to_index_(to),
name_(name) {
DCHECK(type == kContextVariable
|| type == kProperty
|| type == kInternal
|| type == kShortcut
|| type == kWeak);
}
HeapGraphEdge::HeapGraphEdge(Type type, int index, int from, int to)
: bit_field_(TypeField::encode(type) | FromIndexField::encode(from)),
to_index_(to),
index_(index) {
DCHECK(type == kElement || type == kHidden);
}
void HeapGraphEdge::ReplaceToIndexWithEntry(HeapSnapshot* snapshot) {
to_entry_ = &snapshot->entries()[to_index_];
}
const int HeapEntry::kNoEntry = -1;
HeapEntry::HeapEntry(HeapSnapshot* snapshot,
Type type,
const char* name,
SnapshotObjectId id,
size_t self_size,
unsigned trace_node_id)
: type_(type),
children_count_(0),
children_index_(-1),
self_size_(self_size),
snapshot_(snapshot),
name_(name),
id_(id),
trace_node_id_(trace_node_id) { }
void HeapEntry::SetNamedReference(HeapGraphEdge::Type type,
const char* name,
HeapEntry* entry) {
HeapGraphEdge edge(type, name, this->index(), entry->index());
snapshot_->edges().push_back(edge);
++children_count_;
}
void HeapEntry::SetIndexedReference(HeapGraphEdge::Type type,
int index,
HeapEntry* entry) {
HeapGraphEdge edge(type, index, this->index(), entry->index());
snapshot_->edges().push_back(edge);
++children_count_;
}
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/";
default: return "???";
}
}
HeapSnapshot::HeapSnapshot(HeapProfiler* profiler)
: profiler_(profiler),
root_index_(HeapEntry::kNoEntry),
gc_roots_index_(HeapEntry::kNoEntry),
max_snapshot_js_object_id_(0) {
// It is very important to keep objects that form a heap snapshot
// as small as possible. Check assumptions about data structure sizes.
STATIC_ASSERT(((kPointerSize == 4) && (sizeof(HeapGraphEdge) == 12)) ||
((kPointerSize == 8) && (sizeof(HeapGraphEdge) == 24)));
STATIC_ASSERT(((kPointerSize == 4) && (sizeof(HeapEntry) == 28)) ||
((kPointerSize == 8) && (sizeof(HeapEntry) == 40)));
for (int i = 0; i < VisitorSynchronization::kNumberOfSyncTags; ++i) {
gc_subroot_indexes_[i] = HeapEntry::kNoEntry;
}
}
void HeapSnapshot::Delete() {
profiler_->RemoveSnapshot(this);
delete 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 tag = 0; tag < VisitorSynchronization::kNumberOfSyncTags; tag++) {
AddGcSubrootEntry(tag, id);
id += HeapObjectsMap::kObjectIdStep;
}
DCHECK_EQ(HeapObjectsMap::kFirstAvailableObjectId, id);
}
HeapEntry* HeapSnapshot::AddRootEntry() {
DCHECK_EQ(root_index_, HeapEntry::kNoEntry);
DCHECK(entries_.empty()); // Root entry must be the first one.
HeapEntry* entry = AddEntry(HeapEntry::kSynthetic,
"",
HeapObjectsMap::kInternalRootObjectId,
0,
0);
root_index_ = entry->index();
DCHECK_EQ(root_index_, 0);
return entry;
}
HeapEntry* HeapSnapshot::AddGcRootsEntry() {
DCHECK_EQ(gc_roots_index_, HeapEntry::kNoEntry);
HeapEntry* entry = AddEntry(HeapEntry::kSynthetic,
"(GC roots)",
HeapObjectsMap::kGcRootsObjectId,
0,
0);
gc_roots_index_ = entry->index();
return entry;
}
HeapEntry* HeapSnapshot::AddGcSubrootEntry(int tag, SnapshotObjectId id) {
DCHECK_EQ(gc_subroot_indexes_[tag], HeapEntry::kNoEntry);
DCHECK(0 <= tag && tag < VisitorSynchronization::kNumberOfSyncTags);
HeapEntry* entry = AddEntry(HeapEntry::kSynthetic,
VisitorSynchronization::kTagNames[tag], id, 0, 0);
gc_subroot_indexes_[tag] = entry->index();
return entry;
}
HeapEntry* HeapSnapshot::AddEntry(HeapEntry::Type type,
const char* name,
SnapshotObjectId id,
size_t size,
unsigned trace_node_id) {
DCHECK(sorted_entries_.empty());
entries_.emplace_back(this, type, name, id, size, trace_node_id);
return &entries_.back();
}
void HeapSnapshot::FillChildren() {
DCHECK(children().empty());
children().resize(edges().size());
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));
for (HeapGraphEdge& edge : edges()) {
edge.ReplaceToIndexWithEntry(this);
edge.from()->add_child(&edge);
}
}
HeapEntry* HeapSnapshot::GetEntryById(SnapshotObjectId id) {
std::vector<HeapEntry*>* entries_by_id = GetSortedEntriesList();
auto it = std::lower_bound(
entries_by_id->begin(), entries_by_id->end(), id,
[](HeapEntry* first, SnapshotObjectId val) { return first->id() < val; });
if (it == entries_by_id->end() || (*it)->id() != id) return nullptr;
return *it;
}
struct SortByIds {
bool operator()(const HeapEntry* entry1_ptr, const HeapEntry* entry2_ptr) {
return entry1_ptr->id() < entry2_ptr->id();
}
};
std::vector<HeapEntry*>* HeapSnapshot::GetSortedEntriesList() {
if (sorted_entries_.empty()) {
sorted_entries_.reserve(entries_.size());
for (HeapEntry& entry : entries_) {
sorted_entries_.push_back(&entry);
}
std::sort(sorted_entries_.begin(), sorted_entries_.end(), SortByIds());
}
return &sorted_entries_;
}
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 +
VisitorSynchronization::kNumberOfSyncTags * 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, nullptr, 0, true);
}
bool HeapObjectsMap::MoveObject(Address from, Address to, int object_size) {
DCHECK_NOT_NULL(to);
DCHECK_NOT_NULL(from);
if (from == to) return false;
void* from_value = entries_map_.Remove(from, ComputePointerHash(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(to, ComputePointerHash(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 = nullptr;
}
} else {
base::HashMap::Entry* to_entry =
entries_map_.LookupOrInsert(to, ComputePointerHash(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 = nullptr;
}
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",
static_cast<void*>(from), static_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(addr, ComputePointerHash(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(addr, ComputePointerHash(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",
static_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_->CollectAllGarbage(Heap::kMakeHeapIterableMask,
GarbageCollectionReason::kHeapProfiler);
HeapIterator iterator(heap_);
for (HeapObject* obj = iterator.next(); obj != nullptr;
obj = iterator.next()) {
FindOrAddEntry(obj->address(), obj->Size());
if (FLAG_heap_profiler_trace_objects) {
PrintF("Update object : %p %6d. Next address is %p\n",
static_cast<void*>(obj->address()), obj->Size(),
static_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 == nullptr);
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(
entry_info.addr, ComputePointerHash(entry_info.addr));
DCHECK(entry);
entry->value = reinterpret_cast<void*>(first_free_entry);
++first_free_entry;
} else {
if (entry_info.addr) {
entries_map_.Remove(entry_info.addr,
ComputePointerHash(entry_info.addr));
}
}
}
entries_.erase(entries_.begin() + first_free_entry, entries_.end());
DCHECK(static_cast<uint32_t>(entries_.size()) - 1 ==
entries_map_.occupancy());
}
SnapshotObjectId HeapObjectsMap::GenerateId(v8::RetainedObjectInfo* info) {
SnapshotObjectId id = static_cast<SnapshotObjectId>(info->GetHash());
const char* label = info->GetLabel();
id ^= StringHasher::HashSequentialString(label,
static_cast<int>(strlen(label)),
heap_->HashSeed());
intptr_t element_count = info->GetElementCount();
if (element_count != -1) {
id ^= ComputeIntegerHash(static_cast<uint32_t>(element_count));
}
return id << 1;
}
HeapEntriesMap::HeapEntriesMap() : entries_() {}
int HeapEntriesMap::Map(HeapThing thing) {
base::HashMap::Entry* cache_entry = entries_.Lookup(thing, Hash(thing));
if (cache_entry == nullptr) return HeapEntry::kNoEntry;
return static_cast<int>(reinterpret_cast<intptr_t>(cache_entry->value));
}
void HeapEntriesMap::Pair(HeapThing thing, int entry) {
base::HashMap::Entry* cache_entry =
entries_.LookupOrInsert(thing, Hash(thing));
DCHECK_NULL(cache_entry->value);
cache_entry->value = reinterpret_cast<void*>(static_cast<intptr_t>(entry));
}
HeapObjectsSet::HeapObjectsSet() : entries_() {}
void HeapObjectsSet::Clear() {
entries_.Clear();
}
bool HeapObjectsSet::Contains(Object* obj) {
if (!obj->IsHeapObject()) return false;
HeapObject* object = HeapObject::cast(obj);
return entries_.Lookup(object, HeapEntriesMap::Hash(object)) != nullptr;
}
void HeapObjectsSet::Insert(Object* obj) {
if (!obj->IsHeapObject()) return;
HeapObject* object = HeapObject::cast(obj);
entries_.LookupOrInsert(object, HeapEntriesMap::Hash(object));
}
const char* HeapObjectsSet::GetTag(Object* obj) {
HeapObject* object = HeapObject::cast(obj);
base::HashMap::Entry* cache_entry =
entries_.Lookup(object, HeapEntriesMap::Hash(object));
return cache_entry != nullptr
? reinterpret_cast<const char*>(cache_entry->value)
: nullptr;
}
V8_NOINLINE void HeapObjectsSet::SetTag(Object* obj, const char* tag) {
if (!obj->IsHeapObject()) return;
HeapObject* object = HeapObject::cast(obj);
base::HashMap::Entry* cache_entry =
entries_.LookupOrInsert(object, HeapEntriesMap::Hash(object));
cache_entry->value = const_cast<char*>(tag);
}
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),
filler_(nullptr),
global_object_name_resolver_(resolver) {}
V8HeapExplorer::~V8HeapExplorer() {
}
HeapEntry* V8HeapExplorer::AllocateEntry(HeapThing ptr) {
return AddEntry(reinterpret_cast<HeapObject*>(ptr));
}
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()) {
const char* tag = objects_tags_.GetTag(object);
if (tag != nullptr) {
name = names_->GetFormatted("%s / %s", name, tag);
}
}
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)");
if (string->IsSlicedString())
return AddEntry(object,
HeapEntry::kSlicedString,
"(sliced string)");
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->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);
}
class SnapshotFiller {
public:
explicit SnapshotFiller(HeapSnapshot* snapshot, HeapEntriesMap* entries)
: snapshot_(snapshot),
names_(snapshot->profiler()->names()),
entries_(entries) { }
HeapEntry* AddEntry(HeapThing ptr, HeapEntriesAllocator* allocator) {
HeapEntry* entry = allocator->AllocateEntry(ptr);
entries_->Pair(ptr, entry->index());
return entry;
}
HeapEntry* FindEntry(HeapThing ptr) {
int index = entries_->Map(ptr);
return index != HeapEntry::kNoEntry ? &snapshot_->entries()[index]
: nullptr;
}
HeapEntry* FindOrAddEntry(HeapThing ptr, HeapEntriesAllocator* allocator) {
HeapEntry* entry = FindEntry(ptr);
return entry != nullptr ? entry : AddEntry(ptr, allocator);
}
void SetIndexedReference(HeapGraphEdge::Type type,
int parent,
int index,
HeapEntry* child_entry) {
HeapEntry* parent_entry = &snapshot_->entries()[parent];
parent_entry->SetIndexedReference(type, index, child_entry);
}
void SetIndexedAutoIndexReference(HeapGraphEdge::Type type,
int parent,
HeapEntry* child_entry) {
HeapEntry* parent_entry = &snapshot_->entries()[parent];
int index = parent_entry->children_count() + 1;
parent_entry->SetIndexedReference(type, index, child_entry);
}
void SetNamedReference(HeapGraphEdge::Type type,
int parent,
const char* reference_name,
HeapEntry* child_entry) {
HeapEntry* parent_entry = &snapshot_->entries()[parent];
parent_entry->SetNamedReference(type, reference_name, child_entry);
}
void SetNamedAutoIndexReference(HeapGraphEdge::Type type,
int parent,
HeapEntry* child_entry) {
HeapEntry* parent_entry = &snapshot_->entries()[parent];
int index = parent_entry->children_count() + 1;
parent_entry->SetNamedReference(
type,
names_->GetName(index),
child_entry);
}
private:
HeapSnapshot* snapshot_;
StringsStorage* names_;
HeapEntriesMap* entries_;
};
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";
#define MAKE_STRUCT_CASE(NAME, Name, name) \
case NAME##_TYPE: return "system / "#Name;
STRUCT_LIST(MAKE_STRUCT_CASE)
#undef MAKE_STRUCT_CASE
default: return "system";
}
}
int V8HeapExplorer::EstimateObjectsCount(HeapIterator* iterator) {
int objects_count = 0;
for (HeapObject* obj = iterator->next(); obj != nullptr;
obj = iterator->next()) {
objects_count++;
}
return objects_count;
}
class IndexedReferencesExtractor : public ObjectVisitor {
public:
IndexedReferencesExtractor(V8HeapExplorer* generator, HeapObject* parent_obj,
int parent)
: generator_(generator),
parent_obj_(parent_obj),
parent_start_(HeapObject::RawField(parent_obj_, 0)),
parent_end_(HeapObject::RawField(parent_obj_, parent_obj_->Size())),
parent_(parent),
next_index_(0) {}
void VisitPointers(HeapObject* host, Object** start, Object** end) override {
for (Object** p = start; p < end; p++) {
int index = static_cast<int>(p - HeapObject::RawField(parent_obj_, 0));
++next_index_;
// |p| could be outside of the object, e.g., while visiting RelocInfo of
// code objects.
if (p >= parent_start_ && p < parent_end_ && generator_->marks_[index]) {
generator_->marks_[index] = false;
continue;
}
generator_->SetHiddenReference(parent_obj_, parent_, next_index_, *p,
index * kPointerSize);
}
}
private:
V8HeapExplorer* generator_;
HeapObject* parent_obj_;
Object** parent_start_;
Object** parent_end_;
int parent_;
int next_index_;
};
bool V8HeapExplorer::ExtractReferencesPass1(int entry, HeapObject* obj) {
if (obj->IsFixedArray()) return false; // FixedArrays are processed on pass 2
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));
}
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->IsWeakCell()) {
ExtractWeakCellReferences(entry, WeakCell::cast(obj));
} else if (obj->IsPropertyCell()) {
ExtractPropertyCellReferences(entry, PropertyCell::cast(obj));
} else if (obj->IsAllocationSite()) {
ExtractAllocationSiteReferences(entry, AllocationSite::cast(obj));
}
return true;
}
bool V8HeapExplorer::ExtractReferencesPass2(int entry, HeapObject* obj) {
if (!obj->IsFixedArray()) return false;
if (obj->IsContext()) {
ExtractContextReferences(entry, Context::cast(obj));
} else {
ExtractFixedArrayReferences(entry, FixedArray::cast(obj));
}
return true;
}
void V8HeapExplorer::ExtractJSGlobalProxyReferences(
int entry, JSGlobalProxy* proxy) {
SetInternalReference(proxy, entry,
"native_context", proxy->native_context(),
JSGlobalProxy::kNativeContextOffset);
}
void V8HeapExplorer::ExtractJSObjectReferences(
int entry, JSObject* js_obj) {
HeapObject* obj = js_obj;
ExtractPropertyReferences(js_obj, entry);
ExtractElementReferences(js_obj, entry);
ExtractInternalReferences(js_obj, entry);
PrototypeIterator iter(heap_->isolate(), js_obj);
SetPropertyReference(obj, entry, heap_->proto_string(), iter.GetCurrent());
if (obj->IsJSBoundFunction()) {
JSBoundFunction* js_fun = JSBoundFunction::cast(obj);
TagObject(js_fun->bound_arguments(), "(bound arguments)");
SetInternalReference(js_fun, entry, "bindings", js_fun->bound_arguments(),
JSBoundFunction::kBoundArgumentsOffset);
SetInternalReference(js_obj, entry, "bound_this", js_fun->bound_this(),
JSBoundFunction::kBoundThisOffset);
SetInternalReference(js_obj, 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(js_obj, 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(heap_->isolate())) {
if (!proto_or_map->IsMap()) {
SetPropertyReference(obj, entry, heap_->prototype_string(),
proto_or_map, nullptr,
JSFunction::kPrototypeOrInitialMapOffset);
} else {
SetPropertyReference(obj, entry, heap_->prototype_string(),
js_fun->prototype());
SetInternalReference(obj, entry, "initial_map", proto_or_map,
JSFunction::kPrototypeOrInitialMapOffset);
}
}
}
SharedFunctionInfo* shared_info = js_fun->shared();
TagObject(js_fun->feedback_vector_cell(),
"(function feedback vector cell)");
SetInternalReference(js_fun, entry, "feedback_vector_cell",
js_fun->feedback_vector_cell(),
JSFunction::kFeedbackVectorOffset);
TagObject(shared_info, "(shared function info)");
SetInternalReference(js_fun, entry,
"shared", shared_info,
JSFunction::kSharedFunctionInfoOffset);
TagObject(js_fun->context(), "(context)");
SetInternalReference(js_fun, entry,
"context", js_fun->context(),
JSFunction::kContextOffset);
TagCodeObject(js_fun->code());
SetInternalReference(js_fun, entry, "code", js_fun->code(),
JSFunction::kCodeOffset);
} else if (obj->IsJSGlobalObject()) {
JSGlobalObject* global_obj = JSGlobalObject::cast(obj);
SetInternalReference(global_obj, entry, "native_context",
global_obj->native_context(),
JSGlobalObject::kNativeContextOffset);
SetInternalReference(global_obj, entry, "global_proxy",
global_obj->global_proxy(),
JSGlobalObject::kGlobalProxyOffset);
STATIC_ASSERT(JSGlobalObject::kSize - JSObject::kHeaderSize ==
2 * kPointerSize);
} else if (obj->IsJSArrayBufferView()) {
JSArrayBufferView* view = JSArrayBufferView::cast(obj);
SetInternalReference(view, entry, "buffer", view->buffer(),
JSArrayBufferView::kBufferOffset);
}
TagObject(js_obj->raw_properties_or_hash(), "(object properties)");
SetInternalReference(obj, entry, "properties",
js_obj->raw_properties_or_hash(),
JSObject::kPropertiesOrHashOffset);
TagObject(js_obj->elements(), "(object elements)");
SetInternalReference(obj, entry,
"elements", js_obj->elements(),
JSObject::kElementsOffset);
}
void V8HeapExplorer::ExtractStringReferences(int entry, String* string) {
if (string->IsConsString()) {
ConsString* cs = ConsString::cast(string);
SetInternalReference(cs, entry, "first", cs->first(),
ConsString::kFirstOffset);
SetInternalReference(cs, entry, "second", cs->second(),
ConsString::kSecondOffset);
} else if (string->IsSlicedString()) {
SlicedString* ss = SlicedString::cast(string);
SetInternalReference(ss, entry, "parent", ss->parent(),
SlicedString::kParentOffset);
} else if (string->IsThinString()) {
ThinString* ts = ThinString::cast(string);
SetInternalReference(ts, entry, "actual", ts->actual(),
ThinString::kActualOffset);
}
}
void V8HeapExplorer::ExtractSymbolReferences(int entry, Symbol* symbol) {
SetInternalReference(symbol, entry,
"name", symbol->name(),
Symbol::kNameOffset);
}
void V8HeapExplorer::ExtractJSCollectionReferences(int entry,
JSCollection* collection) {
SetInternalReference(collection, entry, "table", collection->table(),
JSCollection::kTableOffset);
}
void V8HeapExplorer::ExtractJSWeakCollectionReferences(int entry,
JSWeakCollection* obj) {
if (obj->table()->IsHashTable()) {
ObjectHashTable* table = ObjectHashTable::cast(obj->table());
TagFixedArraySubType(table, JS_WEAK_COLLECTION_SUB_TYPE);
}
SetInternalReference(obj, entry, "table", obj->table(),
JSWeakCollection::kTableOffset);
}
void V8HeapExplorer::ExtractContextReferences(int entry, Context* context) {
if (context == context->declaration_context()) {
ScopeInfo* scope_info = context->closure()->shared()->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(context, entry, local_name, context->get(idx),
Context::OffsetOfElementAt(idx));
}
if (scope_info->HasFunctionName()) {
String* name = scope_info->FunctionName();
int idx = scope_info->FunctionContextSlotIndex(name);
if (idx >= 0) {
SetContextReference(context, entry, name, context->get(idx),
Context::OffsetOfElementAt(idx));
}
}
}
#define EXTRACT_CONTEXT_FIELD(index, type, name) \
if (Context::index < Context::FIRST_WEAK_SLOT || \
Context::index == Context::MAP_CACHE_INDEX) { \
SetInternalReference(context, entry, #name, context->get(Context::index), \
FixedArray::OffsetOfElementAt(Context::index)); \
} else { \
SetWeakReference(context, entry, #name, context->get(Context::index), \
FixedArray::OffsetOfElementAt(Context::index)); \
}
EXTRACT_CONTEXT_FIELD(CLOSURE_INDEX, JSFunction, closure);
EXTRACT_CONTEXT_FIELD(PREVIOUS_INDEX, Context, previous);
EXTRACT_CONTEXT_FIELD(EXTENSION_INDEX, HeapObject, extension);
EXTRACT_CONTEXT_FIELD(NATIVE_CONTEXT_INDEX, Context, native_context);
if (context->IsNativeContext()) {
TagObject(context->normalized_map_cache(), "(context norm. map cache)");
TagObject(context->embedder_data(), "(context data)");
NATIVE_CONTEXT_FIELDS(EXTRACT_CONTEXT_FIELD)
EXTRACT_CONTEXT_FIELD(OPTIMIZED_CODE_LIST, unused, optimized_code_list);
EXTRACT_CONTEXT_FIELD(DEOPTIMIZED_CODE_LIST, unused, deoptimized_code_list);
#undef EXTRACT_CONTEXT_FIELD
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(int entry, Map* map) {
Object* raw_transitions_or_prototype_info = map->raw_transitions();
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(map, entry, "transitions", transitions,
Map::kTransitionsOrPrototypeInfoOffset);
} else if (raw_transitions_or_prototype_info->IsWeakCell() ||
raw_transitions_or_prototype_info->IsTuple3() ||
raw_transitions_or_prototype_info->IsFixedArray()) {
TagObject(raw_transitions_or_prototype_info, "(transition)");
SetInternalReference(map, entry, "transition",
raw_transitions_or_prototype_info,
Map::kTransitionsOrPrototypeInfoOffset);
} else if (map->is_prototype_map()) {
TagObject(raw_transitions_or_prototype_info, "prototype_info");
SetInternalReference(map, entry, "prototype_info",
raw_transitions_or_prototype_info,
Map::kTransitionsOrPrototypeInfoOffset);
}
DescriptorArray* descriptors = map->instance_descriptors();
TagObject(descriptors, "(map descriptors)");
SetInternalReference(map, entry, "descriptors", descriptors,
Map::kDescriptorsOffset);
SetInternalReference(map, entry, "prototype", map->prototype(),
Map::kPrototypeOffset);
if (FLAG_unbox_double_fields) {
SetInternalReference(map, 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(map, entry, "back_pointer", constructor_or_backpointer,
Map::kConstructorOrBackPointerOffset);
} else if (constructor_or_backpointer->IsFunctionTemplateInfo()) {
TagObject(constructor_or_backpointer, "(constructor function data)");
SetInternalReference(map, entry, "constructor_function_data",
constructor_or_backpointer,
Map::kConstructorOrBackPointerOffset);
} else {
SetInternalReference(map, entry, "constructor", constructor_or_backpointer,
Map::kConstructorOrBackPointerOffset);
}
TagObject(map->dependent_code(), "(dependent code)");
SetInternalReference(map, entry, "dependent_code", map->dependent_code(),
Map::kDependentCodeOffset);
TagObject(map->weak_cell_cache(), "(weak cell)");
SetInternalReference(map, entry, "weak_cell_cache", map->weak_cell_cache(),
Map::kWeakCellCacheOffset);
}
void V8HeapExplorer::ExtractSharedFunctionInfoReferences(
int entry, SharedFunctionInfo* shared) {
HeapObject* obj = shared;
String* shared_name = shared->DebugName();
const char* name = nullptr;
if (shared_name != heap_->empty_string()) {
name = names_->GetName(shared_name);
TagObject(shared->code(), names_->GetFormatted("(code for %s)", name));
} else {
TagObject(shared->code(), names_->GetFormatted("(%s code)",
Code::Kind2String(shared->code()->kind())));
}
SetInternalReference(obj, entry, "raw_name", shared->raw_name(),
SharedFunctionInfo::kNameOffset);
SetInternalReference(obj, entry,
"code", shared->code(),
SharedFunctionInfo::kCodeOffset);
TagObject(shared->scope_info(), "(function scope info)");
SetInternalReference(obj, entry,
"scope_info", shared->scope_info(),
SharedFunctionInfo::kScopeInfoOffset);
SetInternalReference(obj, entry,
"instance_class_name", shared->instance_class_name(),
SharedFunctionInfo::kInstanceClassNameOffset);
SetInternalReference(obj, entry,
"script", shared->script(),
SharedFunctionInfo::kScriptOffset);
const char* construct_stub_name = name ?
names_->GetFormatted("(construct stub code for %s)", name) :
"(construct stub code)";
TagObject(shared->construct_stub(), construct_stub_name);
SetInternalReference(obj, entry,
"construct_stub", shared->construct_stub(),
SharedFunctionInfo::kConstructStubOffset);
SetInternalReference(obj, entry,
"function_data", shared->function_data(),
SharedFunctionInfo::kFunctionDataOffset);
SetInternalReference(obj, entry,
"debug_info", shared->debug_info(),
SharedFunctionInfo::kDebugInfoOffset);
SetInternalReference(obj, entry, "function_identifier",
shared->function_identifier(),
SharedFunctionInfo::kFunctionIdentifierOffset);
SetInternalReference(obj, entry, "feedback_metadata",
shared->feedback_metadata(),
SharedFunctionInfo::kFeedbackMetadataOffset);
}
void V8HeapExplorer::ExtractScriptReferences(int entry, Script* script) {
HeapObject* obj = script;
SetInternalReference(obj, entry,
"source", script->source(),
Script::kSourceOffset);
SetInternalReference(obj, entry,
"name", script->name(),
Script::kNameOffset);
SetInternalReference(obj, entry,
"context_data", script->context_data(),
Script::kContextOffset);
TagObject(script->line_ends(), "(script line ends)");
SetInternalReference(obj, entry,
"line_ends", script->line_ends(),
Script::kLineEndsOffset);
}
void V8HeapExplorer::ExtractAccessorInfoReferences(
int entry, AccessorInfo* accessor_info) {
SetInternalReference(accessor_info, entry, "name", accessor_info->name(),
AccessorInfo::kNameOffset);
SetInternalReference(accessor_info, entry, "expected_receiver_type",
accessor_info->expected_receiver_type(),
AccessorInfo::kExpectedReceiverTypeOffset);
SetInternalReference(accessor_info, entry, "getter", accessor_info->getter(),
AccessorInfo::kGetterOffset);
SetInternalReference(accessor_info, entry, "setter", accessor_info->setter(),
AccessorInfo::kSetterOffset);
SetInternalReference(accessor_info, entry, "data", accessor_info->data(),
AccessorInfo::kDataOffset);
}
void V8HeapExplorer::ExtractAccessorPairReferences(
int entry, AccessorPair* accessors) {
SetInternalReference(accessors, entry, "getter", accessors->getter(),
AccessorPair::kGetterOffset);
SetInternalReference(accessors, entry, "setter", accessors->setter(),
AccessorPair::kSetterOffset);
}
void V8HeapExplorer::TagBuiltinCodeObject(Code* code, const char* name) {
TagObject(code, names_->GetFormatted("(%s builtin)", name));
}
void V8HeapExplorer::TagCodeObject(Code* code) {
if (code->kind() == Code::STUB) {
TagObject(code, names_->GetFormatted(
"(%s code)",
CodeStub::MajorName(CodeStub::GetMajorKey(code))));
}
}
void V8HeapExplorer::ExtractCodeReferences(int entry, Code* code) {
TagCodeObject(code);
TagObject(code->relocation_info(), "(code relocation info)");
SetInternalReference(code, entry,
"relocation_info", code->relocation_info(),
Code::kRelocationInfoOffset);
SetInternalReference(code, entry,
"handler_table", code->handler_table(),
Code::kHandlerTableOffset);
TagObject(code->deoptimization_data(), "(code deopt data)");
SetInternalReference(code, entry,
"deoptimization_data", code->deoptimization_data(),
Code::kDeoptimizationDataOffset);
TagObject(code->source_position_table(), "(source position table)");
SetInternalReference(code, entry, "source_position_table",
code->source_position_table(),
Code::kSourcePositionTableOffset);
}
void V8HeapExplorer::ExtractCellReferences(int entry, Cell* cell) {
SetInternalReference(cell, entry, "value", cell->value(), Cell::kValueOffset);
}
void V8HeapExplorer::ExtractWeakCellReferences(int entry, WeakCell* weak_cell) {
TagObject(weak_cell, "(weak cell)");
SetWeakReference(weak_cell, entry, "value", weak_cell->value(),
WeakCell::kValueOffset);
}
void V8HeapExplorer::ExtractPropertyCellReferences(int entry,
PropertyCell* cell) {
SetInternalReference(cell, entry, "value", cell->value(),
PropertyCell::kValueOffset);
TagObject(cell->dependent_code(), "(dependent code)");
SetInternalReference(cell, entry, "dependent_code", cell->dependent_code(),
PropertyCell::kDependentCodeOffset);
}
void V8HeapExplorer::ExtractAllocationSiteReferences(int entry,
AllocationSite* site) {
SetInternalReference(site, entry, "transition_info",
site->transition_info_or_boilerplate(),
AllocationSite::kTransitionInfoOrBoilerplateOffset);
SetInternalReference(site, entry, "nested_site", site->nested_site(),
AllocationSite::kNestedSiteOffset);
TagObject(site->dependent_code(), "(dependent code)");
SetInternalReference(site, entry, "dependent_code", site->dependent_code(),
AllocationSite::kDependentCodeOffset);
// Do not visit weak_next as it is not visited by the ObjectVisitor,
// and we're not very interested in weak_next field here.
STATIC_ASSERT(AllocationSite::kWeakNextOffset >=
AllocationSite::kPointerFieldsEndOffset);
}
class JSArrayBufferDataEntryAllocator : public HeapEntriesAllocator {
public:
JSArrayBufferDataEntryAllocator(size_t size, V8HeapExplorer* explorer)
: size_(size)
, explorer_(explorer) {
}
virtual HeapEntry* AllocateEntry(HeapThing ptr) {
return explorer_->AddEntry(
static_cast<Address>(ptr),
HeapEntry::kNative, "system / JSArrayBufferData", size_);
}
private:
size_t size_;
V8HeapExplorer* explorer_;
};
void V8HeapExplorer::ExtractJSArrayBufferReferences(
int entry, JSArrayBuffer* buffer) {
// Setup a reference to a native memory backing_store object.
if (!buffer->backing_store())
return;
size_t data_size = NumberToSize(buffer->byte_length());
JSArrayBufferDataEntryAllocator allocator(data_size, this);
HeapEntry* data_entry =
filler_->FindOrAddEntry(buffer->backing_store(), &allocator);
filler_->SetNamedReference(HeapGraphEdge::kInternal,
entry, "backing_store", data_entry);
}
void V8HeapExplorer::ExtractJSPromiseReferences(int entry, JSPromise* promise) {
SetInternalReference(promise, entry, "result", promise->result(),
JSPromise::kResultOffset);
SetInternalReference(promise, entry, "deferred_promise",
promise->deferred_promise(),
JSPromise::kDeferredPromiseOffset);
SetInternalReference(promise, entry, "deferred_on_resolve",
promise->deferred_on_resolve(),
JSPromise::kDeferredOnResolveOffset);
SetInternalReference(promise, entry, "deferred_on_reject",
promise->deferred_on_reject(),
JSPromise::kDeferredOnRejectOffset);
SetInternalReference(promise, entry, "fulfill_reactions",
promise->fulfill_reactions(),
JSPromise::kFulfillReactionsOffset);
SetInternalReference(promise, entry, "reject_reactions",
promise->reject_reactions(),
JSPromise::kRejectReactionsOffset);
}
void V8HeapExplorer::ExtractFixedArrayReferences(int entry, FixedArray* array) {
auto it = array_types_.find(array);
if (it == array_types_.end()) {
for (int i = 0, l = array->length(); i < l; ++i) {
SetInternalReference(array, entry, i, array->get(i),
array->OffsetOfElementAt(i));
}
return;
}
switch (it->second) {
case JS_WEAK_COLLECTION_SUB_TYPE: {
ObjectHashTable* table = ObjectHashTable::cast(array);
for (int i = 0, capacity = table->Capacity(); i < capacity; ++i) {
int key_index =
ObjectHashTable::EntryToIndex(i) + ObjectHashTable::kEntryKeyIndex;
int value_index = ObjectHashTable::EntryToValueIndex(i);
SetWeakReference(table, entry, key_index, table->get(key_index),
table->OffsetOfElementAt(key_index));
SetInternalReference(table, entry, value_index, table->get(value_index),
table->OffsetOfElementAt(value_index));
// TODO(alph): Add a strong link (shortcut?) from key to value per
// WeakMap the key was added to. See crbug.com/778739
}
break;
}
// TODO(alph): Add special processing for other types of FixedArrays.
default:
for (int i = 0, l = array->length(); i < l; ++i) {
SetInternalReference(array, entry, i, array->get(i),
array->OffsetOfElementAt(i));
}
break;
}
}
void V8HeapExplorer::ExtractPropertyReferences(JSObject* js_obj, int 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(), js_obj, entry, k,
value, nullptr, field_offset);
break;
}
case kDescriptor:
SetDataOrAccessorPropertyReference(details.kind(), js_obj, entry,
descs->GetKey(i),
descs->GetValue(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();
for (int i = 0; i < length; ++i) {
if (dictionary->IsKey(isolate, dictionary->KeyAt(i))) {
PropertyCell* cell = dictionary->CellAt(i);
Name* name = cell->name();
Object* value = cell->value();
PropertyDetails details = cell->property_details();
SetDataOrAccessorPropertyReference(details.kind(), js_obj, entry, name,
value);
}
}
} else {
NameDictionary* dictionary = js_obj->property_dictionary();
int length = dictionary->Capacity();
for (int i = 0; i < length; ++i) {
Object* k = dictionary->KeyAt(i);
if (dictionary->IsKey(isolate, k)) {
Object* value = dictionary->ValueAt(i);
PropertyDetails details = dictionary->DetailsAt(i);
SetDataOrAccessorPropertyReference(details.kind(), js_obj, entry,
Name::cast(k), value);
}
}
}
}
void V8HeapExplorer::ExtractAccessorPairProperty(JSObject* js_obj, int entry,
Name* key,
Object* callback_obj,
int field_offset) {
if (!callback_obj->IsAccessorPair()) return;
AccessorPair* accessors = AccessorPair::cast(callback_obj);
SetPropertyReference(js_obj, entry, key, accessors, nullptr, field_offset);
Object* getter = accessors->getter();
if (!getter->IsOddball()) {
SetPropertyReference(js_obj, entry, key, getter, "get %s");
}
Object* setter = accessors->setter();
if (!setter->IsOddball()) {
SetPropertyReference(js_obj, entry, key, setter, "set %s");
}
}
void V8HeapExplorer::ExtractElementReferences(JSObject* js_obj, int entry) {
Isolate* isolate = js_obj->GetIsolate();
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(isolate)) {
SetElementReference(js_obj, 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(isolate, k)) {
DCHECK(k->IsNumber());
uint32_t index = static_cast<uint32_t>(k->Number());
SetElementReference(js_obj, entry, index, dictionary->ValueAt(i));
}
}
}
}
void V8HeapExplorer::ExtractInternalReferences(JSObject* js_obj, int entry) {
int length = js_obj->GetEmbedderFieldCount();
for (int i = 0; i < length; ++i) {
Object* o = js_obj->GetEmbedderField(i);
SetInternalReference(js_obj, entry, i, o,
js_obj->GetEmbedderFieldOffset(i));
}
}
String* V8HeapExplorer::GetConstructorName(JSObject* object) {
Isolate* isolate = object->GetIsolate();
if (object->IsJSFunction()) return isolate->heap()->closure_string();
DisallowHeapAllocation no_gc;
HandleScope scope(isolate);
return *JSReceiver::GetConstructorName(handle(object, isolate));
}
HeapEntry* V8HeapExplorer::GetEntry(Object* obj) {
if (!obj->IsHeapObject()) return nullptr;
return filler_->FindOrAddEntry(obj, this);
}
class RootsReferencesExtractor : public RootVisitor {
private:
struct IndexTag {
IndexTag(size_t index, VisitorSynchronization::SyncTag tag)
: index(index), tag(tag) {}
size_t index;
VisitorSynchronization::SyncTag tag;
};
public:
explicit RootsReferencesExtractor(Heap* heap)
: collecting_all_references_(false),
previous_reference_count_(0),
heap_(heap) {
}
void VisitRootPointers(Root root, Object** start, Object** end) override {
if (collecting_all_references_) {
for (Object** p = start; p < end; p++) all_references_.push_back(*p);
} else {
for (Object** p = start; p < end; p++) strong_references_.push_back(*p);
}
}
void SetCollectingAllReferences() { collecting_all_references_ = true; }
void FillReferences(V8HeapExplorer* explorer) {
DCHECK_LE(strong_references_.size(), all_references_.size());
Builtins* builtins = heap_->isolate()->builtins();
USE(builtins);
size_t strong_index = 0, all_index = 0, tags_index = 0;
int builtin_index = 0;
while (all_index < all_references_.size()) {
bool is_strong =
strong_index < strong_references_.size() &&
strong_references_[strong_index] == all_references_[all_index];
explorer->SetGcSubrootReference(reference_tags_[tags_index].tag,
!is_strong,
all_references_[all_index]);
if (reference_tags_[tags_index].tag ==
VisitorSynchronization::kBuiltins) {
DCHECK(all_references_[all_index]->IsCode());
explorer->TagBuiltinCodeObject(
Code::cast(all_references_[all_index]),
builtins->name(builtin_index++));
}
++all_index;
if (is_strong) ++strong_index;
if (reference_tags_[tags_index].index == all_index) ++tags_index;
}
CHECK_EQ(strong_index, strong_references_.size());
}
void Synchronize(VisitorSynchronization::SyncTag tag) override {
if (collecting_all_references_ &&
previous_reference_count_ != all_references_.size()) {
previous_reference_count_ = all_references_.size();
reference_tags_.emplace_back(previous_reference_count_, tag);
}
}
private:
bool collecting_all_references_;
std::vector<Object*> strong_references_;
std::vector<Object*> all_references_;
size_t previous_reference_count_;
std::vector<IndexTag> reference_tags_;
Heap* heap_;
};
bool V8HeapExplorer::IterateAndExtractReferences(
SnapshotFiller* filler) {
filler_ = filler;
// Create references to the synthetic roots.
SetRootGcRootsReference();
for (int tag = 0; tag < VisitorSynchronization::kNumberOfSyncTags; tag++) {
SetGcRootsReference(static_cast<VisitorSynchronization::SyncTag>(tag));
}
// 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(heap_);
heap_->IterateRoots(&extractor, VISIT_ONLY_STRONG);
extractor.SetCollectingAllReferences();
heap_->IterateRoots(&extractor, VISIT_ALL);
extractor.FillReferences(this);
// We have to do two passes as sometimes FixedArrays are used
// to weakly hold their items, and it's impossible to distinguish
// between these cases without processing the array owner first.
bool interrupted =
IterateAndExtractSinglePass<&V8HeapExplorer::ExtractReferencesPass1>() ||
IterateAndExtractSinglePass<&V8HeapExplorer::ExtractReferencesPass2>();
if (interrupted) {
filler_ = nullptr;
return false;
}
filler_ = nullptr;
return progress_->ProgressReport(true);
}
template<V8HeapExplorer::ExtractReferencesMethod extractor>
bool V8HeapExplorer::IterateAndExtractSinglePass() {
// Now iterate the whole heap.
bool interrupted = false;
HeapIterator iterator(heap_, HeapIterator::kFilterUnreachable);
// Heap iteration with filtering must be finished in any case.
for (HeapObject *obj = iterator.next(); obj != nullptr;
obj = iterator.next(), progress_->ProgressStep()) {
if (interrupted) continue;
size_t max_pointer = obj->Size() / kPointerSize;
if (max_pointer > marks_.size()) {
// Clear the current bits.
std::vector<bool>().swap(marks_);
// Reallocate to right size.
marks_.resize(max_pointer, false);
}
HeapEntry* heap_entry = GetEntry(obj);
int entry = heap_entry->index();
if ((this->*extractor)(entry, obj)) {
SetInternalReference(obj, 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);
}
if (!progress_->ProgressReport(false)) interrupted = true;
}
return interrupted;
}
bool V8HeapExplorer::IsEssentialObject(Object* object) {
return object->IsHeapObject() && !object->IsOddball() &&
object != heap_->empty_byte_array() &&
object != heap_->empty_fixed_array() &&
object != heap_->empty_descriptor_array() &&
object != heap_->fixed_array_map() && object != heap_->cell_map() &&
object != heap_->global_property_cell_map() &&
object != heap_->shared_function_info_map() &&
object != heap_->free_space_map() &&
object != heap_->one_pointer_filler_map() &&
object != heap_->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(HeapObject* parent_obj,
int parent_entry,
String* reference_name,
Object* child_obj,
int field_offset) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
filler_->SetNamedReference(HeapGraphEdge::kContextVariable, parent_entry,
names_->GetName(reference_name), child_entry);
MarkVisitedField(parent_obj, field_offset);
}
void V8HeapExplorer::MarkVisitedField(HeapObject* obj, int offset) {
if (offset < 0) return;
int index = offset / kPointerSize;
DCHECK(!marks_[index]);
marks_[index] = true;
}
void V8HeapExplorer::SetNativeBindReference(HeapObject* parent_obj,
int parent_entry,
const char* reference_name,
Object* child_obj) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
filler_->SetNamedReference(HeapGraphEdge::kShortcut, parent_entry,
reference_name, child_entry);
}
void V8HeapExplorer::SetElementReference(HeapObject* parent_obj,
int parent_entry,
int index,
Object* child_obj) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
filler_->SetIndexedReference(HeapGraphEdge::kElement, parent_entry, index,
child_entry);
}
void V8HeapExplorer::SetInternalReference(HeapObject* parent_obj,
int parent_entry,
const char* reference_name,
Object* child_obj,
int field_offset) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
filler_->SetNamedReference(HeapGraphEdge::kInternal,
parent_entry,
reference_name,
child_entry);
}
MarkVisitedField(parent_obj, field_offset);
}
void V8HeapExplorer::SetInternalReference(HeapObject* parent_obj,
int parent_entry,
int index,
Object* child_obj,
int field_offset) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
filler_->SetNamedReference(HeapGraphEdge::kInternal,
parent_entry,
names_->GetName(index),
child_entry);
}
MarkVisitedField(parent_obj, field_offset);
}
void V8HeapExplorer::SetHiddenReference(HeapObject* parent_obj,
int parent_entry, int index,
Object* child_obj, int field_offset) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry != nullptr && IsEssentialObject(child_obj) &&
IsEssentialHiddenReference(parent_obj, field_offset)) {
filler_->SetIndexedReference(HeapGraphEdge::kHidden, parent_entry, index,
child_entry);
}
}
void V8HeapExplorer::SetWeakReference(HeapObject* parent_obj,
int parent_entry,
const char* reference_name,
Object* child_obj,
int field_offset) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
filler_->SetNamedReference(HeapGraphEdge::kWeak,
parent_entry,
reference_name,
child_entry);
}
MarkVisitedField(parent_obj, field_offset);
}
void V8HeapExplorer::SetWeakReference(HeapObject* parent_obj,
int parent_entry,
int index,
Object* child_obj,
int field_offset) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
if (IsEssentialObject(child_obj)) {
filler_->SetNamedReference(HeapGraphEdge::kWeak,
parent_entry,
names_->GetFormatted("%d", index),
child_entry);
}
MarkVisitedField(parent_obj, field_offset);
}
void V8HeapExplorer::SetDataOrAccessorPropertyReference(
PropertyKind kind, JSObject* parent_obj, int parent_entry,
Name* reference_name, Object* child_obj, const char* name_format_string,
int field_offset) {
if (kind == kAccessor) {
ExtractAccessorPairProperty(parent_obj, parent_entry, reference_name,
child_obj, field_offset);
} else {
SetPropertyReference(parent_obj, parent_entry, reference_name, child_obj,
name_format_string, field_offset);
}
}
void V8HeapExplorer::SetPropertyReference(HeapObject* parent_obj,
int parent_entry,
Name* reference_name,
Object* child_obj,
const char* name_format_string,
int field_offset) {
DCHECK(parent_entry == GetEntry(parent_obj)->index());
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);
filler_->SetNamedReference(type, parent_entry, name, child_entry);
MarkVisitedField(parent_obj, field_offset);
}
void V8HeapExplorer::SetRootGcRootsReference() {
filler_->SetIndexedAutoIndexReference(
HeapGraphEdge::kElement,
snapshot_->root()->index(),
snapshot_->gc_roots());
}
void V8HeapExplorer::SetUserGlobalReference(Object* child_obj) {
HeapEntry* child_entry = GetEntry(child_obj);
DCHECK_NOT_NULL(child_entry);
filler_->SetNamedAutoIndexReference(
HeapGraphEdge::kShortcut,
snapshot_->root()->index(),
child_entry);
}
void V8HeapExplorer::SetGcRootsReference(VisitorSynchronization::SyncTag tag) {
filler_->SetIndexedAutoIndexReference(
HeapGraphEdge::kElement,
snapshot_->gc_roots()->index(),
snapshot_->gc_subroot(tag));
}
void V8HeapExplorer::SetGcSubrootReference(
VisitorSynchronization::SyncTag tag, bool is_weak, Object* child_obj) {
HeapEntry* child_entry = GetEntry(child_obj);
if (child_entry == nullptr) return;
const char* name = GetStrongGcSubrootName(child_obj);
if (name != nullptr) {
DCHECK(!is_weak);
filler_->SetNamedReference(HeapGraphEdge::kInternal,
snapshot_->gc_subroot(tag)->index(), name,
child_entry);
} else {
if (is_weak) {
filler_->SetNamedAutoIndexReference(HeapGraphEdge::kWeak,
snapshot_->gc_subroot(tag)->index(),
child_entry);
} else {
filler_->SetIndexedAutoIndexReference(HeapGraphEdge::kElement,
snapshot_->gc_subroot(tag)->index(),
child_entry);
}
}
// 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 (heap_->isolate()->debug()->IsDebugGlobal(global)) return;
if (user_roots_.Contains(global)) return;
user_roots_.Insert(global);
SetUserGlobalReference(global);
}
const char* V8HeapExplorer::GetStrongGcSubrootName(Object* object) {
if (strong_gc_subroot_names_.is_empty()) {
#define NAME_ENTRY(name) strong_gc_subroot_names_.SetTag(heap_->name(), #name);
#define ROOT_NAME(type, name, camel_name) NAME_ENTRY(name)
STRONG_ROOT_LIST(ROOT_NAME)
#undef ROOT_NAME
#define STRUCT_MAP_NAME(NAME, Name, name) NAME_ENTRY(name##_map)
STRUCT_LIST(STRUCT_MAP_NAME)
#undef STRUCT_MAP_NAME
#define DATA_HANDLER_MAP_NAME(NAME, Name, Size, name) NAME_ENTRY(name##_map)
DATA_HANDLER_LIST(DATA_HANDLER_MAP_NAME)
#undef DATA_HANDLER_MAP_NAME
#define STRING_NAME(name, str) NAME_ENTRY(name)
INTERNALIZED_STRING_LIST(STRING_NAME)
#undef STRING_NAME
#define SYMBOL_NAME(name) NAME_ENTRY(name)
PRIVATE_SYMBOL_LIST(SYMBOL_NAME)
#undef SYMBOL_NAME
#define SYMBOL_NAME(name, description) NAME_ENTRY(name)
PUBLIC_SYMBOL_LIST(SYMBOL_NAME)
WELL_KNOWN_SYMBOL_LIST(SYMBOL_NAME)
#undef SYMBOL_NAME
#define ACCESSOR_NAME(accessor_name, AccessorName) \
NAME_ENTRY(accessor_name##_accessor)
ACCESSOR_INFO_LIST(ACCESSOR_NAME)
#undef ACCESSOR_NAME
#undef NAME_ENTRY
CHECK(!strong_gc_subroot_names_.is_empty());
}
return strong_gc_subroot_names_.GetTag(object);
}
void V8HeapExplorer::TagObject(Object* obj, const char* tag) {
if (IsEssentialObject(obj)) {
HeapEntry* entry = GetEntry(obj);
if (entry->name()[0] == '\0') {
entry->set_name(tag);
}
}
}
void V8HeapExplorer::TagFixedArraySubType(const FixedArray* array,
FixedArraySubInstanceType type) {
DCHECK(array_types_.find(array) == array_types_.end());
array_types_[array] = type;
}
class GlobalObjectsEnumerator : public RootVisitor {
public:
void VisitRootPointers(Root root, Object** start, Object** end) override {
for (Object** 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)));
}
}
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 = heap_->isolate();
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) {
objects_tags_.SetTag(*enumerator.at(i), urls[i]);
}
}
class GlobalHandlesExtractor : public PersistentHandleVisitor {
public:
explicit GlobalHandlesExtractor(NativeObjectsExplorer* explorer)
: explorer_(explorer) {}
~GlobalHandlesExtractor() override {}
void VisitPersistentHandle(Persistent<Value>* value,
uint16_t class_id) override {
Handle<Object> object = Utils::OpenPersistent(value);
explorer_->VisitSubtreeWrapper(object.location(), class_id);
}
private:
NativeObjectsExplorer* explorer_;
};
class BasicHeapEntriesAllocator : public HeapEntriesAllocator {
public:
BasicHeapEntriesAllocator(
HeapSnapshot* snapshot,
HeapEntry::Type entries_type)
: snapshot_(snapshot),
names_(snapshot_->profiler()->names()),
heap_object_map_(snapshot_->profiler()->heap_object_map()),
entries_type_(entries_type) {
}
virtual HeapEntry* AllocateEntry(HeapThing ptr);
private:
HeapSnapshot* snapshot_;
StringsStorage* names_;
HeapObjectsMap* heap_object_map_;
HeapEntry::Type entries_type_;
};
HeapEntry* BasicHeapEntriesAllocator::AllocateEntry(HeapThing ptr) {
v8::RetainedObjectInfo* info = reinterpret_cast<v8::RetainedObjectInfo*>(ptr);
intptr_t elements = info->GetElementCount();
intptr_t size = info->GetSizeInBytes();
const char* name = elements != -1
? names_->GetFormatted("%s / %" V8PRIdPTR " entries",
info->GetLabel(), elements)
: names_->GetCopy(info->GetLabel());
return snapshot_->AddEntry(
entries_type_,
name,
heap_object_map_->GenerateId(info),
size != -1 ? static_cast<int>(size) : 0,
0);
}
NativeObjectsExplorer::NativeObjectsExplorer(
HeapSnapshot* snapshot, SnapshottingProgressReportingInterface* progress)
: isolate_(snapshot->profiler()->heap_object_map()->heap()->isolate()),
snapshot_(snapshot),
names_(snapshot_->profiler()->names()),
embedder_queried_(false),
objects_by_info_(RetainedInfosMatch),
native_groups_(StringsMatch),
filler_(nullptr) {
synthetic_entries_allocator_ =
new BasicHeapEntriesAllocator(snapshot, HeapEntry::kSynthetic);
native_entries_allocator_ =
new BasicHeapEntriesAllocator(snapshot, HeapEntry::kNative);
}
NativeObjectsExplorer::~NativeObjectsExplorer() {
for (base::HashMap::Entry* p = objects_by_info_.Start(); p != nullptr;
p = objects_by_info_.Next(p)) {
v8::RetainedObjectInfo* info =
reinterpret_cast<v8::RetainedObjectInfo*>(p->key);
info->Dispose();
std::vector<HeapObject*>* objects =
reinterpret_cast<std::vector<HeapObject*>*>(p->value);
delete objects;
}
for (base::HashMap::Entry* p = native_groups_.Start(); p != nullptr;
p = native_groups_.Next(p)) {
v8::RetainedObjectInfo* info =
reinterpret_cast<v8::RetainedObjectInfo*>(p->value);
info->Dispose();
}
delete synthetic_entries_allocator_;
delete native_entries_allocator_;
}
int NativeObjectsExplorer::EstimateObjectsCount() {
FillRetainedObjects();
return objects_by_info_.occupancy();
}
void NativeObjectsExplorer::FillRetainedObjects() {
if (embedder_queried_) return;
v8::HandleScope scope(reinterpret_cast<v8::Isolate*>(isolate_));
v8::HeapProfiler::RetainerInfos infos =
snapshot_->profiler()->GetRetainerInfos(isolate_);
for (auto& pair : infos.groups) {
std::vector<HeapObject*>* info = GetVectorMaybeDisposeInfo(pair.first);
for (auto& persistent : pair.second) {
if (persistent->IsEmpty()) continue;
Handle<Object> object = v8::Utils::OpenHandle(
*persistent->Get(reinterpret_cast<v8::Isolate*>(isolate_)));
DCHECK(!object.is_null());
HeapObject* heap_object = HeapObject::cast(*object);
info->push_back(heap_object);
in_groups_.Insert(heap_object);
}
}
// Record objects that are not in ObjectGroups, but have class ID.
GlobalHandlesExtractor extractor(this);
isolate_->global_handles()->IterateAllRootsWithClassIds(&extractor);
edges_ = std::move(infos.edges);
embedder_queried_ = true;
}
void NativeObjectsExplorer::FillEdges() {
v8::HandleScope scope(reinterpret_cast<v8::Isolate*>(isolate_));
// Fill in actual edges found.
for (auto& pair : edges_) {
if (pair.first->IsEmpty() || pair.second->IsEmpty()) continue;
Handle<Object> parent_object = v8::Utils::OpenHandle(
*pair.first->Get(reinterpret_cast<v8::Isolate*>(isolate_)));
HeapObject* parent = HeapObject::cast(*parent_object);
int parent_entry =
filler_->FindOrAddEntry(parent, native_entries_allocator_)->index();
DCHECK_NE(parent_entry, HeapEntry::kNoEntry);
Handle<Object> child_object = v8::Utils::OpenHandle(
*pair.second->Get(reinterpret_cast<v8::Isolate*>(isolate_)));
HeapObject* child = HeapObject::cast(*child_object);
HeapEntry* child_entry =
filler_->FindOrAddEntry(child, native_entries_allocator_);
filler_->SetNamedReference(HeapGraphEdge::kInternal, parent_entry, "native",
child_entry);
}
edges_.clear();
}
std::vector<HeapObject*>* NativeObjectsExplorer::GetVectorMaybeDisposeInfo(
v8::RetainedObjectInfo* info) {
base::HashMap::Entry* entry =
objects_by_info_.LookupOrInsert(info, InfoHash(info));
if (entry->value != nullptr) {
info->Dispose();
} else {
entry->value = new std::vector<HeapObject*>();
}
return reinterpret_cast<std::vector<HeapObject*>*>(entry->value);
}
bool NativeObjectsExplorer::IterateAndExtractReferences(
SnapshotFiller* filler) {
filler_ = filler;
FillRetainedObjects();
FillEdges();
if (EstimateObjectsCount() > 0) {
for (base::HashMap::Entry* p = objects_by_info_.Start(); p != nullptr;
p = objects_by_info_.Next(p)) {
v8::RetainedObjectInfo* info =
reinterpret_cast<v8::RetainedObjectInfo*>(p->key);
SetNativeRootReference(info);
std::vector<HeapObject*>* objects =
reinterpret_cast<std::vector<HeapObject*>*>(p->value);
for (HeapObject* object : *objects) {
SetWrapperNativeReferences(object, info);
}
}
SetRootNativeRootsReference();
}
filler_ = nullptr;
return true;
}
class NativeGroupRetainedObjectInfo : public v8::RetainedObjectInfo {
public:
explicit NativeGroupRetainedObjectInfo(const char* label)
: disposed_(false),
hash_(reinterpret_cast<intptr_t>(label)),
label_(label) {
}
virtual ~NativeGroupRetainedObjectInfo() {}
virtual void Dispose() {
CHECK(!disposed_);
disposed_ = true;
delete this;
}
virtual bool IsEquivalent(RetainedObjectInfo* other) {
return hash_ == other->GetHash() && !strcmp(label_, other->GetLabel());
}
virtual intptr_t GetHash() { return hash_; }
virtual const char* GetLabel() { return label_; }
private:
bool disposed_;
intptr_t hash_;
const char* label_;
};
NativeGroupRetainedObjectInfo* NativeObjectsExplorer::FindOrAddGroupInfo(
const char* label) {
const char* label_copy = names_->GetCopy(label);
uint32_t hash = StringHasher::HashSequentialString(
label_copy,
static_cast<int>(strlen(label_copy)),
isolate_->heap()->HashSeed());
base::HashMap::Entry* entry =
native_groups_.LookupOrInsert(const_cast<char*>(label_copy), hash);
if (entry->value == nullptr) {
entry->value = new NativeGroupRetainedObjectInfo(label);
}
return static_cast<NativeGroupRetainedObjectInfo*>(entry->value);
}
void NativeObjectsExplorer::SetNativeRootReference(
v8::RetainedObjectInfo* info) {
HeapEntry* child_entry =
filler_->FindOrAddEntry(info, native_entries_allocator_);
DCHECK_NOT_NULL(child_entry);
NativeGroupRetainedObjectInfo* group_info =
FindOrAddGroupInfo(info->GetGroupLabel());
HeapEntry* group_entry =
filler_->FindOrAddEntry(group_info, synthetic_entries_allocator_);
// |FindOrAddEntry| can move and resize the entries backing store. Reload
// potentially-stale pointer.
child_entry = filler_->FindEntry(info);
filler_->SetNamedAutoIndexReference(
HeapGraphEdge::kInternal,
group_entry->index(),
child_entry);
}
void NativeObjectsExplorer::SetWrapperNativeReferences(
HeapObject* wrapper, v8::RetainedObjectInfo* info) {
HeapEntry* wrapper_entry = filler_->FindEntry(wrapper);
DCHECK_NOT_NULL(wrapper_entry);
HeapEntry* info_entry =
filler_->FindOrAddEntry(info, native_entries_allocator_);
DCHECK_NOT_NULL(info_entry);
filler_->SetNamedReference(HeapGraphEdge::kInternal,
wrapper_entry->index(),
"native",
info_entry);
filler_->SetIndexedAutoIndexReference(HeapGraphEdge::kElement,
info_entry->index(),
wrapper_entry);
}
void NativeObjectsExplorer::SetRootNativeRootsReference() {
for (base::HashMap::Entry* entry = native_groups_.Start(); entry;
entry = native_groups_.Next(entry)) {
NativeGroupRetainedObjectInfo* group_info =
static_cast<NativeGroupRetainedObjectInfo*>(entry->value);
HeapEntry* group_entry =
filler_->FindOrAddEntry(group_info, native_entries_allocator_);
DCHECK_NOT_NULL(group_entry);
filler_->SetIndexedAutoIndexReference(
HeapGraphEdge::kElement,
snapshot_->root()->index(),
group_entry);
}
}
void NativeObjectsExplorer::VisitSubtreeWrapper(Object** p, uint16_t class_id) {
if (in_groups_.Contains(*p)) return;
Isolate* isolate = isolate_;
v8::RetainedObjectInfo* info =
isolate->heap_profiler()->ExecuteWrapperClassCallback(class_id, p);
if (info == nullptr) return;
GetVectorMaybeDisposeInfo(info)->push_back(HeapObject::cast(*p));
}
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(nullptr);
}
~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_->CollectAllGarbage(Heap::kMakeHeapIterableMask,
GarbageCollectionReason::kHeapProfiler);
heap_->CollectAllGarbage(Heap::kMakeHeapIterableMask,
GarbageCollectionReason::kHeapProfiler);
NullContextScope null_context_scope(heap_->isolate());
#ifdef VERIFY_HEAP
Heap* debug_heap = heap_;
if (FLAG_verify_heap) {
debug_heap->Verify();
}
#endif
SetProgressTotal(2); // 2 passes.
#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::SetProgressTotal(int iterations_count) {
if (control_ == nullptr) return;
HeapIterator iterator(heap_, HeapIterator::kFilterUnreachable);
progress_total_ = iterations_count * (
v8_heap_explorer_.EstimateObjectsCount(&iterator) +
dom_explorer_.EstimateObjectsCount());
progress_counter_ = 0;
}
bool HeapSnapshotGenerator::FillReferences() {
SnapshotFiller filler(snapshot_, &entries_);
return v8_heap_explorer_.IterateAndExtractReferences(&filler)
&& dom_explorer_.IterateAndExtractReferences(&filler);
}
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("\"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(entry_index(edge->to()), buffer, buffer_pos);
buffer[buffer_pos++] = '\n';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.start());
}
void HeapSnapshotJSONSerializer::SerializeEdges() {
std::deque<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 (entry_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-></