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cobalt / cobalt / 0c2b1d4428f8ae16220e86a16bebd07ff691a412 / . / third_party / v8 / src / profiler / heap-snapshot-generator.cc
blob: 2907a215c626ca4346ed31d52a258997e6f7c006 [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/api-inl.h"
#include "src/base/optional.h"
#include "src/codegen/assembler-inl.h"
#include "src/common/globals.h"
#include "src/debug/debug.h"
#include "src/handles/global-handles.h"
#include "src/heap/combined-heap.h"
#include "src/heap/safepoint.h"
#include "src/numbers/conversions.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/layout-descriptor.h"
#include "src/objects/literal-objects-inl.h"
#include "src/objects/objects-body-descriptors.h"
#include "src/objects/objects-inl.h"
#include "src/objects/prototype.h"
#include "src/objects/slots-inl.h"
#include "src/objects/struct-inl.h"
#include "src/objects/transitions-inl.h"
#include "src/objects/visitors.h"
#include "src/profiler/allocation-tracker.h"
#include "src/profiler/heap-profiler.h"
#include "src/profiler/heap-snapshot-generator-inl.h"
#include "src/utils/vector.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) const {
STATIC_ASSERT(sizeof(unsigned) == sizeof(id()));
base::OS::Print("%6zu @%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.begin();
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() const {
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, bool global_objects_as_roots)
: profiler_(profiler),
treat_global_objects_as_roots_(global_objects_as_roots) {
// 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);
STATIC_ASSERT(kSystemPointerSize != 8 || sizeof(HeapGraphEdge) == 24);
STATIC_ASSERT(kSystemPointerSize != 4 || sizeof(HeapEntry) == 32);
#if V8_CC_MSVC
STATIC_ASSERT(kSystemPointerSize != 8 || sizeof(HeapEntry) == 48);
#else // !V8_CC_MSVC
STATIC_ASSERT(kSystemPointerSize != 8 || sizeof(HeapEntry) == 40);
#endif // !V8_CC_MSVC
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 v8::HeapProfiler::kUnknownObjectId;
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;
}
SnapshotObjectId HeapObjectsMap::FindMergedNativeEntry(NativeObject addr) {
auto it = merged_native_entries_map_.find(addr);
if (it == merged_native_entries_map_.end())
return v8::HeapProfiler::kUnknownObjectId;
return entries_[it->second].id;
}
void HeapObjectsMap::AddMergedNativeEntry(NativeObject addr,
Address canonical_addr) {
base::HashMap::Entry* entry =
entries_map_.Lookup(reinterpret_cast<void*>(canonical_addr),
ComputeAddressHash(canonical_addr));
auto result = merged_native_entries_map_.insert(
{addr, reinterpret_cast<size_t>(entry->value)});
if (!result.second) {
result.first->second = reinterpret_cast<size_t>(entry->value);
}
}
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);
CombinedHeapObjectIterator 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);
// Build up temporary reverse map.
std::unordered_map<size_t, NativeObject> reverse_merged_native_entries_map;
for (const auto& it : merged_native_entries_map_) {
auto result =
reverse_merged_native_entries_map.emplace(it.second, it.first);
DCHECK(result.second);
USE(result);
}
size_t first_free_entry = 1;
for (size_t i = 1; i < entries_.size(); ++i) {
EntryInfo& entry_info = entries_.at(i);
auto merged_reverse_it = reverse_merged_native_entries_map.find(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);
if (merged_reverse_it != reverse_merged_native_entries_map.end()) {
auto it = merged_native_entries_map_.find(merged_reverse_it->second);
DCHECK_NE(merged_native_entries_map_.end(), it);
it->second = first_free_entry;
}
++first_free_entry;
} else {
if (entry_info.addr) {
entries_map_.Remove(reinterpret_cast<void*>(entry_info.addr),
ComputeAddressHash(entry_info.addr));
if (merged_reverse_it != reverse_merged_native_entries_map.end()) {
merged_native_entries_map_.erase(merged_reverse_it->second);
}
}
}
}
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();
Script::PositionInfo info;
script.GetPositionInfo(start, &info, Script::WITH_OFFSET);
snapshot_->AddLocation(entry, scriptId, info.line, info.column);
}
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 = global_object_tag_map_.find(JSGlobalObject::cast(object));
if (it != global_object_tag_map_.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() {
CombinedHeapObjectIterator it(heap_, HeapObjectIterator::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::kHeaderSize - 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.description(),
Symbol::kDescriptionOffset);
}
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 (InternalIndex i : table.IterateEntries()) {
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);
HeapEntry* table_entry = GetEntry(table);
if (key_entry && value_entry && !key.IsUndefined()) {
const char* edge_name = names_->GetFormatted(
"part of key (%s @%u) -> value (%s @%u) pair in WeakMap (table @%u)",
key_entry->name(), key_entry->id(), value_entry->name(),
value_entry->id(), table_entry->id());
key_entry->SetNamedAutoIndexReference(HeapGraphEdge::kInternal, edge_name,
value_entry, names_);
table_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 = scope_info.ContextHeaderLength() + 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));
if (context.has_extension()) {
SetInternalReference(
entry, "extension", context.get(Context::EXTENSION_INDEX),
FixedArray::OffsetOfElementAt(Context::EXTENSION_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.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(kRelaxedLoad);
TagObject(descriptors, "(map descriptors)");
SetInternalReference(entry, "descriptors", descriptors,
Map::kInstanceDescriptorsOffset);
SetInternalReference(entry, "prototype", map.prototype(),
Map::kPrototypeOffset);
if (FLAG_unbox_double_fields) {
SetInternalReference(entry, "layout_descriptor",
map.layout_descriptor(kAcquireLoad),
Map::kLayoutDescriptorOffset);
}
if (map.IsContextMap()) {
Object native_context = map.native_context();
TagObject(native_context, "(native context)");
SetInternalReference(entry, "native_context", native_context,
Map::kConstructorOrBackPointerOrNativeContextOffset);
} else {
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::kConstructorOrBackPointerOrNativeContextOffset);
} else if (constructor_or_backpointer.IsFunctionTemplateInfo()) {
TagObject(constructor_or_backpointer, "(constructor function data)");
SetInternalReference(entry, "constructor_function_data",
constructor_or_backpointer,
Map::kConstructorOrBackPointerOrNativeContextOffset);
} else {
SetInternalReference(entry, "constructor", constructor_or_backpointer,
Map::kConstructorOrBackPointerOrNativeContextOffset);
}
}
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)",
CodeKindToString(shared.GetCode().kind())));
}
Object name_or_scope_info = shared.name_or_scope_info(kAcquireLoad);
if (name_or_scope_info.IsScopeInfo()) {
TagObject(name_or_scope_info, "(function scope info)");
}
SetInternalReference(entry, "name_or_scope_info", name_or_scope_info,
SharedFunctionInfo::kNameOrScopeInfoOffset);
SetInternalReference(entry, "script_or_debug_info",
shared.script_or_debug_info(kAcquireLoad),
SharedFunctionInfo::kScriptOrDebugInfoOffset);
SetInternalReference(entry, "function_data",
shared.function_data(kAcquireLoad),
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::kContextDataOffset);
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.maybe_optimized_code();
HeapObject code_heap_object;
if (code->GetHeapObjectIfWeak(&code_heap_object)) {
SetWeakReference(entry, "optimized code", code_heap_object,
FeedbackVector::kMaybeOptimizedCodeOffset);
}
}
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(kRelaxedLoad);
for (InternalIndex i : js_obj.map().IterateOwnDescriptors()) {
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();
ReadOnlyRoots roots(isolate);
for (InternalIndex i : dictionary.IterateEntries()) {
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();
ReadOnlyRoots roots(isolate);
for (InternalIndex i : dictionary.IterateEntries()) {
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();
for (InternalIndex i : dictionary.IterateEntries()) {
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);
}
}
void VisitRootPointers(Root root, const char* description,
OffHeapObjectSlot start,
OffHeapObjectSlot end) override {
DCHECK_EQ(root, Root::kStringTable);
IsolateRoot isolate = Isolate::FromHeap(explorer_->heap_);
for (OffHeapObjectSlot p = start; p < end; ++p) {
explorer_->SetGcSubrootReference(root, description, visiting_weak_roots_,
p.load(isolate));
}
}
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, base::EnumSet<SkipRoot>{SkipRoot::kWeak});
// TODO(ulan): The heap snapshot generator incorrectly considers the weak
// string tables as strong retainers. Move IterateWeakRoots after
// SetVisitingWeakRoots.
heap_->IterateWeakRoots(&extractor, {});
extractor.SetVisitingWeakRoots();
heap_->IterateWeakGlobalHandles(&extractor);
bool interrupted = false;
CombinedHeapObjectIterator iterator(heap_,
HeapObjectIterator::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 (!snapshot_->treat_global_objects_as_roots()) 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:
explicit GlobalObjectsEnumerator(Isolate* isolate) : isolate_(isolate) {}
void VisitRootPointers(Root root, const char* description,
FullObjectSlot start, FullObjectSlot end) override {
VisitRootPointersImpl(root, description, start, end);
}
void VisitRootPointers(Root root, const char* description,
OffHeapObjectSlot start,
OffHeapObjectSlot end) override {
VisitRootPointersImpl(root, description, start, end);
}
int count() const { return static_cast<int>(objects_.size()); }
Handle<JSGlobalObject>& at(int i) { return objects_[i]; }
private:
template <typename TSlot>
void VisitRootPointersImpl(Root root, const char* description, TSlot start,
TSlot end) {
for (TSlot p = start; p < end; ++p) {
Object o = p.load(isolate_);
if (!o.IsNativeContext(isolate_)) continue;
JSObject proxy = Context::cast(o).global_proxy();
if (!proxy.IsJSGlobalProxy(isolate_)) continue;
Object global = proxy.map(isolate_).prototype(isolate_);
if (!global.IsJSGlobalObject(isolate_)) continue;
objects_.push_back(handle(JSGlobalObject::cast(global), isolate_));
}
}
Isolate* isolate_;
std::vector<Handle<JSGlobalObject>> objects_;
};
// Modifies heap. Must not be run during heap traversal.
void V8HeapExplorer::CollectGlobalObjectsTags() {
if (!global_object_name_resolver_) return;
Isolate* isolate = Isolate::FromHeap(heap_);
GlobalObjectsEnumerator enumerator(isolate);
isolate->global_handles()->IterateAllRoots(&enumerator);
for (int i = 0, l = enumerator.count(); i < l; ++i) {
Handle<JSGlobalObject> obj = enumerator.at(i);
const char* tag = global_object_name_resolver_->GetName(
Utils::ToLocal(Handle<JSObject>::cast(obj)));
if (tag) {
global_object_tag_pairs_.emplace_back(obj, tag);
}
}
}
void V8HeapExplorer::MakeGlobalObjectTagMap(
const SafepointScope& safepoint_scope) {
for (const auto& pair : global_object_tag_pairs_) {
global_object_tag_map_.emplace(*pair.first, pair.second);
}
}
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();
Address lookup_address = reinterpret_cast<Address>(node->GetNativeObject());
SnapshotObjectId id =
(lookup_address) ? heap_object_map_->FindOrAddEntry(lookup_address, 0)
: static_cast<SnapshotObjectId>(
reinterpret_cast<uintptr_t>(node) << 1);
auto* heap_entry = snapshot_->AddEntry(EmbedderGraphNodeType(node),
EmbedderGraphNodeName(names_, node),
id, static_cast<int>(size), 0);
heap_entry->set_detachedness(node->GetDetachedness());
return heap_entry;
}
NativeObjectsExplorer::NativeObjectsExplorer(
HeapSnapshot* snapshot, SnapshottingProgressReportingInterface* progress)
: isolate_(
Isolate::FromHeap(snapshot->profiler()->heap_object_map()->heap())),
snapshot_(snapshot),
names_(snapshot_->profiler()->names()),
heap_object_map_(snapshot_->profiler()->heap_object_map()),
embedder_graph_entries_allocator_(
new EmbedderGraphEntriesAllocator(snapshot)) {}
void NativeObjectsExplorer::MergeNodeIntoEntry(
HeapEntry* entry, EmbedderGraph::Node* original_node,
EmbedderGraph::Node* wrapper_node) {
// The wrapper node may be an embedder node (for testing purposes) or a V8
// node (production code).
if (!wrapper_node->IsEmbedderNode()) {
// For V8 nodes only we can add a lookup.
EmbedderGraphImpl::V8NodeImpl* v8_node =
static_cast<EmbedderGraphImpl::V8NodeImpl*>(wrapper_node);
Object object = v8_node->GetObject();
DCHECK(!object.IsSmi());
if (original_node->GetNativeObject()) {
HeapObject heap_object = HeapObject::cast(object);
heap_object_map_->AddMergedNativeEntry(original_node->GetNativeObject(),
heap_object.address());
DCHECK_EQ(entry->id(), heap_object_map_->FindMergedNativeEntry(
original_node->GetNativeObject()));
}
}
entry->set_detachedness(original_node->GetDetachedness());
entry->set_name(MergeNames(
names_, EmbedderGraphNodeName(names_, original_node), entry->name()));
entry->set_type(EmbedderGraphNodeType(original_node));
}
HeapEntry* NativeObjectsExplorer::EntryForEmbedderGraphNode(
EmbedderGraphImpl::Node* node) {
// Return the entry for the wrapper node if present.
if (node->WrapperNode()) {
node = node->WrapperNode();
}
// Node is EmbedderNode.
if (node->IsEmbedderNode()) {
return generator_->FindOrAddEntry(node,
embedder_graph_entries_allocator_.get());
}
// Node is V8NodeImpl.
Object object =
static_cast<EmbedderGraphImpl::V8NodeImpl*>(node)->GetObject();
if (object.IsSmi()) return nullptr;
auto* entry = generator_->FindEntry(
reinterpret_cast<void*>(Object::cast(object).ptr()));
return entry;
}
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()) {
// Only add embedder nodes as V8 nodes have been added already by the
// V8HeapExplorer.
if (!node->IsEmbedderNode()) continue;
if (auto* entry = EntryForEmbedderGraphNode(node.get())) {
if (node->IsRootNode()) {
snapshot_->root()->SetIndexedAutoIndexReference(
HeapGraphEdge::kElement, entry);
}
if (node->WrapperNode()) {
MergeNodeIntoEntry(entry, node.get(), node->WrapperNode());
}
}
}
// Fill edges of the graph.
for (const auto& edge : graph.edges()) {
// |from| and |to| can be nullptr if the corresponding node is a V8 node
// pointing to a Smi.
HeapEntry* from = EntryForEmbedderGraphNode(edge.from);
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,
names_->GetCopy(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 NullContextForSnapshotScope {
public:
explicit NullContextForSnapshotScope(Isolate* isolate)
: isolate_(isolate), prev_(isolate->context()) {
isolate_->set_context(Context());
}
~NullContextForSnapshotScope() { isolate_->set_context(prev_); }
private:
Isolate* isolate_;
Context prev_;
};
} // namespace
bool HeapSnapshotGenerator::GenerateSnapshot() {
Isolate* isolate = Isolate::FromHeap(heap_);
base::Optional<HandleScope> handle_scope(base::in_place, isolate);
v8_heap_explorer_.CollectGlobalObjectsTags();
heap_->CollectAllAvailableGarbage(GarbageCollectionReason::kHeapProfiler);
NullContextForSnapshotScope null_context_scope(isolate);
SafepointScope scope(heap_);
v8_heap_explorer_.MakeGlobalObjectTagMap(scope);
handle_scope.reset();
#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<1> {
static const int kSigned = 3;
static const int kUnsigned = 3;
};
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) {
size_t len = strlen(s);
DCHECK_GE(kMaxInt, len);
AddSubstring(s, static_cast<int>(len));
}
void AddSubstring(const char* s, int n) {
if (n <= 0) return;
DCHECK_LE(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_.begin() + 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.begin());
}
}
void MaybeWriteChunk() {
DCHECK(chunk_pos_ <= chunk_size_);
if (chunk_pos_ == chunk_size_) {
WriteChunk();
}
}
void WriteChunk() {
if (aborted_) return;
if (stream_->WriteAsciiChunk(chunk_.begin(), 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, detachedness.
const int HeapSnapshotJSONSerializer::kNodeFieldsCount = 7;
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<1> {
using Type = uint8_t;
};
template<> struct ToUnsigned<4> {
using Type = uint32_t;
};
template<> struct ToUnsigned<8> {
using Type = uint64_t;
};
} // 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.begin());
}
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 5 unsigned ints, 1 size_t, 1 uint8_t, 7 commas,
// \n and \0
static const int kBufferSize =
5 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned // NOLINT
+ MaxDecimalDigitsIn<sizeof(size_t)>::kUnsigned // NOLINT
+ MaxDecimalDigitsIn<sizeof(uint8_t)>::kUnsigned + 7 + 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++] = ',';
buffer_pos = utoa(entry->detachedness(), buffer, buffer_pos);
buffer[buffer_pos++] = '\n';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.begin());
}
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("detachedness")) ","
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")) ","
JSON_S("edge_fields") ":" JSON_A(
JSON_S("type") ","
JSON_S("name_or_index") ","
JSON_S("to_node")) ","
JSON_S("edge_types") ":" JSON_A(
JSON_A(
JSON_S("context") ","
JSON_S("element") ","
JSON_S("property") ","
JSON_S("internal") ","
JSON_S("hidden") ","
JSON_S("shortcut") ","
JSON_S("weak")) ","
JSON_S("string_or_number") ","
JSON_S("node")) ","
JSON_S("trace_function_info_fields") ":" JSON_A(
JSON_S("function_id") ","
JSON_S("name") ","
JSON_S("script_name") ","
JSON_S("script_id") ","
JSON_S("line") ","
JSON_S("column")) ","
JSON_S("trace_node_fields") ":" JSON_A(
JSON_S("id") ","
JSON_S("function_info_index") ","
JSON_S("count") ","
JSON_S("size") ","
JSON_S("children")) ","
JSON_S("sample_fields") ":" JSON_A(
JSON_S("timestamp_us") ","
JSON_S("last_assigned_id")) ","
JSON_S("location_fields") ":" JSON_A(
JSON_S("object_index") ","
JSON_S("script_id") ","
JSON_S("line") ","
JSON_S("column"))));
// clang-format on
#undef JSON_S
#undef JSON_O
#undef JSON_A
writer_->AddString(",\"node_count\":");
writer_->AddNumber(static_cast<unsigned>(snapshot_->entries().size()));
writer_->AddString(",\"edge_count\":");
writer_->AddNumber(static_cast<double>(snapshot_->edges().size()));
writer_->AddString(",\"trace_function_count\":");
uint32_t count = 0;
AllocationTracker* tracker = snapshot_->profiler()->allocation_tracker();
if (tracker) {
count = static_cast<uint32_t>(tracker->function_info_list().size());
}
writer_->AddNumber(count);
}
static void WriteUChar(OutputStreamWriter* w, unibrow::uchar u) {
static const char hex_chars[] = "0123456789ABCDEF";
w->AddString("\\u");
w->AddCharacter(hex_chars[(u >> 12) & 0xF]);
w->AddCharacter(hex_chars[(u >> 8) & 0xF]);
w->AddCharacter(hex_chars[(u >> 4) & 0xF]);
w->AddCharacter(hex_chars[u & 0xF]);
}
void HeapSnapshotJSONSerializer::SerializeTraceTree() {
AllocationTracker* tracker = snapshot_->profiler()->allocation_tracker();
if (!tracker) return;
AllocationTraceTree* traces = tracker->trace_tree();
SerializeTraceNode(traces->root());
}
void HeapSnapshotJSONSerializer::SerializeTraceNode(AllocationTraceNode* node) {
// The buffer needs space for 4 unsigned ints, 4 commas, [ and \0
const int kBufferSize =
4 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned // NOLINT
+ 4 + 1 + 1;
EmbeddedVector<char, kBufferSize> buffer;
int buffer_pos = 0;
buffer_pos = utoa(node->id(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(node->function_info_index(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(node->allocation_count(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(node->allocation_size(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer[buffer_pos++] = '[';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.begin());
int i = 0;
for (AllocationTraceNode* child : node->children()) {
if (i++ > 0) {
writer_->AddCharacter(',');
}
SerializeTraceNode(child);
}
writer_->AddCharacter(']');
}
// 0-based position is converted to 1-based during the serialization.
static int SerializePosition(int position, const Vector<char>& buffer,
int buffer_pos) {
if (position == -1) {
buffer[buffer_pos++] = '0';
} else {
DCHECK_GE(position, 0);
buffer_pos = utoa(static_cast<unsigned>(position + 1), buffer, buffer_pos);
}
return buffer_pos;
}
void HeapSnapshotJSONSerializer::SerializeTraceNodeInfos() {
AllocationTracker* tracker = snapshot_->profiler()->allocation_tracker();
if (!tracker) return;
// The buffer needs space for 6 unsigned ints, 6 commas, \n and \0
const int kBufferSize =
6 * MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned // NOLINT
+ 6 + 1 + 1;
EmbeddedVector<char, kBufferSize> buffer;
int i = 0;
for (AllocationTracker::FunctionInfo* info : tracker->function_info_list()) {
int buffer_pos = 0;
if (i++ > 0) {
buffer[buffer_pos++] = ',';
}
buffer_pos = utoa(info->function_id, buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(GetStringId(info->name), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(GetStringId(info->script_name), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
// The cast is safe because script id is a non-negative Smi.
buffer_pos = utoa(static_cast<unsigned>(info->script_id), buffer,
buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = SerializePosition(info->line, buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = SerializePosition(info->column, buffer, buffer_pos);
buffer[buffer_pos++] = '\n';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.begin());
}
}
void HeapSnapshotJSONSerializer::SerializeSamples() {
const std::vector<HeapObjectsMap::TimeInterval>& samples =
snapshot_->profiler()->heap_object_map()->samples();
if (samples.empty()) return;
base::TimeTicks start_time = samples[0].timestamp;
// The buffer needs space for 2 unsigned ints, 2 commas, \n and \0
const int kBufferSize = MaxDecimalDigitsIn<sizeof(
base::TimeDelta().InMicroseconds())>::kUnsigned +
MaxDecimalDigitsIn<sizeof(samples[0].id)>::kUnsigned +
2 + 1 + 1;
EmbeddedVector<char, kBufferSize> buffer;
int i = 0;
for (const HeapObjectsMap::TimeInterval& sample : samples) {
int buffer_pos = 0;
if (i++ > 0) {
buffer[buffer_pos++] = ',';
}
base::TimeDelta time_delta = sample.timestamp - start_time;
buffer_pos = utoa(time_delta.InMicroseconds(), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(sample.last_assigned_id(), buffer, buffer_pos);
buffer[buffer_pos++] = '\n';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.begin());
}
}
void HeapSnapshotJSONSerializer::SerializeString(const unsigned char* s) {
writer_->AddCharacter('\n');
writer_->AddCharacter('\"');
for ( ; *s != '\0'; ++s) {
switch (*s) {
case '\b':
writer_->AddString("\\b");
continue;
case '\f':
writer_->AddString("\\f");
continue;
case '\n':
writer_->AddString("\\n");
continue;
case '\r':
writer_->AddString("\\r");
continue;
case '\t':
writer_->AddString("\\t");
continue;
case '\"':
case '\\':
writer_->AddCharacter('\\');
writer_->AddCharacter(*s);
continue;
default:
if (*s > 31 && *s < 128) {
writer_->AddCharacter(*s);
} else if (*s <= 31) {
// Special character with no dedicated literal.
WriteUChar(writer_, *s);
} else {
// Convert UTF-8 into \u UTF-16 literal.
size_t length = 1, cursor = 0;
for ( ; length <= 4 && *(s + length) != '\0'; ++length) { }
unibrow::uchar c = unibrow::Utf8::CalculateValue(s, length, &cursor);
if (c != unibrow::Utf8::kBadChar) {
WriteUChar(writer_, c);
DCHECK_NE(cursor, 0);
s += cursor - 1;
} else {
writer_->AddCharacter('?');
}
}
}
}
writer_->AddCharacter('\"');
}
void HeapSnapshotJSONSerializer::SerializeStrings() {
ScopedVector<const unsigned char*> sorted_strings(
strings_.occupancy() + 1);
for (base::HashMap::Entry* entry = strings_.Start(); entry != nullptr;
entry = strings_.Next(entry)) {
int index = static_cast<int>(reinterpret_cast<uintptr_t>(entry->value));
sorted_strings[index] = reinterpret_cast<const unsigned char*>(entry->key);
}
writer_->AddString("\"<dummy>\"");
for (int i = 1; i < sorted_strings.length(); ++i) {
writer_->AddCharacter(',');
SerializeString(sorted_strings[i]);
if (writer_->aborted()) return;
}
}
void HeapSnapshotJSONSerializer::SerializeLocation(
const SourceLocation& location) {
// The buffer needs space for 4 unsigned ints, 3 commas, \n and \0
static const int kBufferSize =
MaxDecimalDigitsIn<sizeof(unsigned)>::kUnsigned * 4 + 3 + 2;
EmbeddedVector<char, kBufferSize> buffer;
int buffer_pos = 0;
buffer_pos = utoa(to_node_index(location.entry_index), buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(location.scriptId, buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(location.line, buffer, buffer_pos);
buffer[buffer_pos++] = ',';
buffer_pos = utoa(location.col, buffer, buffer_pos);
buffer[buffer_pos++] = '\n';
buffer[buffer_pos++] = '\0';
writer_->AddString(buffer.begin());
}
void HeapSnapshotJSONSerializer::SerializeLocations() {
const std::vector<SourceLocation>& locations = snapshot_->locations();
for (size_t i = 0; i < locations.size(); i++) {
if (i > 0) writer_->AddCharacter(',');
SerializeLocation(locations[i]);
if (writer_->aborted()) return;
}
}
} // namespace internal
} // namespace v8