Source code
Revision control
Copy as Markdown
Other Tools
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "HeapSnapshot.h"
#include <google/protobuf/io/coded_stream.h>
#include <google/protobuf/io/gzip_stream.h>
#include <google/protobuf/io/zero_copy_stream_impl_lite.h>
#include "js/Array.h" // JS::NewArrayObject
#include "js/ColumnNumber.h" // JS::LimitedColumnNumberOneOrigin, JS::TaggedColumnNumberOneOrigin
#include "js/Debug.h"
#include "js/PropertyAndElement.h" // JS_DefineProperty
#include "js/TypeDecls.h"
#include "js/UbiNodeBreadthFirst.h"
#include "js/UbiNodeCensus.h"
#include "js/UbiNodeDominatorTree.h"
#include "js/UbiNodeShortestPaths.h"
#include "mozilla/Attributes.h"
#include "mozilla/CycleCollectedJSContext.h"
#include "mozilla/devtools/AutoMemMap.h"
#include "mozilla/devtools/CoreDump.pb.h"
#include "mozilla/devtools/DeserializedNode.h"
#include "mozilla/devtools/DominatorTree.h"
#include "mozilla/devtools/FileDescriptorOutputStream.h"
#include "mozilla/devtools/HeapSnapshotTempFileHelperChild.h"
#include "mozilla/devtools/ZeroCopyNSIOutputStream.h"
#include "mozilla/dom/ChromeUtils.h"
#include "mozilla/dom/ContentChild.h"
#include "mozilla/dom/HeapSnapshotBinding.h"
#include "mozilla/RangedPtr.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Unused.h"
#include "jsapi.h"
#include "jsfriendapi.h"
#include "js/GCVector.h"
#include "js/MapAndSet.h"
#include "js/Object.h" // JS::GetCompartment
#include "nsComponentManagerUtils.h" // do_CreateInstance
#include "nsCycleCollectionParticipant.h"
#include "nsCRTGlue.h"
#include "nsIFile.h"
#include "nsIOutputStream.h"
#include "nsISupportsImpl.h"
#include "nsNetUtil.h"
#include "nsPrintfCString.h"
#include "prerror.h"
#include "prio.h"
#include "prtypes.h"
#include "SpecialSystemDirectory.h"
namespace mozilla {
namespace devtools {
using namespace JS;
using namespace dom;
using ::google::protobuf::io::ArrayInputStream;
using ::google::protobuf::io::CodedInputStream;
using ::google::protobuf::io::GzipInputStream;
using ::google::protobuf::io::ZeroCopyInputStream;
using JS::ubi::AtomOrTwoByteChars;
using JS::ubi::ShortestPaths;
MallocSizeOf GetCurrentThreadDebuggerMallocSizeOf() {
auto ccjscx = CycleCollectedJSContext::Get();
MOZ_ASSERT(ccjscx);
auto cx = ccjscx->Context();
MOZ_ASSERT(cx);
auto mallocSizeOf = JS::dbg::GetDebuggerMallocSizeOf(cx);
MOZ_ASSERT(mallocSizeOf);
return mallocSizeOf;
}
/*** Cycle Collection Boilerplate *********************************************/
NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HeapSnapshot, mParent)
NS_IMPL_CYCLE_COLLECTING_ADDREF(HeapSnapshot)
NS_IMPL_CYCLE_COLLECTING_RELEASE(HeapSnapshot)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(HeapSnapshot)
NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
/* virtual */
JSObject* HeapSnapshot::WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) {
return HeapSnapshot_Binding::Wrap(aCx, this, aGivenProto);
}
/*** Reading Heap Snapshots ***************************************************/
/* static */
already_AddRefed<HeapSnapshot> HeapSnapshot::Create(JSContext* cx,
GlobalObject& global,
const uint8_t* buffer,
uint32_t size,
ErrorResult& rv) {
RefPtr<HeapSnapshot> snapshot = new HeapSnapshot(cx, global.GetAsSupports());
if (!snapshot->init(cx, buffer, size)) {
rv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
return snapshot.forget();
}
template <typename MessageType>
static bool parseMessage(ZeroCopyInputStream& stream, uint32_t sizeOfMessage,
MessageType& message) {
// We need to create a new `CodedInputStream` for each message so that the
// 64MB limit is applied per-message rather than to the whole stream.
CodedInputStream codedStream(&stream);
// The protobuf message nesting that core dumps exhibit is dominated by
// allocation stacks' frames. In the most deeply nested case, each frame has
// two messages: a StackFrame message and a StackFrame::Data message. These
// frames are on top of a small constant of other messages. There are a
// MAX_STACK_DEPTH number of frames, so we multiply this by 3 to make room for
// the two messages per frame plus some head room for the constant number of
// non-dominating messages.
codedStream.SetRecursionLimit(HeapSnapshot::MAX_STACK_DEPTH * 3);
auto limit = codedStream.PushLimit(sizeOfMessage);
if (NS_WARN_IF(!message.ParseFromCodedStream(&codedStream)) ||
NS_WARN_IF(!codedStream.ConsumedEntireMessage()) ||
NS_WARN_IF(codedStream.BytesUntilLimit() != 0)) {
return false;
}
codedStream.PopLimit(limit);
return true;
}
template <typename CharT, typename InternedStringSet>
struct GetOrInternStringMatcher {
InternedStringSet& internedStrings;
explicit GetOrInternStringMatcher(InternedStringSet& strings)
: internedStrings(strings) {}
const CharT* operator()(const std::string* str) {
MOZ_ASSERT(str);
size_t length = str->length() / sizeof(CharT);
auto tempString = reinterpret_cast<const CharT*>(str->data());
UniqueFreePtr<CharT[]> owned(NS_xstrndup(tempString, length));
if (!internedStrings.append(std::move(owned))) return nullptr;
return internedStrings.back().get();
}
const CharT* operator()(uint64_t ref) {
if (MOZ_LIKELY(ref < internedStrings.length())) {
auto& string = internedStrings[ref];
MOZ_ASSERT(string);
return string.get();
}
return nullptr;
}
};
template <
// Either char or char16_t.
typename CharT,
// A reference to either `internedOneByteStrings` or
// `internedTwoByteStrings` if CharT is char or char16_t respectively.
typename InternedStringSet>
const CharT* HeapSnapshot::getOrInternString(
InternedStringSet& internedStrings, Maybe<StringOrRef>& maybeStrOrRef) {
// Incomplete message: has neither a string nor a reference to an already
// interned string.
if (MOZ_UNLIKELY(maybeStrOrRef.isNothing())) return nullptr;
GetOrInternStringMatcher<CharT, InternedStringSet> m(internedStrings);
return maybeStrOrRef->match(m);
}
// Get a de-duplicated string as a Maybe<StringOrRef> from the given `msg`.
#define GET_STRING_OR_REF_WITH_PROP_NAMES(msg, strPropertyName, \
refPropertyName) \
(msg.has_##refPropertyName() ? Some(StringOrRef(msg.refPropertyName())) \
: msg.has_##strPropertyName() ? Some(StringOrRef(&msg.strPropertyName())) \
: Nothing())
#define GET_STRING_OR_REF(msg, property) \
(msg.has_##property##ref() ? Some(StringOrRef(msg.property##ref())) \
: msg.has_##property() ? Some(StringOrRef(&msg.property())) \
: Nothing())
bool HeapSnapshot::saveNode(const protobuf::Node& node,
NodeIdSet& edgeReferents) {
// NB: de-duplicated string properties must be read back and interned in the
// same order here as they are written and serialized in
// `CoreDumpWriter::writeNode` or else indices in references to already
// serialized strings will be off.
if (NS_WARN_IF(!node.has_id())) return false;
NodeId id = node.id();
// NodeIds are derived from pointers (at most 48 bits) and we rely on them
// fitting into JS numbers (IEEE 754 doubles, can precisely store 53 bit
// integers) despite storing them on disk as 64 bit integers.
if (NS_WARN_IF(!JS::Value::isNumberRepresentable(id))) return false;
// Should only deserialize each node once.
if (NS_WARN_IF(nodes.has(id))) return false;
if (NS_WARN_IF(!JS::ubi::Uint32IsValidCoarseType(node.coarsetype())))
return false;
auto coarseType = JS::ubi::Uint32ToCoarseType(node.coarsetype());
Maybe<StringOrRef> typeNameOrRef =
GET_STRING_OR_REF_WITH_PROP_NAMES(node, typename_, typenameref);
auto typeName =
getOrInternString<char16_t>(internedTwoByteStrings, typeNameOrRef);
if (NS_WARN_IF(!typeName)) return false;
if (NS_WARN_IF(!node.has_size())) return false;
uint64_t size = node.size();
auto edgesLength = node.edges_size();
DeserializedNode::EdgeVector edges;
if (NS_WARN_IF(!edges.reserve(edgesLength))) return false;
for (decltype(edgesLength) i = 0; i < edgesLength; i++) {
auto& protoEdge = node.edges(i);
if (NS_WARN_IF(!protoEdge.has_referent())) return false;
NodeId referent = protoEdge.referent();
if (NS_WARN_IF(!edgeReferents.put(referent))) return false;
const char16_t* edgeName = nullptr;
if (protoEdge.EdgeNameOrRef_case() !=
protobuf::Edge::EDGENAMEORREF_NOT_SET) {
Maybe<StringOrRef> edgeNameOrRef = GET_STRING_OR_REF(protoEdge, name);
edgeName =
getOrInternString<char16_t>(internedTwoByteStrings, edgeNameOrRef);
if (NS_WARN_IF(!edgeName)) return false;
}
edges.infallibleAppend(DeserializedEdge(referent, edgeName));
}
Maybe<StackFrameId> allocationStack;
if (node.has_allocationstack()) {
StackFrameId id = 0;
if (NS_WARN_IF(!saveStackFrame(node.allocationstack(), id))) return false;
allocationStack.emplace(id);
}
MOZ_ASSERT(allocationStack.isSome() == node.has_allocationstack());
const char* jsObjectClassName = nullptr;
if (node.JSObjectClassNameOrRef_case() !=
protobuf::Node::JSOBJECTCLASSNAMEORREF_NOT_SET) {
Maybe<StringOrRef> clsNameOrRef =
GET_STRING_OR_REF(node, jsobjectclassname);
jsObjectClassName =
getOrInternString<char>(internedOneByteStrings, clsNameOrRef);
if (NS_WARN_IF(!jsObjectClassName)) return false;
}
const char* scriptFilename = nullptr;
if (node.ScriptFilenameOrRef_case() !=
protobuf::Node::SCRIPTFILENAMEORREF_NOT_SET) {
Maybe<StringOrRef> scriptFilenameOrRef =
GET_STRING_OR_REF(node, scriptfilename);
scriptFilename =
getOrInternString<char>(internedOneByteStrings, scriptFilenameOrRef);
if (NS_WARN_IF(!scriptFilename)) return false;
}
const char16_t* descriptiveTypeName = nullptr;
if (node.descriptiveTypeNameOrRef_case() !=
protobuf::Node::DESCRIPTIVETYPENAMEORREF_NOT_SET) {
Maybe<StringOrRef> descriptiveTypeNameOrRef =
GET_STRING_OR_REF(node, descriptivetypename);
descriptiveTypeName = getOrInternString<char16_t>(internedTwoByteStrings,
descriptiveTypeNameOrRef);
if (NS_WARN_IF(!descriptiveTypeName)) return false;
}
if (NS_WARN_IF(!nodes.putNew(
id, DeserializedNode(id, coarseType, typeName, size, std::move(edges),
allocationStack, jsObjectClassName,
scriptFilename, descriptiveTypeName, *this)))) {
return false;
};
return true;
}
bool HeapSnapshot::saveStackFrame(const protobuf::StackFrame& frame,
StackFrameId& outFrameId) {
// NB: de-duplicated string properties must be read in the same order here as
// they are written in `CoreDumpWriter::getProtobufStackFrame` or else indices
// in references to already serialized strings will be off.
if (frame.has_ref()) {
// We should only get a reference to the previous frame if we have already
// seen the previous frame.
if (!frames.has(frame.ref())) return false;
outFrameId = frame.ref();
return true;
}
// Incomplete message.
if (!frame.has_data()) return false;
auto data = frame.data();
if (!data.has_id()) return false;
StackFrameId id = data.id();
// This should be the first and only time we see this frame.
if (frames.has(id)) return false;
if (!data.has_line()) return false;
uint32_t line = data.line();
if (!data.has_column()) return false;
JS::TaggedColumnNumberOneOrigin column(
JS::LimitedColumnNumberOneOrigin(data.column()));
if (!data.has_issystem()) return false;
bool isSystem = data.issystem();
if (!data.has_isselfhosted()) return false;
bool isSelfHosted = data.isselfhosted();
Maybe<StringOrRef> sourceOrRef = GET_STRING_OR_REF(data, source);
auto source =
getOrInternString<char16_t>(internedTwoByteStrings, sourceOrRef);
if (!source) return false;
const char16_t* functionDisplayName = nullptr;
if (data.FunctionDisplayNameOrRef_case() !=
protobuf::StackFrame_Data::FUNCTIONDISPLAYNAMEORREF_NOT_SET) {
Maybe<StringOrRef> nameOrRef = GET_STRING_OR_REF(data, functiondisplayname);
functionDisplayName =
getOrInternString<char16_t>(internedTwoByteStrings, nameOrRef);
if (!functionDisplayName) return false;
}
Maybe<StackFrameId> parent;
if (data.has_parent()) {
StackFrameId parentId = 0;
if (!saveStackFrame(data.parent(), parentId)) return false;
parent = Some(parentId);
}
if (!frames.putNew(id,
DeserializedStackFrame(id, parent, line, column, source,
functionDisplayName, isSystem,
isSelfHosted, *this))) {
return false;
}
outFrameId = id;
return true;
}
#undef GET_STRING_OR_REF_WITH_PROP_NAMES
#undef GET_STRING_OR_REF
// Because protobuf messages aren't self-delimiting, we serialize each message
// preceded by its size in bytes. When deserializing, we read this size and then
// limit reading from the stream to the given byte size. If we didn't, then the
// first message would consume the entire stream.
static bool readSizeOfNextMessage(ZeroCopyInputStream& stream,
uint32_t* sizep) {
MOZ_ASSERT(sizep);
CodedInputStream codedStream(&stream);
return codedStream.ReadVarint32(sizep) && *sizep > 0;
}
bool HeapSnapshot::init(JSContext* cx, const uint8_t* buffer, uint32_t size) {
ArrayInputStream stream(buffer, size);
GzipInputStream gzipStream(&stream);
uint32_t sizeOfMessage = 0;
// First is the metadata.
protobuf::Metadata metadata;
if (NS_WARN_IF(!readSizeOfNextMessage(gzipStream, &sizeOfMessage)))
return false;
if (!parseMessage(gzipStream, sizeOfMessage, metadata)) return false;
if (metadata.has_timestamp()) timestamp.emplace(metadata.timestamp());
// Next is the root node.
protobuf::Node root;
if (NS_WARN_IF(!readSizeOfNextMessage(gzipStream, &sizeOfMessage)))
return false;
if (!parseMessage(gzipStream, sizeOfMessage, root)) return false;
// Although the id is optional in the protobuf format for future proofing, we
// can't currently do anything without it.
if (NS_WARN_IF(!root.has_id())) return false;
rootId = root.id();
// The set of all node ids we've found edges pointing to.
NodeIdSet edgeReferents(cx);
if (NS_WARN_IF(!saveNode(root, edgeReferents))) return false;
// Finally, the rest of the nodes in the core dump.
// Test for the end of the stream. The protobuf library gives no way to tell
// the difference between an underlying read error and the stream being
// done. All we can do is attempt to read the size of the next message and
// extrapolate guestimations from the result of that operation.
while (readSizeOfNextMessage(gzipStream, &sizeOfMessage)) {
protobuf::Node node;
if (!parseMessage(gzipStream, sizeOfMessage, node)) return false;
if (NS_WARN_IF(!saveNode(node, edgeReferents))) return false;
}
// Check the set of node ids referred to by edges we found and ensure that we
// have the node corresponding to each id. If we don't have all of them, it is
// unsafe to perform analyses of this heap snapshot.
for (auto iter = edgeReferents.iter(); !iter.done(); iter.next()) {
if (NS_WARN_IF(!nodes.has(iter.get()))) return false;
}
return true;
}
/*** Heap Snapshot Analyses ***************************************************/
void HeapSnapshot::TakeCensus(JSContext* cx, JS::Handle<JSObject*> options,
JS::MutableHandle<JS::Value> rval,
ErrorResult& rv) {
JS::ubi::Census census(cx);
JS::ubi::CountTypePtr rootType;
if (NS_WARN_IF(!JS::ubi::ParseCensusOptions(cx, census, options, rootType))) {
rv.Throw(NS_ERROR_UNEXPECTED);
return;
}
JS::ubi::RootedCount rootCount(cx, rootType->makeCount());
if (NS_WARN_IF(!rootCount)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
JS::ubi::CensusHandler handler(census, rootCount,
GetCurrentThreadDebuggerMallocSizeOf());
{
JS::AutoCheckCannotGC nogc;
JS::ubi::CensusTraversal traversal(cx, handler, nogc);
if (NS_WARN_IF(!traversal.addStart(getRoot()))) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
if (NS_WARN_IF(!traversal.traverse())) {
rv.Throw(NS_ERROR_UNEXPECTED);
return;
}
}
if (NS_WARN_IF(!handler.report(cx, rval))) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
void HeapSnapshot::DescribeNode(JSContext* cx, JS::Handle<JSObject*> breakdown,
uint64_t nodeId,
JS::MutableHandle<JS::Value> rval,
ErrorResult& rv) {
MOZ_ASSERT(breakdown);
JS::Rooted<JS::Value> breakdownVal(cx, JS::ObjectValue(*breakdown));
JS::Rooted<JS::GCVector<JSLinearString*>> seen(cx, cx);
JS::ubi::CountTypePtr rootType =
JS::ubi::ParseBreakdown(cx, breakdownVal, &seen);
if (NS_WARN_IF(!rootType)) {
rv.Throw(NS_ERROR_UNEXPECTED);
return;
}
JS::ubi::RootedCount rootCount(cx, rootType->makeCount());
if (NS_WARN_IF(!rootCount)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
JS::ubi::Node::Id id(nodeId);
Maybe<JS::ubi::Node> node = getNodeById(id);
if (NS_WARN_IF(node.isNothing())) {
rv.Throw(NS_ERROR_INVALID_ARG);
return;
}
MallocSizeOf mallocSizeOf = GetCurrentThreadDebuggerMallocSizeOf();
if (NS_WARN_IF(!rootCount->count(mallocSizeOf, *node))) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
if (NS_WARN_IF(!rootCount->report(cx, rval))) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
already_AddRefed<DominatorTree> HeapSnapshot::ComputeDominatorTree(
ErrorResult& rv) {
Maybe<JS::ubi::DominatorTree> maybeTree;
{
auto ccjscx = CycleCollectedJSContext::Get();
MOZ_ASSERT(ccjscx);
auto cx = ccjscx->Context();
MOZ_ASSERT(cx);
JS::AutoCheckCannotGC nogc(cx);
maybeTree = JS::ubi::DominatorTree::Create(cx, nogc, getRoot());
}
if (NS_WARN_IF(maybeTree.isNothing())) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return nullptr;
}
return MakeAndAddRef<DominatorTree>(std::move(*maybeTree), this, mParent);
}
void HeapSnapshot::ComputeShortestPaths(JSContext* cx, uint64_t start,
const Sequence<uint64_t>& targets,
uint64_t maxNumPaths,
JS::MutableHandle<JSObject*> results,
ErrorResult& rv) {
// First ensure that our inputs are valid.
if (NS_WARN_IF(maxNumPaths == 0)) {
rv.Throw(NS_ERROR_INVALID_ARG);
return;
}
Maybe<JS::ubi::Node> startNode = getNodeById(start);
if (NS_WARN_IF(startNode.isNothing())) {
rv.Throw(NS_ERROR_INVALID_ARG);
return;
}
if (NS_WARN_IF(targets.Length() == 0)) {
rv.Throw(NS_ERROR_INVALID_ARG);
return;
}
// Aggregate the targets into a set and make sure that they exist in the heap
// snapshot.
JS::ubi::NodeSet targetsSet;
for (const auto& target : targets) {
Maybe<JS::ubi::Node> targetNode = getNodeById(target);
if (NS_WARN_IF(targetNode.isNothing())) {
rv.Throw(NS_ERROR_INVALID_ARG);
return;
}
if (NS_WARN_IF(!targetsSet.put(*targetNode))) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
// Walk the heap graph and find the shortest paths.
Maybe<ShortestPaths> maybeShortestPaths;
{
JS::AutoCheckCannotGC nogc(cx);
maybeShortestPaths = ShortestPaths::Create(
cx, nogc, maxNumPaths, *startNode, std::move(targetsSet));
}
if (NS_WARN_IF(maybeShortestPaths.isNothing())) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
auto& shortestPaths = *maybeShortestPaths;
// Convert the results into a Map object mapping target node IDs to arrays of
// paths found.
JS::Rooted<JSObject*> resultsMap(cx, JS::NewMapObject(cx));
if (NS_WARN_IF(!resultsMap)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
for (auto iter = shortestPaths.targetIter(); !iter.done(); iter.next()) {
JS::Rooted<JS::Value> key(cx, JS::NumberValue(iter.get().identifier()));
JS::RootedVector<JS::Value> paths(cx);
bool ok = shortestPaths.forEachPath(iter.get(), [&](JS::ubi::Path& path) {
JS::RootedVector<JS::Value> pathValues(cx);
for (JS::ubi::BackEdge* edge : path) {
JS::Rooted<JSObject*> pathPart(cx, JS_NewPlainObject(cx));
if (!pathPart) {
return false;
}
JS::Rooted<JS::Value> predecessor(
cx, NumberValue(edge->predecessor().identifier()));
if (!JS_DefineProperty(cx, pathPart, "predecessor", predecessor,
JSPROP_ENUMERATE)) {
return false;
}
JS::Rooted<JS::Value> edgeNameVal(cx, NullValue());
if (edge->name()) {
JS::Rooted<JSString*> edgeName(
cx, JS_AtomizeUCString(cx, edge->name().get()));
if (!edgeName) {
return false;
}
edgeNameVal = StringValue(edgeName);
}
if (!JS_DefineProperty(cx, pathPart, "edge", edgeNameVal,
JSPROP_ENUMERATE)) {
return false;
}
if (!pathValues.append(ObjectValue(*pathPart))) {
return false;
}
}
JS::Rooted<JSObject*> pathObj(cx, JS::NewArrayObject(cx, pathValues));
return pathObj && paths.append(ObjectValue(*pathObj));
});
if (NS_WARN_IF(!ok)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
JS::Rooted<JSObject*> pathsArray(cx, JS::NewArrayObject(cx, paths));
if (NS_WARN_IF(!pathsArray)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
JS::Rooted<JS::Value> pathsVal(cx, ObjectValue(*pathsArray));
if (NS_WARN_IF(!JS::MapSet(cx, resultsMap, key, pathsVal))) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return;
}
}
results.set(resultsMap);
}
/*** Saving Heap Snapshots ****************************************************/
// If we are only taking a snapshot of the heap affected by the given set of
// globals, find the set of compartments the globals are allocated
// within. Returns false on OOM failure.
static bool PopulateCompartmentsWithGlobals(
CompartmentSet& compartments, JS::HandleVector<JSObject*> globals) {
unsigned length = globals.length();
for (unsigned i = 0; i < length; i++) {
if (!compartments.put(JS::GetCompartment(globals[i]))) return false;
}
return true;
}
// Add the given set of globals as explicit roots in the given roots
// list. Returns false on OOM failure.
static bool AddGlobalsAsRoots(JS::HandleVector<JSObject*> globals,
ubi::RootList& roots) {
unsigned length = globals.length();
for (unsigned i = 0; i < length; i++) {
if (!roots.addRoot(ubi::Node(globals[i].get()), u"heap snapshot global")) {
return false;
}
}
return true;
}
// Choose roots and limits for a traversal, given `boundaries`. Set `roots` to
// the set of nodes within the boundaries that are referred to by nodes
// outside. If `boundaries` does not include all JS compartments, initialize
// `compartments` to the set of included compartments; otherwise, leave
// `compartments` uninitialized. (You can use compartments.initialized() to
// check.)
//
// If `boundaries` is incoherent, or we encounter an error while trying to
// handle it, or we run out of memory, set `rv` appropriately and return
// `false`.
//
// Return value is a pair of the status and an AutoCheckCannotGC token,
// forwarded from ubi::RootList::init(), to ensure that the caller does
// not GC while the RootList is live and initialized.
static std::pair<bool, AutoCheckCannotGC> EstablishBoundaries(
JSContext* cx, ErrorResult& rv, const HeapSnapshotBoundaries& boundaries,
ubi::RootList& roots, CompartmentSet& compartments) {
MOZ_ASSERT(!roots.initialized());
MOZ_ASSERT(compartments.empty());
bool foundBoundaryProperty = false;
if (boundaries.mRuntime.WasPassed()) {
foundBoundaryProperty = true;
if (!boundaries.mRuntime.Value()) {
rv.Throw(NS_ERROR_INVALID_ARG);
return {false, AutoCheckCannotGC(cx)};
}
auto [ok, nogc] = roots.init();
if (!ok) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return {false, nogc};
}
}
if (boundaries.mDebugger.WasPassed()) {
if (foundBoundaryProperty) {
rv.Throw(NS_ERROR_INVALID_ARG);
return {false, AutoCheckCannotGC(cx)};
}
foundBoundaryProperty = true;
JSObject* dbgObj = boundaries.mDebugger.Value();
if (!dbgObj || !dbg::IsDebugger(*dbgObj)) {
rv.Throw(NS_ERROR_INVALID_ARG);
return {false, AutoCheckCannotGC(cx)};
}
JS::RootedVector<JSObject*> globals(cx);
if (!dbg::GetDebuggeeGlobals(cx, *dbgObj, &globals) ||
!PopulateCompartmentsWithGlobals(compartments, globals) ||
!roots.init(compartments).first || !AddGlobalsAsRoots(globals, roots)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return {false, AutoCheckCannotGC(cx)};
}
}
if (boundaries.mGlobals.WasPassed()) {
if (foundBoundaryProperty) {
rv.Throw(NS_ERROR_INVALID_ARG);
return {false, AutoCheckCannotGC(cx)};
}
foundBoundaryProperty = true;
uint32_t length = boundaries.mGlobals.Value().Length();
if (length == 0) {
rv.Throw(NS_ERROR_INVALID_ARG);
return {false, AutoCheckCannotGC(cx)};
}
JS::RootedVector<JSObject*> globals(cx);
for (uint32_t i = 0; i < length; i++) {
JSObject* global = boundaries.mGlobals.Value().ElementAt(i);
if (!JS_IsGlobalObject(global)) {
rv.Throw(NS_ERROR_INVALID_ARG);
return {false, AutoCheckCannotGC(cx)};
}
if (!globals.append(global)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return {false, AutoCheckCannotGC(cx)};
}
}
if (!PopulateCompartmentsWithGlobals(compartments, globals) ||
!roots.init(compartments).first || !AddGlobalsAsRoots(globals, roots)) {
rv.Throw(NS_ERROR_OUT_OF_MEMORY);
return {false, AutoCheckCannotGC(cx)};
}
}
AutoCheckCannotGC nogc(cx);
if (!foundBoundaryProperty) {
rv.Throw(NS_ERROR_INVALID_ARG);
return {false, nogc};
}
MOZ_ASSERT(roots.initialized());
return {true, nogc};
}
// A variant covering all the various two-byte strings that we can get from the
// ubi::Node API.
class TwoByteString
: public Variant<JSAtom*, const char16_t*, JS::ubi::EdgeName> {
using Base = Variant<JSAtom*, const char16_t*, JS::ubi::EdgeName>;
struct CopyToBufferMatcher {
RangedPtr<char16_t> destination;
size_t maxLength;
CopyToBufferMatcher(RangedPtr<char16_t> destination, size_t maxLength)
: destination(destination), maxLength(maxLength) {}
size_t operator()(JS::ubi::EdgeName& ptr) {
return ptr ? operator()(ptr.get()) : 0;
}
size_t operator()(JSAtom* atom) {
MOZ_ASSERT(atom);
JS::ubi::AtomOrTwoByteChars s(atom);
return s.copyToBuffer(destination, maxLength);
}
size_t operator()(const char16_t* chars) {
MOZ_ASSERT(chars);
JS::ubi::AtomOrTwoByteChars s(chars);
return s.copyToBuffer(destination, maxLength);
}
};
public:
template <typename T>
MOZ_IMPLICIT TwoByteString(T&& rhs) : Base(std::forward<T>(rhs)) {}
template <typename T>
TwoByteString& operator=(T&& rhs) {
MOZ_ASSERT(this != &rhs, "self-move disallowed");
this->~TwoByteString();
new (this) TwoByteString(std::forward<T>(rhs));
return *this;
}
TwoByteString(const TwoByteString&) = delete;
TwoByteString& operator=(const TwoByteString&) = delete;
// Rewrap the inner value of a JS::ubi::AtomOrTwoByteChars as a TwoByteString.
static TwoByteString from(JS::ubi::AtomOrTwoByteChars&& s) {
return s.match([](auto* a) { return TwoByteString(a); });
}
// Returns true if the given TwoByteString is non-null, false otherwise.
bool isNonNull() const {
return match([](auto& t) { return t != nullptr; });
}
// Return the length of the string, 0 if it is null.
size_t length() const {
return match(
[](JSAtom* atom) -> size_t {
MOZ_ASSERT(atom);
JS::ubi::AtomOrTwoByteChars s(atom);
return s.length();
},
[](const char16_t* chars) -> size_t {
MOZ_ASSERT(chars);
return NS_strlen(chars);
},
[](const JS::ubi::EdgeName& ptr) -> size_t {
MOZ_ASSERT(ptr);
return NS_strlen(ptr.get());
});
}
// Copy the contents of a TwoByteString into the provided buffer. The buffer
// is NOT null terminated. The number of characters written is returned.
size_t copyToBuffer(RangedPtr<char16_t> destination, size_t maxLength) {
CopyToBufferMatcher m(destination, maxLength);
return match(m);
}
struct HashPolicy;
};
// A hashing policy for TwoByteString.
//
// Atoms are pointer hashed and use pointer equality, which means that we
// tolerate some duplication across atoms and the other two types of two-byte
// strings. In practice, we expect the amount of this duplication to be very low
// because each type is generally a different semantic thing in addition to
// having a slightly different representation. For example, the set of edge
// names and the set stack frames' source names naturally tend not to overlap
// very much if at all.
struct TwoByteString::HashPolicy {
using Lookup = TwoByteString;
static js::HashNumber hash(const Lookup& l) {
return l.match(
[](const JSAtom* atom) {
return js::DefaultHasher<const JSAtom*>::hash(atom);
},
[](const char16_t* chars) {
MOZ_ASSERT(chars);
auto length = NS_strlen(chars);
return HashString(chars, length);
},
[](const JS::ubi::EdgeName& ptr) {
const char16_t* chars = ptr.get();
MOZ_ASSERT(chars);
auto length = NS_strlen(chars);
return HashString(chars, length);
});
}
struct EqualityMatcher {
const TwoByteString& rhs;
explicit EqualityMatcher(const TwoByteString& rhs) : rhs(rhs) {}
bool operator()(const JSAtom* atom) {
return rhs.is<JSAtom*>() && rhs.as<JSAtom*>() == atom;
}
bool operator()(const char16_t* chars) {
MOZ_ASSERT(chars);
const char16_t* rhsChars = nullptr;
if (rhs.is<const char16_t*>())
rhsChars = rhs.as<const char16_t*>();
else if (rhs.is<JS::ubi::EdgeName>())
rhsChars = rhs.as<JS::ubi::EdgeName>().get();
else
return false;
MOZ_ASSERT(rhsChars);
auto length = NS_strlen(chars);
if (NS_strlen(rhsChars) != length) return false;
return memcmp(chars, rhsChars, length * sizeof(char16_t)) == 0;
}
bool operator()(const JS::ubi::EdgeName& ptr) {
MOZ_ASSERT(ptr);
return operator()(ptr.get());
}
};
static bool match(const TwoByteString& k, const Lookup& l) {
EqualityMatcher eq(l);
return k.match(eq);
}
static void rekey(TwoByteString& k, TwoByteString&& newKey) {
k = std::move(newKey);
}
};
// Returns whether `edge` should be included in a heap snapshot of
// `compartments`. The optional `policy` out-param is set to INCLUDE_EDGES
// if we want to include the referent's edges, or EXCLUDE_EDGES if we don't
// want to include them.
static bool ShouldIncludeEdge(JS::CompartmentSet* compartments,
const ubi::Node& origin, const ubi::Edge& edge,
CoreDumpWriter::EdgePolicy* policy = nullptr) {
if (policy) {
*policy = CoreDumpWriter::INCLUDE_EDGES;
}
if (!compartments) {
// We aren't targeting a particular set of compartments, so serialize all
// the things!
return true;
}
// We are targeting a particular set of compartments. If this node is in our
// target set, serialize it and all of its edges. If this node is _not_ in our
// target set, we also serialize under the assumption that it is a shared
// resource being used by something in our target compartments since we
// reached it by traversing the heap graph. However, we do not serialize its
// outgoing edges and we abandon further traversal from this node.
//
// If the node does not belong to any compartment, we also serialize its
// outgoing edges. This case is relevant for Shapes: they don't belong to a
// specific compartment and contain edges to parent/kids Shapes we want to
// include. Note that these Shapes may contain pointers into our target
// compartment (the Shape's getter/setter JSObjects). However, we do not
// serialize nodes in other compartments that are reachable from these
// non-compartment nodes.
JS::Compartment* compartment = edge.referent.compartment();
if (!compartment || compartments->has(compartment)) {
return true;
}
if (policy) {
*policy = CoreDumpWriter::EXCLUDE_EDGES;
}
return !!origin.compartment();
}
// A `CoreDumpWriter` that serializes nodes to protobufs and writes them to the
// given `ZeroCopyOutputStream`.
class MOZ_STACK_CLASS StreamWriter : public CoreDumpWriter {
using FrameSet = js::HashSet<uint64_t>;
using TwoByteStringMap =
js::HashMap<TwoByteString, uint64_t, TwoByteString::HashPolicy>;
using OneByteStringMap = js::HashMap<const char*, uint64_t>;
JSContext* cx;
bool wantNames;
// The set of |JS::ubi::StackFrame::identifier()|s that have already been
// serialized and written to the core dump.
FrameSet framesAlreadySerialized;
// The set of two-byte strings that have already been serialized and written
// to the core dump.
TwoByteStringMap twoByteStringsAlreadySerialized;
// The set of one-byte strings that have already been serialized and written
// to the core dump.
OneByteStringMap oneByteStringsAlreadySerialized;
::google::protobuf::io::ZeroCopyOutputStream& stream;
JS::CompartmentSet* compartments;
bool writeMessage(const ::google::protobuf::MessageLite& message) {
// We have to create a new CodedOutputStream when writing each message so
// that the 64MB size limit used by Coded{Output,Input}Stream to prevent
// integer overflow is enforced per message rather than on the whole stream.
::google::protobuf::io::CodedOutputStream codedStream(&stream);
codedStream.WriteVarint32(message.ByteSizeLong());
message.SerializeWithCachedSizes(&codedStream);
return !codedStream.HadError();
}
// Attach the full two-byte string or a reference to a two-byte string that
// has already been serialized to a protobuf message.
template <typename SetStringFunction, typename SetRefFunction>
bool attachTwoByteString(TwoByteString& string, SetStringFunction setString,
SetRefFunction setRef) {
auto ptr = twoByteStringsAlreadySerialized.lookupForAdd(string);
if (ptr) {
setRef(ptr->value());
return true;
}
auto length = string.length();
auto stringData = MakeUnique<std::string>(length * sizeof(char16_t), '\0');
if (!stringData) return false;
auto buf = const_cast<char16_t*>(
reinterpret_cast<const char16_t*>(stringData->data()));
string.copyToBuffer(RangedPtr<char16_t>(buf, length), length);
uint64_t ref = twoByteStringsAlreadySerialized.count();
if (!twoByteStringsAlreadySerialized.add(ptr, std::move(string), ref))
return false;
setString(stringData.release());
return true;
}
// Attach the full one-byte string or a reference to a one-byte string that
// has already been serialized to a protobuf message.
template <typename SetStringFunction, typename SetRefFunction>
bool attachOneByteString(const char* string, SetStringFunction setString,
SetRefFunction setRef) {
auto ptr = oneByteStringsAlreadySerialized.lookupForAdd(string);
if (ptr) {
setRef(ptr->value());
return true;
}
auto length = strlen(string);
auto stringData = MakeUnique<std::string>(string, length);
if (!stringData) return false;
uint64_t ref = oneByteStringsAlreadySerialized.count();
if (!oneByteStringsAlreadySerialized.add(ptr, string, ref)) return false;
setString(stringData.release());
return true;
}
protobuf::StackFrame* getProtobufStackFrame(JS::ubi::StackFrame& frame,
size_t depth = 1) {
// NB: de-duplicated string properties must be written in the same order
// here as they are read in `HeapSnapshot::saveStackFrame` or else indices
// in references to already serialized strings will be off.
MOZ_ASSERT(frame,
"null frames should be represented as the lack of a serialized "
"stack frame");
auto id = frame.identifier();
auto protobufStackFrame = MakeUnique<protobuf::StackFrame>();
if (!protobufStackFrame) return nullptr;
if (framesAlreadySerialized.has(id)) {
protobufStackFrame->set_ref(id);
return protobufStackFrame.release();
}
auto data = MakeUnique<protobuf::StackFrame_Data>();
if (!data) return nullptr;
data->set_id(id);
data->set_line(frame.line());
data->set_column(frame.column().oneOriginValue());
data->set_issystem(frame.isSystem());
data->set_isselfhosted(frame.isSelfHosted(cx));
auto dupeSource = TwoByteString::from(frame.source());
if (!attachTwoByteString(
dupeSource,
[&](std::string* source) { data->set_allocated_source(source); },
[&](uint64_t ref) { data->set_sourceref(ref); })) {
return nullptr;
}
auto dupeName = TwoByteString::from(frame.functionDisplayName());
if (dupeName.isNonNull()) {
if (!attachTwoByteString(
dupeName,
[&](std::string* name) {
data->set_allocated_functiondisplayname(name);
},
[&](uint64_t ref) { data->set_functiondisplaynameref(ref); })) {
return nullptr;
}
}
auto parent = frame.parent();
if (parent && depth < HeapSnapshot::MAX_STACK_DEPTH) {
auto protobufParent = getProtobufStackFrame(parent, depth + 1);
if (!protobufParent) return nullptr;
data->set_allocated_parent(protobufParent);
}
protobufStackFrame->set_allocated_data(data.release());
if (!framesAlreadySerialized.put(id)) return nullptr;
return protobufStackFrame.release();
}
public:
StreamWriter(JSContext* cx,
::google::protobuf::io::ZeroCopyOutputStream& stream,
bool wantNames, JS::CompartmentSet* compartments)
: cx(cx),
wantNames(wantNames),
framesAlreadySerialized(cx),
twoByteStringsAlreadySerialized(cx),
oneByteStringsAlreadySerialized(cx),
stream(stream),
compartments(compartments) {}
~StreamWriter() override {}
bool writeMetadata(uint64_t timestamp) final {
protobuf::Metadata metadata;
metadata.set_timestamp(timestamp);
return writeMessage(metadata);
}
bool writeNode(const JS::ubi::Node& ubiNode, EdgePolicy includeEdges) final {
// NB: de-duplicated string properties must be written in the same order
// here as they are read in `HeapSnapshot::saveNode` or else indices in
// references to already serialized strings will be off.
protobuf::Node protobufNode;
protobufNode.set_id(ubiNode.identifier());
protobufNode.set_coarsetype(
JS::ubi::CoarseTypeToUint32(ubiNode.coarseType()));
auto typeName = TwoByteString(ubiNode.typeName());
if (NS_WARN_IF(!attachTwoByteString(
typeName,
[&](std::string* name) {
protobufNode.set_allocated_typename_(name);
},
[&](uint64_t ref) { protobufNode.set_typenameref(ref); }))) {
return false;
}
mozilla::MallocSizeOf mallocSizeOf = dbg::GetDebuggerMallocSizeOf(cx);
MOZ_ASSERT(mallocSizeOf);
protobufNode.set_size(ubiNode.size(mallocSizeOf));
if (includeEdges) {
auto edges = ubiNode.edges(cx, wantNames);
if (NS_WARN_IF(!edges)) return false;
for (; !edges->empty(); edges->popFront()) {
ubi::Edge& ubiEdge = edges->front();
if (!ShouldIncludeEdge(compartments, ubiNode, ubiEdge)) {
continue;
}
protobuf::Edge* protobufEdge = protobufNode.add_edges();
if (NS_WARN_IF(!protobufEdge)) {
return false;
}
protobufEdge->set_referent(ubiEdge.referent.identifier());
if (wantNames && ubiEdge.name) {
TwoByteString edgeName(std::move(ubiEdge.name));
if (NS_WARN_IF(!attachTwoByteString(
edgeName,
[&](std::string* name) {
protobufEdge->set_allocated_name(name);
},
[&](uint64_t ref) { protobufEdge->set_nameref(ref); }))) {
return false;
}
}
}
}
if (ubiNode.hasAllocationStack()) {
auto ubiStackFrame = ubiNode.allocationStack();
auto protoStackFrame = getProtobufStackFrame(ubiStackFrame);
if (NS_WARN_IF(!protoStackFrame)) return false;
protobufNode.set_allocated_allocationstack(protoStackFrame);
}
if (auto className = ubiNode.jsObjectClassName()) {
if (NS_WARN_IF(!attachOneByteString(
className,
[&](std::string* name) {
protobufNode.set_allocated_jsobjectclassname(name);
},
[&](uint64_t ref) {
protobufNode.set_jsobjectclassnameref(ref);
}))) {
return false;
}
}
if (auto scriptFilename = ubiNode.scriptFilename()) {
if (NS_WARN_IF(!attachOneByteString(
scriptFilename,
[&](std::string* name) {
protobufNode.set_allocated_scriptfilename(name);
},
[&](uint64_t ref) {
protobufNode.set_scriptfilenameref(ref);
}))) {
return false;
}
}
if (ubiNode.descriptiveTypeName()) {
auto descriptiveTypeName = TwoByteString(ubiNode.descriptiveTypeName());
if (NS_WARN_IF(!attachTwoByteString(
descriptiveTypeName,
[&](std::string* name) {
protobufNode.set_allocated_descriptivetypename(name);
},
[&](uint64_t ref) {
protobufNode.set_descriptivetypenameref(ref);
}))) {
return false;
}
}
return writeMessage(protobufNode);
}
};
// A JS::ubi::BreadthFirst handler that serializes a snapshot of the heap into a
// core dump.
class MOZ_STACK_CLASS HeapSnapshotHandler {
CoreDumpWriter& writer;
JS::CompartmentSet* compartments;
public:
// For telemetry.
uint32_t nodeCount;
uint32_t edgeCount;
HeapSnapshotHandler(CoreDumpWriter& writer, JS::CompartmentSet* compartments)
: writer(writer),
compartments(compartments),
nodeCount(0),
edgeCount(0) {}
// JS::ubi::BreadthFirst handler interface.
class NodeData {};
typedef JS::ubi::BreadthFirst<HeapSnapshotHandler> Traversal;
bool operator()(Traversal& traversal, JS::ubi::Node origin,
const JS::ubi::Edge& edge, NodeData*, bool first) {
edgeCount++;
// We're only interested in the first time we reach edge.referent, not in
// every edge arriving at that node. "But, don't we want to serialize every
// edge in the heap graph?" you ask. Don't worry! This edge is still
// serialized into the core dump. Serializing a node also serializes each of
// its edges, and if we are traversing a given edge, we must have already
// visited and serialized the origin node and its edges.
if (!first) return true;
CoreDumpWriter::EdgePolicy policy;
if (!ShouldIncludeEdge(compartments, origin, edge, &policy)) {
// Because ShouldIncludeEdge considers the |origin| node as well, we don't
// want to consider this node 'visited' until we write it to the core
// dump.
traversal.doNotMarkReferentAsVisited();
return true;
}
nodeCount++;
if (policy == CoreDumpWriter::EXCLUDE_EDGES) traversal.abandonReferent();
return writer.writeNode(edge.referent, policy);
}
};
bool WriteHeapGraph(JSContext* cx, const JS::ubi::Node& node,
CoreDumpWriter& writer, bool wantNames,
JS::CompartmentSet* compartments,
JS::AutoCheckCannotGC& noGC, uint32_t& outNodeCount,
uint32_t& outEdgeCount) {
// Serialize the starting node to the core dump.
if (NS_WARN_IF(!writer.writeNode(node, CoreDumpWriter::INCLUDE_EDGES))) {
return false;
}
// Walk the heap graph starting from the given node and serialize it into the
// core dump.
HeapSnapshotHandler handler(writer, compartments);
HeapSnapshotHandler::Traversal traversal(cx, handler, noGC);
traversal.wantNames = wantNames;
bool ok = traversal.addStartVisited(node) && traversal.traverse();
if (ok) {
outNodeCount = handler.nodeCount;
outEdgeCount = handler.edgeCount;
}
return ok;
}
static unsigned long msSinceProcessCreation(const TimeStamp& now) {
auto duration = now - TimeStamp::ProcessCreation();
return (unsigned long)duration.ToMilliseconds();
}
/* static */
already_AddRefed<nsIFile> HeapSnapshot::CreateUniqueCoreDumpFile(
ErrorResult& rv, const TimeStamp& now, nsAString& outFilePath,
nsAString& outSnapshotId) {
MOZ_RELEASE_ASSERT(XRE_IsParentProcess());
nsCOMPtr<nsIFile> file;
rv = GetSpecialSystemDirectory(OS_TemporaryDirectory, getter_AddRefs(file));
if (NS_WARN_IF(rv.Failed())) return nullptr;
nsAutoString tempPath;
rv = file->GetPath(tempPath);
if (NS_WARN_IF(rv.Failed())) return nullptr;
auto ms = msSinceProcessCreation(now);
rv = file->AppendNative(nsPrintfCString("%lu.fxsnapshot", ms));
if (NS_WARN_IF(rv.Failed())) return nullptr;
rv = file->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0666);
if (NS_WARN_IF(rv.Failed())) return nullptr;
rv = file->GetPath(outFilePath);
if (NS_WARN_IF(rv.Failed())) return nullptr;
// The snapshot ID must be computed in the process that created the
// temp file, because TmpD may not be the same in all processes.
outSnapshotId.Assign(Substring(
outFilePath, tempPath.Length() + 1,
outFilePath.Length() - tempPath.Length() - sizeof(".fxsnapshot")));
return file.forget();
}
// Deletion policy for cleaning up PHeapSnapshotTempFileHelperChild pointers.
class DeleteHeapSnapshotTempFileHelperChild {
public:
constexpr DeleteHeapSnapshotTempFileHelperChild() {}
void operator()(PHeapSnapshotTempFileHelperChild* ptr) const {
Unused << NS_WARN_IF(!HeapSnapshotTempFileHelperChild::Send__delete__(ptr));
}
};
// A UniquePtr alias to automatically manage PHeapSnapshotTempFileHelperChild
// pointers.
using UniqueHeapSnapshotTempFileHelperChild =
UniquePtr<PHeapSnapshotTempFileHelperChild,
DeleteHeapSnapshotTempFileHelperChild>;
// Get an nsIOutputStream that we can write the heap snapshot to. In non-e10s
// and in the e10s parent process, open a file directly and create an output
// stream for it. In e10s child processes, we are sandboxed without access to
// the filesystem. Use IPDL to request a file descriptor from the parent
// process.
static already_AddRefed<nsIOutputStream> getCoreDumpOutputStream(
ErrorResult& rv, TimeStamp& start, nsAString& outFilePath,
nsAString& outSnapshotId) {
if (XRE_IsParentProcess()) {
// Create the file and open the output stream directly.
nsCOMPtr<nsIFile> file = HeapSnapshot::CreateUniqueCoreDumpFile(
rv, start, outFilePath, outSnapshotId);
if (NS_WARN_IF(rv.Failed())) return nullptr;
nsCOMPtr<nsIOutputStream> outputStream;
rv = NS_NewLocalFileOutputStream(getter_AddRefs(outputStream), file,
PR_WRONLY, -1, 0);
if (NS_WARN_IF(rv.Failed())) return nullptr;
return outputStream.forget();
}
// Request a file descriptor from the parent process over IPDL.
auto cc = ContentChild::GetSingleton();
if (!cc) {
rv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
UniqueHeapSnapshotTempFileHelperChild helper(
cc->SendPHeapSnapshotTempFileHelperConstructor());
if (NS_WARN_IF(!helper)) {
rv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
OpenHeapSnapshotTempFileResponse response;
if (!helper->SendOpenHeapSnapshotTempFile(&response)) {
rv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
if (response.type() == OpenHeapSnapshotTempFileResponse::Tnsresult) {
rv.Throw(response.get_nsresult());
return nullptr;
}
auto opened = response.get_OpenedFile();
outFilePath = opened.path();
outSnapshotId = opened.snapshotId();
nsCOMPtr<nsIOutputStream> outputStream =
FileDescriptorOutputStream::Create(opened.descriptor());
if (NS_WARN_IF(!outputStream)) {
rv.Throw(NS_ERROR_UNEXPECTED);
return nullptr;
}
return outputStream.forget();
}
} // namespace devtools
namespace dom {
using namespace JS;
using namespace devtools;
/* static */
void ChromeUtils::SaveHeapSnapshotShared(
GlobalObject& global, const HeapSnapshotBoundaries& boundaries,
nsAString& outFilePath, nsAString& outSnapshotId, ErrorResult& rv) {
auto start = TimeStamp::Now();
bool wantNames = true;
CompartmentSet compartments;
uint32_t nodeCount = 0;
uint32_t edgeCount = 0;
nsCOMPtr<nsIOutputStream> outputStream =
getCoreDumpOutputStream(rv, start, outFilePath, outSnapshotId);
if (NS_WARN_IF(rv.Failed())) return;
ZeroCopyNSIOutputStream zeroCopyStream(outputStream);
::google::protobuf::io::GzipOutputStream gzipStream(&zeroCopyStream);
JSContext* cx = global.Context();
{
ubi::RootList rootList(cx, wantNames);
auto [ok, nogc] =
EstablishBoundaries(cx, rv, boundaries, rootList, compartments);
if (!ok) {
return;
}
StreamWriter writer(cx, gzipStream, wantNames,
!compartments.empty() ? &compartments : nullptr);
ubi::Node roots(&rootList);
// Serialize the initial heap snapshot metadata to the core dump.
if (!writer.writeMetadata(PR_Now()) ||
// Serialize the heap graph to the core dump, starting from our list of
// roots.
!WriteHeapGraph(cx, roots, writer, wantNames,
!compartments.empty() ? &compartments : nullptr, nogc,
nodeCount, edgeCount)) {
rv.Throw(zeroCopyStream.failed() ? zeroCopyStream.result()
: NS_ERROR_UNEXPECTED);
return;
}
}
Telemetry::AccumulateTimeDelta(Telemetry::DEVTOOLS_SAVE_HEAP_SNAPSHOT_MS,
start);
Telemetry::Accumulate(Telemetry::DEVTOOLS_HEAP_SNAPSHOT_NODE_COUNT,
nodeCount);
Telemetry::Accumulate(Telemetry::DEVTOOLS_HEAP_SNAPSHOT_EDGE_COUNT,
edgeCount);
}
/* static */
uint64_t ChromeUtils::GetObjectNodeId(GlobalObject& global,
JS::Handle<JSObject*> val) {
JS::Rooted<JSObject*> obj(global.Context(), val);
JS::ubi::Node node(obj);
return node.identifier();
}
/* static */
void ChromeUtils::SaveHeapSnapshot(GlobalObject& global,
const HeapSnapshotBoundaries& boundaries,
nsAString& outFilePath, ErrorResult& rv) {
nsAutoString snapshotId;
SaveHeapSnapshotShared(global, boundaries, outFilePath, snapshotId, rv);
}
/* static */
void ChromeUtils::SaveHeapSnapshotGetId(
GlobalObject& global, const HeapSnapshotBoundaries& boundaries,
nsAString& outSnapshotId, ErrorResult& rv) {
nsAutoString filePath;
SaveHeapSnapshotShared(global, boundaries, filePath, outSnapshotId, rv);
}
/* static */
already_AddRefed<HeapSnapshot> ChromeUtils::ReadHeapSnapshot(
GlobalObject& global, const nsAString& filePath, ErrorResult& rv) {
auto start = TimeStamp::Now();
nsCOMPtr<nsIFile> snapshotFile;
rv = NS_NewLocalFile(filePath, getter_AddRefs(snapshotFile));
if (rv.Failed()) {
return nullptr;
}
AutoMemMap mm;
rv = mm.init(snapshotFile);
if (rv.Failed()) return nullptr;
RefPtr<HeapSnapshot> snapshot = HeapSnapshot::Create(
global.Context(), global, reinterpret_cast<const uint8_t*>(mm.address()),
mm.size(), rv);
if (!rv.Failed())
Telemetry::AccumulateTimeDelta(Telemetry::DEVTOOLS_READ_HEAP_SNAPSHOT_MS,
start);
return snapshot.forget();
}
} // namespace dom
} // namespace mozilla