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Diffstat (limited to 'devtools/shared/heapsnapshot/HeapSnapshot.cpp')
| -rw-r--r-- | devtools/shared/heapsnapshot/HeapSnapshot.cpp | 1579 |
1 files changed, 1579 insertions, 0 deletions
diff --git a/devtools/shared/heapsnapshot/HeapSnapshot.cpp b/devtools/shared/heapsnapshot/HeapSnapshot.cpp new file mode 100644 index 0000000000..fce5d1ceac --- /dev/null +++ b/devtools/shared/heapsnapshot/HeapSnapshot.cpp @@ -0,0 +1,1579 @@ +/* -*- 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 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#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/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/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; + uint32_t column = 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::ubi::CountTypePtr rootType = JS::ubi::ParseBreakdown(cx, breakdownVal); + 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()); + 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(); + + nsresult nsrv; + nsCOMPtr<nsIFile> snapshotFile = + do_CreateInstance("@mozilla.org/file/local;1", &nsrv); + + if (NS_FAILED(nsrv)) { + rv = nsrv; + return nullptr; + } + + rv = snapshotFile->InitWithPath(filePath); + 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 |