Example #1
0
bool JSObject::getPropertySlot(ExecState *exec, unsigned propertyName, PropertySlot& slot)
{
  JSObject *imp = this;

  while (true) {
    if (imp->getOwnPropertySlot(exec, propertyName, slot))
      return true;

    JSValue *proto = imp->_proto;
    if (!proto->isObject())
      break;

    imp = static_cast<JSObject *>(proto);
  }

  return false;
}
Example #2
0
bool JSString::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
{
    // The semantics here are really getPropertySlot, not getOwnPropertySlot.
    // This function should only be called by JSValue::get.
    if (getStringPropertySlot(exec, propertyName, slot))
        return true;
    if (propertyName == exec->propertyNames().underscoreProto) {
        slot.setValue(exec->lexicalGlobalObject()->stringPrototype());
        return true;
    }
    slot.setBase(this);
    JSObject* object;
    for (JSValue prototype = exec->lexicalGlobalObject()->stringPrototype(); !prototype.isNull(); prototype = object->prototype()) {
        object = asObject(prototype);
        if (object->getOwnPropertySlot(exec, propertyName, slot))
            return true;
    }
    slot.setUndefined();
    return true;
}
String HeapSnapshotBuilder::json(Function<bool (const HeapSnapshotNode&)> allowNodeCallback)
{
    VM& vm = m_profiler.vm();
    DeferGCForAWhile deferGC(vm.heap);

    // Build a node to identifier map of allowed nodes to use when serializing edges.
    HashMap<JSCell*, NodeIdentifier> allowedNodeIdentifiers;

    // Build a list of used class names.
    HashMap<String, unsigned> classNameIndexes;
    classNameIndexes.set("<root>"_s, 0);
    unsigned nextClassNameIndex = 1;

    // Build a list of labels (this is just a string table).
    HashMap<String, unsigned> labelIndexes;
    labelIndexes.set(emptyString(), 0);
    unsigned nextLabelIndex = 1;

    // Build a list of used edge names.
    HashMap<UniquedStringImpl*, unsigned> edgeNameIndexes;
    unsigned nextEdgeNameIndex = 0;

    StringBuilder json;

    auto appendNodeJSON = [&] (const HeapSnapshotNode& node) {
        // Let the client decide if they want to allow or disallow certain nodes.
        if (!allowNodeCallback(node))
            return;

        unsigned flags = 0;

        allowedNodeIdentifiers.set(node.cell, node.identifier);

        String className = node.cell->classInfo(vm)->className;
        if (node.cell->isObject() && className == JSObject::info()->className) {
            flags |= static_cast<unsigned>(NodeFlags::ObjectSubtype);

            // Skip calculating a class name if this object has a `constructor` own property.
            // These cases are typically F.prototype objects and we want to treat these as
            // "Object" in snapshots and not get the name of the prototype's parent.
            JSObject* object = asObject(node.cell);
            if (JSGlobalObject* globalObject = object->globalObject(vm)) {
                ExecState* exec = globalObject->globalExec();
                PropertySlot slot(object, PropertySlot::InternalMethodType::VMInquiry);
                if (!object->getOwnPropertySlot(object, exec, vm.propertyNames->constructor, slot))
                    className = JSObject::calculatedClassName(object);
            }
        }

        auto result = classNameIndexes.add(className, nextClassNameIndex);
        if (result.isNewEntry)
            nextClassNameIndex++;
        unsigned classNameIndex = result.iterator->value;

        void* wrappedAddress = 0;
        unsigned labelIndex = 0;
        if (!node.cell->isString()) {
            Structure* structure = node.cell->structure(vm);
            if (!structure || !structure->globalObject())
                flags |= static_cast<unsigned>(NodeFlags::Internal);

            if (m_snapshotType == SnapshotType::GCDebuggingSnapshot) {
                String nodeLabel;
                auto it = m_cellLabels.find(node.cell);
                if (it != m_cellLabels.end())
                    nodeLabel = it->value;

                if (nodeLabel.isEmpty()) {
                    if (auto* object = jsDynamicCast<JSObject*>(vm, node.cell)) {
                        if (auto* function = jsDynamicCast<JSFunction*>(vm, object))
                            nodeLabel = function->calculatedDisplayName(vm);
                    }
                }

                String description = descriptionForCell(node.cell);
                if (description.length()) {
                    if (nodeLabel.length())
                        nodeLabel.append(' ');
                    nodeLabel.append(description);
                }

                if (!nodeLabel.isEmpty() && m_snapshotType == SnapshotType::GCDebuggingSnapshot) {
                    auto result = labelIndexes.add(nodeLabel, nextLabelIndex);
                    if (result.isNewEntry)
                        nextLabelIndex++;
                    labelIndex = result.iterator->value;
                }

                wrappedAddress = m_wrappedObjectPointers.get(node.cell);
            }
        }

        // <nodeId>, <sizeInBytes>, <nodeClassNameIndex>, <flags>, [<labelIndex>, <cellEddress>, <wrappedAddress>]
        json.append(',');
        json.appendNumber(node.identifier);
        json.append(',');
        json.appendNumber(node.cell->estimatedSizeInBytes(vm));
        json.append(',');
        json.appendNumber(classNameIndex);
        json.append(',');
        json.appendNumber(flags);
        if (m_snapshotType == SnapshotType::GCDebuggingSnapshot) {
            json.append(',');
            json.appendNumber(labelIndex);
            json.appendLiteral(",\"0x");
            appendUnsignedAsHex(reinterpret_cast<uintptr_t>(node.cell), json, Lowercase);
            json.appendLiteral("\",\"0x");
            appendUnsignedAsHex(reinterpret_cast<uintptr_t>(wrappedAddress), json, Lowercase);
            json.append('"');
        }
    };

    bool firstEdge = true;
    auto appendEdgeJSON = [&] (const HeapSnapshotEdge& edge) {
        if (!firstEdge)
            json.append(',');
        firstEdge = false;

        // <fromNodeId>, <toNodeId>, <edgeTypeIndex>, <edgeExtraData>
        json.appendNumber(edge.from.identifier);
        json.append(',');
        json.appendNumber(edge.to.identifier);
        json.append(',');
        json.appendNumber(edgeTypeToNumber(edge.type));
        json.append(',');
        switch (edge.type) {
        case EdgeType::Property:
        case EdgeType::Variable: {
            auto result = edgeNameIndexes.add(edge.u.name, nextEdgeNameIndex);
            if (result.isNewEntry)
                nextEdgeNameIndex++;
            unsigned edgeNameIndex = result.iterator->value;
            json.appendNumber(edgeNameIndex);
            break;
        }
        case EdgeType::Index:
            json.appendNumber(edge.u.index);
            break;
        default:
            // No data for this edge type.
            json.append('0');
            break;
        }
    };

    json.append('{');

    // version
    json.appendLiteral("\"version\":2");

    // type
    json.append(',');
    json.appendLiteral("\"type\":");
    json.appendQuotedJSONString(snapshotTypeToString(m_snapshotType));

    // nodes
    json.append(',');
    json.appendLiteral("\"nodes\":");
    json.append('[');
    // <root>
    if (m_snapshotType == SnapshotType::GCDebuggingSnapshot)
        json.appendLiteral("0,0,0,0,0,\"0x0\",\"0x0\"");
    else
        json.appendLiteral("0,0,0,0");

    for (HeapSnapshot* snapshot = m_profiler.mostRecentSnapshot(); snapshot; snapshot = snapshot->previous()) {
        for (auto& node : snapshot->m_nodes)
            appendNodeJSON(node);
    }
    json.append(']');

    // node class names
    json.append(',');
    json.appendLiteral("\"nodeClassNames\":");
    json.append('[');
    Vector<String> orderedClassNames(classNameIndexes.size());
    for (auto& entry : classNameIndexes)
        orderedClassNames[entry.value] = entry.key;
    classNameIndexes.clear();
    bool firstClassName = true;
    for (auto& className : orderedClassNames) {
        if (!firstClassName)
            json.append(',');
        firstClassName = false;
        json.appendQuotedJSONString(className);
    }
    orderedClassNames.clear();
    json.append(']');

    // Process edges.
    // Replace pointers with identifiers.
    // Remove any edges that we won't need.
    m_edges.removeAllMatching([&] (HeapSnapshotEdge& edge) {
        // If the from cell is null, this means a <root> edge.
        if (!edge.from.cell)
            edge.from.identifier = 0;
        else {
            auto fromLookup = allowedNodeIdentifiers.find(edge.from.cell);
            if (fromLookup == allowedNodeIdentifiers.end()) {
                if (m_snapshotType == SnapshotType::GCDebuggingSnapshot)
                    WTFLogAlways("Failed to find node for from-edge cell %p", edge.from.cell);
                return true;
            }
            edge.from.identifier = fromLookup->value;
        }

        if (!edge.to.cell)
            edge.to.identifier = 0;
        else {
            auto toLookup = allowedNodeIdentifiers.find(edge.to.cell);
            if (toLookup == allowedNodeIdentifiers.end()) {
                if (m_snapshotType == SnapshotType::GCDebuggingSnapshot)
                    WTFLogAlways("Failed to find node for to-edge cell %p", edge.to.cell);
                return true;
            }
            edge.to.identifier = toLookup->value;
        }

        return false;
    });

    allowedNodeIdentifiers.clear();
    m_edges.shrinkToFit();

    // Sort edges based on from identifier.
    std::sort(m_edges.begin(), m_edges.end(), [&] (const HeapSnapshotEdge& a, const HeapSnapshotEdge& b) {
        return a.from.identifier < b.from.identifier;
    });

    // edges
    json.append(',');
    json.appendLiteral("\"edges\":");
    json.append('[');
    for (auto& edge : m_edges)
        appendEdgeJSON(edge);
    json.append(']');

    // edge types
    json.append(',');
    json.appendLiteral("\"edgeTypes\":");
    json.append('[');
    json.appendQuotedJSONString(edgeTypeToString(EdgeType::Internal));
    json.append(',');
    json.appendQuotedJSONString(edgeTypeToString(EdgeType::Property));
    json.append(',');
    json.appendQuotedJSONString(edgeTypeToString(EdgeType::Index));
    json.append(',');
    json.appendQuotedJSONString(edgeTypeToString(EdgeType::Variable));
    json.append(']');

    // edge names
    json.append(',');
    json.appendLiteral("\"edgeNames\":");
    json.append('[');
    Vector<UniquedStringImpl*> orderedEdgeNames(edgeNameIndexes.size());
    for (auto& entry : edgeNameIndexes)
        orderedEdgeNames[entry.value] = entry.key;
    edgeNameIndexes.clear();
    bool firstEdgeName = true;
    for (auto& edgeName : orderedEdgeNames) {
        if (!firstEdgeName)
            json.append(',');
        firstEdgeName = false;
        json.appendQuotedJSONString(edgeName);
    }
    orderedEdgeNames.clear();
    json.append(']');

    if (m_snapshotType == SnapshotType::GCDebuggingSnapshot) {
        json.append(',');
        json.appendLiteral("\"roots\":");
        json.append('[');

        HeapSnapshot* snapshot = m_profiler.mostRecentSnapshot();

        bool firstNode = true;
        for (auto it : m_rootData) {
            auto snapshotNode = snapshot->nodeForCell(it.key);
            if (!snapshotNode) {
                WTFLogAlways("Failed to find snapshot node for cell %p", it.key);
                continue;
            }

            if (!firstNode)
                json.append(',');

            firstNode = false;
            json.appendNumber(snapshotNode.value().identifier);

            // Maybe we should just always encode the root names.
            const char* rootName = rootTypeToString(it.value.markReason);
            auto result = labelIndexes.add(rootName, nextLabelIndex);
            if (result.isNewEntry)
                nextLabelIndex++;
            unsigned labelIndex = result.iterator->value;
            json.append(',');
            json.appendNumber(labelIndex);

            unsigned reachabilityReasonIndex = 0;
            if (it.value.reachabilityFromOpaqueRootReasons) {
                auto result = labelIndexes.add(it.value.reachabilityFromOpaqueRootReasons, nextLabelIndex);
                if (result.isNewEntry)
                    nextLabelIndex++;
                reachabilityReasonIndex = result.iterator->value;
            }
            json.append(',');
            json.appendNumber(reachabilityReasonIndex);
        }

        json.append(']');
    }

    if (m_snapshotType == SnapshotType::GCDebuggingSnapshot) {
        // internal node descriptions
        json.append(',');
        json.appendLiteral("\"labels\":");
        json.append('[');

        Vector<String> orderedLabels(labelIndexes.size());
        for (auto& entry : labelIndexes)
            orderedLabels[entry.value] = entry.key;
        labelIndexes.clear();
        bool firstLabel = true;
        for (auto& label : orderedLabels) {
            if (!firstLabel)
                json.append(',');

            firstLabel = false;
            json.appendQuotedJSONString(label);
        }
        orderedLabels.clear();

        json.append(']');
    }

    json.append('}');
    return json.toString();
}