コード例 #1
0
EncodedJSValue JSC_HOST_CALL webAssemblyModuleImports(ExecState* exec)
{
    VM& vm = exec->vm();
    auto* globalObject = exec->lexicalGlobalObject();
    auto throwScope = DECLARE_THROW_SCOPE(vm);

    JSWebAssemblyModule* module = jsDynamicCast<JSWebAssemblyModule*>(vm, exec->argument(0));
    if (!module)
        return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, "WebAssembly.Module.imports called with non WebAssembly.Module argument"_s)));

    JSArray* result = constructEmptyArray(exec, nullptr, globalObject);
    RETURN_IF_EXCEPTION(throwScope, { });

    const auto& imports = module->moduleInformation().imports;
    if (imports.size()) {
        Identifier module = Identifier::fromString(exec, "module");
        Identifier name = Identifier::fromString(exec, "name");
        Identifier kind = Identifier::fromString(exec, "kind");
        for (const Wasm::Import& imp : imports) {
            JSObject* obj = constructEmptyObject(exec);
            RETURN_IF_EXCEPTION(throwScope, { });
            obj->putDirect(vm, module, jsString(exec, String::fromUTF8(imp.module)));
            obj->putDirect(vm, name, jsString(exec, String::fromUTF8(imp.field)));
            obj->putDirect(vm, kind, jsString(exec, String(makeString(imp.kind))));
            result->push(exec, obj);
            RETURN_IF_EXCEPTION(throwScope, { });
        }
    }

    return JSValue::encode(result);
}
コード例 #2
0
EncodedJSValue JSC_HOST_CALL webAssemblyModuleCustomSections(ExecState* exec)
{
    VM& vm = exec->vm();
    auto* globalObject = exec->lexicalGlobalObject();
    auto throwScope = DECLARE_THROW_SCOPE(vm);

    JSWebAssemblyModule* module = jsDynamicCast<JSWebAssemblyModule*>(vm, exec->argument(0));
    if (!module)
        return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, "WebAssembly.Module.customSections called with non WebAssembly.Module argument"_s)));

    const String sectionNameString = exec->argument(1).getString(exec);
    RETURN_IF_EXCEPTION(throwScope, { });

    JSArray* result = constructEmptyArray(exec, nullptr, globalObject);
    RETURN_IF_EXCEPTION(throwScope, { });

    const auto& customSections = module->moduleInformation().customSections;
    for (const Wasm::CustomSection& section : customSections) {
        if (String::fromUTF8(section.name) == sectionNameString) {
            auto buffer = ArrayBuffer::tryCreate(section.payload.data(), section.payload.size());
            if (!buffer)
                return JSValue::encode(throwException(exec, throwScope, createOutOfMemoryError(exec)));

            result->push(exec, JSArrayBuffer::create(vm, globalObject->arrayBufferStructure(ArrayBufferSharingMode::Default), WTFMove(buffer)));
            RETURN_IF_EXCEPTION(throwScope, { });
        }
    }

    return JSValue::encode(result);
}
コード例 #3
0
static EncodedJSValue JSC_HOST_CALL constructJSWebAssemblyInstance(ExecState* exec)
{
    auto& vm = exec->vm();
    auto throwScope = DECLARE_THROW_SCOPE(vm);
    auto* globalObject = exec->lexicalGlobalObject();

    // If moduleObject is not a WebAssembly.Module instance, a TypeError is thrown.
    JSWebAssemblyModule* jsModule = jsDynamicCast<JSWebAssemblyModule*>(vm, exec->argument(0));
    if (!jsModule)
        return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, ASCIILiteral("first argument to WebAssembly.Instance must be a WebAssembly.Module"), defaultSourceAppender, runtimeTypeForValue(exec->argument(0)))));
    const Wasm::ModuleInformation& moduleInformation = jsModule->moduleInformation();

    // If the importObject parameter is not undefined and Type(importObject) is not Object, a TypeError is thrown.
    JSValue importArgument = exec->argument(1);
    JSObject* importObject = importArgument.getObject();
    if (!importArgument.isUndefined() && !importObject)
        return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, ASCIILiteral("second argument to WebAssembly.Instance must be undefined or an Object"), defaultSourceAppender, runtimeTypeForValue(importArgument))));

    // If the list of module.imports is not empty and Type(importObject) is not Object, a TypeError is thrown.
    if (moduleInformation.imports.size() && !importObject)
        return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, ASCIILiteral("second argument to WebAssembly.Instance must be Object because the WebAssembly.Module has imports"), defaultSourceAppender, runtimeTypeForValue(importArgument))));

    Identifier moduleKey = Identifier::fromUid(PrivateName(PrivateName::Description, "WebAssemblyInstance"));
    WebAssemblyModuleRecord* moduleRecord = WebAssemblyModuleRecord::create(exec, vm, globalObject->webAssemblyModuleRecordStructure(), moduleKey, moduleInformation);
    RETURN_IF_EXCEPTION(throwScope, encodedJSValue());

    Structure* instanceStructure = InternalFunction::createSubclassStructure(exec, exec->newTarget(), globalObject->WebAssemblyInstanceStructure());
    RETURN_IF_EXCEPTION(throwScope, encodedJSValue());

    JSWebAssemblyInstance* instance = JSWebAssemblyInstance::create(vm, instanceStructure, jsModule, moduleRecord->getModuleNamespace(exec));
    RETURN_IF_EXCEPTION(throwScope, encodedJSValue());
    {
        // Always start with a dummy Memory, so that wasm -> wasm thunks avoid checking for a nullptr Memory when trying to set pinned registers.
        Wasm::Memory memory;
        instance->setMemory(vm, JSWebAssemblyMemory::create(vm, exec->lexicalGlobalObject()->WebAssemblyMemoryStructure(), WTFMove(memory)));
    }

    // Let funcs, memories and tables be initially-empty lists of callable JavaScript objects, WebAssembly.Memory objects and WebAssembly.Table objects, respectively.
    // Let imports be an initially-empty list of external values.
    unsigned numImportFunctions = 0;
    unsigned numImportGlobals = 0;

    bool hasMemoryImport = false;
    bool hasTableImport = false;
    // For each import i in module.imports:
    for (auto& import : moduleInformation.imports) {
        // 1. Let o be the resultant value of performing Get(importObject, i.module_name).
        JSValue importModuleValue = importObject->get(exec, import.module);
        RETURN_IF_EXCEPTION(throwScope, encodedJSValue());
        // 2. If Type(o) is not Object, throw a TypeError.
        if (!importModuleValue.isObject())
            return JSValue::encode(throwException(exec, throwScope, createTypeError(exec, ASCIILiteral("import must be an object"), defaultSourceAppender, runtimeTypeForValue(importModuleValue))));

        // 3. Let v be the value of performing Get(o, i.item_name)
        JSObject* object = jsCast<JSObject*>(importModuleValue);
        JSValue value = object->get(exec, import.field);
        RETURN_IF_EXCEPTION(throwScope, encodedJSValue());

        switch (import.kind) {
        case Wasm::ExternalKind::Function: {
            // 4. If i is a function import:
            // i. If IsCallable(v) is false, throw a WebAssembly.LinkError.
            if (!value.isFunction())
                return JSValue::encode(throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("import function must be callable"))));
            JSCell* cell = value.asCell();
            // ii. If v is an Exported Function Exotic Object:
            if (WebAssemblyFunction* importedExport = jsDynamicCast<WebAssemblyFunction*>(vm, cell)) {
                // a. If the signature of v does not match the signature of i, throw a WebAssembly.LinkError.
                Wasm::SignatureIndex importedSignatureIndex = importedExport->signatureIndex();
                Wasm::SignatureIndex expectedSignatureIndex = moduleInformation.importFunctionSignatureIndices[import.kindIndex];
                if (importedSignatureIndex != expectedSignatureIndex)
                    return JSValue::encode(throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("imported function's signature doesn't match the provided WebAssembly function's signature"))));
                // b. Let closure be v.[[Closure]].
            }
            // iii. Otherwise:
            // a. Let closure be a new host function of the given signature which calls v by coercing WebAssembly arguments to JavaScript arguments via ToJSValue and returns the result, if any, by coercing via ToWebAssemblyValue.
            // Note: done as part of Plan compilation.
            // iv. Append v to funcs.
            // Note: adding the JSCell to the instance list fulfills closure requirements b. above (the WebAssembly.Instance wil be kept alive) and v. below (the JSFunction).
            instance->setImportFunction(vm, cell, numImportFunctions++);
            // v. Append closure to imports.
            break;
        }
        case Wasm::ExternalKind::Table: {
            RELEASE_ASSERT(!hasTableImport); // This should be guaranteed by a validation failure.
            // 7. Otherwise (i is a table import):
            hasTableImport = true;
            JSWebAssemblyTable* table = jsDynamicCast<JSWebAssemblyTable*>(vm, value);
            // i. If v is not a WebAssembly.Table object, throw a WebAssembly.LinkError.
            if (!table)
                return JSValue::encode(throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Table import is not an instance of WebAssembly.Table"))));

            uint32_t expectedInitial = moduleInformation.tableInformation.initial();
            uint32_t actualInitial = table->size();
            if (actualInitial < expectedInitial)
                return JSValue::encode(throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Table import provided an 'initial' that is too small"))));

            if (std::optional<uint32_t> expectedMaximum = moduleInformation.tableInformation.maximum()) {
                std::optional<uint32_t> actualMaximum = table->maximum();
                if (!actualMaximum) {
                    return JSValue::encode(
                        throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Table import does not have a 'maximum' but the module requires that it does"))));
                }
                if (*actualMaximum > *expectedMaximum) {
                    return JSValue::encode(
                        throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Imported Table's 'maximum' is larger than the module's expected 'maximum'"))));
                }
            }

            // ii. Append v to tables.
            // iii. Append v.[[Table]] to imports.
            instance->setTable(vm, table);
            break;
        }
        case Wasm::ExternalKind::Memory: {
            // 6. If i is a memory import:
            RELEASE_ASSERT(!hasMemoryImport); // This should be guaranteed by a validation failure.
            RELEASE_ASSERT(moduleInformation.memory);
            hasMemoryImport = true;
            JSWebAssemblyMemory* memory = jsDynamicCast<JSWebAssemblyMemory*>(vm, value);
            // i. If v is not a WebAssembly.Memory object, throw a WebAssembly.LinkError.
            if (!memory)
                return JSValue::encode(throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Memory import is not an instance of WebAssembly.Memory"))));

            Wasm::PageCount expectedInitial = moduleInformation.memory.initial();
            Wasm::PageCount actualInitial = memory->memory()->initial();
            if (actualInitial < expectedInitial)
                return JSValue::encode(throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Memory import provided an 'initial' that is too small"))));

            if (Wasm::PageCount expectedMaximum = moduleInformation.memory.maximum()) {
                Wasm::PageCount actualMaximum = memory->memory()->maximum();
                if (!actualMaximum) {
                    return JSValue::encode(
                        throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Memory import did not have a 'maximum' but the module requires that it does"))));
                }

                if (actualMaximum > expectedMaximum) {
                    return JSValue::encode(
                        throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("Memory imports 'maximum' is larger than the module's expected 'maximum'"))));
                }
            }
            // ii. Append v to memories.
            // iii. Append v.[[Memory]] to imports.
            instance->setMemory(vm, memory);
            break;
        }
        case Wasm::ExternalKind::Global: {
            // 5. If i is a global import:
            // i. If i is not an immutable global, throw a TypeError.
            ASSERT(moduleInformation.globals[import.kindIndex].mutability == Wasm::Global::Immutable);
            // ii. If Type(v) is not Number, throw a TypeError.
            if (!value.isNumber())
                return JSValue::encode(throwException(exec, throwScope, createJSWebAssemblyLinkError(exec, vm, ASCIILiteral("imported global must be a number"))));
            // iii. Append ToWebAssemblyValue(v) to imports.
            switch (moduleInformation.globals[import.kindIndex].type) {
            case Wasm::I32:
                instance->setGlobal(numImportGlobals++, value.toInt32(exec));
                break;
            case Wasm::F32:
                instance->setGlobal(numImportGlobals++, bitwise_cast<uint32_t>(value.toFloat(exec)));
                break;
            case Wasm::F64:
                instance->setGlobal(numImportGlobals++, bitwise_cast<uint64_t>(value.asNumber()));
                break;
            default:
                RELEASE_ASSERT_NOT_REACHED();
            }
            ASSERT(!throwScope.exception());
            break;
        }
        }
    }

    {
        if (!!moduleInformation.memory && moduleInformation.memory.isImport()) {
            // We should either have a Memory import or we should have thrown an exception.
            RELEASE_ASSERT(hasMemoryImport);
        }

        if (moduleInformation.memory && !hasMemoryImport) {
            RELEASE_ASSERT(!moduleInformation.memory.isImport());
            // We create a memory when it's a memory definition.
            bool failed;
            Wasm::Memory memory(moduleInformation.memory.initial(), moduleInformation.memory.maximum(), failed);
            if (failed)
                return JSValue::encode(throwException(exec, throwScope, createOutOfMemoryError(exec)));
            instance->setMemory(vm,
               JSWebAssemblyMemory::create(vm, exec->lexicalGlobalObject()->WebAssemblyMemoryStructure(), WTFMove(memory)));
        }
    }

    {
        if (!!moduleInformation.tableInformation && moduleInformation.tableInformation.isImport()) {
            // We should either have a Table import or we should have thrown an exception.
            RELEASE_ASSERT(hasTableImport);
        }

        if (!!moduleInformation.tableInformation && !hasTableImport) {
            RELEASE_ASSERT(!moduleInformation.tableInformation.isImport());
            // We create a Table when it's a Table definition.
            JSWebAssemblyTable* table = JSWebAssemblyTable::create(exec, vm, exec->lexicalGlobalObject()->WebAssemblyTableStructure(),
                moduleInformation.tableInformation.initial(), moduleInformation.tableInformation.maximum());
            // We should always be able to allocate a JSWebAssemblyTable we've defined.
            // If it's defined to be too large, we should have thrown a validation error.
            ASSERT(!throwScope.exception());
            ASSERT(table); 
            instance->setTable(vm, table);
        }
    }

    // Globals
    {
        ASSERT(numImportGlobals == moduleInformation.firstInternalGlobal);
        for (size_t globalIndex = numImportGlobals; globalIndex < moduleInformation.globals.size(); ++globalIndex) {
            const auto& global = moduleInformation.globals[globalIndex];
            ASSERT(global.initializationType != Wasm::Global::IsImport);
            if (global.initializationType == Wasm::Global::FromGlobalImport) {
                ASSERT(global.initialBitsOrImportNumber < numImportGlobals);
                instance->setGlobal(globalIndex, instance->loadI64Global(global.initialBitsOrImportNumber));
            } else
                instance->setGlobal(globalIndex, global.initialBitsOrImportNumber);
        }
    }

    moduleRecord->link(exec, instance);
    RETURN_IF_EXCEPTION(throwScope, encodedJSValue());

    if (verbose)
        moduleRecord->dump();
    JSValue startResult = moduleRecord->evaluate(exec);
    UNUSED_PARAM(startResult);
    RETURN_IF_EXCEPTION(throwScope, encodedJSValue());

    return JSValue::encode(instance);
}
コード例 #4
0
void WebAssemblyModuleRecord::link(ExecState* state, JSWebAssemblyInstance* instance)
{
    VM& vm = state->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);
    UNUSED_PARAM(scope);
    auto* globalObject = state->lexicalGlobalObject();

    JSWebAssemblyModule* module = instance->module();
    const Wasm::ModuleInformation& moduleInformation = module->moduleInformation();

    SymbolTable* exportSymbolTable = module->exportSymbolTable();
    unsigned functionImportCount = module->functionImportCount();

    // FIXME wire up the imports. https://bugs.webkit.org/show_bug.cgi?id=165118

    // Let exports be a list of (string, JS value) pairs that is mapped from each external value e in instance.exports as follows:
    JSModuleEnvironment* moduleEnvironment = JSModuleEnvironment::create(vm, globalObject, nullptr, exportSymbolTable, JSValue(), this);
    for (const auto& exp : moduleInformation.exports) {
        JSValue exportedValue;
        switch (exp.kind) {
        case Wasm::ExternalKind::Function: {
            // 1. If e is a closure c:
            //   i. If there is an Exported Function Exotic Object func in funcs whose func.[[Closure]] equals c, then return func.
            //   ii. (Note: At most one wrapper is created for any closure, so func is unique, even if there are multiple occurrances in the list. Moreover, if the item was an import that is already an Exported Function Exotic Object, then the original function object will be found. For imports that are regular JS functions, a new wrapper will be created.)
            if (exp.kindIndex < functionImportCount) {
                // FIXME Implement re-exporting an import. https://bugs.webkit.org/show_bug.cgi?id=165510
                RELEASE_ASSERT_NOT_REACHED();
            }
            //   iii. Otherwise:
            //     a. Let func be an Exported Function Exotic Object created from c.
            //     b. Append func to funcs.
            //     c. Return func.
            JSWebAssemblyCallee* jsEntrypointCallee = module->jsEntrypointCalleeFromFunctionIndexSpace(exp.kindIndex);
            JSWebAssemblyCallee* wasmEntrypointCallee = module->wasmEntrypointCalleeFromFunctionIndexSpace(exp.kindIndex);
            Wasm::SignatureIndex signatureIndex = module->signatureIndexFromFunctionIndexSpace(exp.kindIndex);
            const Wasm::Signature* signature = Wasm::SignatureInformation::get(&vm, signatureIndex);
            WebAssemblyFunction* function = WebAssemblyFunction::create(vm, globalObject, signature->argumentCount(), exp.field.string(), instance, jsEntrypointCallee, wasmEntrypointCallee, signatureIndex);
            exportedValue = function;
            break;
        }
        case Wasm::ExternalKind::Table: {
            // This should be guaranteed by module verification.
            RELEASE_ASSERT(instance->table()); 
            ASSERT(exp.kindIndex == 0);

            exportedValue = instance->table();
            break;
        }
        case Wasm::ExternalKind::Memory: {
            ASSERT(exp.kindIndex == 0);

            exportedValue = instance->memory();
            break;
        }
        case Wasm::ExternalKind::Global: {
            // Assert: the global is immutable by MVP validation constraint.
            const Wasm::Global& global = moduleInformation.globals[exp.kindIndex];
            ASSERT(global.mutability == Wasm::Global::Immutable);
            // Return ToJSValue(v).
            switch (global.type) {
            case Wasm::I32:
                exportedValue = JSValue(instance->loadI32Global(exp.kindIndex));
                break;

            case Wasm::F32:
                exportedValue = JSValue(instance->loadF32Global(exp.kindIndex));
                break;

            case Wasm::F64:
                exportedValue = JSValue(instance->loadF64Global(exp.kindIndex));
                break;

            default:
                RELEASE_ASSERT_NOT_REACHED();
            }
            break;
        }
        }

        bool shouldThrowReadOnlyError = false;
        bool ignoreReadOnlyErrors = true;
        bool putResult = false;
        symbolTablePutTouchWatchpointSet(moduleEnvironment, state, exp.field, exportedValue, shouldThrowReadOnlyError, ignoreReadOnlyErrors, putResult);
        RELEASE_ASSERT(putResult);
    }

    bool hasStart = !!moduleInformation.startFunctionIndexSpace;
    if (hasStart) {
        auto startFunctionIndexSpace = moduleInformation.startFunctionIndexSpace.value_or(0);
        Wasm::SignatureIndex signatureIndex = module->signatureIndexFromFunctionIndexSpace(startFunctionIndexSpace);
        const Wasm::Signature* signature = Wasm::SignatureInformation::get(&vm, signatureIndex);
        // The start function must not take any arguments or return anything. This is enforced by the parser.
        ASSERT(!signature->argumentCount());
        ASSERT(signature->returnType() == Wasm::Void);
        if (startFunctionIndexSpace < module->functionImportCount()) {
            JSCell* startFunction = instance->importFunction(startFunctionIndexSpace)->get();
            m_startFunction.set(vm, this, startFunction);
        } else {
            JSWebAssemblyCallee* jsEntrypointCallee = module->jsEntrypointCalleeFromFunctionIndexSpace(startFunctionIndexSpace);
            JSWebAssemblyCallee* wasmEntrypointCallee = module->wasmEntrypointCalleeFromFunctionIndexSpace(startFunctionIndexSpace);
            WebAssemblyFunction* function = WebAssemblyFunction::create(vm, globalObject, signature->argumentCount(), "start", instance, jsEntrypointCallee, wasmEntrypointCallee, signatureIndex);
            m_startFunction.set(vm, this, function);
        }
    }

    RELEASE_ASSERT(!m_instance);
    m_instance.set(vm, this, instance);
    m_moduleEnvironment.set(vm, this, moduleEnvironment);
}
コード例 #5
0
JSValue WebAssemblyModuleRecord::evaluate(ExecState* state)
{
    VM& vm = state->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    {
        JSWebAssemblyModule* module = m_instance->module();
        const Wasm::ModuleInformation& moduleInformation = module->moduleInformation();
        JSWebAssemblyTable* table = m_instance->table();
        for (const Wasm::Element& element : moduleInformation.elements) {
            // It should be a validation error to have any elements without a table.
            // Also, it could be that a table wasn't imported, or that the table
            // imported wasn't compatible. However, those should error out before
            // getting here.
            ASSERT(!!table);
            if (!element.functionIndices.size())
                continue;

            uint32_t tableIndex = element.offset;
            uint64_t lastWrittenIndex = static_cast<uint64_t>(tableIndex) + static_cast<uint64_t>(element.functionIndices.size()) - 1;
            if (lastWrittenIndex >= table->size())
                return throwException(state, scope, createJSWebAssemblyLinkError(state, vm, ASCIILiteral("Element is trying to set an out of bounds table index")));

            for (uint32_t i = 0; i < element.functionIndices.size(); ++i) {
                // FIXME: This essentially means we're exporting an import.
                // We need a story here. We need to create a WebAssemblyFunction
                // for the import.
                // https://bugs.webkit.org/show_bug.cgi?id=165510
                uint32_t functionIndex = element.functionIndices[i];
                if (functionIndex < module->functionImportCount()) {
                    return JSValue::decode(
                        throwVMRangeError(state, scope, ASCIILiteral("Element is setting the table value with an import. This is not yet implemented. FIXME.")));
                }

                JSWebAssemblyCallee* jsEntrypointCallee = module->jsEntrypointCalleeFromFunctionIndexSpace(functionIndex);
                JSWebAssemblyCallee* wasmEntrypointCallee = module->wasmEntrypointCalleeFromFunctionIndexSpace(functionIndex);
                Wasm::SignatureIndex signatureIndex = module->signatureIndexFromFunctionIndexSpace(functionIndex);
                const Wasm::Signature* signature = Wasm::SignatureInformation::get(&vm, signatureIndex);
                // FIXME: Say we export local function "foo" at funciton index 0.
                // What if we also set it to the table an Element w/ index 0.
                // Does (new Instance(...)).exports.foo === table.get(0)?
                // https://bugs.webkit.org/show_bug.cgi?id=165825
                WebAssemblyFunction* function = WebAssemblyFunction::create(
                    vm, m_instance->globalObject(), signature->argumentCount(), String(), m_instance.get(), jsEntrypointCallee, wasmEntrypointCallee, signatureIndex);

                table->setFunction(vm, tableIndex, function);
                ++tableIndex;
            }
        }
    }

    {
        const Vector<Wasm::Segment::Ptr>& data = m_instance->module()->moduleInformation().data;
        JSWebAssemblyMemory* jsMemory = m_instance->memory();
        if (!data.isEmpty()) {
            uint8_t* memory = reinterpret_cast<uint8_t*>(jsMemory->memory()->memory());
            uint64_t sizeInBytes = jsMemory->memory()->size();
            for (auto& segment : data) {
                if (segment->sizeInBytes) {
                    uint32_t offset;
                    if (segment->offset.isGlobalImport())
                        offset = static_cast<uint32_t>(m_instance->loadI32Global(segment->offset.globalImportIndex()));
                    else
                        offset = segment->offset.constValue();

                    if (UNLIKELY(sizeInBytes < segment->sizeInBytes))
                        return dataSegmentFail(state, vm, scope, sizeInBytes, segment->sizeInBytes, offset, ASCIILiteral(", segment is too big"));
                    if (UNLIKELY(offset > sizeInBytes - segment->sizeInBytes))
                        return dataSegmentFail(state, vm, scope, sizeInBytes, segment->sizeInBytes, offset, ASCIILiteral(", segment writes outside of memory"));
                    RELEASE_ASSERT(memory);
                    memcpy(memory + offset, &segment->byte(0), segment->sizeInBytes);
                }
            }
        }
    }

    if (JSCell* startFunction = m_startFunction.get()) {
        CallData callData;
        CallType callType = JSC::getCallData(startFunction, callData);
        call(state, startFunction, callType, callData, jsUndefined(), state->emptyList());
        RETURN_IF_EXCEPTION(scope, { });
    }

    return jsUndefined();
}