bool
Module::instantiate(JSContext* cx,
Handle<FunctionVector> funcImports,
HandleWasmTableObject tableImport,
HandleWasmMemoryObject memoryImport,
const ValVector& globalImports,
HandleObject instanceProto,
MutableHandleWasmInstanceObject instanceObj) const
{
MOZ_ASSERT(funcImports.length() == metadata_->funcImports.length());
RootedWasmMemoryObject memory(cx, memoryImport);
if (!instantiateMemory(cx, &memory))
return false;
auto codeSegment = CodeSegment::create(cx, code_, linkData_, *metadata_, memory);
if (!codeSegment)
return false;
SharedTableVector tables;
if (!instantiateTable(cx, tableImport, &tables))
return false;
// To support viewing the source of an instance (Instance::createText), the
// instance must hold onto a ref of the bytecode (keeping it alive). This
// wastes memory for most users, so we try to only save the source when a
// developer actually cares: when the compartment is debuggable (which is
// true when the web console is open) or a names section is present (since
// this going to be stripped for non-developer builds).
const ShareableBytes* maybeBytecode = nullptr;
if (cx->compartment()->isDebuggee() || !metadata_->funcNames.empty())
maybeBytecode = bytecode_.get();
// Create the Instance, ensuring that it is traceable via 'instanceObj'
// before any GC can occur and invalidate the pointers stored in global
// memory.
{
instanceObj.set(WasmInstanceObject::create(cx, instanceProto));
if (!instanceObj)
return false;
auto instance = cx->make_unique<Instance>(cx,
Move(codeSegment),
*metadata_,
maybeBytecode,
memory,
Move(tables),
funcImports,
globalImports);
if (!instance)
return false;
instanceObj->init(Move(instance));
}
if (!instanceObj->instance().init(cx))
return false;
// Create the export object.
RootedObject exportObj(cx);
RootedWasmTableObject table(cx, tableImport);
if (!CreateExportObject(cx, instanceObj, &table, memory, globalImports, exports_, &exportObj))
return false;
JSAtom* atom = Atomize(cx, InstanceExportField, strlen(InstanceExportField));
if (!atom)
return false;
RootedId id(cx, AtomToId(atom));
RootedValue val(cx, ObjectValue(*exportObj));
if (!JS_DefinePropertyById(cx, instanceObj, id, val, JSPROP_ENUMERATE))
return false;
// Initialize table elements only after the instance is fully initialized
// since the Table object needs to point to a valid instance object. Perform
// initialization as the final step after the instance is fully live since
// it is observable (in the case of an imported Table object).
if (!initElems(cx, instanceObj, globalImports, table))
return false;
// Done! Notify the Debugger of the new Instance.
Debugger::onNewWasmInstance(cx, instanceObj);
// Call the start function, if there's one. By specification, it does not
// take any arguments nor does it return a value, so just create a dummy
// arguments object.
if (metadata_->hasStartFunction()) {
FixedInvokeArgs<0> args(cx);
if (!instanceObj->instance().callExport(cx, metadata_->startFuncIndex(), args))
return false;
}
return true;
}
