[modules] Detect and throw exceptions for cyclic dependencies

src/factory.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/factory.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 1741 matching lines @@
 Handle<Module> Factory::NewModule(Handle<SharedFunctionInfo> code) {
   Handle<ModuleInfo> module_info(code->scope_info()->ModuleDescriptorInfo(),
                                  isolate());
   Handle<ObjectHashTable> exports =
       ObjectHashTable::New(isolate(), module_info->regular_exports()->length());
   int requested_modules_length = module_info->module_requests()->length();
   Handle<FixedArray> requested_modules =
       requested_modules_length > 0 ? NewFixedArray(requested_modules_length)
                                    : empty_fixed_array();
 
+  // To make it easy to hash Modules, we set a new symbol as the name of
+  // SharedFunctionInfo representing this Module.
+  Handle<Symbol> name_symbol = NewSymbol();
+  code->set_name(*name_symbol);
+
   Handle<Module> module = Handle<Module>::cast(NewStruct(MODULE_TYPE));
   module->set_code(*code);
   module->set_exports(*exports);
   module->set_requested_modules(*requested_modules);
   module->set_flags(0);
   module->set_embedder_data(isolate()->heap()->undefined_value());
   return module;
 }
 
 Handle<JSArrayBuffer> Factory::NewJSArrayBuffer(SharedFlag shared,
@@ skipping 827 matching lines @@
     Handle<AccessorInfo> prototype =
         Accessors::FunctionPrototypeInfo(isolate(), attribs);
     AccessorConstantDescriptor d(Handle<Name>(Name::cast(prototype->name())),
                                  prototype, attribs);
     map->AppendDescriptor(&d);
   }
 }
 
 }  // namespace internal
 }  // namespace v8