[modules] Detect and throw exceptions for cyclic dependencies

src/module-resolve-set-inl.h

+// Copyright 2015 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.
+
+#ifndef V8_MODULE_RESOLVE_SET_INL_H_
+#define V8_MODULE_RESOLVE_SET_INL_H_
+
+#include <unordered_map>
+#include <unordered_set>
+#include <utility>
+
+#include "src/objects-inl.h"  // inl version required for hashing
+#include "src/zone/zone-allocator.h"
+#include "src/zone/zone.h"
+
+namespace v8 {
+namespace internal {
+
+template <typename T>
+struct Module::HandleValueHash {
+  V8_INLINE size_t operator()(Handle<T> handle) const { return handle->Hash(); }
+};
+
+struct Module::ModuleHandleEqual {
+  V8_INLINE bool operator()(Handle<Module> lhs, Handle<Module> rhs) const {
+    return *lhs == *rhs;
+  }
+};
+
+struct Module::StringHandleEqual {
+  V8_INLINE bool operator()(Handle<String> lhs, Handle<String> rhs) const {
+    return lhs->Equals(*rhs);
+  }
+};
+
+class Module::UnorderedStringSet
+    : public std::unordered_set<Handle<String>, HandleValueHash<String>,
+                                StringHandleEqual,
+                                zone_allocator<Handle<String>>> {
+ public:
+  explicit UnorderedStringSet(Zone* zone)
+      : std::unordered_set<Handle<String>, HandleValueHash<String>,
+                           StringHandleEqual, zone_allocator<Handle<String>>>(
+            2, HandleValueHash<String>(), StringHandleEqual(),
+            zone_allocator<Handle<String>>(zone)) {}
+};
+
+class Module::ResolveSet
+    : public std::unordered_map<
+          Handle<Module>, UnorderedStringSet*, HandleValueHash<Module>,
+          ModuleHandleEqual, zone_allocator<std::pair<const Handle<Module>,
+                                                      UnorderedStringSet*>>> {
+ public:
+  explicit ResolveSet(Zone* zone)
+      : std::unordered_map<Handle<Module>, UnorderedStringSet*,
+                           HandleValueHash<Module>, ModuleHandleEqual,
+                           zone_allocator<std::pair<const Handle<Module>,
+                                                    UnorderedStringSet*>>>(
+            2 /* bucket count */, HandleValueHash<Module>(),
+            ModuleHandleEqual(),
+            zone_allocator<
+                std::pair<const Handle<Module>, UnorderedStringSet*>>(zone)) {}
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_MODULE_RESOLVE_SET_INL_H_