Implement global proposal

The proposal is currently at Stage 3 of the TC39 process.
Repository: https://github.com/tc39/proposal-global

Bug: v8:5537
Change-Id: I36c39fdab049497f50685c6672655b67ec4d8ce9
Reviewed-on: https://chromium-review.googlesource.com/1174113
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55159}

src/bootstrapper.cc

@@ -4244,6 +4244,17 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_numeric_separator)
 
 #undef EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE
 
+void Genesis::InitializeGlobal_harmony_global() {
+  if (!FLAG_harmony_global) return;
+
+  Factory* factory = isolate()->factory();
+  Handle<JSGlobalObject> global(native_context()->global_object(), isolate());
+  Handle<JSGlobalProxy> global_proxy(native_context()->global_proxy(),
+                                     isolate());
+  JSObject::AddProperty(isolate_, global, factory->globalThis_string(),
+                        global_proxy, DONT_ENUM);
+}
+
 void Genesis::InitializeGlobal_harmony_sharedarraybuffer() {
   if (!FLAG_harmony_sharedarraybuffer) return;
 

src/flag-definitions.h

@@ -230,7 +230,8 @@ DEFINE_IMPLICATION(harmony_class_fields, harmony_private_fields)
   V(harmony_public_fields, "harmony public fields in class literals")      \
   V(harmony_private_fields, "harmony private fields in class literals")    \
   V(harmony_numeric_separator, "harmony numeric separator between digits") \
-  V(harmony_string_matchall, "harmony String.prototype.matchAll")
+  V(harmony_string_matchall, "harmony String.prototype.matchAll")          \
+  V(harmony_global, "harmony global")
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING(V)                                              \

src/heap-symbols.h

@@ -96,6 +96,7 @@
   V(getOwnPropertyDescriptors_string, "getOwnPropertyDescriptors") \
   V(getPrototypeOf_string, "getPrototypeOf")                       \
   V(global_string, "global")                                       \
+  V(globalThis_string, "globalThis")                               \
   V(group_string, "group")                                         \
   V(groups_string, "groups")                                       \
   V(has_string, "has")                                             \

test/mjsunit/harmony/global-configurable.js

+// Copyright 2018 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.
+
+// Flags: --harmony-global
+
+assertTrue(delete globalThis);
+assertEquals(this.globalThis, undefined);

test/mjsunit/harmony/global-writable.js

+// Copyright 2018 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.
+
+// Flags: --harmony-global
+
+globalThis = '[[Writable]]';
+assertEquals(globalThis, '[[Writable]]');

test/mjsunit/harmony/global.js

+// Copyright 2018 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.
+
+// Flags: --harmony-global
+
+assertEquals(globalThis, this);
+assertEquals(this.globalThis, this);
+assertEquals(globalThis.globalThis, this);
+assertEquals(globalThis.globalThis.globalThis, this);
+assertEquals(globalThis.globalThis.globalThis.globalThis, this);
+
+{
+  const realm = Realm.create();
+  assertEquals(Realm.global(realm), Realm.eval(realm, 'globalThis'));
+  assertTrue(Realm.global(realm) !== globalThis);
+}
+
+{
+  const descriptor = Object.getOwnPropertyDescriptor(
+    this,
+    'globalThis'
+  );
+  assertEquals(descriptor.value, this);
+  assertEquals(descriptor.writable, true);
+  assertEquals(descriptor.enumerable, false);
+  assertEquals(descriptor.configurable, true);
+}

test/mkgrokdump/mkgrokdump.cc

@@ -16,7 +16,7 @@
 namespace v8 {
 
 static const char* kHeader =
-    "# Copyright 2017 the V8 project authors. All rights reserved.\n"
+    "# Copyright 2018 the V8 project authors. All rights reserved.\n"
     "# Use of this source code is governed by a BSD-style license that can\n"
     "# be found in the LICENSE file.\n"
     "\n"

tools/v8heapconst.py

-# Copyright 2017 the V8 project authors. All rights reserved.
+# Copyright 2018 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.
 
@@ -283,33 +283,33 @@ KNOWN_MAPS = {
   ("RO_SPACE", 0x04771): (171, "Tuple2Map"),
   ("RO_SPACE", 0x04a99): (161, "InterceptorInfoMap"),
   ("RO_SPACE", 0x04b91): (169, "ScriptMap"),
-  ("RO_SPACE", 0x09a11): (154, "AccessorInfoMap"),
-  ("RO_SPACE", 0x09a61): (153, "AccessCheckInfoMap"),
-  ("RO_SPACE", 0x09ab1): (155, "AccessorPairMap"),
-  ("RO_SPACE", 0x09b01): (156, "AliasedArgumentsEntryMap"),
-  ("RO_SPACE", 0x09b51): (157, "AllocationMementoMap"),
-  ("RO_SPACE", 0x09ba1): (158, "AsyncGeneratorRequestMap"),
-  ("RO_SPACE", 0x09bf1): (159, "DebugInfoMap"),
-  ("RO_SPACE", 0x09c41): (160, "FunctionTemplateInfoMap"),
-  ("RO_SPACE", 0x09c91): (162, "InterpreterDataMap"),
-  ("RO_SPACE", 0x09ce1): (163, "ModuleInfoEntryMap"),
-  ("RO_SPACE", 0x09d31): (164, "ModuleMap"),
-  ("RO_SPACE", 0x09d81): (165, "ObjectTemplateInfoMap"),
-  ("RO_SPACE", 0x09dd1): (166, "PromiseCapabilityMap"),
-  ("RO_SPACE", 0x09e21): (167, "PromiseReactionMap"),
-  ("RO_SPACE", 0x09e71): (168, "PrototypeInfoMap"),
-  ("RO_SPACE", 0x09ec1): (170, "StackFrameInfoMap"),
-  ("RO_SPACE", 0x09f11): (172, "Tuple3Map"),
-  ("RO_SPACE", 0x09f61): (173, "ArrayBoilerplateDescriptionMap"),
-  ("RO_SPACE", 0x09fb1): (174, "WasmDebugInfoMap"),
-  ("RO_SPACE", 0x0a001): (175, "WasmExportedFunctionDataMap"),
-  ("RO_SPACE", 0x0a051): (176, "CallableTaskMap"),
-  ("RO_SPACE", 0x0a0a1): (177, "CallbackTaskMap"),
-  ("RO_SPACE", 0x0a0f1): (178, "PromiseFulfillReactionJobTaskMap"),
-  ("RO_SPACE", 0x0a141): (179, "PromiseRejectReactionJobTaskMap"),
-  ("RO_SPACE", 0x0a191): (180, "PromiseResolveThenableJobTaskMap"),
-  ("RO_SPACE", 0x0a1e1): (181, "AllocationSiteMap"),
-  ("RO_SPACE", 0x0a231): (181, "AllocationSiteMap"),
+  ("RO_SPACE", 0x09a39): (154, "AccessorInfoMap"),
+  ("RO_SPACE", 0x09a89): (153, "AccessCheckInfoMap"),
+  ("RO_SPACE", 0x09ad9): (155, "AccessorPairMap"),
+  ("RO_SPACE", 0x09b29): (156, "AliasedArgumentsEntryMap"),
+  ("RO_SPACE", 0x09b79): (157, "AllocationMementoMap"),
+  ("RO_SPACE", 0x09bc9): (158, "AsyncGeneratorRequestMap"),
+  ("RO_SPACE", 0x09c19): (159, "DebugInfoMap"),
+  ("RO_SPACE", 0x09c69): (160, "FunctionTemplateInfoMap"),
+  ("RO_SPACE", 0x09cb9): (162, "InterpreterDataMap"),
+  ("RO_SPACE", 0x09d09): (163, "ModuleInfoEntryMap"),
+  ("RO_SPACE", 0x09d59): (164, "ModuleMap"),
+  ("RO_SPACE", 0x09da9): (165, "ObjectTemplateInfoMap"),
+  ("RO_SPACE", 0x09df9): (166, "PromiseCapabilityMap"),
+  ("RO_SPACE", 0x09e49): (167, "PromiseReactionMap"),
+  ("RO_SPACE", 0x09e99): (168, "PrototypeInfoMap"),
+  ("RO_SPACE", 0x09ee9): (170, "StackFrameInfoMap"),
+  ("RO_SPACE", 0x09f39): (172, "Tuple3Map"),
+  ("RO_SPACE", 0x09f89): (173, "ArrayBoilerplateDescriptionMap"),
+  ("RO_SPACE", 0x09fd9): (174, "WasmDebugInfoMap"),
+  ("RO_SPACE", 0x0a029): (175, "WasmExportedFunctionDataMap"),
+  ("RO_SPACE", 0x0a079): (176, "CallableTaskMap"),
+  ("RO_SPACE", 0x0a0c9): (177, "CallbackTaskMap"),
+  ("RO_SPACE", 0x0a119): (178, "PromiseFulfillReactionJobTaskMap"),
+  ("RO_SPACE", 0x0a169): (179, "PromiseRejectReactionJobTaskMap"),
+  ("RO_SPACE", 0x0a1b9): (180, "PromiseResolveThenableJobTaskMap"),
+  ("RO_SPACE", 0x0a209): (181, "AllocationSiteMap"),
+  ("RO_SPACE", 0x0a259): (181, "AllocationSiteMap"),
   ("MAP_SPACE", 0x02201): (1057, "ExternalMap"),
   ("MAP_SPACE", 0x02251): (1072, "JSMessageObjectMap"),
 }