[Temporal] Add Temporal.Calendar.prototype.month

Spec Text:
https://tc39.es/proposal-temporal/#sec-temporal.calendar.prototype.month

Note- this is only the non-intl version. intl version in
https://tc39.es/proposal-temporal/#sup-temporal.calendar.prototype.month
will be implemented in later cl.

Bug: v8:11544
Change-Id: Ibbbb00faa0bdb4d49784cd9aae69fb779d95f924
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3531554
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80359}

src/builtins/builtins-temporal.cc

@@ -298,8 +298,6 @@ TO_BE_IMPLEMENTED(TemporalCalendarPrototypeYearMonthFromFields)
 TO_BE_IMPLEMENTED(TemporalCalendarPrototypeMonthDayFromFields)
 /* Temporal #sec-temporal.calendar.prototype.dateadd */
 TO_BE_IMPLEMENTED(TemporalCalendarPrototypeDateAdd)
-/* Temporal #sec-temporal.calendar.prototype.month */
-TO_BE_IMPLEMENTED(TemporalCalendarPrototypeMonth)
 /* Temporal #sec-temporal.calendar.prototype.weekofyear */
 TO_BE_IMPLEMENTED(TemporalCalendarPrototypeWeekOfYear)
 /* Temporal #sec-temporal.calendar.prototype.tojson */
@@ -795,6 +793,7 @@ TEMPORAL_PROTOTYPE_METHOD1(Calendar, DayOfWeek, dayOfWeek)
 TEMPORAL_PROTOTYPE_METHOD1(Calendar, DayOfYear, dayOfYear)
 TEMPORAL_PROTOTYPE_METHOD1(Calendar, InLeapYear, inLeapYear)
 TEMPORAL_PROTOTYPE_METHOD2(Calendar, MergeFields, mergeFields)
+TEMPORAL_PROTOTYPE_METHOD1(Calendar, Month, month)
 TEMPORAL_PROTOTYPE_METHOD1(Calendar, MonthCode, monthCode)
 TEMPORAL_PROTOTYPE_METHOD1(Calendar, MonthsInYear, monthsInYear)
 TEMPORAL_PROTOTYPE_METHOD1(Calendar, Year, year)

src/objects/js-temporal-objects.cc

@@ -6281,6 +6281,47 @@ MaybeHandle<String> JSTemporalCalendar::MonthCode(
   return builder.Finish();
 }
 
+// #sec-temporal.calendar.prototype.month
+MaybeHandle<Smi> JSTemporalCalendar::Month(Isolate* isolate,
+                                           Handle<JSTemporalCalendar> calendar,
+                                           Handle<Object> temporal_date_like) {
+  // 4. If Type(temporalDateLike) is Object and temporalDateLike has an
+  // [[InitializedTemporalMonthDay]] internal slot, then
+  if (temporal_date_like->IsJSTemporalPlainMonthDay()) {
+    // a. Throw a TypeError exception.
+    THROW_NEW_ERROR(isolate, NEW_TEMPORAL_INVALID_ARG_TYPE_ERROR(), Smi);
+  }
+  // 5. If Type(temporalDateLike) is not Object or temporalDateLike does not
+  // have an [[InitializedTemporalDate]], [[InitializedTemporalDateTime]],
+  // or [[InitializedTemporalYearMonth]]
+  // internal slot, then
+  if (!IsPlainDatePlainDateTimeOrPlainYearMonth(temporal_date_like)) {
+    // a. Set temporalDateLike to ? ToTemporalDate(temporalDateLike).
+    ASSIGN_RETURN_ON_EXCEPTION(
+        isolate, temporal_date_like,
+        ToTemporalDate(isolate, temporal_date_like,
+                       isolate->factory()->NewJSObjectWithNullProto(),
+                       "Temporal.Calendar.prototype.month"),
+        Smi);
+  }
+
+  // 6. Return ! ISOMonth(temporalDateLike).
+  int32_t month;
+  if (temporal_date_like->IsJSTemporalPlainDate()) {
+    month = Handle<JSTemporalPlainDate>::cast(temporal_date_like)->iso_month();
+  } else if (temporal_date_like->IsJSTemporalPlainDateTime()) {
+    month =
+        Handle<JSTemporalPlainDateTime>::cast(temporal_date_like)->iso_month();
+  } else {
+    DCHECK(temporal_date_like->IsJSTemporalPlainYearMonth());
+    month =
+        Handle<JSTemporalPlainYearMonth>::cast(temporal_date_like)->iso_month();
+  }
+
+  // 7. Return 𝔽(month).
+  return handle(Smi::FromInt(month), isolate);
+}
+
 // #sec-temporal.calendar.prototype.tostring
 MaybeHandle<String> JSTemporalCalendar::ToString(
     Isolate* isolate, Handle<JSTemporalCalendar> calendar,

src/objects/js-temporal-objects.h

@@ -112,6 +112,11 @@ class JSTemporalCalendar
       Isolate* isolate, Handle<JSTemporalCalendar> calendar,
       Handle<Object> temporal_date_like);
 
+  // #sec-temporal.calendar.prototype.month
+  V8_WARN_UNUSED_RESULT static MaybeHandle<Smi> Month(
+      Isolate* isolate, Handle<JSTemporalCalendar> calendar,
+      Handle<Object> temporal_date_like);
+
   // #sec-temporal.calendar.prototype.day
   V8_WARN_UNUSED_RESULT static MaybeHandle<Smi> Day(
       Isolate* isolate, Handle<JSTemporalCalendar> calendar,

test/mjsunit/mjsunit.status

@@ -48,7 +48,6 @@
   'temporal/calendar-date-add': [FAIL],
   'temporal/calendar-date-from-fields': [FAIL],
   'temporal/calendar-date-until': [FAIL],
-  'temporal/calendar-month': [FAIL],
   'temporal/calendar-month-day-from-fields': [FAIL],
   'temporal/calendar-week-of-year': [FAIL],
   'temporal/calendar-year-month-from-fields': [FAIL],