[Temporal] Add PlainDateTime.prototype.toPlain(Date|Time)

Spec Text:
https://tc39.es/proposal-temporal/#sec-temporal.plaindatetime.prototype.toplaindate
https://tc39.es/proposal-temporal/#sec-temporal.plaindatetime.prototype.toplaintime

Bug: v8:11544
Change-Id: Ifb7115823d1d3d1ff53806f1b376d69302e00ae1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3385761Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80731}

src/builtins/builtins-temporal.cc

@@ -100,10 +100,6 @@ TO_BE_IMPLEMENTED(TemporalPlainDateTimePrototypeToLocaleString)
 TO_BE_IMPLEMENTED(TemporalPlainDateTimePrototypeToString)
 /* Temporal #sec-temporal.plainddatetimeprototype.tojson */
 TO_BE_IMPLEMENTED(TemporalPlainDateTimePrototypeToJSON)
-/* Temporal #sec-temporal.plaindatetime.prototype.toplaindate */
-TO_BE_IMPLEMENTED(TemporalPlainDateTimePrototypeToPlainDate)
-/* Temporal #sec-temporal.plaindatetime.prototype.toplaintime */
-TO_BE_IMPLEMENTED(TemporalPlainDateTimePrototypeToPlainTime)
 
 /* Temporal.ZonedDateTime */
 /* Temporal #sec-temporal.zoneddatetime.from */
@@ -488,6 +484,8 @@ TEMPORAL_PROTOTYPE_METHOD0(PlainDateTime, ToPlainMonthDay, toPlainMonthDay)
 TEMPORAL_PROTOTYPE_METHOD2(PlainDateTime, ToZonedDateTime, toZonedDateTime)
 TEMPORAL_PROTOTYPE_METHOD0(PlainDateTime, GetISOFields, getISOFields)
 TEMPORAL_VALUE_OF(PlainDateTime)
+TEMPORAL_PROTOTYPE_METHOD0(PlainDateTime, ToPlainDate, toPlainDate)
+TEMPORAL_PROTOTYPE_METHOD0(PlainDateTime, ToPlainTime, toPlainTime)
 
 // PlainYearMonth
 BUILTIN(TemporalPlainYearMonthConstructor) {

src/objects/js-temporal-objects.cc

@@ -8715,6 +8715,36 @@ MaybeHandle<JSReceiver> JSTemporalPlainDateTime::GetISOFields(
   return fields;
 }
 
+// #sec-temporal.plaindatetime.prototype.toplaindate
+MaybeHandle<JSTemporalPlainDate> JSTemporalPlainDateTime::ToPlainDate(
+    Isolate* isolate, Handle<JSTemporalPlainDateTime> date_time) {
+  // 1. Let dateTime be the this value.
+  // 2. Perform ? RequireInternalSlot(dateTime,
+  // [[InitializedTemporalDateTime]]).
+  // 3. Return ? CreateTemporalDate(dateTime.[[ISOYear]], dateTime.[[ISOMonth]],
+  // dateTime.[[ISODay]], dateTime.[[Calendar]]).
+  return CreateTemporalDate(
+      isolate,
+      {date_time->iso_year(), date_time->iso_month(), date_time->iso_day()},
+      Handle<JSReceiver>(date_time->calendar(), isolate));
+}
+
+// #sec-temporal.plaindatetime.prototype.toplaintime
+MaybeHandle<JSTemporalPlainTime> JSTemporalPlainDateTime::ToPlainTime(
+    Isolate* isolate, Handle<JSTemporalPlainDateTime> date_time) {
+  // 1. Let dateTime be the this value.
+  // 2. Perform ? RequireInternalSlot(dateTime,
+  // [[InitializedTemporalDateTime]]).
+  // 3. Return ? CreateTemporalTime(dateTime.[[ISOHour]],
+  // dateTime.[[ISOMinute]], dateTime.[[ISOSecond]],
+  // dateTime.[[ISOMillisecond]], dateTime.[[ISOMicrosecond]],
+  // dateTime.[[ISONanosecond]]).
+  return CreateTemporalTime(
+      isolate, {date_time->iso_hour(), date_time->iso_minute(),
+                date_time->iso_second(), date_time->iso_millisecond(),
+                date_time->iso_microsecond(), date_time->iso_nanosecond()});
+}
+
 // #sec-temporal.plainmonthday
 MaybeHandle<JSTemporalPlainMonthDay> JSTemporalPlainMonthDay::Constructor(
     Isolate* isolate, Handle<JSFunction> target, Handle<HeapObject> new_target,

src/objects/js-temporal-objects.h

@@ -378,6 +378,14 @@ class JSTemporalPlainDateTime
   V8_WARN_UNUSED_RESULT static MaybeHandle<JSTemporalPlainDateTime> NowISO(
       Isolate* isolate, Handle<Object> temporal_time_zone_like);
 
+  // #sec-temporal.plaindatetime.prototype.toplaindate
+  V8_WARN_UNUSED_RESULT static MaybeHandle<JSTemporalPlainDate> ToPlainDate(
+      Isolate* isolate, Handle<JSTemporalPlainDateTime> date_time);
+
+  // #sec-temporal.plaindatetime.prototype.toplaintime
+  V8_WARN_UNUSED_RESULT static MaybeHandle<JSTemporalPlainTime> ToPlainTime(
+      Isolate* isolate, Handle<JSTemporalPlainDateTime> date_time);
+
   DECL_PRINTER(JSTemporalPlainDateTime)
 
   DEFINE_TORQUE_GENERATED_JS_TEMPORAL_YEAR_MONTH_DAY()

test/mjsunit/mjsunit.status

@@ -68,8 +68,6 @@
   'temporal/plain-date-time-equals': [FAIL],
   'temporal/plain-date-time-subtract': [FAIL],
   'temporal/plain-date-time-to-json': [FAIL],
-  'temporal/plain-date-time-to-plain-date': [FAIL],
-  'temporal/plain-date-time-to-plain-time': [FAIL],
   'temporal/plain-date-time-with': [FAIL],
   'temporal/plain-date-time-with-plain-date': [FAIL],
   'temporal/plain-date-to-plain-date-time': [FAIL],

test/test262/test262.status

@@ -942,9 +942,7 @@
   'built-ins/Temporal/PlainDateTime/prototype/toJSON/year-format': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/toLocaleString/branding': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/toLocaleString/return-string': [FAIL],
-  'built-ins/Temporal/PlainDateTime/prototype/toPlainDate/branding': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/toPlainDate/limits': [FAIL],
-  'built-ins/Temporal/PlainDateTime/prototype/toPlainTime/branding': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/toString/branding': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/toString/calendarname-invalid-string': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/toString/calendarname-undefined': [FAIL],
@@ -1801,7 +1799,6 @@
   'built-ins/Temporal/PlainDateTime/prototype/since/largestunit-smallestunit-mismatch': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/since/year-zero': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/subtract/argument-string-fractional-units-rounding-mode': [FAIL],
-  'built-ins/Temporal/PlainDateTime/prototype/toPlainTime/basic': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/until/largestunit-smallestunit-mismatch': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/until/year-zero': [FAIL],
   'built-ins/Temporal/PlainDateTime/prototype/with/copy-properties-not-undefined': [FAIL],