[Temporal] Add Date.prototype.toTemporalInstant

Spec Text:
https://tc39.es/proposal-temporal/#sec-date.prototype.totemporalinstant

Bug: v8:11544
Change-Id: I65315152333291f76edc05cc41a528912a185d02
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3609214
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80755}

src/builtins/builtins-date.cc

@@ -9,11 +9,13 @@
 #include "src/date/dateparser-inl.h"
 #include "src/logging/counters.h"
 #include "src/numbers/conversions.h"
-#include "src/objects/objects-inl.h"
+#include "src/objects/bigint.h"
 #ifdef V8_INTL_SUPPORT
 #include "src/objects/intl-objects.h"
 #include "src/objects/js-date-time-format.h"
 #endif
+#include "src/objects/js-temporal-objects-inl.h"
+#include "src/objects/objects-inl.h"
 #include "src/strings/string-stream.h"
 
 namespace v8 {
@@ -868,5 +870,23 @@ BUILTIN(DatePrototypeToJson) {
   }
 }
 
+// Temporal #sec-date.prototype.totemporalinstant
+BUILTIN(DatePrototypeToTemporalInstant) {
+  HandleScope scope(isolate);
+  CHECK_RECEIVER(JSDate, date, "Date.prototype.toTemporalInstant");
+  // 1. Let t be ? thisTimeValue(this value).
+  Handle<BigInt> t;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, t,
+      BigInt::FromNumber(isolate, Handle<Object>(date->value(), isolate)));
+  // 2. Let ns be ? NumberToBigInt(t) × 10^6.
+  Handle<BigInt> ns;
+  ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
+      isolate, ns,
+      BigInt::Multiply(isolate, t, BigInt::FromInt64(isolate, 1000000)));
+  // 3. Return ! CreateTemporalInstant(ns).
+  return *temporal::CreateTemporalInstant(isolate, ns).ToHandleChecked();
+}
+
 }  // namespace internal
 }  // namespace v8

src/builtins/builtins-definitions.h

@@ -1676,6 +1676,8 @@ namespace internal {
   CPP(TemporalCalendarPrototypeToString)                                       \
   /* Temporal #sec-temporal.calendar.prototype.tojson */                       \
   CPP(TemporalCalendarPrototypeToJSON)                                         \
+  /* Temporal #sec-date.prototype.totemporalinstant */                         \
+  CPP(DatePrototypeToTemporalInstant)                                          \
                                                                                \
   /* "Private" (created but not exposed) Bulitins needed by Temporal */        \
   TFJ(StringFixedArrayFromIterable, kJSArgcReceiverSlots, kIterable)           \

src/init/bootstrapper.cc

@@ -5355,6 +5355,18 @@ void Genesis::InitializeGlobal_harmony_temporal() {
 #undef INSTALL_TEMPORAL_CTOR_AND_PROTOTYPE
 #undef INSTALL_TEMPORAL_FUNC
 
+  {  // -- D a t e
+    // #sec-date.prototype.totemporalinstant
+    Handle<JSFunction> date_func(native_context()->date_function(), isolate());
+    // Setup %DatePrototype%.
+    Handle<JSObject> date_prototype(
+        JSObject::cast(date_func->instance_prototype()), isolate());
+
+    // Install the Date.prototype.toTemporalInstant().
+    SimpleInstallFunction(isolate_, date_prototype, "toTemporalInstant",
+                          Builtin::kDatePrototypeToTemporalInstant, 0, false);
+  }
+
   // The StringListFromIterable functions is created but not
   // exposed, as it is used internally by CalendarFields.
   {

test/mjsunit/temporal/function-exist.js

@@ -112,6 +112,7 @@ const funcs = [
   "get Temporal.ZonedDateTime.prototype.timeZone",
   "get Temporal.ZonedDateTime.prototype.weekOfYear",
   "get Temporal.ZonedDateTime.prototype.year",
+  "Date.prototype.toTemporalInstant ( )",
   "Temporal.Calendar.from ( _item_ )",
   "Temporal.Calendar ( _id_ )",
   "Temporal.Calendar.prototype.dateAdd ( _date_, _duration_ [ , _options_ ] )",