[Intl] Move caching of default locale from JS into Intl::DefaultLocale

Bug: v8:7988
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: Ib06e07b20c4a80baac7667241906142d60ada8e8
Reviewed-on: https://chromium-review.googlesource.com/1152453
Commit-Queue: Frank Tang <ftang@chromium.org>
Reviewed-by: Jungshik Shin <jshin@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54797}

src/isolate.cc

@@ -2486,6 +2486,7 @@ Isolate::Isolate()
       language_singleton_regexp_matcher_(nullptr),
       language_tag_regexp_matcher_(nullptr),
       language_variant_regexp_matcher_(nullptr),
+      default_locale_(""),
 #endif  // V8_INTL_SUPPORT
       serializer_enabled_(false),
       has_fatal_error_(false),

src/isolate.h

@@ -1116,6 +1116,13 @@ class Isolate : private HiddenFactory {
     return language_variant_regexp_matcher_;
   }
 
+  const std::string& default_locale() { return default_locale_; }
+
+  void set_default_locale(const std::string& locale) {
+    DCHECK_EQ(default_locale_.length(), 0);
+    default_locale_ = locale;
+  }
+
   void set_language_tag_regexp_matchers(
       icu::RegexMatcher* language_singleton_regexp_matcher,
       icu::RegexMatcher* language_tag_regexp_matcher,
@@ -1625,6 +1632,7 @@ class Isolate : private HiddenFactory {
   icu::RegexMatcher* language_singleton_regexp_matcher_;
   icu::RegexMatcher* language_tag_regexp_matcher_;
   icu::RegexMatcher* language_variant_regexp_matcher_;
+  std::string default_locale_;
 #endif  // V8_INTL_SUPPORT
 
   // Whether the isolate has been created for snapshotting.

src/js/intl.js

@@ -141,18 +141,6 @@ var AVAILABLE_LOCALES = {
   'listformat': UNDEFINED,
 };
 
-/**
- * Caches default ICU locale.
- */
-var DEFAULT_ICU_LOCALE = UNDEFINED;
-
-function GetDefaultICULocaleJS() {
-  if (IS_UNDEFINED(DEFAULT_ICU_LOCALE)) {
-    DEFAULT_ICU_LOCALE = %GetDefaultICULocale();
-  }
-  return DEFAULT_ICU_LOCALE;
-}
-
 /**
  * Unicode extension regular expression.
  */
@@ -453,7 +441,7 @@ function lookupMatcher(service, requestedLocales) {
     }
   }
 
-  var defLocale = GetDefaultICULocaleJS();
+  var defLocale = %GetDefaultICULocale();
 
   // While ECMA-402 returns defLocale directly, we have to check if it is
   // supported, as such support is not guaranteed.

src/objects/intl-objects.cc

@@ -1203,25 +1203,25 @@ V8_WARN_UNUSED_RESULT MaybeHandle<JSObject> Intl::AvailableLocalesOf(
 }
 
 V8_WARN_UNUSED_RESULT Handle<String> Intl::DefaultLocale(Isolate* isolate) {
-  Factory* factory = isolate->factory();
-
-  icu::Locale default_locale;
-
-  // Translate ICU's fallback locale to a well-known locale.
-  if (strcmp(default_locale.getName(), "en_US_POSIX") == 0) {
-    return factory->NewStringFromStaticChars("en-US");
-  }
-
-  // Set the locale
-  char result[ULOC_FULLNAME_CAPACITY];
-  UErrorCode status = U_ZERO_ERROR;
-  uloc_toLanguageTag(default_locale.getName(), result, ULOC_FULLNAME_CAPACITY,
-                     FALSE, &status);
-  if (U_SUCCESS(status)) {
-    return factory->NewStringFromAsciiChecked(result);
+  if (isolate->default_locale().empty()) {
+    icu::Locale default_locale;
+    // Translate ICU's fallback locale to a well-known locale.
+    if (strcmp(default_locale.getName(), "en_US_POSIX") == 0) {
+      isolate->set_default_locale("en-US");
+    } else {
+      // Set the locale
+      char result[ULOC_FULLNAME_CAPACITY];
+      UErrorCode status = U_ZERO_ERROR;
+      int32_t length =
+          uloc_toLanguageTag(default_locale.getName(), result,
+                             ULOC_FULLNAME_CAPACITY, FALSE, &status);
+      isolate->set_default_locale(
+          U_SUCCESS(status) ? std::string(result, length) : "und");
+    }
+    DCHECK(!isolate->default_locale().empty());
   }
-
-  return factory->NewStringFromStaticChars("und");
+  return isolate->factory()->NewStringFromAsciiChecked(
+      isolate->default_locale().c_str());
 }
 
 bool Intl::IsObjectOfType(Isolate* isolate, Handle<Object> input,