Add UseCounter for Date.parse's legacy parse heuristics.

R=adamk@chromium.org, jochen@chromium.org
BUG=chromium:618595

Review-Url: https://codereview.chromium.org/2050733004
Cr-Commit-Position: refs/heads/master@{#36846}

include/v8.h

@@ -5681,6 +5681,7 @@ class V8_EXPORT Isolate {
     kRegExpPrototypeSourceGetter = 30,
     kRegExpPrototypeOldFlagGetter = 31,
     kDecimalWithLeadingZeroInStrictMode = 32,
+    kLegacyDateParser = 33,
 
     // If you add new values here, you'll also need to update Chromium's:
     // UseCounter.h, V8PerIsolateData.cpp, histograms.xml

src/builtins.cc

@@ -3291,11 +3291,9 @@ double ParseDateTimeString(Handle<String> str) {
   String::FlatContent str_content = str->GetFlatContent();
   bool result;
   if (str_content.IsOneByte()) {
-    result = DateParser::Parse(str_content.ToOneByteVector(), *tmp,
-                               isolate->unicode_cache());
+    result = DateParser::Parse(isolate, str_content.ToOneByteVector(), *tmp);
   } else {
-    result = DateParser::Parse(str_content.ToUC16Vector(), *tmp,
-                               isolate->unicode_cache());
+    result = DateParser::Parse(isolate, str_content.ToUC16Vector(), *tmp);
   }
   if (!result) return std::numeric_limits<double>::quiet_NaN();
   double const day = MakeDay(tmp->get(0)->Number(), tmp->get(1)->Number(),

src/dateparser-inl.h

@@ -13,9 +13,8 @@ namespace v8 {
 namespace internal {
 
 template <typename Char>
-bool DateParser::Parse(Vector<Char> str,
-                       FixedArray* out,
-                       UnicodeCache* unicode_cache) {
+bool DateParser::Parse(Isolate* isolate, Vector<Char> str, FixedArray* out) {
+  UnicodeCache* unicode_cache = isolate->unicode_cache();
   DCHECK(out->length() >= OUTPUT_SIZE);
   InputReader<Char> in(unicode_cache, str);
   DateStringTokenizer<Char> scanner(&in);
@@ -76,6 +75,7 @@ bool DateParser::Parse(Vector<Char> str,
   if (next_unhandled_token.IsInvalid()) return false;
   bool has_read_number = !day.IsEmpty();
   // If there's anything left, continue with the legacy parser.
+  bool legacy_parser = !next_unhandled_token.IsEndOfInput();
   for (DateToken token = next_unhandled_token;
        !token.IsEndOfInput();
        token = scanner.Next()) {
@@ -170,7 +170,13 @@ bool DateParser::Parse(Vector<Char> str,
     }
   }
 
-  return day.Write(out) && time.Write(out) && tz.Write(out);
+  bool success = day.Write(out) && time.Write(out) && tz.Write(out);
+
+  if (legacy_parser && success) {
+    isolate->CountUsage(v8::Isolate::kLegacyDateParser);
+  }
+
+  return success;
 }
 
 

src/dateparser.h

@@ -26,7 +26,7 @@ class DateParser : public AllStatic {
   // [7]: UTC offset in seconds, or null value if no timezone specified
   // If parsing fails, return false (content of output array is not defined).
   template <typename Char>
-  static bool Parse(Vector<Char> str, FixedArray* output, UnicodeCache* cache);
+  static bool Parse(Isolate* isolate, Vector<Char> str, FixedArray* output);
 
   enum {
     YEAR, MONTH, DAY, HOUR, MINUTE, SECOND, MILLISECOND, UTC_OFFSET, OUTPUT_SIZE