Remove always-true --harmony-subsume-json flag

The ECMAScript ⊃ JSON proposal shipped in V8 v6.6 and Chrome 66.

Bug: v8:7418
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Change-Id: Id8979d0cec6d61ef4a7e9982142a3f3dcf7c326b
Reviewed-on: https://chromium-review.googlesource.com/1067857
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53271}

src/bootstrapper.cc

@@ -4181,7 +4181,6 @@ EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_class_fields)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_dynamic_import)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_import_meta)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_optional_catch_binding)
-EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_subsume_json)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_numeric_separator)
 
 #undef EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE

src/flag-definitions.h

@@ -231,7 +231,6 @@ DEFINE_IMPLICATION(harmony_class_fields, harmony_private_fields)
 
 // Features that are shipping (turned on by default, but internal flag remains).
 #define HARMONY_SHIPPING(V)                                                   \
-  V(harmony_subsume_json, "harmony subsume JSON")                             \
   V(harmony_string_trimming, "harmony String.prototype.trim{Start,End}")      \
   V(harmony_sharedarraybuffer, "harmony sharedarraybuffer")                   \
   V(harmony_regexp_named_captures, "harmony regexp named captures")           \

src/parsing/scanner.cc

@@ -1073,11 +1073,8 @@ Token::Value Scanner::ScanString() {
     AddLiteralChar(c);
   }
 
-  bool (*line_terminator_func)(unsigned int) =
-      FLAG_harmony_subsume_json ? unibrow::IsStringLiteralLineTerminator
-                                : unibrow::IsLineTerminator;
-
-  while (c0_ != quote && c0_ != kEndOfInput && !line_terminator_func(c0_)) {
+  while (c0_ != quote && c0_ != kEndOfInput &&
+         !unibrow::IsStringLiteralLineTerminator(c0_)) {
     uc32 c = c0_;
     Advance();
     if (c == '\\') {

test/cctest/test-parsing.cc

@@ -3731,24 +3731,9 @@ TEST(LineOrParagraphSeparatorAsLineTerminator) {
 }
 
 TEST(LineOrParagraphSeparatorInStringLiteral) {
-  // Tests that both preparsing and parsing treat U+2028 LINE SEPARATOR and
-  // U+2029 PARAGRAPH SEPARATOR as line terminators within string literals
-  // when the "subsume JSON" flag is disabled.
-  v8::internal::FLAG_harmony_subsume_json = false;
-  const char* context_data[][2] = {
-      {"\"", "\""}, {"'", "'"}, {nullptr, nullptr}};
-  const char* statement_data[] = {"\x31\xE2\x80\xA8\x32",  // 1<U+2028>2
-                                  "\x31\xE2\x80\xA9\x32",  // 1<U+2029>2
-                                  nullptr};
-
-  RunParserSyncTest(context_data, statement_data, kError);
-}
-
-TEST(LineOrParagraphSeparatorInStringLiteralHarmony) {
   // Tests that both preparsing and parsing don't treat U+2028 LINE SEPARATOR
-  // and U+2029 PARAGRAPH SEPARATOR as line terminators within string literals
-  // when the "subsume JSON" flag is enabled.
-  v8::internal::FLAG_harmony_subsume_json = true;
+  // and U+2029 PARAGRAPH SEPARATOR as line terminators within string literals.
+  // https://github.com/tc39/proposal-json-superset
   const char* context_data[][2] = {
       {"\"", "\""}, {"'", "'"}, {nullptr, nullptr}};
   const char* statement_data[] = {"\x31\xE2\x80\xA8\x32",  // 1<U+2028>2

test/mjsunit/harmony/linecontinuation.js

@@ -1,42 +0,0 @@
-// Copyright 2018 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --harmony-subsume-json
-
-// https://tc39.github.io/ecma262/#sec-literals-string-literals
-//
-// LineContinuation ::
-//   \ LineTerminatorSequence
-//
-// LineTerminatorSequence ::
-//   <LF>
-//   <CR>[lookahead ≠ <LF>]
-//   <LS>
-//   <PS>
-//   <CR><LF>
-
-// LineTerminatorSequence :: <LF>
-assertEquals('', eval('"\\\n"'));
-assertEquals('', eval("'\\\n'"));
-assertEquals('', eval('`\\\n`'));
-
-// LineTerminatorSequence :: <CR>[lookahead ≠ <LF>]
-assertEquals('', eval('"\\\r"'));
-assertEquals('', eval("'\\\r'"));
-assertEquals('', eval('`\\\r`'));
-
-// LineTerminatorSequence :: <LS>
-assertEquals('', eval('"\\\u2028"'));
-assertEquals('', eval("'\\\u2028'"));
-assertEquals('', eval('`\\\u2028`'));
-
-// LineTerminatorSequence :: <PS>
-assertEquals('', eval('"\\\u2029"'));
-assertEquals('', eval("'\\\u2029'"));
-assertEquals('', eval('`\\\u2029`'));
-
-// LineTerminatorSequence :: <CR><LF>
-assertEquals('', eval('"\\\r\n"'));
-assertEquals('', eval("'\\\r\n'"));
-assertEquals('', eval('`\\\r\n`'));

test/test262/test262.status

@@ -498,6 +498,8 @@
   'built-ins/Array/prototype/sort/bug_596_1': [PASS, FAIL_OK],
 
   # https://bugs.chromium.org/p/v8/issues/detail?id=7418
+  # TODO(mathias): These tests have been removed in upstream Test262.
+  # Remove them once we sync.
   'language/line-terminators/S7.3_A2.3': [FAIL],
   'language/line-terminators/S7.3_A2.4': [FAIL],