[regexp] Handle marker value 0x10ffff in MakeRangeArray

Unfortunately, CharacterRanges may use 0x10ffff as a marker value
signifying 'highest possible code unit' irrespective of whether the
regexp instance has the unicode flag or not. This value makes it
through RegExpCharacterClass::ToNode unmodified (since no surrogate
desugaring takes place without /u). Correctly mask out the 0xffff
value for purposes of building our uint16_t range array.

Note: It'd be better to never introduce 0x10ffff in the first place,
but given the irregexp pipeline's lack of hackability I hesitate to
change this - we are sure to rely on it implicitly in other spots.

Drive-by: Refactors.

Fixed: chromium:1264508
Bug: v8:11069
Change-Id: Ib3c5780e91f682f1a6d15f26eb4cf03636d93c25
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3256549
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Mathias Bynens <mathias@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77673}

src/regexp/regexp-ast.h

@@ -112,9 +112,6 @@ class CharacterRange {
     return list;
   }
 
-  V8_EXPORT_PRIVATE static void AddClassEscape(
-      StandardCharacterSet standard_character_set,
-      ZoneList<CharacterRange>* ranges, Zone* zone);
   // Add class escapes. Add case equivalent closure for \w and \W if necessary.
   V8_EXPORT_PRIVATE static void AddClassEscape(
       StandardCharacterSet standard_character_set,

src/regexp/regexp-compiler-tonode.cc

@@ -50,17 +50,17 @@ namespace {
 bool CompareInverseRanges(ZoneList<CharacterRange>* ranges,
                           const int* special_class, int length) {
   length--;  // Remove final marker.
+
   DCHECK_EQ(kRangeEndMarker, special_class[length]);
   DCHECK_NE(0, ranges->length());
   DCHECK_NE(0, length);
   DCHECK_NE(0, special_class[0]);
-  if (ranges->length() != (length >> 1) + 1) {
-    return false;
-  }
+
+  if (ranges->length() != (length >> 1) + 1) return false;
+
   CharacterRange range = ranges->at(0);
-  if (range.from() != 0) {
-    return false;
-  }
+  if (range.from() != 0) return false;
+
   for (int i = 0; i < length; i += 2) {
     if (static_cast<base::uc32>(special_class[i]) != (range.to() + 1)) {
       return false;
@@ -70,19 +70,17 @@ bool CompareInverseRanges(ZoneList<CharacterRange>* ranges,
       return false;
     }
   }
-  if (range.to() != kMaxCodePoint) {
-    return false;
-  }
-  return true;
+
+  return range.to() == kMaxCodePoint;
 }
 
 bool CompareRanges(ZoneList<CharacterRange>* ranges, const int* special_class,
                    int length) {
   length--;  // Remove final marker.
+
   DCHECK_EQ(kRangeEndMarker, special_class[length]);
-  if (ranges->length() * 2 != length) {
-    return false;
-  }
+  if (ranges->length() * 2 != length) return false;
+
   for (int i = 0; i < length; i += 2) {
     CharacterRange range = ranges->at(i >> 1);
     if (range.from() != static_cast<base::uc32>(special_class[i]) ||
@@ -1157,12 +1155,7 @@ void CharacterRange::AddClassEscape(StandardCharacterSet standard_character_set,
     ranges->AddAll(*new_ranges, zone);
     return;
   }
-  AddClassEscape(standard_character_set, ranges, zone);
-}
 
-void CharacterRange::AddClassEscape(StandardCharacterSet standard_character_set,
-                                    ZoneList<CharacterRange>* ranges,
-                                    Zone* zone) {
   switch (standard_character_set) {
     case StandardCharacterSet::kWhitespace:
       AddClass(kSpaceRanges, kSpaceRangeCount, ranges, zone);

src/regexp/regexp-macro-assembler.cc

@@ -115,9 +115,16 @@ uint32_t Hash(const ZoneList<CharacterRange>* ranges) {
   return static_cast<uint32_t>(seed);
 }
 
+constexpr base::uc32 MaskEndOfRangeMarker(base::uc32 c) {
+  // CharacterRanges may use 0x10ffff as the end-of-range marker irrespective
+  // of whether the regexp IsUnicode or not; translate the marker value here.
+  DCHECK_IMPLIES(c > kMaxUInt16, c == String::kMaxCodePoint);
+  return c & 0xffff;
+}
+
 int RangeArrayLengthFor(const ZoneList<CharacterRange>* ranges) {
   const int ranges_length = ranges->length();
-  return ranges->at(ranges_length - 1).to() == kMaxUInt16
+  return MaskEndOfRangeMarker(ranges->at(ranges_length - 1).to()) == kMaxUInt16
              ? ranges_length * 2 - 1
              : ranges_length * 2;
 }
@@ -146,11 +153,13 @@ Handle<ByteArray> MakeRangeArray(Isolate* isolate,
     const CharacterRange& r = ranges->at(i);
     DCHECK_LE(r.from(), kMaxUInt16);
     range_array->set_uint16(i * 2 + 0, r.from());
-    if (i == ranges_length - 1 && r.to() == kMaxUInt16) {
+    const base::uc32 to = MaskEndOfRangeMarker(r.to());
+    if (i == ranges_length - 1 && to == kMaxUInt16) {
+      DCHECK_EQ(byte_array_length, ranges_length * 2 - 1);
       break;  // Avoid overflow by leaving the last range open-ended.
     }
-    DCHECK_LT(r.to(), kMaxUInt16);
-    range_array->set_uint16(i * 2 + 1, r.to() + 1);  // Exclusive.
+    DCHECK_LT(to, kMaxUInt16);
+    range_array->set_uint16(i * 2 + 1, to + 1);  // Exclusive.
   }
   return range_array;
 }

test/cctest/test-regexp.cc

@@ -510,7 +510,7 @@ static void TestCharacterClassEscapes(StandardCharacterSet c,
   Zone zone(CcTest::i_isolate()->allocator(), ZONE_NAME);
   ZoneList<CharacterRange>* ranges =
       zone.New<ZoneList<CharacterRange>>(2, &zone);
-  CharacterRange::AddClassEscape(c, ranges, &zone);
+  CharacterRange::AddClassEscape(c, ranges, false, &zone);
   for (base::uc32 i = 0; i < (1 << 16); i++) {
     bool in_class = false;
     for (int j = 0; !in_class && j < ranges->length(); j++) {

test/mjsunit/regress/regress-1264508.js

@@ -0,0 +1,7 @@
+// Copyright 2021 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: --no-regexp-tier-up
+
+assertNotNull(/[nyreekp\W]/isy.exec("\u2603"));