Revert of [regexp] implement character classes for unicode regexps.

src/regexp/jsregexp.cc

Index: src/regexp/jsregexp.cc
diff --git a/src/regexp/jsregexp.cc b/src/regexp/jsregexp.cc
index 3559bcd111a4c19eb5755dd264d6a4a8cf39a88a..34d20fe781d291b14e785a803e3e0f07e188bcb6 100644
--- a/src/regexp/jsregexp.cc
+++ b/src/regexp/jsregexp.cc
@@ -72,7 +72,7 @@
                             int ranges_length,
                             Interval new_range) {
   DCHECK((ranges_length & 1) == 1);
-  DCHECK(ranges[ranges_length - 1] == String::kMaxCodePoint + 1);
+  DCHECK(ranges[ranges_length - 1] == String::kMaxUtf16CodeUnit + 1);
   if (containment == kLatticeUnknown) return containment;
   bool inside = false;
   int last = 0;
@@ -145,8 +145,9 @@
   PostponeInterruptsScope postpone(isolate);
   RegExpCompileData parse_result;
   FlatStringReader reader(isolate, pattern);
-  if (!RegExpParser::ParseRegExp(re->GetIsolate(), &zone, &reader, flags,
-                                 &parse_result)) {
+  if (!RegExpParser::ParseRegExp(re->GetIsolate(), &zone, &reader,
+                                 flags & JSRegExp::kMultiline,
+                                 flags & JSRegExp::kUnicode, &parse_result)) {
     // Throw an exception if we fail to parse the pattern.
     return ThrowRegExpException(re, pattern, parse_result.error);
   }
@@ -370,16 +371,18 @@
   pattern = String::Flatten(pattern);
   RegExpCompileData compile_data;
   FlatStringReader reader(isolate, pattern);
-  if (!RegExpParser::ParseRegExp(isolate, &zone, &reader, flags,
-                                 &compile_data)) {
+  if (!RegExpParser::ParseRegExp(isolate, &zone, &reader,
+                                 flags & JSRegExp::kMultiline,
+                                 flags & JSRegExp::kUnicode, &compile_data)) {
     // Throw an exception if we fail to parse the pattern.
     // THIS SHOULD NOT HAPPEN. We already pre-parsed it successfully once.
     USE(ThrowRegExpException(re, pattern, compile_data.error));
     return false;
   }
-  RegExpEngine::CompilationResult result =
-      RegExpEngine::Compile(isolate, &zone, &compile_data, flags, pattern,
-                            sample_subject, is_one_byte);
+  RegExpEngine::CompilationResult result = RegExpEngine::Compile(
+      isolate, &zone, &compile_data, flags & JSRegExp::kIgnoreCase,
+      flags & JSRegExp::kGlobal, flags & JSRegExp::kMultiline,
+      flags & JSRegExp::kSticky, pattern, sample_subject, is_one_byte);
   if (result.error_message != NULL) {
     // Unable to compile regexp.
     Handle<String> error_message = isolate->factory()->NewStringFromUtf8(
@@ -942,7 +945,7 @@
 class RegExpCompiler {
  public:
   RegExpCompiler(Isolate* isolate, Zone* zone, int capture_count,
-                 JSRegExp::Flags flags, bool is_one_byte);
+                 bool ignore_case, bool is_one_byte);
 
   int AllocateRegister() {
     if (next_register_ >= RegExpMacroAssembler::kMaxRegister) {
@@ -952,22 +955,6 @@
     return next_register_++;
   }
 
-  // Lookarounds to match lone surrogates for unicode character class matches
-  // are never nested. We can therefore reuse registers.
-  int UnicodeLookaroundStackRegister() {
-    if (unicode_lookaround_stack_register_ == kNoRegister) {
-      unicode_lookaround_stack_register_ = AllocateRegister();
-    }
-    return unicode_lookaround_stack_register_;
-  }
-
-  int UnicodeLookaroundPositionRegister() {
-    if (unicode_lookaround_position_register_ == kNoRegister) {
-      unicode_lookaround_position_register_ = AllocateRegister();
-    }
-    return unicode_lookaround_position_register_;
-  }
-
   RegExpEngine::CompilationResult Assemble(RegExpMacroAssembler* assembler,
                                            RegExpNode* start,
                                            int capture_count,
@@ -994,8 +981,7 @@
 
   void SetRegExpTooBig() { reg_exp_too_big_ = true; }
 
-  inline bool ignore_case() { return (flags_ & JSRegExp::kIgnoreCase) != 0; }
-  inline bool unicode() { return (flags_ & JSRegExp::kUnicode) != 0; }
+  inline bool ignore_case() { return ignore_case_; }
   inline bool one_byte() { return one_byte_; }
   inline bool optimize() { return optimize_; }
   inline void set_optimize(bool value) { optimize_ = value; }
@@ -1020,12 +1006,10 @@
  private:
   EndNode* accept_;
   int next_register_;
-  int unicode_lookaround_stack_register_;
-  int unicode_lookaround_position_register_;
   List<RegExpNode*>* work_list_;
   int recursion_depth_;
   RegExpMacroAssembler* macro_assembler_;
-  JSRegExp::Flags flags_;
+  bool ignore_case_;
   bool one_byte_;
   bool reg_exp_too_big_;
   bool limiting_recursion_;
@@ -1057,13 +1041,11 @@
 // Attempts to compile the regexp using an Irregexp code generator.  Returns
 // a fixed array or a null handle depending on whether it succeeded.
 RegExpCompiler::RegExpCompiler(Isolate* isolate, Zone* zone, int capture_count,
-                               JSRegExp::Flags flags, bool one_byte)
+                               bool ignore_case, bool one_byte)
     : next_register_(2 * (capture_count + 1)),
-      unicode_lookaround_stack_register_(kNoRegister),
-      unicode_lookaround_position_register_(kNoRegister),
       work_list_(NULL),
       recursion_depth_(0),
-      flags_(flags),
+      ignore_case_(ignore_case),
       one_byte_(one_byte),
       reg_exp_too_big_(false),
       limiting_recursion_(false),
@@ -2116,7 +2098,9 @@
                           Label* on_failure, int cp_offset, bool check_offset,
                           bool preloaded, Zone* zone) {
   ZoneList<CharacterRange>* ranges = cc->ranges(zone);
-  CharacterRange::Canonicalize(ranges);
+  if (!CharacterRange::IsCanonical(ranges)) {
+    CharacterRange::Canonicalize(ranges);
+  }
 
   int max_char;
   if (one_byte) {
@@ -2158,14 +2142,23 @@
     }
     return;
   }
+  if (last_valid_range == 0 &&
+      !cc->is_negated() &&
+      ranges->at(0).IsEverything(max_char)) {
+    // This is a common case hit by non-anchored expressions.
+    if (check_offset) {
+      macro_assembler->CheckPosition(cp_offset, on_failure);
+    }
+    return;
+  }
 
   if (!preloaded) {
     macro_assembler->LoadCurrentCharacter(cp_offset, on_failure, check_offset);
   }
 
   if (cc->is_standard(zone) &&
-      macro_assembler->CheckSpecialCharacterClass(cc->standard_type(),
-                                                  on_failure)) {
+        macro_assembler->CheckSpecialCharacterClass(cc->standard_type(),
+                                                    on_failure)) {
       return;
   }
 
@@ -2805,7 +2798,9 @@
       DCHECK(elm.text_type() == TextElement::CHAR_CLASS);
       RegExpCharacterClass* cc = elm.char_class();
       ZoneList<CharacterRange>* ranges = cc->ranges(zone());
-      CharacterRange::Canonicalize(ranges);
+      if (!CharacterRange::IsCanonical(ranges)) {
+        CharacterRange::Canonicalize(ranges);
+      }
       // Now they are in order so we only need to look at the first.
       int range_count = ranges->length();
       if (cc->is_negated()) {
@@ -3294,36 +3289,6 @@
 }
 
 
-TextNode* TextNode::CreateForCharacterRanges(Zone* zone,
-                                             ZoneList<CharacterRange>* ranges,
-                                             bool read_backward,
-                                             RegExpNode* on_success) {
-  DCHECK_NOT_NULL(ranges);
-  ZoneList<TextElement>* elms = new (zone) ZoneList<TextElement>(1, zone);
-  elms->Add(
-      TextElement::CharClass(new (zone) RegExpCharacterClass(ranges, false)),
-      zone);
-  return new (zone) TextNode(elms, read_backward, on_success);
-}
-
-
-TextNode* TextNode::CreateForSurrogatePair(Zone* zone, CharacterRange lead,
-                                           CharacterRange trail,
-                                           bool read_backward,
-                                           RegExpNode* on_success) {
-  ZoneList<CharacterRange>* lead_ranges = CharacterRange::List(zone, lead);
-  ZoneList<CharacterRange>* trail_ranges = CharacterRange::List(zone, trail);
-  ZoneList<TextElement>* elms = new (zone) ZoneList<TextElement>(2, zone);
-  elms->Add(TextElement::CharClass(
-                new (zone) RegExpCharacterClass(lead_ranges, false)),
-            zone);
-  elms->Add(TextElement::CharClass(
-                new (zone) RegExpCharacterClass(trail_ranges, false)),
-            zone);
-  return new (zone) TextNode(elms, read_backward, on_success);
-}
-
-
 // This generates the code to match a text node.  A text node can contain
 // straight character sequences (possibly to be matched in a case-independent
 // way) and character classes.  For efficiency we do not do this in a single
@@ -3440,7 +3405,9 @@
   if (elm.text_type() != TextElement::CHAR_CLASS) return NULL;
   RegExpCharacterClass* node = elm.char_class();
   ZoneList<CharacterRange>* ranges = node->ranges(zone());
-  CharacterRange::Canonicalize(ranges);
+  if (!CharacterRange::IsCanonical(ranges)) {
+    CharacterRange::Canonicalize(ranges);
+  }
   if (node->is_negated()) {
     return ranges->length() == 0 ? on_success() : NULL;
   }
@@ -3587,34 +3554,26 @@
 };
 
 
-static const uc32 kLeadSurrogateStart = 0xd800;
-static const uc32 kLeadSurrogateEnd = 0xdbff;
-static const uc32 kTrailSurrogateStart = 0xdc00;
-static const uc32 kTrailSurrogateEnd = 0xdfff;
-static const uc32 kNonBmpStart = 0x10000;
-static const uc32 kNonBmpEnd = 0x10ffff;
-static const uc32 kRangeEndMarker = 0x110000;
-
 // The '2' variant is has inclusive from and exclusive to.
 // This covers \s as defined in ECMA-262 5.1, 15.10.2.12,
 // which include WhiteSpace (7.2) or LineTerminator (7.3) values.
-static const int kSpaceRanges[] = {
-    '\t',   '\r' + 1, ' ',    ' ' + 1, 0x00A0, 0x00A1, 0x1680,         0x1681,
-    0x180E, 0x180F,   0x2000, 0x200B,  0x2028, 0x202A, 0x202F,         0x2030,
-    0x205F, 0x2060,   0x3000, 0x3001,  0xFEFF, 0xFF00, kRangeEndMarker};
+static const int kSpaceRanges[] = { '\t', '\r' + 1, ' ', ' ' + 1,
+    0x00A0, 0x00A1, 0x1680, 0x1681, 0x180E, 0x180F, 0x2000, 0x200B,
+    0x2028, 0x202A, 0x202F, 0x2030, 0x205F, 0x2060, 0x3000, 0x3001,
+    0xFEFF, 0xFF00, 0x10000 };
 static const int kSpaceRangeCount = arraysize(kSpaceRanges);
 
 static const int kWordRanges[] = {
-    '0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1, kRangeEndMarker};
+    '0', '9' + 1, 'A', 'Z' + 1, '_', '_' + 1, 'a', 'z' + 1, 0x10000 };
 static const int kWordRangeCount = arraysize(kWordRanges);
-static const int kDigitRanges[] = {'0', '9' + 1, kRangeEndMarker};
+static const int kDigitRanges[] = { '0', '9' + 1, 0x10000 };
 static const int kDigitRangeCount = arraysize(kDigitRanges);
-static const int kSurrogateRanges[] = {
-    kLeadSurrogateStart, kLeadSurrogateStart + 1, kRangeEndMarker};
+static const int kSurrogateRanges[] = { 0xd800, 0xe000, 0x10000 };
 static const int kSurrogateRangeCount = arraysize(kSurrogateRanges);
-static const int kLineTerminatorRanges[] = {
-    0x000A, 0x000B, 0x000D, 0x000E, 0x2028, 0x202A, kRangeEndMarker};
+static const int kLineTerminatorRanges[] = { 0x000A, 0x000B, 0x000D, 0x000E,
+    0x2028, 0x202A, 0x10000 };
 static const int kLineTerminatorRangeCount = arraysize(kLineTerminatorRanges);
+
 
 void BoyerMoorePositionInfo::Set(int character) {
   SetInterval(Interval(character, character));
@@ -4773,8 +4732,8 @@
 static bool CompareInverseRanges(ZoneList<CharacterRange>* ranges,
                                  const int* special_class,
                                  int length) {
-  length--;  // Remove final marker.
-  DCHECK(special_class[length] == kRangeEndMarker);
+  length--;  // Remove final 0x10000.
+  DCHECK(special_class[length] == 0x10000);
   DCHECK(ranges->length() != 0);
   DCHECK(length != 0);
   DCHECK(special_class[0] != 0);
@@ -4804,8 +4763,8 @@
 static bool CompareRanges(ZoneList<CharacterRange>* ranges,
                           const int* special_class,
                           int length) {
-  length--;  // Remove final marker.
-  DCHECK(special_class[length] == kRangeEndMarker);
+  length--;  // Remove final 0x10000.
+  DCHECK(special_class[length] == 0x10000);
   if (ranges->length() * 2 != length) {
     return false;
   }
@@ -4861,257 +4820,10 @@
 }
 
 
-bool RegExpCharacterClass::NeedsDesugaringForUnicode(Zone* zone) {
-  ZoneList<CharacterRange>* ranges = this->ranges(zone);
-  CharacterRange::Canonicalize(ranges);
-  for (int i = ranges->length() - 1; i >= 0; i--) {
-    uc32 from = ranges->at(i).from();
-    uc32 to = ranges->at(i).to();
-    // Check for non-BMP characters.
-    if (to >= kNonBmpStart) return true;
-    // Check for lone surrogates.
-    if (from <= kTrailSurrogateEnd && to >= kLeadSurrogateStart) return true;
-  }
-  return false;
-}
-
-
-UnicodeRangeSplitter::UnicodeRangeSplitter(Zone* zone,
-                                           ZoneList<CharacterRange>* base)
-    : zone_(zone),
-      table_(zone),
-      bmp_(nullptr),
-      lead_surrogates_(nullptr),
-      trail_surrogates_(nullptr),
-      non_bmp_(nullptr) {
-  // The unicode range splitter categorizes given character ranges into:
-  // - Code points from the BMP representable by one code unit.
-  // - Code points outside the BMP that need to be split into surrogate pairs.
-  // - Lone lead surrogates.
-  // - Lone trail surrogates.
-  // Lone surrogates are valid code points, even though no actual characters.
-  // They require special matching to make sure we do not split surrogate pairs.
-  // We use the dispatch table to accomplish this. The base range is split up
-  // by the table by the overlay ranges, and the Call callback is used to
-  // filter and collect ranges for each category.
-  for (int i = 0; i < base->length(); i++) {
-    table_.AddRange(base->at(i), kBase, zone_);
-  }
-  // Add overlay ranges.
-  table_.AddRange(CharacterRange(0, kLeadSurrogateStart - 1), kBmpCodePoints,
-                  zone_);
-  table_.AddRange(CharacterRange(kLeadSurrogateStart, kLeadSurrogateEnd),
-                  kLeadSurrogates, zone_);
-  table_.AddRange(CharacterRange(kTrailSurrogateStart, kTrailSurrogateEnd),
-                  kTrailSurrogates, zone_);
-  table_.AddRange(CharacterRange(kTrailSurrogateEnd, kNonBmpStart - 1),
-                  kBmpCodePoints, zone_);
-  table_.AddRange(CharacterRange(kNonBmpStart, kNonBmpEnd), kNonBmpCodePoints,
-                  zone_);
-  table_.ForEach(this);
-}
-
-
-void UnicodeRangeSplitter::Call(uc32 from, DispatchTable::Entry entry) {
-  OutSet* outset = entry.out_set();
-  if (!outset->Get(kBase)) return;
-  ZoneList<CharacterRange>** target = NULL;
-  if (outset->Get(kBmpCodePoints)) {
-    target = &bmp_;
-  } else if (outset->Get(kLeadSurrogates)) {
-    target = &lead_surrogates_;
-  } else if (outset->Get(kTrailSurrogates)) {
-    target = &trail_surrogates_;
-  } else {
-    DCHECK(outset->Get(kNonBmpCodePoints));
-    target = &non_bmp_;
-  }
-  if (*target == NULL) *target = new (zone_) ZoneList<CharacterRange>(2, zone_);
-  (*target)->Add(CharacterRange::Range(entry.from(), entry.to()), zone_);
-}
-
-
-void AddBmpCharacters(RegExpCompiler* compiler, ChoiceNode* result,
-                      RegExpNode* on_success, UnicodeRangeSplitter* splitter) {
-  ZoneList<CharacterRange>* bmp = splitter->bmp();
-  if (bmp == nullptr) return;
-  result->AddAlternative(GuardedAlternative(TextNode::CreateForCharacterRanges(
-      compiler->zone(), bmp, compiler->read_backward(), on_success)));
-}
-
-
-void AddNonBmpSurrogatePairs(RegExpCompiler* compiler, ChoiceNode* result,
-                             RegExpNode* on_success,
-                             UnicodeRangeSplitter* splitter) {
-  ZoneList<CharacterRange>* non_bmp = splitter->non_bmp();
-  if (non_bmp == nullptr) return;
-  DCHECK(compiler->unicode());
-  DCHECK(!compiler->one_byte());
-  Zone* zone = compiler->zone();
-  CharacterRange::Canonicalize(non_bmp);
-  for (int i = 0; i < non_bmp->length(); i++) {
-    // Match surrogate pair.
-    // E.g. [\u10005-\u11005] becomes
-    //      \ud800[\udc05-\udfff]|
-    //      [\ud801-\ud803][\udc00-\udfff]|
-    //      \ud804[\udc00-\udc05]
-    uc32 from = non_bmp->at(i).from();
-    uc32 to = non_bmp->at(i).to();
-    uc16 from_l = unibrow::Utf16::LeadSurrogate(from);
-    uc16 from_t = unibrow::Utf16::TrailSurrogate(from);
-    uc16 to_l = unibrow::Utf16::LeadSurrogate(to);
-    uc16 to_t = unibrow::Utf16::TrailSurrogate(to);
-    if (from_l == to_l) {
-      // The lead surrogate is the same.
-      result->AddAlternative(
-          GuardedAlternative(TextNode::CreateForSurrogatePair(
-              zone, CharacterRange::Singleton(from_l),
-              CharacterRange::Range(from_t, to_t), compiler->read_backward(),
-              on_success)));
-    } else {
-      if (from_t != kTrailSurrogateStart) {
-        // Add [from_l][from_t-\udfff]
-        result->AddAlternative(
-            GuardedAlternative(TextNode::CreateForSurrogatePair(
-                zone, CharacterRange::Singleton(from_l),
-                CharacterRange::Range(from_t, kTrailSurrogateEnd),
-                compiler->read_backward(), on_success)));
-        from_l++;
-      }
-      if (to_t != kTrailSurrogateEnd) {
-        // Add [to_l][\udc00-to_t]
-        result->AddAlternative(
-            GuardedAlternative(TextNode::CreateForSurrogatePair(
-                zone, CharacterRange::Singleton(to_l),
-                CharacterRange::Range(kTrailSurrogateStart, to_t),
-                compiler->read_backward(), on_success)));
-        to_l--;
-      }
-      if (from_l <= to_l) {
-        // Add [from_l-to_l][\udc00-\udfff]
-        result->AddAlternative(
-            GuardedAlternative(TextNode::CreateForSurrogatePair(
-                zone, CharacterRange::Range(from_l, to_l),
-                CharacterRange::Range(kTrailSurrogateStart, kTrailSurrogateEnd),
-                compiler->read_backward(), on_success)));
-      }
-    }
-  }
-}
-
-
-RegExpNode* NegativeLookaroundAgainstReadDirectionAndMatch(
-    RegExpCompiler* compiler, ZoneList<CharacterRange>* lookbehind,
-    ZoneList<CharacterRange>* match, RegExpNode* on_success,
-    bool read_backward) {
-  Zone* zone = compiler->zone();
-  RegExpNode* match_node = TextNode::CreateForCharacterRanges(
-      zone, match, read_backward, on_success);
-  int stack_register = compiler->UnicodeLookaroundStackRegister();
-  int position_register = compiler->UnicodeLookaroundPositionRegister();
-  RegExpLookaround::Builder lookaround(false, match_node, stack_register,
-                                       position_register);
-  RegExpNode* negative_match = TextNode::CreateForCharacterRanges(
-      zone, lookbehind, !read_backward, lookaround.on_match_success());
-  return lookaround.ForMatch(negative_match);
-}
-
-
-RegExpNode* MatchAndNegativeLookaroundInReadDirection(
-    RegExpCompiler* compiler, ZoneList<CharacterRange>* match,
-    ZoneList<CharacterRange>* lookahead, RegExpNode* on_success,
-    bool read_backward) {
-  Zone* zone = compiler->zone();
-  int stack_register = compiler->UnicodeLookaroundStackRegister();
-  int position_register = compiler->UnicodeLookaroundPositionRegister();
-  RegExpLookaround::Builder lookaround(false, on_success, stack_register,
-                                       position_register);
-  RegExpNode* negative_match = TextNode::CreateForCharacterRanges(
-      zone, lookahead, read_backward, lookaround.on_match_success());
-  return TextNode::CreateForCharacterRanges(
-      zone, match, read_backward, lookaround.ForMatch(negative_match));
-}
-
-
-void AddLoneLeadSurrogates(RegExpCompiler* compiler, ChoiceNode* result,
-                           RegExpNode* on_success,
-                           UnicodeRangeSplitter* splitter) {
-  ZoneList<CharacterRange>* lead_surrogates = splitter->lead_surrogates();
-  if (lead_surrogates == nullptr) return;
-  Zone* zone = compiler->zone();
-  // E.g. \ud801 becomes \ud801(?![\udc00-\udfff]).
-  ZoneList<CharacterRange>* trail_surrogates =
-      new (zone) ZoneList<CharacterRange>(1, zone);
-  trail_surrogates->Add(
-      CharacterRange::Range(kTrailSurrogateStart, kTrailSurrogateEnd), zone);
-
-  RegExpNode* match =
-      compiler->read_backward()
-          // Reading backward. Assert that reading forward, there is no trail
-          // surrogate, and then backward match the lead surrogate.
-          ? NegativeLookaroundAgainstReadDirectionAndMatch(
-                compiler, trail_surrogates, lead_surrogates, on_success, true)
-          // Reading forward. Forwrad match the lead surrogate and assert that
-          // no
-          // trail surrogate follows.
-          : MatchAndNegativeLookaroundInReadDirection(
-                compiler, lead_surrogates, trail_surrogates, on_success, false);
-  result->AddAlternative(GuardedAlternative(match));
-}
-
-
-void AddLoneTrailSurrogates(RegExpCompiler* compiler, ChoiceNode* result,
-                            RegExpNode* on_success,
-                            UnicodeRangeSplitter* splitter) {
-  ZoneList<CharacterRange>* trail_surrogates = splitter->trail_surrogates();
-  if (trail_surrogates == nullptr) return;
-  Zone* zone = compiler->zone();
-  // E.g. \udc01 becomes (?<![\ud800-\udbff])\udc01
-  ZoneList<CharacterRange>* lead_surrogates =
-      new (zone) ZoneList<CharacterRange>(1, zone);
-  lead_surrogates->Add(
-      CharacterRange::Range(kLeadSurrogateStart, kLeadSurrogateEnd), zone);
-
-  RegExpNode* match =
-      compiler->read_backward()
-          // Reading backward. Backward match the trail surrogate and assert
-          // that no lead surrogate precedes it.
-          ? MatchAndNegativeLookaroundInReadDirection(
-                compiler, trail_surrogates, lead_surrogates, on_success, true)
-          // Reading forward. Assert that reading backward, there is no lead
-          // surrogate, and then forward match the trail surrogate.
-          : NegativeLookaroundAgainstReadDirectionAndMatch(
-                compiler, lead_surrogates, trail_surrogates, on_success, false);
-  result->AddAlternative(GuardedAlternative(match));
-}
-
-
 RegExpNode* RegExpCharacterClass::ToNode(RegExpCompiler* compiler,
                                          RegExpNode* on_success) {
-  set_.Canonicalize();
-  Zone* zone = compiler->zone();
-  ZoneList<CharacterRange>* ranges = this->ranges(zone);
-  if (compiler->unicode() && !compiler->one_byte()) {
-    if (is_negated()) {
-      ZoneList<CharacterRange>* negated =
-          new (zone) ZoneList<CharacterRange>(2, zone);
-      CharacterRange::Negate(ranges, negated, zone);
-      ranges = negated;
-    }
-    if (ranges->length() == 0) {
-      // No matches possible.
-      return new (zone) EndNode(EndNode::BACKTRACK, zone);
-    }
-    UnicodeRangeSplitter splitter(zone, ranges);
-    ChoiceNode* result = new (compiler->zone()) ChoiceNode(2, compiler->zone());
-    AddBmpCharacters(compiler, result, on_success, &splitter);
-    AddNonBmpSurrogatePairs(compiler, result, on_success, &splitter);
-    AddLoneLeadSurrogates(compiler, result, on_success, &splitter);
-    AddLoneTrailSurrogates(compiler, result, on_success, &splitter);
-    return result;
-  } else {
-    return new (zone) TextNode(this, compiler->read_backward(), on_success);
-  }
+  return new (compiler->zone())
+      TextNode(this, compiler->read_backward(), on_success);
 }
 
 
@@ -5626,47 +5338,6 @@
 }
 
 
-RegExpLookaround::Builder::Builder(bool is_positive, RegExpNode* on_success,
-                                   int stack_pointer_register,
-                                   int position_register,
-                                   int capture_register_count,
-                                   int capture_register_start)
-    : is_positive_(is_positive),
-      on_success_(on_success),
-      stack_pointer_register_(stack_pointer_register),
-      position_register_(position_register) {
-  if (is_positive_) {
-    on_match_success_ = ActionNode::PositiveSubmatchSuccess(
-        stack_pointer_register, position_register, capture_register_count,
-        capture_register_start, on_success_);
-  } else {
-    Zone* zone = on_success_->zone();
-    on_match_success_ = new (zone) NegativeSubmatchSuccess(
-        stack_pointer_register, position_register, capture_register_count,
-        capture_register_start, zone);
-  }
-}
-
-
-RegExpNode* RegExpLookaround::Builder::ForMatch(RegExpNode* match) {
-  if (is_positive_) {
-    return ActionNode::BeginSubmatch(stack_pointer_register_,
-                                     position_register_, match);
-  } else {
-    Zone* zone = on_success_->zone();
-    // We use a ChoiceNode to represent the negative lookaround. The first
-    // alternative is the negative match. On success, the end node backtracks.
-    // On failure, the second alternative is tried and leads to success.
-    // NegativeLookaheadChoiceNode is a special ChoiceNode that ignores the
-    // first exit when calculating quick checks.
-    ChoiceNode* choice_node = new (zone) NegativeLookaroundChoiceNode(
-        GuardedAlternative(match), GuardedAlternative(on_success_), zone);
-    return ActionNode::BeginSubmatch(stack_pointer_register_,
-                                     position_register_, choice_node);
-  }
-}
-
-
 RegExpNode* RegExpLookaround::ToNode(RegExpCompiler* compiler,
                                      RegExpNode* on_success) {
   int stack_pointer_register = compiler->AllocateRegister();
@@ -5681,10 +5352,35 @@
   RegExpNode* result;
   bool was_reading_backward = compiler->read_backward();
   compiler->set_read_backward(type() == LOOKBEHIND);
-  Builder builder(is_positive(), on_success, stack_pointer_register,
-                  position_register, register_count, register_start);
-  RegExpNode* match = body_->ToNode(compiler, builder.on_match_success());
-  result = builder.ForMatch(match);
+  if (is_positive()) {
+    result = ActionNode::BeginSubmatch(
+        stack_pointer_register, position_register,
+        body()->ToNode(compiler,
+                       ActionNode::PositiveSubmatchSuccess(
+                           stack_pointer_register, position_register,
+                           register_count, register_start, on_success)));
+  } else {
+    // We use a ChoiceNode for a negative lookahead because it has most of
+    // the characteristics we need.  It has the body of the lookahead as its
+    // first alternative and the expression after the lookahead of the second
+    // alternative.  If the first alternative succeeds then the
+    // NegativeSubmatchSuccess will unwind the stack including everything the
+    // choice node set up and backtrack.  If the first alternative fails then
+    // the second alternative is tried, which is exactly the desired result
+    // for a negative lookahead.  The NegativeLookaheadChoiceNode is a special
+    // ChoiceNode that knows to ignore the first exit when calculating quick
+    // checks.
+    Zone* zone = compiler->zone();
+
+    GuardedAlternative body_alt(
+        body()->ToNode(compiler, new (zone) NegativeSubmatchSuccess(
+                                     stack_pointer_register, position_register,
+                                     register_count, register_start, zone)));
+    ChoiceNode* choice_node = new (zone) NegativeLookaroundChoiceNode(
+        body_alt, GuardedAlternative(on_success), zone);
+    result = ActionNode::BeginSubmatch(stack_pointer_register,
+                                       position_register, choice_node);
+  }
   compiler->set_read_backward(was_reading_backward);
   return result;
 }
@@ -5732,7 +5428,7 @@
                      ZoneList<CharacterRange>* ranges,
                      Zone* zone) {
   elmc--;
-  DCHECK(elmv[elmc] == kRangeEndMarker);
+  DCHECK(elmv[elmc] == 0x10000);
   for (int i = 0; i < elmc; i += 2) {
     DCHECK(elmv[i] < elmv[i + 1]);
     ranges->Add(CharacterRange(elmv[i], elmv[i + 1] - 1), zone);
@@ -5745,9 +5441,9 @@
                             ZoneList<CharacterRange>* ranges,
                             Zone* zone) {
   elmc--;
-  DCHECK(elmv[elmc] == kRangeEndMarker);
+  DCHECK(elmv[elmc] == 0x10000);
   DCHECK(elmv[0] != 0x0000);
-  DCHECK(elmv[elmc - 1] != String::kMaxCodePoint);
+  DCHECK(elmv[elmc-1] != String::kMaxUtf16CodeUnit);
   uc16 last = 0x0000;
   for (int i = 0; i < elmc; i += 2) {
     DCHECK(last <= elmv[i] - 1);
@@ -5755,7 +5451,7 @@
     ranges->Add(CharacterRange(last, elmv[i] - 1), zone);
     last = elmv[i + 1];
   }
-  ranges->Add(CharacterRange(last, String::kMaxCodePoint), zone);
+  ranges->Add(CharacterRange(last, String::kMaxUtf16CodeUnit), zone);
 }
 
 
@@ -5812,13 +5508,60 @@
 }
 
 
+class CharacterRangeSplitter {
+ public:
+  CharacterRangeSplitter(ZoneList<CharacterRange>** included,
+                         ZoneList<CharacterRange>** excluded,
+                         Zone* zone)
+      : included_(included),
+        excluded_(excluded),
+        zone_(zone) { }
+  void Call(uc16 from, DispatchTable::Entry entry);
+
+  static const int kInBase = 0;
+  static const int kInOverlay = 1;
+
+ private:
+  ZoneList<CharacterRange>** included_;
+  ZoneList<CharacterRange>** excluded_;
+  Zone* zone_;
+};
+
+
+void CharacterRangeSplitter::Call(uc16 from, DispatchTable::Entry entry) {
+  if (!entry.out_set()->Get(kInBase)) return;
+  ZoneList<CharacterRange>** target = entry.out_set()->Get(kInOverlay)
+    ? included_
+    : excluded_;
+  if (*target == NULL) *target = new(zone_) ZoneList<CharacterRange>(2, zone_);
+  (*target)->Add(CharacterRange(entry.from(), entry.to()), zone_);
+}
+
+
+void CharacterRange::Split(ZoneList<CharacterRange>* base,
+                           Vector<const int> overlay,
+                           ZoneList<CharacterRange>** included,
+                           ZoneList<CharacterRange>** excluded,
+                           Zone* zone) {
+  DCHECK_NULL(*included);
+  DCHECK_NULL(*excluded);
+  DispatchTable table(zone);
+  for (int i = 0; i < base->length(); i++)
+    table.AddRange(base->at(i), CharacterRangeSplitter::kInBase, zone);
+  for (int i = 0; i < overlay.length(); i += 2) {
+    table.AddRange(CharacterRange(overlay[i], overlay[i + 1] - 1),
+                   CharacterRangeSplitter::kInOverlay, zone);
+  }
+  CharacterRangeSplitter callback(included, excluded, zone);
+  table.ForEach(&callback);
+}
+
+
 void CharacterRange::AddCaseEquivalents(Isolate* isolate, Zone* zone,
                                         ZoneList<CharacterRange>* ranges,
                                         bool is_one_byte) {
-  uc32 bottom = from();
-  uc32 top = to();
-  // Nothing to be done for surrogates.
-  if (bottom >= kLeadSurrogateStart && top <= kTrailSurrogateEnd) return;
+  uc16 bottom = from();
+  uc16 top = to();
   if (is_one_byte && !RangeContainsLatin1Equivalents(*this)) {
     if (bottom > String::kMaxOneByteCharCode) return;
     if (top > String::kMaxOneByteCharCode) top = String::kMaxOneByteCharCode;
@@ -5856,7 +5599,7 @@
     int pos = bottom;
     while (pos <= top) {
       int length = isolate->jsregexp_canonrange()->get(pos, '\0', range);
-      uc32 block_end;
+      uc16 block_end;
       if (length == 0) {
         block_end = pos;
       } else {
@@ -5867,8 +5610,8 @@
       length = isolate->jsregexp_uncanonicalize()->get(block_end, '\0', range);
       for (int i = 0; i < length; i++) {
         uc32 c = range[i];
-        uc32 range_from = c - (block_end - pos);
-        uc32 range_to = c - (block_end - end);
+        uc16 range_from = c - (block_end - pos);
+        uc16 range_to = c - (block_end - end);
         if (!(bottom <= range_from && range_to <= top)) {
           ranges->Add(CharacterRange(range_from, range_to), zone);
         }
@@ -5929,8 +5672,8 @@
   // list[0..count] for the result. Returns the number of resulting
   // canonicalized ranges. Inserting a range may collapse existing ranges into
   // fewer ranges, so the return value can be anything in the range 1..count+1.
-  uc32 from = insert.from();
-  uc32 to = insert.to();
+  uc16 from = insert.from();
+  uc16 to = insert.to();
   int start_pos = 0;
   int end_pos = count;
   for (int i = count - 1; i >= 0; i--) {
@@ -6030,7 +5773,7 @@
   DCHECK(CharacterRange::IsCanonical(ranges));
   DCHECK_EQ(0, negated_ranges->length());
   int range_count = ranges->length();
-  uc32 from = 0;
+  uc16 from = 0;
   int i = 0;
   if (range_count > 0 && ranges->at(0).from() == 0) {
     from = ranges->at(0).to();
@@ -6042,8 +5785,9 @@
     from = range.to();
     i++;
   }
-  if (from < String::kMaxCodePoint) {
-    negated_ranges->Add(CharacterRange(from + 1, String::kMaxCodePoint), zone);
+  if (from < String::kMaxUtf16CodeUnit) {
+    negated_ranges->Add(CharacterRange(from + 1, String::kMaxUtf16CodeUnit),
+                        zone);
   }
 }
 
@@ -6094,7 +5838,7 @@
 }
 
 
-const uc32 DispatchTable::Config::kNoKey = unibrow::Utf8::kBadChar;
+const uc16 DispatchTable::Config::kNoKey = unibrow::Utf8::kBadChar;
 
 
 void DispatchTable::AddRange(CharacterRange full_range, int value,
@@ -6196,7 +5940,7 @@
 }
 
 
-OutSet* DispatchTable::Get(uc32 value) {
+OutSet* DispatchTable::Get(uc16 value) {
   ZoneSplayTree<Config>::Locator loc;
   if (!tree()->FindGreatestLessThan(value, &loc))
     return empty();
@@ -6514,16 +6258,13 @@
 
 
 RegExpEngine::CompilationResult RegExpEngine::Compile(
-    Isolate* isolate, Zone* zone, RegExpCompileData* data,
-    JSRegExp::Flags flags, Handle<String> pattern,
+    Isolate* isolate, Zone* zone, RegExpCompileData* data, bool ignore_case,
+    bool is_global, bool is_multiline, bool is_sticky, Handle<String> pattern,
     Handle<String> sample_subject, bool is_one_byte) {
   if ((data->capture_count + 1) * 2 - 1 > RegExpMacroAssembler::kMaxRegister) {
     return IrregexpRegExpTooBig(isolate);
   }
-  bool ignore_case = flags & JSRegExp::kIgnoreCase;
-  bool is_sticky = flags & JSRegExp::kSticky;
-  bool is_global = flags & JSRegExp::kGlobal;
-  RegExpCompiler compiler(isolate, zone, data->capture_count, flags,
+  RegExpCompiler compiler(isolate, zone, data->capture_count, ignore_case,
                           is_one_byte);
 
   if (compiler.optimize()) compiler.set_optimize(!TooMuchRegExpCode(pattern));