Move V8 to external/v8

Change-Id: If68025d67453785a651c5dfb34fad298c16676a4

1 files changed, 1283 insertions, 0 deletions

diff --git a/src/jsregexp.h b/src/jsregexp.h
new file mode 100644
index 00000000..3bc30b6a
--- /dev/null
+++ b/src/jsregexp.h
@@ -0,0 +1,1283 @@
+// Copyright 2006-2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_JSREGEXP_H_
+#define V8_JSREGEXP_H_
+
+namespace v8 {
+namespace internal {
+
+
+class RegExpMacroAssembler;
+
+
+class RegExpImpl {
+ public:
+  // Whether V8 is compiled with native regexp support or not.
+  static bool UsesNativeRegExp() {
+#ifdef V8_NATIVE_REGEXP
+    return true;
+#else
+    return false;
+#endif
+  }
+
+  // Creates a regular expression literal in the old space.
+  // This function calls the garbage collector if necessary.
+  static Handle<Object> CreateRegExpLiteral(Handle<JSFunction> constructor,
+                                            Handle<String> pattern,
+                                            Handle<String> flags,
+                                            bool* has_pending_exception);
+
+  // Returns a string representation of a regular expression.
+  // Implements RegExp.prototype.toString, see ECMA-262 section 15.10.6.4.
+  // This function calls the garbage collector if necessary.
+  static Handle<String> ToString(Handle<Object> value);
+
+  // Parses the RegExp pattern and prepares the JSRegExp object with
+  // generic data and choice of implementation - as well as what
+  // the implementation wants to store in the data field.
+  // Returns false if compilation fails.
+  static Handle<Object> Compile(Handle<JSRegExp> re,
+                                Handle<String> pattern,
+                                Handle<String> flags);
+
+  // See ECMA-262 section 15.10.6.2.
+  // This function calls the garbage collector if necessary.
+  static Handle<Object> Exec(Handle<JSRegExp> regexp,
+                             Handle<String> subject,
+                             int index,
+                             Handle<JSArray> lastMatchInfo);
+
+  // Call RegExp.prototyp.exec(string) in a loop.
+  // Used by String.prototype.match and String.prototype.replace.
+  // This function calls the garbage collector if necessary.
+  static Handle<Object> ExecGlobal(Handle<JSRegExp> regexp,
+                                   Handle<String> subject,
+                                   Handle<JSArray> lastMatchInfo);
+
+  // Prepares a JSRegExp object with Irregexp-specific data.
+  static void IrregexpPrepare(Handle<JSRegExp> re,
+                              Handle<String> pattern,
+                              JSRegExp::Flags flags,
+                              int capture_register_count);
+
+
+  static void AtomCompile(Handle<JSRegExp> re,
+                          Handle<String> pattern,
+                          JSRegExp::Flags flags,
+                          Handle<String> match_pattern);
+
+  static Handle<Object> AtomExec(Handle<JSRegExp> regexp,
+                                 Handle<String> subject,
+                                 int index,
+                                 Handle<JSArray> lastMatchInfo);
+
+  // Execute an Irregexp bytecode pattern.
+  // On a successful match, the result is a JSArray containing
+  // captured positions. On a failure, the result is the null value.
+  // Returns an empty handle in case of an exception.
+  static Handle<Object> IrregexpExec(Handle<JSRegExp> regexp,
+                                     Handle<String> subject,
+                                     int index,
+                                     Handle<JSArray> lastMatchInfo);
+
+  // Offsets in the lastMatchInfo array.
+  static const int kLastCaptureCount = 0;
+  static const int kLastSubject = 1;
+  static const int kLastInput = 2;
+  static const int kFirstCapture = 3;
+  static const int kLastMatchOverhead = 3;
+
+  // Used to access the lastMatchInfo array.
+  static int GetCapture(FixedArray* array, int index) {
+    return Smi::cast(array->get(index + kFirstCapture))->value();
+  }
+
+  static void SetLastCaptureCount(FixedArray* array, int to) {
+    array->set(kLastCaptureCount, Smi::FromInt(to));
+  }
+
+  static void SetLastSubject(FixedArray* array, String* to) {
+    array->set(kLastSubject, to);
+  }
+
+  static void SetLastInput(FixedArray* array, String* to) {
+    array->set(kLastInput, to);
+  }
+
+  static void SetCapture(FixedArray* array, int index, int to) {
+    array->set(index + kFirstCapture, Smi::FromInt(to));
+  }
+
+  static int GetLastCaptureCount(FixedArray* array) {
+    return Smi::cast(array->get(kLastCaptureCount))->value();
+  }
+
+  // For acting on the JSRegExp data FixedArray.
+  static int IrregexpMaxRegisterCount(FixedArray* re);
+  static void SetIrregexpMaxRegisterCount(FixedArray* re, int value);
+  static int IrregexpNumberOfCaptures(FixedArray* re);
+  static int IrregexpNumberOfRegisters(FixedArray* re);
+  static ByteArray* IrregexpByteCode(FixedArray* re, bool is_ascii);
+  static Code* IrregexpNativeCode(FixedArray* re, bool is_ascii);
+
+ private:
+  static String* last_ascii_string_;
+  static String* two_byte_cached_string_;
+
+  static bool CompileIrregexp(Handle<JSRegExp> re, bool is_ascii);
+  static inline bool EnsureCompiledIrregexp(Handle<JSRegExp> re, bool is_ascii);
+
+
+  // Set the subject cache.  The previous string buffer is not deleted, so the
+  // caller should ensure that it doesn't leak.
+  static void SetSubjectCache(String* subject,
+                              char* utf8_subject,
+                              int uft8_length,
+                              int character_position,
+                              int utf8_position);
+
+  // A one element cache of the last utf8_subject string and its length.  The
+  // subject JS String object is cached in the heap.  We also cache a
+  // translation between position and utf8 position.
+  static char* utf8_subject_cache_;
+  static int utf8_length_cache_;
+  static int utf8_position_;
+  static int character_position_;
+};
+
+
+class CharacterRange {
+ public:
+  CharacterRange() : from_(0), to_(0) { }
+  // For compatibility with the CHECK_OK macro
+  CharacterRange(void* null) { ASSERT_EQ(NULL, null); }  //NOLINT
+  CharacterRange(uc16 from, uc16 to) : from_(from), to_(to) { }
+  static void AddClassEscape(uc16 type, ZoneList<CharacterRange>* ranges);
+  static Vector<const uc16> GetWordBounds();
+  static inline CharacterRange Singleton(uc16 value) {
+    return CharacterRange(value, value);
+  }
+  static inline CharacterRange Range(uc16 from, uc16 to) {
+    ASSERT(from <= to);
+    return CharacterRange(from, to);
+  }
+  static inline CharacterRange Everything() {
+    return CharacterRange(0, 0xFFFF);
+  }
+  bool Contains(uc16 i) { return from_ <= i && i <= to_; }
+  uc16 from() const { return from_; }
+  void set_from(uc16 value) { from_ = value; }
+  uc16 to() const { return to_; }
+  void set_to(uc16 value) { to_ = value; }
+  bool is_valid() { return from_ <= to_; }
+  bool IsEverything(uc16 max) { return from_ == 0 && to_ >= max; }
+  bool IsSingleton() { return (from_ == to_); }
+  void AddCaseEquivalents(ZoneList<CharacterRange>* ranges);
+  static void Split(ZoneList<CharacterRange>* base,
+                    Vector<const uc16> overlay,
+                    ZoneList<CharacterRange>** included,
+                    ZoneList<CharacterRange>** excluded);
+
+  static const int kRangeCanonicalizeMax = 0x346;
+  static const int kStartMarker = (1 << 24);
+  static const int kPayloadMask = (1 << 24) - 1;
+
+ private:
+  uc16 from_;
+  uc16 to_;
+};
+
+
+// A set of unsigned integers that behaves especially well on small
+// integers (< 32).  May do zone-allocation.
+class OutSet: public ZoneObject {
+ public:
+  OutSet() : first_(0), remaining_(NULL), successors_(NULL) { }
+  OutSet* Extend(unsigned value);
+  bool Get(unsigned value);
+  static const unsigned kFirstLimit = 32;
+
+ private:
+  // Destructively set a value in this set.  In most cases you want
+  // to use Extend instead to ensure that only one instance exists
+  // that contains the same values.
+  void Set(unsigned value);
+
+  // The successors are a list of sets that contain the same values
+  // as this set and the one more value that is not present in this
+  // set.
+  ZoneList<OutSet*>* successors() { return successors_; }
+
+  OutSet(uint32_t first, ZoneList<unsigned>* remaining)
+      : first_(first), remaining_(remaining), successors_(NULL) { }
+  uint32_t first_;
+  ZoneList<unsigned>* remaining_;
+  ZoneList<OutSet*>* successors_;
+  friend class Trace;
+};
+
+
+// A mapping from integers, specified as ranges, to a set of integers.
+// Used for mapping character ranges to choices.
+class DispatchTable : public ZoneObject {
+ public:
+  class Entry {
+   public:
+    Entry() : from_(0), to_(0), out_set_(NULL) { }
+    Entry(uc16 from, uc16 to, OutSet* out_set)
+        : from_(from), to_(to), out_set_(out_set) { }
+    uc16 from() { return from_; }
+    uc16 to() { return to_; }
+    void set_to(uc16 value) { to_ = value; }
+    void AddValue(int value) { out_set_ = out_set_->Extend(value); }
+    OutSet* out_set() { return out_set_; }
+   private:
+    uc16 from_;
+    uc16 to_;
+    OutSet* out_set_;
+  };
+
+  class Config {
+   public:
+    typedef uc16 Key;
+    typedef Entry Value;
+    static const uc16 kNoKey;
+    static const Entry kNoValue;
+    static inline int Compare(uc16 a, uc16 b) {
+      if (a == b)
+        return 0;
+      else if (a < b)
+        return -1;
+      else
+        return 1;
+    }
+  };
+
+  void AddRange(CharacterRange range, int value);
+  OutSet* Get(uc16 value);
+  void Dump();
+
+  template <typename Callback>
+  void ForEach(Callback* callback) { return tree()->ForEach(callback); }
+ private:
+  // There can't be a static empty set since it allocates its
+  // successors in a zone and caches them.
+  OutSet* empty() { return &empty_; }
+  OutSet empty_;
+  ZoneSplayTree<Config>* tree() { return &tree_; }
+  ZoneSplayTree<Config> tree_;
+};
+
+
+#define FOR_EACH_NODE_TYPE(VISIT)                                    \
+  VISIT(End)                                                         \
+  VISIT(Action)                                                      \
+  VISIT(Choice)                                                      \
+  VISIT(BackReference)                                               \
+  VISIT(Assertion)                                                   \
+  VISIT(Text)
+
+
+#define FOR_EACH_REG_EXP_TREE_TYPE(VISIT)                            \
+  VISIT(Disjunction)                                                 \
+  VISIT(Alternative)                                                 \
+  VISIT(Assertion)                                                   \
+  VISIT(CharacterClass)                                              \
+  VISIT(Atom)                                                        \
+  VISIT(Quantifier)                                                  \
+  VISIT(Capture)                                                     \
+  VISIT(Lookahead)                                                   \
+  VISIT(BackReference)                                               \
+  VISIT(Empty)                                                       \
+  VISIT(Text)
+
+
+#define FORWARD_DECLARE(Name) class RegExp##Name;
+FOR_EACH_REG_EXP_TREE_TYPE(FORWARD_DECLARE)
+#undef FORWARD_DECLARE
+
+
+class TextElement {
+ public:
+  enum Type {UNINITIALIZED, ATOM, CHAR_CLASS};
+  TextElement() : type(UNINITIALIZED) { }
+  explicit TextElement(Type t) : type(t), cp_offset(-1) { }
+  static TextElement Atom(RegExpAtom* atom);
+  static TextElement CharClass(RegExpCharacterClass* char_class);
+  int length();
+  Type type;
+  union {
+    RegExpAtom* u_atom;
+    RegExpCharacterClass* u_char_class;
+  } data;
+  int cp_offset;
+};
+
+
+class Trace;
+
+
+struct NodeInfo {
+  NodeInfo()
+      : being_analyzed(false),
+        been_analyzed(false),
+        follows_word_interest(false),
+        follows_newline_interest(false),
+        follows_start_interest(false),
+        at_end(false),
+        visited(false) { }
+
+  // Returns true if the interests and assumptions of this node
+  // matches the given one.
+  bool Matches(NodeInfo* that) {
+    return (at_end == that->at_end) &&
+           (follows_word_interest == that->follows_word_interest) &&
+           (follows_newline_interest == that->follows_newline_interest) &&
+           (follows_start_interest == that->follows_start_interest);
+  }
+
+  // Updates the interests of this node given the interests of the
+  // node preceding it.
+  void AddFromPreceding(NodeInfo* that) {
+    at_end |= that->at_end;
+    follows_word_interest |= that->follows_word_interest;
+    follows_newline_interest |= that->follows_newline_interest;
+    follows_start_interest |= that->follows_start_interest;
+  }
+
+  bool HasLookbehind() {
+    return follows_word_interest ||
+           follows_newline_interest ||
+           follows_start_interest;
+  }
+
+  // Sets the interests of this node to include the interests of the
+  // following node.
+  void AddFromFollowing(NodeInfo* that) {
+    follows_word_interest |= that->follows_word_interest;
+    follows_newline_interest |= that->follows_newline_interest;
+    follows_start_interest |= that->follows_start_interest;
+  }
+
+  void ResetCompilationState() {
+    being_analyzed = false;
+    been_analyzed = false;
+  }
+
+  bool being_analyzed: 1;
+  bool been_analyzed: 1;
+
+  // These bits are set of this node has to know what the preceding
+  // character was.
+  bool follows_word_interest: 1;
+  bool follows_newline_interest: 1;
+  bool follows_start_interest: 1;
+
+  bool at_end: 1;
+  bool visited: 1;
+};
+
+
+class SiblingList {
+ public:
+  SiblingList() : list_(NULL) { }
+  int length() {
+    return list_ == NULL ? 0 : list_->length();
+  }
+  void Ensure(RegExpNode* parent) {
+    if (list_ == NULL) {
+      list_ = new ZoneList<RegExpNode*>(2);
+      list_->Add(parent);
+    }
+  }
+  void Add(RegExpNode* node) { list_->Add(node); }
+  RegExpNode* Get(int index) { return list_->at(index); }
+ private:
+  ZoneList<RegExpNode*>* list_;
+};
+
+
+// Details of a quick mask-compare check that can look ahead in the
+// input stream.
+class QuickCheckDetails {
+ public:
+  QuickCheckDetails()
+      : characters_(0),
+        mask_(0),
+        value_(0),
+        cannot_match_(false) { }
+  explicit QuickCheckDetails(int characters)
+      : characters_(characters),
+        mask_(0),
+        value_(0),
+        cannot_match_(false) { }
+  bool Rationalize(bool ascii);
+  // Merge in the information from another branch of an alternation.
+  void Merge(QuickCheckDetails* other, int from_index);
+  // Advance the current position by some amount.
+  void Advance(int by, bool ascii);
+  void Clear();
+  bool cannot_match() { return cannot_match_; }
+  void set_cannot_match() { cannot_match_ = true; }
+  struct Position {
+    Position() : mask(0), value(0), determines_perfectly(false) { }
+    uc16 mask;
+    uc16 value;
+    bool determines_perfectly;
+  };
+  int characters() { return characters_; }
+  void set_characters(int characters) { characters_ = characters; }
+  Position* positions(int index) {
+    ASSERT(index >= 0);
+    ASSERT(index < characters_);
+    return positions_ + index;
+  }
+  uint32_t mask() { return mask_; }
+  uint32_t value() { return value_; }
+
+ private:
+  // How many characters do we have quick check information from.  This is
+  // the same for all branches of a choice node.
+  int characters_;
+  Position positions_[4];
+  // These values are the condensate of the above array after Rationalize().
+  uint32_t mask_;
+  uint32_t value_;
+  // If set to true, there is no way this quick check can match at all.
+  // E.g., if it requires to be at the start of the input, and isn't.
+  bool cannot_match_;
+};
+
+
+class RegExpNode: public ZoneObject {
+ public:
+  RegExpNode() : trace_count_(0) { }
+  virtual ~RegExpNode();
+  virtual void Accept(NodeVisitor* visitor) = 0;
+  // Generates a goto to this node or actually generates the code at this point.
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace) = 0;
+  // How many characters must this node consume at a minimum in order to
+  // succeed.  If we have found at least 'still_to_find' characters that
+  // must be consumed there is no need to ask any following nodes whether
+  // they are sure to eat any more characters.
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth) = 0;
+  // Emits some quick code that checks whether the preloaded characters match.
+  // Falls through on certain failure, jumps to the label on possible success.
+  // If the node cannot make a quick check it does nothing and returns false.
+  bool EmitQuickCheck(RegExpCompiler* compiler,
+                      Trace* trace,
+                      bool preload_has_checked_bounds,
+                      Label* on_possible_success,
+                      QuickCheckDetails* details_return,
+                      bool fall_through_on_failure);
+  // For a given number of characters this returns a mask and a value.  The
+  // next n characters are anded with the mask and compared with the value.
+  // A comparison failure indicates the node cannot match the next n characters.
+  // A comparison success indicates the node may match.
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int characters_filled_in,
+                                    bool not_at_start) = 0;
+  static const int kNodeIsTooComplexForGreedyLoops = -1;
+  virtual int GreedyLoopTextLength() { return kNodeIsTooComplexForGreedyLoops; }
+  Label* label() { return &label_; }
+  // If non-generic code is generated for a node (ie the node is not at the
+  // start of the trace) then it cannot be reused.  This variable sets a limit
+  // on how often we allow that to happen before we insist on starting a new
+  // trace and generating generic code for a node that can be reused by flushing
+  // the deferred actions in the current trace and generating a goto.
+  static const int kMaxCopiesCodeGenerated = 10;
+
+  NodeInfo* info() { return &info_; }
+
+  void AddSibling(RegExpNode* node) { siblings_.Add(node); }
+
+  // Static version of EnsureSibling that expresses the fact that the
+  // result has the same type as the input.
+  template <class C>
+  static C* EnsureSibling(C* node, NodeInfo* info, bool* cloned) {
+    return static_cast<C*>(node->EnsureSibling(info, cloned));
+  }
+
+  SiblingList* siblings() { return &siblings_; }
+  void set_siblings(SiblingList* other) { siblings_ = *other; }
+
+ protected:
+  enum LimitResult { DONE, CONTINUE };
+  LimitResult LimitVersions(RegExpCompiler* compiler, Trace* trace);
+
+  // Returns a sibling of this node whose interests and assumptions
+  // match the ones in the given node info.  If no sibling exists NULL
+  // is returned.
+  RegExpNode* TryGetSibling(NodeInfo* info);
+
+  // Returns a sibling of this node whose interests match the ones in
+  // the given node info.  The info must not contain any assertions.
+  // If no node exists a new one will be created by cloning the current
+  // node.  The result will always be an instance of the same concrete
+  // class as this node.
+  RegExpNode* EnsureSibling(NodeInfo* info, bool* cloned);
+
+  // Returns a clone of this node initialized using the copy constructor
+  // of its concrete class.  Note that the node may have to be pre-
+  // processed before it is on a usable state.
+  virtual RegExpNode* Clone() = 0;
+
+ private:
+  Label label_;
+  NodeInfo info_;
+  SiblingList siblings_;
+  // This variable keeps track of how many times code has been generated for
+  // this node (in different traces).  We don't keep track of where the
+  // generated code is located unless the code is generated at the start of
+  // a trace, in which case it is generic and can be reused by flushing the
+  // deferred operations in the current trace and generating a goto.
+  int trace_count_;
+};
+
+
+// A simple closed interval.
+class Interval {
+ public:
+  Interval() : from_(kNone), to_(kNone) { }
+  Interval(int from, int to) : from_(from), to_(to) { }
+  Interval Union(Interval that) {
+    if (that.from_ == kNone)
+      return *this;
+    else if (from_ == kNone)
+      return that;
+    else
+      return Interval(Min(from_, that.from_), Max(to_, that.to_));
+  }
+  bool Contains(int value) {
+    return (from_ <= value) && (value <= to_);
+  }
+  bool is_empty() { return from_ == kNone; }
+  int from() { return from_; }
+  int to() { return to_; }
+  static Interval Empty() { return Interval(); }
+  static const int kNone = -1;
+ private:
+  int from_;
+  int to_;
+};
+
+
+class SeqRegExpNode: public RegExpNode {
+ public:
+  explicit SeqRegExpNode(RegExpNode* on_success)
+      : on_success_(on_success) { }
+  RegExpNode* on_success() { return on_success_; }
+  void set_on_success(RegExpNode* node) { on_success_ = node; }
+ private:
+  RegExpNode* on_success_;
+};
+
+
+class ActionNode: public SeqRegExpNode {
+ public:
+  enum Type {
+    SET_REGISTER,
+    INCREMENT_REGISTER,
+    STORE_POSITION,
+    BEGIN_SUBMATCH,
+    POSITIVE_SUBMATCH_SUCCESS,
+    EMPTY_MATCH_CHECK,
+    CLEAR_CAPTURES
+  };
+  static ActionNode* SetRegister(int reg, int val, RegExpNode* on_success);
+  static ActionNode* IncrementRegister(int reg, RegExpNode* on_success);
+  static ActionNode* StorePosition(int reg,
+                                   bool is_capture,
+                                   RegExpNode* on_success);
+  static ActionNode* ClearCaptures(Interval range, RegExpNode* on_success);
+  static ActionNode* BeginSubmatch(int stack_pointer_reg,
+                                   int position_reg,
+                                   RegExpNode* on_success);
+  static ActionNode* PositiveSubmatchSuccess(int stack_pointer_reg,
+                                             int restore_reg,
+                                             int clear_capture_count,
+                                             int clear_capture_from,
+                                             RegExpNode* on_success);
+  static ActionNode* EmptyMatchCheck(int start_register,
+                                     int repetition_register,
+                                     int repetition_limit,
+                                     RegExpNode* on_success);
+  virtual void Accept(NodeVisitor* visitor);
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth);
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int filled_in,
+                                    bool not_at_start) {
+    return on_success()->GetQuickCheckDetails(
+        details, compiler, filled_in, not_at_start);
+  }
+  Type type() { return type_; }
+  // TODO(erikcorry): We should allow some action nodes in greedy loops.
+  virtual int GreedyLoopTextLength() { return kNodeIsTooComplexForGreedyLoops; }
+  virtual ActionNode* Clone() { return new ActionNode(*this); }
+
+ private:
+  union {
+    struct {
+      int reg;
+      int value;
+    } u_store_register;
+    struct {
+      int reg;
+    } u_increment_register;
+    struct {
+      int reg;
+      bool is_capture;
+    } u_position_register;
+    struct {
+      int stack_pointer_register;
+      int current_position_register;
+      int clear_register_count;
+      int clear_register_from;
+    } u_submatch;
+    struct {
+      int start_register;
+      int repetition_register;
+      int repetition_limit;
+    } u_empty_match_check;
+    struct {
+      int range_from;
+      int range_to;
+    } u_clear_captures;
+  } data_;
+  ActionNode(Type type, RegExpNode* on_success)
+      : SeqRegExpNode(on_success),
+        type_(type) { }
+  Type type_;
+  friend class DotPrinter;
+};
+
+
+class TextNode: public SeqRegExpNode {
+ public:
+  TextNode(ZoneList<TextElement>* elms,
+           RegExpNode* on_success)
+      : SeqRegExpNode(on_success),
+        elms_(elms) { }
+  TextNode(RegExpCharacterClass* that,
+           RegExpNode* on_success)
+      : SeqRegExpNode(on_success),
+        elms_(new ZoneList<TextElement>(1)) {
+    elms_->Add(TextElement::CharClass(that));
+  }
+  virtual void Accept(NodeVisitor* visitor);
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth);
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int characters_filled_in,
+                                    bool not_at_start);
+  ZoneList<TextElement>* elements() { return elms_; }
+  void MakeCaseIndependent();
+  virtual int GreedyLoopTextLength();
+  virtual TextNode* Clone() {
+    TextNode* result = new TextNode(*this);
+    result->CalculateOffsets();
+    return result;
+  }
+  void CalculateOffsets();
+
+ private:
+  enum TextEmitPassType {
+    NON_ASCII_MATCH,             // Check for characters that can't match.
+    SIMPLE_CHARACTER_MATCH,      // Case-dependent single character check.
+    NON_LETTER_CHARACTER_MATCH,  // Check characters that have no case equivs.
+    CASE_CHARACTER_MATCH,        // Case-independent single character check.
+    CHARACTER_CLASS_MATCH        // Character class.
+  };
+  static bool SkipPass(int pass, bool ignore_case);
+  static const int kFirstRealPass = SIMPLE_CHARACTER_MATCH;
+  static const int kLastPass = CHARACTER_CLASS_MATCH;
+  void TextEmitPass(RegExpCompiler* compiler,
+                    TextEmitPassType pass,
+                    bool preloaded,
+                    Trace* trace,
+                    bool first_element_checked,
+                    int* checked_up_to);
+  int Length();
+  ZoneList<TextElement>* elms_;
+};
+
+
+class AssertionNode: public SeqRegExpNode {
+ public:
+  enum AssertionNodeType {
+    AT_END,
+    AT_START,
+    AT_BOUNDARY,
+    AT_NON_BOUNDARY,
+    AFTER_NEWLINE
+  };
+  static AssertionNode* AtEnd(RegExpNode* on_success) {
+    return new AssertionNode(AT_END, on_success);
+  }
+  static AssertionNode* AtStart(RegExpNode* on_success) {
+    return new AssertionNode(AT_START, on_success);
+  }
+  static AssertionNode* AtBoundary(RegExpNode* on_success) {
+    return new AssertionNode(AT_BOUNDARY, on_success);
+  }
+  static AssertionNode* AtNonBoundary(RegExpNode* on_success) {
+    return new AssertionNode(AT_NON_BOUNDARY, on_success);
+  }
+  static AssertionNode* AfterNewline(RegExpNode* on_success) {
+    return new AssertionNode(AFTER_NEWLINE, on_success);
+  }
+  virtual void Accept(NodeVisitor* visitor);
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth);
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int filled_in,
+                                    bool not_at_start);
+  virtual AssertionNode* Clone() { return new AssertionNode(*this); }
+  AssertionNodeType type() { return type_; }
+ private:
+  AssertionNode(AssertionNodeType t, RegExpNode* on_success)
+      : SeqRegExpNode(on_success), type_(t) { }
+  AssertionNodeType type_;
+};
+
+
+class BackReferenceNode: public SeqRegExpNode {
+ public:
+  BackReferenceNode(int start_reg,
+                    int end_reg,
+                    RegExpNode* on_success)
+      : SeqRegExpNode(on_success),
+        start_reg_(start_reg),
+        end_reg_(end_reg) { }
+  virtual void Accept(NodeVisitor* visitor);
+  int start_register() { return start_reg_; }
+  int end_register() { return end_reg_; }
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth);
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int characters_filled_in,
+                                    bool not_at_start) {
+    return;
+  }
+  virtual BackReferenceNode* Clone() { return new BackReferenceNode(*this); }
+
+ private:
+  int start_reg_;
+  int end_reg_;
+};
+
+
+class EndNode: public RegExpNode {
+ public:
+  enum Action { ACCEPT, BACKTRACK, NEGATIVE_SUBMATCH_SUCCESS };
+  explicit EndNode(Action action) : action_(action) { }
+  virtual void Accept(NodeVisitor* visitor);
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth) { return 0; }
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int characters_filled_in,
+                                    bool not_at_start) {
+    // Returning 0 from EatsAtLeast should ensure we never get here.
+    UNREACHABLE();
+  }
+  virtual EndNode* Clone() { return new EndNode(*this); }
+
+ private:
+  Action action_;
+};
+
+
+class NegativeSubmatchSuccess: public EndNode {
+ public:
+  NegativeSubmatchSuccess(int stack_pointer_reg,
+                          int position_reg,
+                          int clear_capture_count,
+                          int clear_capture_start)
+      : EndNode(NEGATIVE_SUBMATCH_SUCCESS),
+        stack_pointer_register_(stack_pointer_reg),
+        current_position_register_(position_reg),
+        clear_capture_count_(clear_capture_count),
+        clear_capture_start_(clear_capture_start) { }
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+
+ private:
+  int stack_pointer_register_;
+  int current_position_register_;
+  int clear_capture_count_;
+  int clear_capture_start_;
+};
+
+
+class Guard: public ZoneObject {
+ public:
+  enum Relation { LT, GEQ };
+  Guard(int reg, Relation op, int value)
+      : reg_(reg),
+        op_(op),
+        value_(value) { }
+  int reg() { return reg_; }
+  Relation op() { return op_; }
+  int value() { return value_; }
+
+ private:
+  int reg_;
+  Relation op_;
+  int value_;
+};
+
+
+class GuardedAlternative {
+ public:
+  explicit GuardedAlternative(RegExpNode* node) : node_(node), guards_(NULL) { }
+  void AddGuard(Guard* guard);
+  RegExpNode* node() { return node_; }
+  void set_node(RegExpNode* node) { node_ = node; }
+  ZoneList<Guard*>* guards() { return guards_; }
+
+ private:
+  RegExpNode* node_;
+  ZoneList<Guard*>* guards_;
+};
+
+
+class AlternativeGeneration;
+
+
+class ChoiceNode: public RegExpNode {
+ public:
+  explicit ChoiceNode(int expected_size)
+      : alternatives_(new ZoneList<GuardedAlternative>(expected_size)),
+        table_(NULL),
+        not_at_start_(false),
+        being_calculated_(false) { }
+  virtual void Accept(NodeVisitor* visitor);
+  void AddAlternative(GuardedAlternative node) { alternatives()->Add(node); }
+  ZoneList<GuardedAlternative>* alternatives() { return alternatives_; }
+  DispatchTable* GetTable(bool ignore_case);
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth);
+  int EatsAtLeastHelper(int still_to_find,
+                        int recursion_depth,
+                        RegExpNode* ignore_this_node);
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int characters_filled_in,
+                                    bool not_at_start);
+  virtual ChoiceNode* Clone() { return new ChoiceNode(*this); }
+
+  bool being_calculated() { return being_calculated_; }
+  bool not_at_start() { return not_at_start_; }
+  void set_not_at_start() { not_at_start_ = true; }
+  void set_being_calculated(bool b) { being_calculated_ = b; }
+  virtual bool try_to_emit_quick_check_for_alternative(int i) { return true; }
+
+ protected:
+  int GreedyLoopTextLength(GuardedAlternative* alternative);
+  ZoneList<GuardedAlternative>* alternatives_;
+
+ private:
+  friend class DispatchTableConstructor;
+  friend class Analysis;
+  void GenerateGuard(RegExpMacroAssembler* macro_assembler,
+                     Guard* guard,
+                     Trace* trace);
+  int CalculatePreloadCharacters(RegExpCompiler* compiler);
+  void EmitOutOfLineContinuation(RegExpCompiler* compiler,
+                                 Trace* trace,
+                                 GuardedAlternative alternative,
+                                 AlternativeGeneration* alt_gen,
+                                 int preload_characters,
+                                 bool next_expects_preload);
+  DispatchTable* table_;
+  // If true, this node is never checked at the start of the input.
+  // Allows a new trace to start with at_start() set to false.
+  bool not_at_start_;
+  bool being_calculated_;
+};
+
+
+class NegativeLookaheadChoiceNode: public ChoiceNode {
+ public:
+  explicit NegativeLookaheadChoiceNode(GuardedAlternative this_must_fail,
+                                       GuardedAlternative then_do_this)
+      : ChoiceNode(2) {
+    AddAlternative(this_must_fail);
+    AddAlternative(then_do_this);
+  }
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth);
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int characters_filled_in,
+                                    bool not_at_start);
+  // For a negative lookahead we don't emit the quick check for the
+  // alternative that is expected to fail.  This is because quick check code
+  // starts by loading enough characters for the alternative that takes fewest
+  // characters, but on a negative lookahead the negative branch did not take
+  // part in that calculation (EatsAtLeast) so the assumptions don't hold.
+  virtual bool try_to_emit_quick_check_for_alternative(int i) { return i != 0; }
+};
+
+
+class LoopChoiceNode: public ChoiceNode {
+ public:
+  explicit LoopChoiceNode(bool body_can_be_zero_length)
+      : ChoiceNode(2),
+        loop_node_(NULL),
+        continue_node_(NULL),
+        body_can_be_zero_length_(body_can_be_zero_length) { }
+  void AddLoopAlternative(GuardedAlternative alt);
+  void AddContinueAlternative(GuardedAlternative alt);
+  virtual void Emit(RegExpCompiler* compiler, Trace* trace);
+  virtual int EatsAtLeast(int still_to_find, int recursion_depth);
+  virtual void GetQuickCheckDetails(QuickCheckDetails* details,
+                                    RegExpCompiler* compiler,
+                                    int characters_filled_in,
+                                    bool not_at_start);
+  virtual LoopChoiceNode* Clone() { return new LoopChoiceNode(*this); }
+  RegExpNode* loop_node() { return loop_node_; }
+  RegExpNode* continue_node() { return continue_node_; }
+  bool body_can_be_zero_length() { return body_can_be_zero_length_; }
+  virtual void Accept(NodeVisitor* visitor);
+
+ private:
+  // AddAlternative is made private for loop nodes because alternatives
+  // should not be added freely, we need to keep track of which node
+  // goes back to the node itself.
+  void AddAlternative(GuardedAlternative node) {
+    ChoiceNode::AddAlternative(node);
+  }
+
+  RegExpNode* loop_node_;
+  RegExpNode* continue_node_;
+  bool body_can_be_zero_length_;
+};
+
+
+// There are many ways to generate code for a node.  This class encapsulates
+// the current way we should be generating.  In other words it encapsulates
+// the current state of the code generator.  The effect of this is that we
+// generate code for paths that the matcher can take through the regular
+// expression.  A given node in the regexp can be code-generated several times
+// as it can be part of several traces.  For example for the regexp:
+// /foo(bar|ip)baz/ the code to match baz will be generated twice, once as part
+// of the foo-bar-baz trace and once as part of the foo-ip-baz trace.  The code
+// to match foo is generated only once (the traces have a common prefix).  The
+// code to store the capture is deferred and generated (twice) after the places
+// where baz has been matched.
+class Trace {
+ public:
+  // A value for a property that is either known to be true, know to be false,
+  // or not known.
+  enum TriBool {
+    UNKNOWN = -1, FALSE = 0, TRUE = 1
+  };
+
+  class DeferredAction {
+   public:
+    DeferredAction(ActionNode::Type type, int reg)
+        : type_(type), reg_(reg), next_(NULL) { }
+    DeferredAction* next() { return next_; }
+    bool Mentions(int reg);
+    int reg() { return reg_; }
+    ActionNode::Type type() { return type_; }
+   private:
+    ActionNode::Type type_;
+    int reg_;
+    DeferredAction* next_;
+    friend class Trace;
+  };
+
+  class DeferredCapture : public DeferredAction {
+   public:
+    DeferredCapture(int reg, bool is_capture, Trace* trace)
+        : DeferredAction(ActionNode::STORE_POSITION, reg),
+          cp_offset_(trace->cp_offset()),
+          is_capture_(is_capture) { }
+    int cp_offset() { return cp_offset_; }
+    bool is_capture() { return is_capture_; }
+   private:
+    int cp_offset_;
+    bool is_capture_;
+    void set_cp_offset(int cp_offset) { cp_offset_ = cp_offset; }
+  };
+
+  class DeferredSetRegister : public DeferredAction {
+   public:
+    DeferredSetRegister(int reg, int value)
+        : DeferredAction(ActionNode::SET_REGISTER, reg),
+          value_(value) { }
+    int value() { return value_; }
+   private:
+    int value_;
+  };
+
+  class DeferredClearCaptures : public DeferredAction {
+   public:
+    explicit DeferredClearCaptures(Interval range)
+        : DeferredAction(ActionNode::CLEAR_CAPTURES, -1),
+          range_(range) { }
+    Interval range() { return range_; }
+   private:
+    Interval range_;
+  };
+
+  class DeferredIncrementRegister : public DeferredAction {
+   public:
+    explicit DeferredIncrementRegister(int reg)
+        : DeferredAction(ActionNode::INCREMENT_REGISTER, reg) { }
+  };
+
+  Trace()
+      : cp_offset_(0),
+        actions_(NULL),
+        backtrack_(NULL),
+        stop_node_(NULL),
+        loop_label_(NULL),
+        characters_preloaded_(0),
+        bound_checked_up_to_(0),
+        flush_budget_(100),
+        at_start_(UNKNOWN) { }
+
+  // End the trace.  This involves flushing the deferred actions in the trace
+  // and pushing a backtrack location onto the backtrack stack.  Once this is
+  // done we can start a new trace or go to one that has already been
+  // generated.
+  void Flush(RegExpCompiler* compiler, RegExpNode* successor);
+  int cp_offset() { return cp_offset_; }
+  DeferredAction* actions() { return actions_; }
+  // A trivial trace is one that has no deferred actions or other state that
+  // affects the assumptions used when generating code.  There is no recorded
+  // backtrack location in a trivial trace, so with a trivial trace we will
+  // generate code that, on a failure to match, gets the backtrack location
+  // from the backtrack stack rather than using a direct jump instruction.  We
+  // always start code generation with a trivial trace and non-trivial traces
+  // are created as we emit code for nodes or add to the list of deferred
+  // actions in the trace.  The location of the code generated for a node using
+  // a trivial trace is recorded in a label in the node so that gotos can be
+  // generated to that code.
+  bool is_trivial() {
+    return backtrack_ == NULL &&
+           actions_ == NULL &&
+           cp_offset_ == 0 &&
+           characters_preloaded_ == 0 &&
+           bound_checked_up_to_ == 0 &&
+           quick_check_performed_.characters() == 0 &&
+           at_start_ == UNKNOWN;
+  }
+  TriBool at_start() { return at_start_; }
+  void set_at_start(bool at_start) { at_start_ = at_start ? TRUE : FALSE; }
+  Label* backtrack() { return backtrack_; }
+  Label* loop_label() { return loop_label_; }
+  RegExpNode* stop_node() { return stop_node_; }
+  int characters_preloaded() { return characters_preloaded_; }
+  int bound_checked_up_to() { return bound_checked_up_to_; }
+  int flush_budget() { return flush_budget_; }
+  QuickCheckDetails* quick_check_performed() { return &quick_check_performed_; }
+  bool mentions_reg(int reg);
+  // Returns true if a deferred position store exists to the specified
+  // register and stores the offset in the out-parameter.  Otherwise
+  // returns false.
+  bool GetStoredPosition(int reg, int* cp_offset);
+  // These set methods and AdvanceCurrentPositionInTrace should be used only on
+  // new traces - the intention is that traces are immutable after creation.
+  void add_action(DeferredAction* new_action) {
+    ASSERT(new_action->next_ == NULL);
+    new_action->next_ = actions_;
+    actions_ = new_action;
+  }
+  void set_backtrack(Label* backtrack) { backtrack_ = backtrack; }
+  void set_stop_node(RegExpNode* node) { stop_node_ = node; }
+  void set_loop_label(Label* label) { loop_label_ = label; }
+  void set_characters_preloaded(int cpre) { characters_preloaded_ = cpre; }
+  void set_bound_checked_up_to(int to) { bound_checked_up_to_ = to; }
+  void set_flush_budget(int to) { flush_budget_ = to; }
+  void set_quick_check_performed(QuickCheckDetails* d) {
+    quick_check_performed_ = *d;
+  }
+  void InvalidateCurrentCharacter();
+  void AdvanceCurrentPositionInTrace(int by, RegExpCompiler* compiler);
+ private:
+  int FindAffectedRegisters(OutSet* affected_registers);
+  void PerformDeferredActions(RegExpMacroAssembler* macro,
+                               int max_register,
+                               OutSet& affected_registers,
+                               OutSet* registers_to_pop,
+                               OutSet* registers_to_clear);
+  void RestoreAffectedRegisters(RegExpMacroAssembler* macro,
+                                int max_register,
+                                OutSet& registers_to_pop,
+                                OutSet& registers_to_clear);
+  int cp_offset_;
+  DeferredAction* actions_;
+  Label* backtrack_;
+  RegExpNode* stop_node_;
+  Label* loop_label_;
+  int characters_preloaded_;
+  int bound_checked_up_to_;
+  QuickCheckDetails quick_check_performed_;
+  int flush_budget_;
+  TriBool at_start_;
+};
+
+
+class NodeVisitor {
+ public:
+  virtual ~NodeVisitor() { }
+#define DECLARE_VISIT(Type)                                          \
+  virtual void Visit##Type(Type##Node* that) = 0;
+FOR_EACH_NODE_TYPE(DECLARE_VISIT)
+#undef DECLARE_VISIT
+  virtual void VisitLoopChoice(LoopChoiceNode* that) { VisitChoice(that); }
+};
+
+
+// Node visitor used to add the start set of the alternatives to the
+// dispatch table of a choice node.
+class DispatchTableConstructor: public NodeVisitor {
+ public:
+  DispatchTableConstructor(DispatchTable* table, bool ignore_case)
+      : table_(table),
+        choice_index_(-1),
+        ignore_case_(ignore_case) { }
+
+  void BuildTable(ChoiceNode* node);
+
+  void AddRange(CharacterRange range) {
+    table()->AddRange(range, choice_index_);
+  }
+
+  void AddInverse(ZoneList<CharacterRange>* ranges);
+
+#define DECLARE_VISIT(Type)                                          \
+  virtual void Visit##Type(Type##Node* that);
+FOR_EACH_NODE_TYPE(DECLARE_VISIT)
+#undef DECLARE_VISIT
+
+  DispatchTable* table() { return table_; }
+  void set_choice_index(int value) { choice_index_ = value; }
+
+ protected:
+  DispatchTable* table_;
+  int choice_index_;
+  bool ignore_case_;
+};
+
+
+// Assertion propagation moves information about assertions such as
+// \b to the affected nodes.  For instance, in /.\b./ information must
+// be propagated to the first '.' that whatever follows needs to know
+// if it matched a word or a non-word, and to the second '.' that it
+// has to check if it succeeds a word or non-word.  In this case the
+// result will be something like:
+//
+//   +-------+        +------------+
+//   |   .   |        |      .     |
+//   +-------+  --->  +------------+
+//   | word? |        | check word |
+//   +-------+        +------------+
+class Analysis: public NodeVisitor {
+ public:
+  explicit Analysis(bool ignore_case)
+      : ignore_case_(ignore_case), error_message_(NULL) { }
+  void EnsureAnalyzed(RegExpNode* node);
+
+#define DECLARE_VISIT(Type)                                          \
+  virtual void Visit##Type(Type##Node* that);
+FOR_EACH_NODE_TYPE(DECLARE_VISIT)
+#undef DECLARE_VISIT
+  virtual void VisitLoopChoice(LoopChoiceNode* that);
+
+  bool has_failed() { return error_message_ != NULL; }
+  const char* error_message() {
+    ASSERT(error_message_ != NULL);
+    return error_message_;
+  }
+  void fail(const char* error_message) {
+    error_message_ = error_message;
+  }
+ private:
+  bool ignore_case_;
+  const char* error_message_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Analysis);
+};
+
+
+struct RegExpCompileData {
+  RegExpCompileData()
+    : tree(NULL),
+      node(NULL),
+      simple(true),
+      contains_anchor(false),
+      capture_count(0) { }
+  RegExpTree* tree;
+  RegExpNode* node;
+  bool simple;
+  bool contains_anchor;
+  Handle<String> error;
+  int capture_count;
+};
+
+
+class RegExpEngine: public AllStatic {
+ public:
+  struct CompilationResult {
+    explicit CompilationResult(const char* error_message)
+        : error_message(error_message),
+          code(Heap::the_hole_value()),
+          num_registers(0) {}
+    CompilationResult(Object* code, int registers)
+      : error_message(NULL),
+        code(code),
+        num_registers(registers) {}
+    const char* error_message;
+    Object* code;
+    int num_registers;
+  };
+
+  static CompilationResult Compile(RegExpCompileData* input,
+                                   bool ignore_case,
+                                   bool multiline,
+                                   Handle<String> pattern,
+                                   bool is_ascii);
+
+  static void DotPrint(const char* label, RegExpNode* node, bool ignore_case);
+};
+
+
+} }  // namespace v8::internal
+
+#endif  // V8_JSREGEXP_H_