Periodic merge of bleeding_edge to experimental code generator branch....

src/jsregexp.cc

 // 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.
 
+#define _HAS_EXCEPTIONS 0
+#include <set>
+
 #include "v8.h"
 
+#include "ast.h"
 #include "execution.h"
 #include "factory.h"
-#include "jsregexp.h"
+#include "jsregexp-inl.h"
 #include "platform.h"
 #include "runtime.h"
 #include "top.h"
 #include "compilation-cache.h"
+#include "string-stream.h"
+#include "parser.h"
+#include "regexp-macro-assembler.h"
+#include "regexp-macro-assembler-tracer.h"
+#include "regexp-macro-assembler-irregexp.h"
+
+#ifdef ARM
+#include "regexp-macro-assembler-arm.h"
+#else  // IA32
+#include "macro-assembler-ia32.h"
+#include "regexp-macro-assembler-ia32.h"
+#endif
+
+#include "interpreter-irregexp.h"
 
 // Including pcre.h undefines DEBUG to avoid getting debug output from
 // the JSCRE implementation. Make sure to redefine it in debug mode
 // after having included the header file.
 #ifdef DEBUG
 #include "third_party/jscre/pcre.h"
 #define DEBUG
 #else
 #include "third_party/jscre/pcre.h"
 #endif
 
+
 namespace v8 { namespace internal {
 
 
-#define CAPTURE_INDEX 0
-#define INTERNAL_INDEX 1
-
 static Failure* malloc_failure;
 
 static void* JSREMalloc(size_t size) {
   Object* obj = Heap::AllocateByteArray(size);
 
   // If allocation failed, return a NULL pointer to JSRE, and jsRegExpCompile
   // will return NULL to the caller, performs GC there.
   // Also pass failure information to the caller.
   if (obj->IsFailure()) {
     malloc_failure = Failure::cast(obj);
@@ skipping 105 matching lines @@
         break;
       case 'm':
         flags |= JSRegExp::MULTILINE;
         break;
     }
   }
   return JSRegExp::Flags(flags);
 }
 
 
-unibrow::Predicate<unibrow::RegExpSpecialChar, 128> is_reg_exp_special_char;
+static inline void ThrowRegExpException(Handle<JSRegExp> re,
+                                        Handle<String> pattern,
+                                        Handle<String> error_text,
+                                        const char* message) {
+  Handle<JSArray> array = Factory::NewJSArray(2);
+  SetElement(array, 0, pattern);
+  SetElement(array, 1, error_text);
+  Handle<Object> regexp_err = Factory::NewSyntaxError(message, array);
+  Top::Throw(*regexp_err);
+}
 
 
 Handle<Object> RegExpImpl::Compile(Handle<JSRegExp> re,
                                    Handle<String> pattern,
                                    Handle<String> flag_str) {
   JSRegExp::Flags flags = RegExpFlagsFromString(flag_str);
   Handle<FixedArray> cached = CompilationCache::LookupRegExp(pattern, flags);
   bool in_cache = !cached.is_null();
   Handle<Object> result;
-  StringShape shape(*pattern);
   if (in_cache) {
     re->set_data(*cached);
     result = re;
   } else {
-    bool is_atom = !flags.is_ignore_case();
-    for (int i = 0; is_atom && i < pattern->length(shape); i++) {
-      if (is_reg_exp_special_char.get(pattern->Get(shape, i)))
-        is_atom = false;
+    FlattenString(pattern);
+    RegExpParseResult parse_result;
+    FlatStringReader reader(pattern);
+    if (!ParseRegExp(&reader, flags.is_multiline(), &parse_result)) {
+      // Throw an exception if we fail to parse the pattern.
+      ThrowRegExpException(re,
+                           pattern,
+                           parse_result.error,
+                           "malformed_regexp");
+      return Handle<Object>();
     }
-    if (is_atom) {
-      result = AtomCompile(re, pattern, flags);
+    RegExpAtom* atom = parse_result.tree->AsAtom();
+    if (atom != NULL && !flags.is_ignore_case()) {
+      if (parse_result.has_character_escapes) {
+        Vector<const uc16> atom_pattern = atom->data();
+        Handle<String> atom_string =
+            Factory::NewStringFromTwoByte(atom_pattern);
+        result = AtomCompile(re, pattern, flags, atom_string);
+      } else {
+        result = AtomCompile(re, pattern, flags, pattern);
+      }
     } else {
-      result = JsreCompile(re, pattern, flags);
+      RegExpNode* node = NULL;
+      Handle<FixedArray> irregexp_data =
+          RegExpEngine::Compile(&parse_result,
+                                &node,
+                                flags.is_ignore_case(),
+                                flags.is_multiline());
+      if (irregexp_data.is_null()) {
+        if (FLAG_disable_jscre) {
+          UNIMPLEMENTED();
+        }
+        result = JscrePrepare(re, pattern, flags);
+      } else {
+        result = IrregexpPrepare(re, pattern, flags, irregexp_data);
+      }
     }
     Object* data = re->data();
     if (data->IsFixedArray()) {
       // If compilation succeeded then the data is set on the regexp
       // and we can store it in the cache.
       Handle<FixedArray> data(FixedArray::cast(re->data()));
       CompilationCache::PutRegExp(pattern, flags, data);
     }
   }
 
   LOG(RegExpCompileEvent(re, in_cache));
   return result;
 }
 
 
 Handle<Object> RegExpImpl::Exec(Handle<JSRegExp> regexp,
                                 Handle<String> subject,
                                 Handle<Object> index) {
   switch (regexp->TypeTag()) {
     case JSRegExp::JSCRE:
-      return JsreExec(regexp, subject, index);
+      if (FLAG_disable_jscre) {
+        UNIMPLEMENTED();
+      }
+      return JscreExec(regexp, subject, index);
     case JSRegExp::ATOM:
       return AtomExec(regexp, subject, index);
+    case JSRegExp::IRREGEXP:
+      return IrregexpExec(regexp, subject, index);
     default:
       UNREACHABLE();
       return Handle<Object>();
   }
 }
 
 
 Handle<Object> RegExpImpl::ExecGlobal(Handle<JSRegExp> regexp,
                                 Handle<String> subject) {
   switch (regexp->TypeTag()) {
     case JSRegExp::JSCRE:
-      return JsreExecGlobal(regexp, subject);
+      if (FLAG_disable_jscre) {
+        UNIMPLEMENTED();
+      }
+      return JscreExecGlobal(regexp, subject);
     case JSRegExp::ATOM:
       return AtomExecGlobal(regexp, subject);
+    case JSRegExp::IRREGEXP:
+      return IrregexpExecGlobal(regexp, subject);
     default:
       UNREACHABLE();
       return Handle<Object>();
   }
 }
 
 
 Handle<Object> RegExpImpl::AtomCompile(Handle<JSRegExp> re,
                                        Handle<String> pattern,
-                                       JSRegExp::Flags flags) {
-  Factory::SetRegExpData(re, JSRegExp::ATOM, pattern, flags, pattern);
+                                       JSRegExp::Flags flags,
+                                       Handle<String> match_pattern) {
+  Factory::SetRegExpData(re, JSRegExp::ATOM, pattern, flags, match_pattern);
   return re;
 }
 
 
 Handle<Object> RegExpImpl::AtomExec(Handle<JSRegExp> re,
                                     Handle<String> subject,
                                     Handle<Object> index) {
   Handle<String> needle(String::cast(re->DataAt(JSRegExp::kAtomPatternIndex)));
 
   uint32_t start_index;
   if (!Array::IndexFromObject(*index, &start_index)) {
     return Handle<Smi>(Smi::FromInt(-1));
   }
 
   LOG(RegExpExecEvent(re, start_index, subject));
   int value = Runtime::StringMatch(subject, needle, start_index);
   if (value == -1) return Factory::null_value();
 
   Handle<FixedArray> array = Factory::NewFixedArray(2);
-  array->set(0,
-             Smi::FromInt(value),
-             SKIP_WRITE_BARRIER);
-  array->set(1,
-             Smi::FromInt(value + needle->length()),
-             SKIP_WRITE_BARRIER);
+  array->set(0, Smi::FromInt(value));
+  array->set(1, Smi::FromInt(value + needle->length()));
   return Factory::NewJSArrayWithElements(array);
 }
 
 
 Handle<Object> RegExpImpl::AtomExecGlobal(Handle<JSRegExp> re,
                                           Handle<String> subject) {
   Handle<String> needle(String::cast(re->DataAt(JSRegExp::kAtomPatternIndex)));
   Handle<JSArray> result = Factory::NewJSArray(1);
   int index = 0;
   int match_count = 0;
   int subject_length = subject->length();
   int needle_length = needle->length();
   while (true) {
     LOG(RegExpExecEvent(re, index, subject));
     int value = -1;
     if (index + needle_length <= subject_length) {
       value = Runtime::StringMatch(subject, needle, index);
     }
     if (value == -1) break;
     HandleScope scope;
     int end = value + needle_length;
 
     Handle<FixedArray> array = Factory::NewFixedArray(2);
-    array->set(0,
-               Smi::FromInt(value),
-               SKIP_WRITE_BARRIER);
-    array->set(1,
-               Smi::FromInt(end),
-               SKIP_WRITE_BARRIER);
+    array->set(0, Smi::FromInt(value));
+    array->set(1, Smi::FromInt(end));
     Handle<JSArray> pair = Factory::NewJSArrayWithElements(array);
     SetElement(result, match_count, pair);
     match_count++;
     index = end;
     if (needle_length == 0) index++;
   }
   return result;
 }
 
 
+Handle<Object>RegExpImpl::JscrePrepare(Handle<JSRegExp> re,
+                                       Handle<String> pattern,
+                                       JSRegExp::Flags flags) {
+  Handle<Object> value(Heap::undefined_value());
+  Factory::SetRegExpData(re, JSRegExp::JSCRE, pattern, flags, value);
+  return re;
+}
+
+
+Handle<Object>RegExpImpl::IrregexpPrepare(Handle<JSRegExp> re,
+                                          Handle<String> pattern,
+                                          JSRegExp::Flags flags,
+                                          Handle<FixedArray> irregexp_data) {
+  Factory::SetRegExpData(re, JSRegExp::IRREGEXP, pattern, flags, irregexp_data);
+  return re;
+}
+
+
 static inline Object* DoCompile(String* pattern,
                                 JSRegExp::Flags flags,
                                 unsigned* number_of_captures,
                                 const char** error_message,
-                                JscreRegExp** code) {
-  JSRegExpIgnoreCaseOption case_option = flags.is_ignore_case()
-    ? JSRegExpIgnoreCase
-    : JSRegExpDoNotIgnoreCase;
-  JSRegExpMultilineOption multiline_option = flags.is_multiline()
-    ? JSRegExpMultiline
-    : JSRegExpSingleLine;
+                                v8::jscre::JscreRegExp** code) {
+  v8::jscre::JSRegExpIgnoreCaseOption case_option = flags.is_ignore_case()
+    ? v8::jscre::JSRegExpIgnoreCase
+    : v8::jscre::JSRegExpDoNotIgnoreCase;
+  v8::jscre::JSRegExpMultilineOption multiline_option = flags.is_multiline()
+    ? v8::jscre::JSRegExpMultiline
+    : v8::jscre::JSRegExpSingleLine;
   *error_message = NULL;
   malloc_failure = Failure::Exception();
-  *code = jsRegExpCompile(pattern->GetTwoByteData(),
-                          pattern->length(),
-                          case_option,
-                          multiline_option,
-                          number_of_captures,
-                          error_message,
-                          &JSREMalloc,
-                          &JSREFree);
+  *code = v8::jscre::jsRegExpCompile(pattern->GetTwoByteData(),
+                                     pattern->length(),
+                                     case_option,
+                                     multiline_option,
+                                     number_of_captures,
+                                     error_message,
+                                     &JSREMalloc,
+                                     &JSREFree);
   if (*code == NULL && (malloc_failure->IsRetryAfterGC() ||
                        malloc_failure->IsOutOfMemoryFailure())) {
     return malloc_failure;
   } else {
     // It doesn't matter which object we return here, we just need to return
     // a non-failure to indicate to the GC-retry code that there was no
     // allocation failure.
     return pattern;
   }
 }
 
 
 void CompileWithRetryAfterGC(Handle<String> pattern,
                              JSRegExp::Flags flags,
                              unsigned* number_of_captures,
                              const char** error_message,
-                             JscreRegExp** code) {
+                             v8::jscre::JscreRegExp** code) {
   CALL_HEAP_FUNCTION_VOID(DoCompile(*pattern,
                                     flags,
                                     number_of_captures,
                                     error_message,
                                     code));
 }
 
 
-Handle<Object> RegExpImpl::JsreCompile(Handle<JSRegExp> re,
-                                       Handle<String> pattern,
-                                       JSRegExp::Flags flags) {
+Handle<Object> RegExpImpl::JscreCompile(Handle<JSRegExp> re) {
+  ASSERT_EQ(re->TypeTag(), JSRegExp::JSCRE);
+  ASSERT(re->DataAt(JSRegExp::kJscreDataIndex)->IsUndefined());
+
+  Handle<String> pattern(re->Pattern());
+  JSRegExp::Flags flags = re->GetFlags();
+
   Handle<String> two_byte_pattern = StringToTwoByte(pattern);
 
   unsigned number_of_captures;
   const char* error_message = NULL;
 
-  JscreRegExp* code = NULL;
+  v8::jscre::JscreRegExp* code = NULL;
   FlattenString(pattern);
 
   CompileWithRetryAfterGC(two_byte_pattern,
                           flags,
                           &number_of_captures,
                           &error_message,
                           &code);
 
   if (code == NULL) {
     // Throw an exception.
     Handle<JSArray> array = Factory::NewJSArray(2);
     SetElement(array, 0, pattern);
     SetElement(array, 1, Factory::NewStringFromUtf8(CStrVector(
         (error_message == NULL) ? "Unknown regexp error" : error_message)));
     Handle<Object> regexp_err =
         Factory::NewSyntaxError("malformed_regexp", array);
     Top::Throw(*regexp_err);
     return Handle<Object>();
   }
 
   // Convert the return address to a ByteArray pointer.
   Handle<ByteArray> internal(
       ByteArray::FromDataStartAddress(reinterpret_cast<Address>(code)));
 
-  Handle<FixedArray> value = Factory::NewFixedArray(2);
-  value->set(CAPTURE_INDEX, Smi::FromInt(number_of_captures));
-  value->set(INTERNAL_INDEX, *internal);
+  Handle<FixedArray> value = Factory::NewFixedArray(kJscreDataLength);
+  value->set(kJscreNumberOfCapturesIndex, Smi::FromInt(number_of_captures));
+  value->set(kJscreInternalIndex, *internal);
   Factory::SetRegExpData(re, JSRegExp::JSCRE, pattern, flags, value);
 
   return re;
 }
 
 
-Handle<Object> RegExpImpl::JsreExecOnce(Handle<JSRegExp> regexp,
-                                        int num_captures,
-                                        Handle<String> subject,
-                                        int previous_index,
-                                        const uc16* two_byte_subject,
-                                        int* offsets_vector,
-                                        int offsets_vector_length) {
+Handle<Object> RegExpImpl::IrregexpExecOnce(Handle<JSRegExp> regexp,
+                                            int num_captures,
+                                            Handle<String> two_byte_subject,
+                                            int previous_index,
+                                            int* offsets_vector,
+                                            int offsets_vector_length) {
+#ifdef DEBUG
+  if (FLAG_trace_regexp_bytecodes) {
+    String* pattern = regexp->Pattern();
+    PrintF("\n\nRegexp match:   /%s/\n\n", *(pattern->ToCString()));
+    PrintF("\n\nSubject string: '%s'\n\n", *(two_byte_subject->ToCString()));
+  }
+#endif
+  ASSERT(StringShape(*two_byte_subject).IsTwoByteRepresentation());
+  ASSERT(two_byte_subject->IsFlat(StringShape(*two_byte_subject)));
+  bool rc;
+
+  for (int i = (num_captures + 1) * 2 - 1; i >= 0; i--) {
+    offsets_vector[i] = -1;
+  }
+
+  LOG(RegExpExecEvent(regexp, previous_index, two_byte_subject));
+
+  FixedArray* irregexp =
+      FixedArray::cast(regexp->DataAt(JSRegExp::kIrregexpDataIndex));
+  int tag = Smi::cast(irregexp->get(kIrregexpImplementationIndex))->value();
+
+  switch (tag) {
+    case RegExpMacroAssembler::kIA32Implementation: {
+      Code* code = Code::cast(irregexp->get(kIrregexpCodeIndex));
+      Address start_addr =
+          Handle<SeqTwoByteString>::cast(two_byte_subject)->GetCharsAddress();
+      int string_offset =
+          start_addr - reinterpret_cast<Address>(*two_byte_subject);
+      int start_offset = string_offset + previous_index * sizeof(uc16);
+      int end_offset =
+          string_offset + two_byte_subject->length() * sizeof(uc16);
+      typedef bool testfunc(String**, int, int, int*);
+      testfunc* test = FUNCTION_CAST<testfunc*>(code->entry());
+      rc = test(two_byte_subject.location(),
+                start_offset,
+                end_offset,
+                offsets_vector);
+      if (rc) {
+        // Capture values are relative to start_offset only.
+        for (int i = 0; i < offsets_vector_length; i++) {
+          if (offsets_vector[i] >= 0) {
+            offsets_vector[i] += previous_index;
+          }
+        }
+      }
+      break;
+    }
+    case RegExpMacroAssembler::kBytecodeImplementation: {
+      Handle<ByteArray> byte_codes = IrregexpCode(regexp);
+
+      rc = IrregexpInterpreter::Match(byte_codes,
+                                      two_byte_subject,
+                                      offsets_vector,
+                                      previous_index);
+      break;
+    }
+    case RegExpMacroAssembler::kARMImplementation:
+    default:
+      UNREACHABLE();
+      rc = false;
+      break;
+  }
+
+  if (!rc) {
+    return Factory::null_value();
+  }
+
+  Handle<FixedArray> array = Factory::NewFixedArray(2 * (num_captures+1));
+  // The captures come in (start, end+1) pairs.
+  for (int i = 0; i < 2 * (num_captures+1); i += 2) {
+    array->set(i, Smi::FromInt(offsets_vector[i]));
+    array->set(i+1, Smi::FromInt(offsets_vector[i+1]));
+  }
+  return Factory::NewJSArrayWithElements(array);
+}
+
+
+Handle<Object> RegExpImpl::JscreExecOnce(Handle<JSRegExp> regexp,
+                                         int num_captures,
+                                         Handle<String> subject,
+                                         int previous_index,
+                                         const uc16* two_byte_subject,
+                                         int* offsets_vector,
+                                         int offsets_vector_length) {
   int rc;
   {
     AssertNoAllocation a;
-    ByteArray* internal = JsreInternal(regexp);
-    const JscreRegExp* js_regexp =
-        reinterpret_cast<JscreRegExp*>(internal->GetDataStartAddress());
+    ByteArray* internal = JscreInternal(regexp);
+    const v8::jscre::JscreRegExp* js_regexp =
+        reinterpret_cast<v8::jscre::JscreRegExp*>(
+            internal->GetDataStartAddress());
 
     LOG(RegExpExecEvent(regexp, previous_index, subject));
 
-    rc = jsRegExpExecute(js_regexp,
-                         two_byte_subject,
-                         subject->length(),
-                         previous_index,
-                         offsets_vector,
-                         offsets_vector_length);
+    rc = v8::jscre::jsRegExpExecute(js_regexp,
+                                    two_byte_subject,
+                                    subject->length(),
+                                    previous_index,
+                                    offsets_vector,
+                                    offsets_vector_length);
   }
 
   // The KJS JavaScript engine returns null (ie, a failed match) when
   // JSRE's internal match limit is exceeded.  We duplicate that behavior here.
-  if (rc == JSRegExpErrorNoMatch
-      || rc == JSRegExpErrorHitLimit) {
+  if (rc == v8::jscre::JSRegExpErrorNoMatch
+      || rc == v8::jscre::JSRegExpErrorHitLimit) {
     return Factory::null_value();
   }
 
   // Other JSRE errors:
   if (rc < 0) {
     // Throw an exception.
     Handle<Object> code(Smi::FromInt(rc));
     Handle<Object> args[2] = { Factory::LookupAsciiSymbol("jsre_exec"), code };
     Handle<Object> regexp_err(
         Factory::NewTypeError("jsre_error", HandleVector(args, 2)));
     return Handle<Object>(Top::Throw(*regexp_err));
   }
 
   Handle<FixedArray> array = Factory::NewFixedArray(2 * (num_captures+1));
   // The captures come in (start, end+1) pairs.
   for (int i = 0; i < 2 * (num_captures+1); i += 2) {
-    array->set(i,
-               Smi::FromInt(offsets_vector[i]),
-               SKIP_WRITE_BARRIER);
-    array->set(i+1,
-               Smi::FromInt(offsets_vector[i+1]),
-               SKIP_WRITE_BARRIER);
+    array->set(i, Smi::FromInt(offsets_vector[i]));
+    array->set(i+1, Smi::FromInt(offsets_vector[i+1]));
   }
   return Factory::NewJSArrayWithElements(array);
 }
 
 
 class OffsetsVector {
  public:
-  inline OffsetsVector(int num_captures) {
-    offsets_vector_length_ = (num_captures + 1) * 3;
+  inline OffsetsVector(int num_registers)
+      : offsets_vector_length_(num_registers) {
     if (offsets_vector_length_ > kStaticOffsetsVectorSize) {
       vector_ = NewArray<int>(offsets_vector_length_);
     } else {
       vector_ = static_offsets_vector_;
     }
   }
 
 
   inline ~OffsetsVector() {
     if (offsets_vector_length_ > kStaticOffsetsVectorSize) {
       DeleteArray(vector_);
       vector_ = NULL;
     }
   }
 
 
   inline int* vector() {
     return vector_;
   }
 
 
   inline int length() {
     return offsets_vector_length_;
   }
 
  private:
   int* vector_;
   int offsets_vector_length_;
-  static const int kStaticOffsetsVectorSize = 30;
+  static const int kStaticOffsetsVectorSize = 50;
   static int static_offsets_vector_[kStaticOffsetsVectorSize];
 };
 
 
 int OffsetsVector::static_offsets_vector_[
     OffsetsVector::kStaticOffsetsVectorSize];
 
 
-Handle<Object> RegExpImpl::JsreExec(Handle<JSRegExp> regexp,
-                                    Handle<String> subject,
-                                    Handle<Object> index) {
+Handle<Object> RegExpImpl::IrregexpExec(Handle<JSRegExp> regexp,
+                                        Handle<String> subject,
+                                        Handle<Object> index) {
+  ASSERT_EQ(regexp->TypeTag(), JSRegExp::IRREGEXP);
+  ASSERT(!regexp->DataAt(JSRegExp::kIrregexpDataIndex)->IsUndefined());
+
   // Prepare space for the return values.
-  int num_captures = JsreCapture(regexp);
+  int number_of_registers = IrregexpNumberOfRegisters(regexp);
+  OffsetsVector offsets(number_of_registers);
 
-  OffsetsVector offsets(num_captures);
+  int num_captures = IrregexpNumberOfCaptures(regexp);
 
   int previous_index = static_cast<int>(DoubleToInteger(index->Number()));
 
   Handle<String> subject16 = CachedStringToTwoByte(subject);
 
-  Handle<Object> result(JsreExecOnce(regexp, num_captures, subject,
-                                     previous_index,
-                                     subject16->GetTwoByteData(),
-                                     offsets.vector(), offsets.length()));
+  Handle<Object> result(IrregexpExecOnce(regexp,
+                                         num_captures,
+                                         subject16,
+                                         previous_index,
+                                         offsets.vector(),
+                                         offsets.length()));
+  return result;
+}
+
+
+Handle<Object> RegExpImpl::JscreExec(Handle<JSRegExp> regexp,
+                                     Handle<String> subject,
+                                     Handle<Object> index) {
+  ASSERT_EQ(regexp->TypeTag(), JSRegExp::JSCRE);
+  if (regexp->DataAt(JSRegExp::kJscreDataIndex)->IsUndefined()) {
+    Handle<Object> compile_result = JscreCompile(regexp);
+    if (compile_result.is_null()) return compile_result;
+  }
+  ASSERT(regexp->DataAt(JSRegExp::kJscreDataIndex)->IsFixedArray());
+
+  int num_captures = JscreNumberOfCaptures(regexp);
+
+  OffsetsVector offsets((num_captures + 1) * 3);
+
+  int previous_index = static_cast<int>(DoubleToInteger(index->Number()));
+
+  Handle<String> subject16 = CachedStringToTwoByte(subject);
+
+  Handle<Object> result(JscreExecOnce(regexp,
+                                      num_captures,
+                                      subject,
+                                      previous_index,
+                                      subject16->GetTwoByteData(),
+                                      offsets.vector(),
+                                      offsets.length()));
 
   return result;
 }
 
 
-Handle<Object> RegExpImpl::JsreExecGlobal(Handle<JSRegExp> regexp,
-                                          Handle<String> subject) {
+Handle<Object> RegExpImpl::IrregexpExecGlobal(Handle<JSRegExp> regexp,
+                                              Handle<String> subject) {
+  ASSERT_EQ(regexp->TypeTag(), JSRegExp::IRREGEXP);
+  ASSERT(!regexp->DataAt(JSRegExp::kIrregexpDataIndex)->IsUndefined());
+
   // Prepare space for the return values.
-  int num_captures = JsreCapture(regexp);
-
-  OffsetsVector offsets(num_captures);
+  int number_of_registers = IrregexpNumberOfRegisters(regexp);
+  OffsetsVector offsets(number_of_registers);
 
   int previous_index = 0;
 
   Handle<JSArray> result = Factory::NewJSArray(0);
+  int i = 0;
+  Handle<Object> matches;
+
+  Handle<String> subject16 = CachedStringToTwoByte(subject);
+
+  do {
+    if (previous_index > subject->length() || previous_index < 0) {
+      // Per ECMA-262 15.10.6.2, if the previous index is greater than the
+      // string length, there is no match.
+      matches = Factory::null_value();
+    } else {
+      matches = IrregexpExecOnce(regexp,
+                                 IrregexpNumberOfCaptures(regexp),
+                                 subject16,
+                                 previous_index,
+                                 offsets.vector(),
+                                 offsets.length());
+
+      if (matches->IsJSArray()) {
+        SetElement(result, i, matches);
+        i++;
+        previous_index = offsets.vector()[1];
+        if (offsets.vector()[0] == offsets.vector()[1]) {
+          previous_index++;
+        }
+      }
+    }
+  } while (matches->IsJSArray());
+
+  // If we exited the loop with an exception, throw it.
+  if (matches->IsNull()) {
+    // Exited loop normally.
+    return result;
+  } else {
+    // Exited loop with the exception in matches.
+    return matches;
+  }
+}
+
+
+Handle<Object> RegExpImpl::JscreExecGlobal(Handle<JSRegExp> regexp,
+                                           Handle<String> subject) {
+  ASSERT_EQ(regexp->TypeTag(), JSRegExp::JSCRE);
+  if (regexp->DataAt(JSRegExp::kJscreDataIndex)->IsUndefined()) {
+    Handle<Object> compile_result = JscreCompile(regexp);
+    if (compile_result.is_null()) return compile_result;
+  }
+  ASSERT(regexp->DataAt(JSRegExp::kJscreDataIndex)->IsFixedArray());
+
+  // Prepare space for the return values.
+  int num_captures = JscreNumberOfCaptures(regexp);
+
+  OffsetsVector offsets((num_captures + 1) * 3);
+
+  int previous_index = 0;
+
+  Handle<JSArray> result = Factory::NewJSArray(0);
   int i = 0;
   Handle<Object> matches;
 
   Handle<String> subject16 = CachedStringToTwoByte(subject);
 
   do {
     if (previous_index > subject->length() || previous_index < 0) {
       // Per ECMA-262 15.10.6.2, if the previous index is greater than the
       // string length, there is no match.
       matches = Factory::null_value();
     } else {
-      matches = JsreExecOnce(regexp, num_captures, subject, previous_index,
-                             subject16->GetTwoByteData(),
-                             offsets.vector(), offsets.length());
+      matches = JscreExecOnce(regexp,
+                              num_captures,
+                              subject,
+                              previous_index,
+                              subject16->GetTwoByteData(),
+                              offsets.vector(),
+                              offsets.length());
 
       if (matches->IsJSArray()) {
         SetElement(result, i, matches);
         i++;
         previous_index = offsets.vector()[1];
         if (offsets.vector()[0] == offsets.vector()[1]) {
           previous_index++;
         }
       }
     }
   } while (matches->IsJSArray());
 
   // If we exited the loop with an exception, throw it.
-  if (matches->IsNull()) {  // Exited loop normally.
+  if (matches->IsNull()) {
+    // Exited loop normally.
     return result;
-  } else {  // Exited loop with the exception in matches.
+  } else {
+    // Exited loop with the exception in matches.
     return matches;
   }
 }
 
 
-int RegExpImpl::JsreCapture(Handle<JSRegExp> re) {
+int RegExpImpl::JscreNumberOfCaptures(Handle<JSRegExp> re) {
   FixedArray* value = FixedArray::cast(re->DataAt(JSRegExp::kJscreDataIndex));
-  return Smi::cast(value->get(CAPTURE_INDEX))->value();
-}
-
-
-ByteArray* RegExpImpl::JsreInternal(Handle<JSRegExp> re) {
+  return Smi::cast(value->get(kJscreNumberOfCapturesIndex))->value();
+}
+
+
+ByteArray* RegExpImpl::JscreInternal(Handle<JSRegExp> re) {
   FixedArray* value = FixedArray::cast(re->DataAt(JSRegExp::kJscreDataIndex));
-  return ByteArray::cast(value->get(INTERNAL_INDEX));
-}
+  return ByteArray::cast(value->get(kJscreInternalIndex));
+}
+
+
+int RegExpImpl::IrregexpNumberOfCaptures(Handle<JSRegExp> re) {
+  FixedArray* value =
+      FixedArray::cast(re->DataAt(JSRegExp::kIrregexpDataIndex));
+  return Smi::cast(value->get(kIrregexpNumberOfCapturesIndex))->value();
+}
+
+
+int RegExpImpl::IrregexpNumberOfRegisters(Handle<JSRegExp> re) {
+  FixedArray* value =
+      FixedArray::cast(re->DataAt(JSRegExp::kIrregexpDataIndex));
+  return Smi::cast(value->get(kIrregexpNumberOfRegistersIndex))->value();
+}
+
+
+Handle<ByteArray> RegExpImpl::IrregexpCode(Handle<JSRegExp> re) {
+  FixedArray* value =
+      FixedArray::cast(re->DataAt(JSRegExp::kIrregexpDataIndex));
+  return Handle<ByteArray>(ByteArray::cast(value->get(kIrregexpCodeIndex)));
+}
+
+
+// -------------------------------------------------------------------
+// Implmentation of the Irregexp regular expression engine.
+
+
+void RegExpTree::AppendToText(RegExpText* text) {
+  UNREACHABLE();
+}
+
+
+void RegExpAtom::AppendToText(RegExpText* text) {
+  text->AddElement(TextElement::Atom(this));
+}
+
+
+void RegExpCharacterClass::AppendToText(RegExpText* text) {
+  text->AddElement(TextElement::CharClass(this));
+}
+
+
+void RegExpText::AppendToText(RegExpText* text) {
+  for (int i = 0; i < elements()->length(); i++)
+    text->AddElement(elements()->at(i));
+}
+
+
+TextElement TextElement::Atom(RegExpAtom* atom) {
+  TextElement result = TextElement(ATOM);
+  result.data.u_atom = atom;
+  return result;
+}
+
+
+TextElement TextElement::CharClass(
+      RegExpCharacterClass* char_class) {
+  TextElement result = TextElement(CHAR_CLASS);
+  result.data.u_char_class = char_class;
+  return result;
+}
+
+
+class RegExpCompiler {
+ public:
+  RegExpCompiler(int capture_count, bool ignore_case);
+
+  int AllocateRegister() { return next_register_++; }
+
+  Handle<FixedArray> Assemble(RegExpMacroAssembler* assembler,
+                              RegExpNode* start,
+                              int capture_count);
+
+  inline void AddWork(RegExpNode* node) { work_list_->Add(node); }
+
+  static const int kImplementationOffset = 0;
+  static const int kNumberOfRegistersOffset = 0;
+  static const int kCodeOffset = 1;
+
+  RegExpMacroAssembler* macro_assembler() { return macro_assembler_; }
+  EndNode* accept() { return accept_; }
+  EndNode* backtrack() { return backtrack_; }
+
+  static const int kMaxRecursion = 100;
+  inline int recursion_depth() { return recursion_depth_; }
+  inline void IncrementRecursionDepth() { recursion_depth_++; }
+  inline void DecrementRecursionDepth() { recursion_depth_--; }
+
+  inline bool ignore_case() { return ignore_case_; }
+
+ private:
+  EndNode* accept_;
+  EndNode* backtrack_;
+  int next_register_;
+  List<RegExpNode*>* work_list_;
+  int recursion_depth_;
+  RegExpMacroAssembler* macro_assembler_;
+  bool ignore_case_;
+};
+
+
+// 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(int capture_count, bool ignore_case)
+    : next_register_(2 * (capture_count + 1)),
+      work_list_(NULL),
+      recursion_depth_(0),
+      ignore_case_(ignore_case) {
+  accept_ = new EndNode(EndNode::ACCEPT);
+  backtrack_ = new EndNode(EndNode::BACKTRACK);
+}
+
+
+Handle<FixedArray> RegExpCompiler::Assemble(
+    RegExpMacroAssembler* macro_assembler,
+    RegExpNode* start,
+    int capture_count) {
+#ifdef DEBUG
+  if (FLAG_trace_regexp_assembler)
+    macro_assembler_ = new RegExpMacroAssemblerTracer(macro_assembler);
+  else
+#endif
+    macro_assembler_ = macro_assembler;
+  List <RegExpNode*> work_list(0);
+  work_list_ = &work_list;
+  Label fail;
+  macro_assembler_->PushBacktrack(&fail);
+  if (!start->GoTo(this)) {
+    fail.Unuse();
+    return Handle<FixedArray>::null();
+  }
+  while (!work_list.is_empty()) {
+    if (!work_list.RemoveLast()->GoTo(this)) {
+      fail.Unuse();
+      return Handle<FixedArray>::null();
+    }
+  }
+  macro_assembler_->Bind(&fail);
+  macro_assembler_->Fail();
+  Handle<FixedArray> array =
+      Factory::NewFixedArray(RegExpImpl::kIrregexpDataLength);
+  array->set(RegExpImpl::kIrregexpImplementationIndex,
+             Smi::FromInt(macro_assembler_->Implementation()));
+  array->set(RegExpImpl::kIrregexpNumberOfRegistersIndex,
+             Smi::FromInt(next_register_));
+  array->set(RegExpImpl::kIrregexpNumberOfCapturesIndex,
+             Smi::FromInt(capture_count));
+  Handle<Object> code = macro_assembler_->GetCode();
+  array->set(RegExpImpl::kIrregexpCodeIndex, *code);
+  work_list_ = NULL;
+#ifdef DEBUG
+  if (FLAG_trace_regexp_assembler) {
+    delete macro_assembler_;
+  }
+#endif
+  return array;
+}
+
+
+bool RegExpNode::GoTo(RegExpCompiler* compiler) {
+  // TODO(erikcorry): Implement support.
+  if (info_.follows_word_interest ||
+      info_.follows_newline_interest ||
+      info_.follows_start_interest) {
+    return false;
+  }
+  if (label_.is_bound()) {
+    compiler->macro_assembler()->GoTo(&label_);
+    return true;
+  } else {
+    if (compiler->recursion_depth() > RegExpCompiler::kMaxRecursion) {
+      compiler->macro_assembler()->GoTo(&label_);
+      compiler->AddWork(this);
+      return true;
+    } else {
+      compiler->IncrementRecursionDepth();
+      bool how_it_went = Emit(compiler);
+      compiler->DecrementRecursionDepth();
+      return how_it_went;
+    }
+  }
+}
+
+
+// EndNodes are special.  Because they can be very common and they are very
+// short we normally inline them.  That is, if we are asked to emit a GoTo
+// we just emit the entire node.  Since they don't have successors this
+// works.
+bool EndNode::GoTo(RegExpCompiler* compiler) {
+  if (info()->follows_word_interest ||
+      info()->follows_newline_interest ||
+      info()->follows_start_interest) {
+    return false;
+  }
+  return Emit(compiler);
+}
+
+
+Label* RegExpNode::label() {
+  return &label_;
+}
+
+
+bool EndNode::Emit(RegExpCompiler* compiler) {
+  RegExpMacroAssembler* macro = compiler->macro_assembler();
+  switch (action_) {
+    case ACCEPT:
+      if (!label()->is_bound()) Bind(macro);
+      if (info()->at_end) {
+        Label succeed;
+        // LoadCurrentCharacter will go to the label if we are at the end of the
+        // input string.
+        macro->LoadCurrentCharacter(0, &succeed);
+        macro->Backtrack();
+        macro->Bind(&succeed);
+      }
+      macro->Succeed();
+      return true;
+    case BACKTRACK:
+      if (!label()->is_bound()) Bind(macro);
+      ASSERT(!info()->at_end);
+      macro->Backtrack();
+      return true;
+  }
+  return false;
+}
+
+
+void GuardedAlternative::AddGuard(Guard* guard) {
+  if (guards_ == NULL)
+    guards_ = new ZoneList<Guard*>(1);
+  guards_->Add(guard);
+}
+
+
+ActionNode* ActionNode::StoreRegister(int reg,
+                                      int val,
+                                      RegExpNode* on_success) {
+  ActionNode* result = new ActionNode(STORE_REGISTER, on_success);
+  result->data_.u_store_register.reg = reg;
+  result->data_.u_store_register.value = val;
+  return result;
+}
+
+
+ActionNode* ActionNode::IncrementRegister(int reg, RegExpNode* on_success) {
+  ActionNode* result = new ActionNode(INCREMENT_REGISTER, on_success);
+  result->data_.u_increment_register.reg = reg;
+  return result;
+}
+
+
+ActionNode* ActionNode::StorePosition(int reg, RegExpNode* on_success) {
+  ActionNode* result = new ActionNode(STORE_POSITION, on_success);
+  result->data_.u_position_register.reg = reg;
+  return result;
+}
+
+
+ActionNode* ActionNode::RestorePosition(int reg, RegExpNode* on_success) {
+  ActionNode* result = new ActionNode(RESTORE_POSITION, on_success);
+  result->data_.u_position_register.reg = reg;
+  return result;
+}
+
+
+ActionNode* ActionNode::BeginSubmatch(int stack_reg,
+                                      int position_reg,
+                                      RegExpNode* on_success) {
+  ActionNode* result = new ActionNode(BEGIN_SUBMATCH, on_success);
+  result->data_.u_submatch.stack_pointer_register = stack_reg;
+  result->data_.u_submatch.current_position_register = position_reg;
+  return result;
+}
+
+
+ActionNode* ActionNode::EscapeSubmatch(int stack_reg,
+                                       bool restore_position,
+                                       int position_reg,
+                                       RegExpNode* on_success) {
+  ActionNode* result = new ActionNode(ESCAPE_SUBMATCH, on_success);
+  result->data_.u_submatch.stack_pointer_register = stack_reg;
+  if (restore_position) {
+    result->data_.u_submatch.current_position_register = position_reg;
+  } else {
+    result->data_.u_submatch.current_position_register = -1;
+  }
+  return result;
+}
+
+
+#define DEFINE_ACCEPT(Type)                                          \
+  void Type##Node::Accept(NodeVisitor* visitor) {                    \
+    visitor->Visit##Type(this);                                      \
+  }
+FOR_EACH_NODE_TYPE(DEFINE_ACCEPT)
+#undef DEFINE_ACCEPT
+
+
+// -------------------------------------------------------------------
+// Emit code.
+
+
+void ChoiceNode::GenerateGuard(RegExpMacroAssembler* macro_assembler,
+                               Guard* guard,
+                               Label* on_failure) {
+  switch (guard->op()) {
+    case Guard::LT:
+      macro_assembler->IfRegisterGE(guard->reg(), guard->value(), on_failure);
+      break;
+    case Guard::GEQ:
+      macro_assembler->IfRegisterLT(guard->reg(), guard->value(), on_failure);
+      break;
+  }
+}
+
+
+static unibrow::Mapping<unibrow::Ecma262UnCanonicalize> uncanonicalize;
+static unibrow::Mapping<unibrow::CanonicalizationRange> canonrange;
+
+
+static inline void EmitAtomNonLetters(
+    RegExpMacroAssembler* macro_assembler,
+    TextElement elm,
+    Vector<const uc16> quarks,
+    Label* on_failure,
+    int cp_offset) {
+  unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
+  for (int i = quarks.length() - 1; i >= 0; i--) {
+    uc16 c = quarks[i];
+    int length = uncanonicalize.get(c, '\0', chars);
+    if (length <= 1) {
+      macro_assembler->LoadCurrentCharacter(cp_offset + i, on_failure);
+      macro_assembler->CheckNotCharacter(c, on_failure);
+    }
+  }
+}
+
+
+static bool ShortCutEmitCharacterPair(RegExpMacroAssembler* macro_assembler,
+                                      uc16 c1,
+                                      uc16 c2,
+                                      Label* on_failure) {
+  uc16 exor = c1 ^ c2;
+  // Check whether exor has only one bit set.
+  if (((exor - 1) & exor) == 0) {
+    // If c1 and c2 differ only by one bit.
+    // Ecma262UnCanonicalize always gives the highest number last.
+    ASSERT(c2 > c1);
+    macro_assembler->CheckNotCharacterAfterOr(c2, exor, on_failure);
+    return true;
+  }
+  ASSERT(c2 > c1);
+  uc16 diff = c2 - c1;
+  if (((diff - 1) & diff) == 0 && c1 >= diff) {
+    // If the characters differ by 2^n but don't differ by one bit then
+    // subtract the difference from the found character, then do the or
+    // trick.  We avoid the theoretical case where negative numbers are
+    // involved in order to simplify code generation.
+    macro_assembler->CheckNotCharacterAfterMinusOr(c2 - diff,
+                                                   diff,
+                                                   on_failure);
+    return true;
+  }
+  return false;
+}
+
+
+static inline void EmitAtomLetters(
+    RegExpMacroAssembler* macro_assembler,
+    TextElement elm,
+    Vector<const uc16> quarks,
+    Label* on_failure,
+    int cp_offset) {
+  unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
+  for (int i = quarks.length() - 1; i >= 0; i--) {
+    uc16 c = quarks[i];
+    int length = uncanonicalize.get(c, '\0', chars);
+    if (length <= 1) continue;
+    macro_assembler->LoadCurrentCharacter(cp_offset + i, on_failure);
+    Label ok;
+    ASSERT(unibrow::Ecma262UnCanonicalize::kMaxWidth == 4);
+    switch (length) {
+      case 2: {
+        if (ShortCutEmitCharacterPair(macro_assembler,
+                                      chars[0],
+                                      chars[1],
+                                      on_failure)) {
+          ok.Unuse();
+        } else {
+          macro_assembler->CheckCharacter(chars[0], &ok);
+          macro_assembler->CheckNotCharacter(chars[1], on_failure);
+          macro_assembler->Bind(&ok);
+        }
+        break;
+      }
+      case 4:
+        macro_assembler->CheckCharacter(chars[3], &ok);
+        // Fall through!
+      case 3:
+        macro_assembler->CheckCharacter(chars[0], &ok);
+        macro_assembler->CheckCharacter(chars[1], &ok);
+        macro_assembler->CheckNotCharacter(chars[2], on_failure);
+        macro_assembler->Bind(&ok);
+        break;
+      default:
+        UNREACHABLE();
+        break;
+    }
+  }
+}
+
+
+static void EmitCharClass(RegExpMacroAssembler* macro_assembler,
+                          RegExpCharacterClass* cc,
+                          int cp_offset,
+                          Label* on_failure) {
+  macro_assembler->LoadCurrentCharacter(cp_offset, on_failure);
+  cp_offset++;
+
+  ZoneList<CharacterRange>* ranges = cc->ranges();
+
+  Label success;
+
+  Label* char_is_in_class =
+      cc->is_negated() ? on_failure : &success;
+
+  int range_count = ranges->length();
+
+  if (range_count == 0) {
+    if (!cc->is_negated()) {
+      macro_assembler->GoTo(on_failure);
+    }
+    return;
+  }
+
+  for (int i = 0; i < range_count - 1; i++) {
+    CharacterRange& range = ranges->at(i);
+    Label next_range;
+    uc16 from = range.from();
+    uc16 to = range.to();
+    if (to == from) {
+      macro_assembler->CheckCharacter(to, char_is_in_class);
+    } else {
+      if (from != 0) {
+        macro_assembler->CheckCharacterLT(from, &next_range);
+      }
+      if (to != 0xffff) {
+        macro_assembler->CheckCharacterLT(to + 1, char_is_in_class);
+      } else {
+        macro_assembler->GoTo(char_is_in_class);
+      }
+    }
+    macro_assembler->Bind(&next_range);
+  }
+
+  CharacterRange& range = ranges->at(range_count - 1);
+  uc16 from = range.from();
+  uc16 to = range.to();
+
+  if (to == from) {
+    if (cc->is_negated()) {
+      macro_assembler->CheckCharacter(to, on_failure);
+    } else {
+      macro_assembler->CheckNotCharacter(to, on_failure);
+    }
+  } else {
+    if (from != 0) {
+      if (cc->is_negated()) {
+        macro_assembler->CheckCharacterLT(from, &success);
+      } else {
+        macro_assembler->CheckCharacterLT(from, on_failure);
+      }
+    }
+    if (to != 0xffff) {
+      if (cc->is_negated()) {
+        macro_assembler->CheckCharacterLT(to + 1, on_failure);
+      } else {
+        macro_assembler->CheckCharacterGT(to, on_failure);
+      }
+    } else {
+      if (cc->is_negated()) {
+        macro_assembler->GoTo(on_failure);
+      }
+    }
+  }
+  macro_assembler->Bind(&success);
+}
+
+
+
+bool TextNode::Emit(RegExpCompiler* compiler) {
+  RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+  Bind(macro_assembler);
+  int element_count = elms_->length();
+  ASSERT(element_count != 0);
+  int cp_offset = 0;
+  if (info()->at_end) {
+    macro_assembler->Backtrack();
+    return true;
+  }
+  // First, handle straight character matches.
+  for (int i = 0; i < element_count; i++) {
+    TextElement elm = elms_->at(i);
+    if (elm.type == TextElement::ATOM) {
+      Vector<const uc16> quarks = elm.data.u_atom->data();
+      if (compiler->ignore_case()) {
+        EmitAtomNonLetters(macro_assembler,
+                           elm,
+                           quarks,
+                           on_failure_->label(),
+                           cp_offset);
+      } else {
+        macro_assembler->CheckCharacters(quarks,
+                                         cp_offset,
+                                         on_failure_->label());
+      }
+      cp_offset += quarks.length();
+    } else {
+      ASSERT_EQ(elm.type, TextElement::CHAR_CLASS);
+      cp_offset++;
+    }
+  }
+  // Second, handle case independent letter matches if any.
+  if (compiler->ignore_case()) {
+    cp_offset = 0;
+    for (int i = 0; i < element_count; i++) {
+      TextElement elm = elms_->at(i);
+      if (elm.type == TextElement::ATOM) {
+        Vector<const uc16> quarks = elm.data.u_atom->data();
+        EmitAtomLetters(macro_assembler,
+                        elm,
+                        quarks,
+                        on_failure_->label(),
+                        cp_offset);
+        cp_offset += quarks.length();
+      } else {
+        cp_offset++;
+      }
+    }
+  }
+  // If the fast character matches passed then do the character classes.
+  cp_offset = 0;
+  for (int i = 0; i < element_count; i++) {
+    TextElement elm = elms_->at(i);
+    if (elm.type == TextElement::CHAR_CLASS) {
+      RegExpCharacterClass* cc = elm.data.u_char_class;
+      EmitCharClass(macro_assembler, cc, cp_offset, on_failure_->label());
+      cp_offset++;
+    } else {
+      cp_offset += elm.data.u_atom->data().length();
+    }
+  }
+
+  compiler->AddWork(on_failure_);
+  macro_assembler->AdvanceCurrentPosition(cp_offset);
+  return on_success()->GoTo(compiler);
+}
+
+
+void TextNode::MakeCaseIndependent() {
+  int element_count = elms_->length();
+  for (int i = 0; i < element_count; i++) {
+    TextElement elm = elms_->at(i);
+    if (elm.type == TextElement::CHAR_CLASS) {
+      RegExpCharacterClass* cc = elm.data.u_char_class;
+      ZoneList<CharacterRange>* ranges = cc->ranges();
+      int range_count = ranges->length();
+      for (int i = 0; i < range_count; i++) {
+        ranges->at(i).AddCaseEquivalents(ranges);
+      }
+    }
+  }
+}
+
+
+bool ChoiceNode::Emit(RegExpCompiler* compiler) {
+  int choice_count = alternatives_->length();
+  RegExpMacroAssembler* macro_assembler = compiler->macro_assembler();
+  Bind(macro_assembler);
+  // For now we just call all choices one after the other.  The idea ultimately
+  // is to use the Dispatch table to try only the relevant ones.
+  for (int i = 0; i < choice_count - 1; i++) {
+    GuardedAlternative alternative = alternatives_->at(i);
+    Label after;
+    Label after_no_pop_cp;
+    ZoneList<Guard*>* guards = alternative.guards();
+    if (guards != NULL) {
+      int guard_count = guards->length();
+      for (int j = 0; j < guard_count; j++) {
+        GenerateGuard(macro_assembler, guards->at(j), &after_no_pop_cp);
+      }
+    }
+    macro_assembler->PushCurrentPosition();
+    macro_assembler->PushBacktrack(&after);
+    if (!alternative.node()->GoTo(compiler)) {
+      after.Unuse();
+      after_no_pop_cp.Unuse();
+      return false;
+    }
+    macro_assembler->Bind(&after);
+    macro_assembler->PopCurrentPosition();
+    macro_assembler->Bind(&after_no_pop_cp);
+  }
+  GuardedAlternative alternative = alternatives_->at(choice_count - 1);
+  ZoneList<Guard*>* guards = alternative.guards();
+  if (guards != NULL) {
+    int guard_count = guards->length();
+    for (int j = 0; j < guard_count; j++) {
+      GenerateGuard(macro_assembler, guards->at(j), on_failure_->label());
+    }
+  }
+  if (!on_failure_->IsBacktrack()) {
+    ASSERT_NOT_NULL(on_failure_ -> label());
+    macro_assembler->PushBacktrack(on_failure_->label());
+    compiler->AddWork(on_failure_);
+  }
+  if (!alternative.node()->GoTo(compiler)) {
+    return false;
+  }
+  return true;
+}
+
+
+bool ActionNode::Emit(RegExpCompiler* compiler) {
+  RegExpMacroAssembler* macro = compiler->macro_assembler();
+  Bind(macro);
+  switch (type_) {
+    case STORE_REGISTER:
+      macro->SetRegister(data_.u_store_register.reg,
+                         data_.u_store_register.value);
+      break;
+    case INCREMENT_REGISTER: {
+      Label undo;
+      macro->PushBacktrack(&undo);
+      macro->AdvanceRegister(data_.u_increment_register.reg, 1);
+      bool ok = on_success()->GoTo(compiler);
+      if (!ok) {
+        undo.Unuse();
+        return false;
+      }
+      macro->Bind(&undo);
+      macro->AdvanceRegister(data_.u_increment_register.reg, -1);
+      macro->Backtrack();
+      break;
+    }
+    case STORE_POSITION: {
+      Label undo;
+      macro->PushRegister(data_.u_position_register.reg);
+      macro->PushBacktrack(&undo);
+      macro->WriteCurrentPositionToRegister(data_.u_position_register.reg);
+      bool ok = on_success()->GoTo(compiler);
+      if (!ok) {
+        undo.Unuse();
+        return false;
+      }
+      macro->Bind(&undo);
+      macro->PopRegister(data_.u_position_register.reg);
+      macro->Backtrack();
+      break;
+    }
+    case RESTORE_POSITION:
+      macro->ReadCurrentPositionFromRegister(
+          data_.u_position_register.reg);
+      break;
+    case BEGIN_SUBMATCH:
+      macro->WriteCurrentPositionToRegister(
+          data_.u_submatch.current_position_register);
+      macro->WriteStackPointerToRegister(
+          data_.u_submatch.stack_pointer_register);
+      break;
+    case ESCAPE_SUBMATCH:
+      if (info()->at_end) {
+        Label at_end;
+        // Load current character jumps to the label if we are beyond the string
+        // end.
+        macro->LoadCurrentCharacter(0, &at_end);
+        macro->Backtrack();
+        macro->Bind(&at_end);
+      }
+      if (data_.u_submatch.current_position_register != -1) {
+        macro->ReadCurrentPositionFromRegister(
+            data_.u_submatch.current_position_register);
+      }
+      macro->ReadStackPointerFromRegister(
+          data_.u_submatch.stack_pointer_register);
+      break;
+    default:
+      UNREACHABLE();
+      return false;
+  }
+  return on_success()->GoTo(compiler);
+}
+
+
+bool BackReferenceNode::Emit(RegExpCompiler* compiler) {
+  RegExpMacroAssembler* macro = compiler->macro_assembler();
+  Bind(macro);
+  // Check whether the registers are uninitialized and always
+  // succeed if they are.
+  macro->IfRegisterLT(start_reg_, 0, on_success()->label());
+  macro->IfRegisterLT(end_reg_, 0, on_success()->label());
+  ASSERT_EQ(start_reg_ + 1, end_reg_);
+  if (info()->at_end) {
+    // If we are constrained to match at the end of the input then succeed
+    // iff the back reference is empty.
+    macro->CheckNotRegistersEqual(start_reg_, end_reg_, on_failure_->label());
+  } else {
+    if (compiler->ignore_case()) {
+      macro->CheckNotBackReferenceIgnoreCase(start_reg_, on_failure_->label());
+    } else {
+      macro->CheckNotBackReference(start_reg_, on_failure_->label());
+    }
+  }
+  return on_success()->GoTo(compiler);
+}
+
+
+// -------------------------------------------------------------------
+// Dot/dotty output
+
+
+#ifdef DEBUG
+
+
+class DotPrinter: public NodeVisitor {
+ public:
+  DotPrinter() : stream_(&alloc_) { }
+  void PrintNode(const char* label, RegExpNode* node);
+  void Visit(RegExpNode* node);
+  void PrintOnFailure(RegExpNode* from, RegExpNode* on_failure);
+  void PrintAttributes(RegExpNode* from);
+  StringStream* stream() { return &stream_; }
+#define DECLARE_VISIT(Type)                                          \
+  virtual void Visit##Type(Type##Node* that);
+FOR_EACH_NODE_TYPE(DECLARE_VISIT)
+#undef DECLARE_VISIT
+ private:
+  HeapStringAllocator alloc_;
+  StringStream stream_;
+  std::set<RegExpNode*> seen_;
+};
+
+
+void DotPrinter::PrintNode(const char* label, RegExpNode* node) {
+  stream()->Add("digraph G {\n  graph [label=\"");
+  for (int i = 0; label[i]; i++) {
+    switch (label[i]) {
+      case '\\':
+        stream()->Add("\\\\");
+        break;
+      case '"':
+        stream()->Add("\"");
+        break;
+      default:
+        stream()->Put(label[i]);
+        break;
+    }
+  }
+  stream()->Add("\"];\n");
+  Visit(node);
+  stream()->Add("}\n");
+  printf("%s", *(stream()->ToCString()));
+}
+
+
+void DotPrinter::Visit(RegExpNode* node) {
+  if (seen_.find(node) != seen_.end())
+    return;
+  seen_.insert(node);
+  node->Accept(this);
+}
+
+
+void DotPrinter::PrintOnFailure(RegExpNode* from, RegExpNode* on_failure) {
+  if (on_failure->IsBacktrack()) return;
+  stream()->Add("  n%p -> n%p [style=dotted];\n", from, on_failure);
+  Visit(on_failure);
+}
+
+
+class TableEntryBodyPrinter {
+ public:
+  TableEntryBodyPrinter(StringStream* stream, ChoiceNode* choice)
+      : stream_(stream), choice_(choice) { }
+  void Call(uc16 from, DispatchTable::Entry entry) {
+    OutSet* out_set = entry.out_set();
+    for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
+      if (out_set->Get(i)) {
+        stream()->Add("    n%p:s%io%i -> n%p;\n",
+                      choice(),
+                      from,
+                      i,
+                      choice()->alternatives()->at(i).node());
+      }
+    }
+  }
+ private:
+  StringStream* stream() { return stream_; }
+  ChoiceNode* choice() { return choice_; }
+  StringStream* stream_;
+  ChoiceNode* choice_;
+};
+
+
+class TableEntryHeaderPrinter {
+ public:
+  explicit TableEntryHeaderPrinter(StringStream* stream)
+      : first_(true), stream_(stream) { }
+  void Call(uc16 from, DispatchTable::Entry entry) {
+    if (first_) {
+      first_ = false;
+    } else {
+      stream()->Add("|");
+    }
+    stream()->Add("{\\%k-\\%k|{", from, entry.to());
+    OutSet* out_set = entry.out_set();
+    int priority = 0;
+    for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
+      if (out_set->Get(i)) {
+        if (priority > 0) stream()->Add("|");
+        stream()->Add("<s%io%i> %i", from, i, priority);
+        priority++;
+      }
+    }
+    stream()->Add("}}");
+  }
+ private:
+  bool first_;
+  StringStream* stream() { return stream_; }
+  StringStream* stream_;
+};
+
+
+void DotPrinter::PrintAttributes(RegExpNode* that) {
+  stream()->Add("  a%p [shape=Mrecord, style=dashed, color=lightgrey, "
+                "fontcolor=lightgrey, margin=0.1, fontsize=10, label=\"{",
+                that);
+  NodeInfo* info = that->info();
+  stream()->Add("{NI|%i}|{WI|%i}|{SI|%i}",
+                info->follows_newline_interest,
+                info->follows_word_interest,
+                info->follows_start_interest);
+  stream()->Add("|{DN|%i}|{DW|%i}|{DS|%i}|{AE|%i}",
+                info->determine_newline,
+                info->determine_word,
+                info->determine_start,
+                info->at_end);
+  if (info->follows_newline != NodeInfo::UNKNOWN)
+    stream()->Add("|{FN|%i}", info->follows_newline);
+  if (info->follows_word != NodeInfo::UNKNOWN)
+    stream()->Add("|{FW|%i}", info->follows_word);
+  if (info->follows_start != NodeInfo::UNKNOWN)
+    stream()->Add("|{FS|%i}", info->follows_start);
+  Label* label = that->label();
+  if (label->is_bound())
+    stream()->Add("|{@|%x}", label->pos());
+  stream()->Add("}\"];\n");
+  stream()->Add("  a%p -> n%p [style=dashed, color=lightgrey, "
+                "arrowhead=none];\n", that, that);
+}
+
+
+void DotPrinter::VisitChoice(ChoiceNode* that) {
+  stream()->Add("  n%p [shape=Mrecord, label=\"", that);
+  TableEntryHeaderPrinter header_printer(stream());
+  that->table()->ForEach(&header_printer);
+  stream()->Add("\"]\n", that);
+  PrintAttributes(that);
+  TableEntryBodyPrinter body_printer(stream(), that);
+  that->table()->ForEach(&body_printer);
+  PrintOnFailure(that, that->on_failure());
+  for (int i = 0; i < that->alternatives()->length(); i++) {
+    GuardedAlternative alt = that->alternatives()->at(i);
+    alt.node()->Accept(this);
+  }
+}
+
+
+void DotPrinter::VisitText(TextNode* that) {
+  stream()->Add("  n%p [label=\"", that);
+  for (int i = 0; i < that->elements()->length(); i++) {
+    if (i > 0) stream()->Add(" ");
+    TextElement elm = that->elements()->at(i);
+    switch (elm.type) {
+      case TextElement::ATOM: {
+        stream()->Add("'%w'", elm.data.u_atom->data());
+        break;
+      }
+      case TextElement::CHAR_CLASS: {
+        RegExpCharacterClass* node = elm.data.u_char_class;
+        stream()->Add("[");
+        if (node->is_negated())
+          stream()->Add("^");
+        for (int j = 0; j < node->ranges()->length(); j++) {
+          CharacterRange range = node->ranges()->at(j);
+          stream()->Add("%k-%k", range.from(), range.to());
+        }
+        stream()->Add("]");
+        break;
+      }
+      default:
+        UNREACHABLE();
+    }
+  }
+  stream()->Add("\", shape=box, peripheries=2];\n");
+  PrintAttributes(that);
+  stream()->Add("  n%p -> n%p;\n", that, that->on_success());
+  Visit(that->on_success());
+  PrintOnFailure(that, that->on_failure());
+}
+
+
+void DotPrinter::VisitBackReference(BackReferenceNode* that) {
+  stream()->Add("  n%p [label=\"$%i..$%i\", shape=doubleoctagon];\n",
+                that,
+                that->start_register(),
+                that->end_register());
+  PrintAttributes(that);
+  stream()->Add("  n%p -> n%p;\n", that, that->on_success());
+  Visit(that->on_success());
+  PrintOnFailure(that, that->on_failure());
+}
+
+
+void DotPrinter::VisitEnd(EndNode* that) {
+  stream()->Add("  n%p [style=bold, shape=point];\n", that);
+  PrintAttributes(that);
+}
+
+
+void DotPrinter::VisitAction(ActionNode* that) {
+  stream()->Add("  n%p [", that);
+  switch (that->type_) {
+    case ActionNode::STORE_REGISTER:
+      stream()->Add("label=\"$%i:=%i\", shape=octagon",
+                    that->data_.u_store_register.reg,
+                    that->data_.u_store_register.value);
+      break;
+    case ActionNode::INCREMENT_REGISTER:
+      stream()->Add("label=\"$%i++\", shape=octagon",
+                    that->data_.u_increment_register.reg);
+      break;
+    case ActionNode::STORE_POSITION:
+      stream()->Add("label=\"$%i:=$pos\", shape=octagon",
+                    that->data_.u_position_register.reg);
+      break;
+    case ActionNode::RESTORE_POSITION:
+      stream()->Add("label=\"$pos:=$%i\", shape=octagon",
+                    that->data_.u_position_register.reg);
+      break;
+    case ActionNode::BEGIN_SUBMATCH:
+      stream()->Add("label=\"$%i:=$pos,begin\", shape=septagon",
+                    that->data_.u_submatch.current_position_register);
+      break;
+    case ActionNode::ESCAPE_SUBMATCH:
+      stream()->Add("label=\"escape\", shape=septagon");
+      break;
+  }
+  stream()->Add("];\n");
+  PrintAttributes(that);
+  stream()->Add("  n%p -> n%p;\n", that, that->on_success());
+  Visit(that->on_success());
+}
+
+
+class DispatchTableDumper {
+ public:
+  explicit DispatchTableDumper(StringStream* stream) : stream_(stream) { }
+  void Call(uc16 key, DispatchTable::Entry entry);
+  StringStream* stream() { return stream_; }
+ private:
+  StringStream* stream_;
+};
+
+
+void DispatchTableDumper::Call(uc16 key, DispatchTable::Entry entry) {
+  stream()->Add("[%k-%k]: {", key, entry.to());
+  OutSet* set = entry.out_set();
+  bool first = true;
+  for (unsigned i = 0; i < OutSet::kFirstLimit; i++) {
+    if (set->Get(i)) {
+      if (first) {
+        first = false;
+      } else {
+        stream()->Add(", ");
+      }
+      stream()->Add("%i", i);
+    }
+  }
+  stream()->Add("}\n");
+}
+
+
+void DispatchTable::Dump() {
+  HeapStringAllocator alloc;
+  StringStream stream(&alloc);
+  DispatchTableDumper dumper(&stream);
+  tree()->ForEach(&dumper);
+  OS::PrintError("%s", *stream.ToCString());
+}
+
+
+void RegExpEngine::DotPrint(const char* label, RegExpNode* node) {
+  DotPrinter printer;
+  printer.PrintNode(label, node);
+}
+
+
+#endif  // DEBUG
+
+
+// -------------------------------------------------------------------
+// Tree to graph conversion
+
+
+RegExpNode* RegExpAtom::ToNode(RegExpCompiler* compiler,
+                               RegExpNode* on_success,
+                               RegExpNode* on_failure) {
+  ZoneList<TextElement>* elms = new ZoneList<TextElement>(1);
+  elms->Add(TextElement::Atom(this));
+  return new TextNode(elms, on_success, on_failure);
+}
+
+
+RegExpNode* RegExpText::ToNode(RegExpCompiler* compiler,
+                               RegExpNode* on_success,
+                               RegExpNode* on_failure) {
+  return new TextNode(elements(), on_success, on_failure);
+}
+
+
+RegExpNode* RegExpCharacterClass::ToNode(RegExpCompiler* compiler,
+                                         RegExpNode* on_success,
+                                         RegExpNode* on_failure) {
+  ZoneList<TextElement>* elms = new ZoneList<TextElement>(1);
+  elms->Add(TextElement::CharClass(this));
+  return new TextNode(elms, on_success, on_failure);
+}
+
+
+RegExpNode* RegExpDisjunction::ToNode(RegExpCompiler* compiler,
+                                      RegExpNode* on_success,
+                                      RegExpNode* on_failure) {
+  ZoneList<RegExpTree*>* alternatives = this->alternatives();
+  int length = alternatives->length();
+  ChoiceNode* result = new ChoiceNode(length, on_failure);
+  for (int i = 0; i < length; i++) {
+    GuardedAlternative alternative(alternatives->at(i)->ToNode(compiler,
+                                                               on_success,
+                                                               on_failure));
+    result->AddAlternative(alternative);
+  }
+  return result;
+}
+
+
+RegExpNode* RegExpQuantifier::ToNode(RegExpCompiler* compiler,
+                                     RegExpNode* on_success,
+                                     RegExpNode* on_failure) {
+  return ToNode(min(),
+                max(),
+                is_greedy(),
+                body(),
+                compiler,
+                on_success,
+                on_failure);
+}
+
+
+RegExpNode* RegExpQuantifier::ToNode(int min,
+                                     int max,
+                                     bool is_greedy,
+                                     RegExpTree* body,
+                                     RegExpCompiler* compiler,
+                                     RegExpNode* on_success,
+                                     RegExpNode* on_failure) {
+  // x{f, t} becomes this:
+  //
+  //             (r++)<-.
+  //               |     `
+  //               |     (x)
+  //               v     ^
+  //      (r=0)-->(?)---/ [if r < t]
+  //               |
+  //   [if r >= f] \----> ...
+  //
+  //
+  // TODO(someone): clear captures on repetition and handle empty
+  //   matches.
+  bool has_min = min > 0;
+  bool has_max = max < RegExpQuantifier::kInfinity;
+  bool needs_counter = has_min || has_max;
+  int reg_ctr = needs_counter ? compiler->AllocateRegister() : -1;
+  ChoiceNode* center = new ChoiceNode(2, on_failure);
+  RegExpNode* loop_return = needs_counter
+      ? static_cast<RegExpNode*>(ActionNode::IncrementRegister(reg_ctr, center))
+      : static_cast<RegExpNode*>(center);
+  RegExpNode* body_node = body->ToNode(compiler, loop_return, on_failure);
+  GuardedAlternative body_alt(body_node);
+  if (has_max) {
+    Guard* body_guard = new Guard(reg_ctr, Guard::LT, max);
+    body_alt.AddGuard(body_guard);
+  }
+  GuardedAlternative rest_alt(on_success);
+  if (has_min) {
+    Guard* rest_guard = new Guard(reg_ctr, Guard::GEQ, min);
+    rest_alt.AddGuard(rest_guard);
+  }
+  if (is_greedy) {
+    center->AddAlternative(body_alt);
+    center->AddAlternative(rest_alt);
+  } else {
+    center->AddAlternative(rest_alt);
+    center->AddAlternative(body_alt);
+  }
+  if (needs_counter) {
+    return ActionNode::StoreRegister(reg_ctr, 0, center);
+  } else {
+    return center;
+  }
+}
+
+
+RegExpNode* RegExpAssertion::ToNode(RegExpCompiler* compiler,
+                                    RegExpNode* on_success,
+                                    RegExpNode* on_failure) {
+  NodeInfo info;
+  switch (type()) {
+    case START_OF_LINE:
+      info.follows_newline_interest = true;
+      break;
+    case START_OF_INPUT:
+      info.follows_start_interest = true;
+      break;
+    case BOUNDARY: case NON_BOUNDARY:
+      info.follows_word_interest = true;
+      break;
+    case END_OF_INPUT:
+      info.at_end = true;
+      break;
+    case END_OF_LINE:
+      // This is wrong but has the effect of making the compiler abort.
+      info.at_end = true;
+  }
+  return on_success->PropagateForward(&info);
+}
+
+
+RegExpNode* RegExpBackReference::ToNode(RegExpCompiler* compiler,
+                                        RegExpNode* on_success,
+                                        RegExpNode* on_failure) {
+  return new BackReferenceNode(RegExpCapture::StartRegister(index()),
+                               RegExpCapture::EndRegister(index()),
+                               on_success,
+                               on_failure);
+}
+
+
+RegExpNode* RegExpEmpty::ToNode(RegExpCompiler* compiler,
+                                RegExpNode* on_success,
+                                RegExpNode* on_failure) {
+  return on_success;
+}
+
+
+RegExpNode* RegExpLookahead::ToNode(RegExpCompiler* compiler,
+                                    RegExpNode* on_success,
+                                    RegExpNode* on_failure) {
+  int stack_pointer_register = compiler->AllocateRegister();
+  int position_register = compiler->AllocateRegister();
+  if (is_positive()) {
+    // begin submatch scope
+    // $reg = $pos
+    // if [body]
+    // then
+    //   $pos = $reg
+    //   escape submatch scope (drop all backtracks created in scope)
+    //   succeed
+    // else
+    //   end submatch scope (nothing to clean up, just exit the scope)
+    //   fail
+    return ActionNode::BeginSubmatch(
+        stack_pointer_register,
+        position_register,
+        body()->ToNode(
+            compiler,
+            ActionNode::EscapeSubmatch(
+                stack_pointer_register,
+                true,                    // Also restore input position.
+                position_register,
+                on_success),
+            on_failure));
+  } else {
+    // begin submatch scope
+    // try
+    // first if (body)
+    //       then
+    //         escape submatch scope
+    //         fail
+    //       else
+    //         backtrack
+    // second
+    //       end submatch scope
+    //       restore current position
+    //       succeed
+    ChoiceNode* try_node =
+        new ChoiceNode(1, ActionNode::RestorePosition(position_register,
+                                                      on_success));
+    RegExpNode* body_node = body()->ToNode(
+        compiler,
+        ActionNode::EscapeSubmatch(stack_pointer_register,
+                                   false,        // Don't also restore position
+                                   0,            // Unused arguments.
+                                   on_failure),
+        compiler->backtrack());
+    GuardedAlternative body_alt(body_node);
+    try_node->AddAlternative(body_alt);
+    return ActionNode::BeginSubmatch(stack_pointer_register,
+                                     position_register,
+                                     try_node);
+  }
+}
+
+
+RegExpNode* RegExpCapture::ToNode(RegExpCompiler* compiler,
+                                  RegExpNode* on_success,
+                                  RegExpNode* on_failure) {
+  return ToNode(body(), index(), compiler, on_success, on_failure);
+}
+
+
+RegExpNode* RegExpCapture::ToNode(RegExpTree* body,
+                                  int index,
+                                  RegExpCompiler* compiler,
+                                  RegExpNode* on_success,
+                                  RegExpNode* on_failure) {
+  int start_reg = RegExpCapture::StartRegister(index);
+  int end_reg = RegExpCapture::EndRegister(index);
+  RegExpNode* store_end = ActionNode::StorePosition(end_reg, on_success);
+  RegExpNode* body_node = body->ToNode(compiler, store_end, on_failure);
+  return ActionNode::StorePosition(start_reg, body_node);
+}
+
+
+RegExpNode* RegExpAlternative::ToNode(RegExpCompiler* compiler,
+                                      RegExpNode* on_success,
+                                      RegExpNode* on_failure) {
+  ZoneList<RegExpTree*>* children = nodes();
+  RegExpNode* current = on_success;
+  for (int i = children->length() - 1; i >= 0; i--) {
+    current = children->at(i)->ToNode(compiler, current, on_failure);
+  }
+  return current;
+}
+
+
+static const int kSpaceRangeCount = 20;
+static const uc16 kSpaceRanges[kSpaceRangeCount] = {
+  0x0009, 0x000D, 0x0020, 0x0020, 0x00A0, 0x00A0, 0x1680,
+  0x1680, 0x180E, 0x180E, 0x2000, 0x200A, 0x2028, 0x2029,
+  0x202F, 0x202F, 0x205F, 0x205F, 0x3000, 0x3000
+};
+
+
+static const int kWordRangeCount = 8;
+static const uc16 kWordRanges[kWordRangeCount] = {
+  '0', '9', 'A', 'Z', '_', '_', 'a', 'z'
+};
+
+
+static const int kDigitRangeCount = 2;
+static const uc16 kDigitRanges[kDigitRangeCount] = {
+  '0', '9'
+};
+
+
+static const int kLineTerminatorRangeCount = 6;
+static const uc16 kLineTerminatorRanges[kLineTerminatorRangeCount] = {
+  0x000A, 0x000A, 0x000D, 0x000D, 0x2028, 0x2029
+};
+
+
+static void AddClass(const uc16* elmv,
+                     int elmc,
+                     ZoneList<CharacterRange>* ranges) {
+  for (int i = 0; i < elmc; i += 2) {
+    ASSERT(elmv[i] <= elmv[i + 1]);
+    ranges->Add(CharacterRange(elmv[i], elmv[i + 1]));
+  }
+}
+
+
+static void AddClassNegated(const uc16 *elmv,
+                            int elmc,
+                            ZoneList<CharacterRange>* ranges) {
+  ASSERT(elmv[0] != 0x0000);
+  ASSERT(elmv[elmc-1] != 0xFFFF);
+  uc16 last = 0x0000;
+  for (int i = 0; i < elmc; i += 2) {
+    ASSERT(last <= elmv[i] - 1);
+    ASSERT(elmv[i] <= elmv[i + 1]);
+    ranges->Add(CharacterRange(last, elmv[i] - 1));
+    last = elmv[i + 1] + 1;
+  }
+  ranges->Add(CharacterRange(last, 0xFFFF));
+}
+
+
+void CharacterRange::AddClassEscape(uc16 type,
+                                    ZoneList<CharacterRange>* ranges) {
+  switch (type) {
+    case 's':
+      AddClass(kSpaceRanges, kSpaceRangeCount, ranges);
+      break;
+    case 'S':
+      AddClassNegated(kSpaceRanges, kSpaceRangeCount, ranges);
+      break;
+    case 'w':
+      AddClass(kWordRanges, kWordRangeCount, ranges);
+      break;
+    case 'W':
+      AddClassNegated(kWordRanges, kWordRangeCount, ranges);
+      break;
+    case 'd':
+      AddClass(kDigitRanges, kDigitRangeCount, ranges);
+      break;
+    case 'D':
+      AddClassNegated(kDigitRanges, kDigitRangeCount, ranges);
+      break;
+    case '.':
+      AddClassNegated(kLineTerminatorRanges,
+                      kLineTerminatorRangeCount,
+                      ranges);
+      break;
+    // This is not a character range as defined by the spec but a
+    // convenient shorthand for a character class that matches any
+    // character.
+    case '*':
+      ranges->Add(CharacterRange::Everything());
+      break;
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void CharacterRange::AddCaseEquivalents(ZoneList<CharacterRange>* ranges) {
+  unibrow::uchar chars[unibrow::Ecma262UnCanonicalize::kMaxWidth];
+  if (IsSingleton()) {
+    // If this is a singleton we just expand the one character.
+    int length = uncanonicalize.get(from(), '\0', chars);
+    for (int i = 0; i < length; i++) {
+      uc32 chr = chars[i];
+      if (chr != from()) {
+        ranges->Add(CharacterRange::Singleton(chars[i]));
+      }
+    }
+  } else if (from() <= kRangeCanonicalizeMax &&
+             to() <= kRangeCanonicalizeMax) {
+    // If this is a range we expand the characters block by block,
+    // expanding contiguous subranges (blocks) one at a time.
+    // The approach is as follows.  For a given start character we
+    // look up the block that contains it, for instance 'a' if the
+    // start character is 'c'.  A block is characterized by the property
+    // that all characters uncanonicalize in the same way as the first
+    // element, except that each entry in the result is incremented
+    // by the distance from the first element.  So a-z is a block
+    // because 'a' uncanonicalizes to ['a', 'A'] and the k'th letter
+    // uncanonicalizes to ['a' + k, 'A' + k].
+    // Once we've found the start point we look up its uncanonicalization
+    // and produce a range for each element.  For instance for [c-f]
+    // we look up ['a', 'A'] and produce [c-f] and [C-F].  We then only
+    // add a range if it is not already contained in the input, so [c-f]
+    // will be skipped but [C-F] will be added.  If this range is not
+    // completely contained in a block we do this for all the blocks
+    // covered by the range.
+    unibrow::uchar range[unibrow::Ecma262UnCanonicalize::kMaxWidth];
+    // First, look up the block that contains the 'from' character.
+    int length = canonrange.get(from(), '\0', range);
+    if (length == 0) {
+      range[0] = from();
+    } else {
+      ASSERT_EQ(1, length);
+    }
+    int pos = from();
+    // The start of the current block.  Note that except for the first
+    // iteration 'start' is always equal to 'pos'.
+    int start;
+    // If it is not the start point of a block the entry contains the
+    // offset of the character from the start point.
+    if ((range[0] & kStartMarker) == 0) {
+      start = pos - range[0];
+    } else {
+      start = pos;
+    }
+    // Then we add the ranges on at a time, incrementing the current
+    // position to be after the last block each time.  The position
+    // always points to the start of a block.
+    while (pos < to()) {
+      length = canonrange.get(start, '\0', range);
+      if (length == 0) {
+        range[0] = start;
+      } else {
+        ASSERT_EQ(1, length);
+      }
+      ASSERT((range[0] & kStartMarker) != 0);
+      // The start point of a block contains the distance to the end
+      // of the range.
+      int block_end = start + (range[0] & kPayloadMask) - 1;
+      int end = (block_end > to()) ? to() : block_end;
+      length = uncanonicalize.get(start, '\0', range);
+      for (int i = 0; i < length; i++) {
+        uc32 c = range[i];
+        uc16 range_from = c + (pos - start);
+        uc16 range_to = c + (end - start);
+        if (!(from() <= range_from && range_to <= to())) {
+          ranges->Add(CharacterRange(range_from, range_to));
+        }
+      }
+      start = pos = block_end + 1;
+    }
+  } else {
+    // TODO(plesner) when we've fixed the 2^11 bug in unibrow.
+  }
+}
+
+
+// -------------------------------------------------------------------
+// Interest propagation
+
+
+RegExpNode* RegExpNode::GetSibling(NodeInfo* info) {
+  for (int i = 0; i < siblings_.length(); i++) {
+    RegExpNode* sibling = siblings_.Get(i);
+    if (sibling->info()->HasSameForwardInterests(info))
+      return sibling;
+  }
+  return NULL;
+}
+
+
+template <class C>
+static RegExpNode* PropagateToEndpoint(C* node, NodeInfo* info) {
+  NodeInfo full_info(*node->info());
+  full_info.AddFromPreceding(info);
+  RegExpNode* sibling = node->GetSibling(&full_info);
+  if (sibling != NULL) return sibling;
+  node->EnsureSiblings();
+  sibling = new C(*node);
+  sibling->info()->AddFromPreceding(&full_info);
+  node->AddSibling(sibling);
+  return sibling;
+}
+
+
+RegExpNode* ActionNode::PropagateForward(NodeInfo* info) {
+  NodeInfo full_info(*this->info());
+  full_info.AddFromPreceding(info);
+  RegExpNode* sibling = GetSibling(&full_info);
+  if (sibling != NULL) return sibling;
+  EnsureSiblings();
+  ActionNode* action = new ActionNode(*this);
+  action->info()->AddFromPreceding(&full_info);
+  AddSibling(action);
+  if (type_ != ESCAPE_SUBMATCH) {
+    action->set_on_success(action->on_success()->PropagateForward(info));
+  }
+  return action;
+}
+
+
+RegExpNode* ChoiceNode::PropagateForward(NodeInfo* info) {
+  NodeInfo full_info(*this->info());
+  full_info.AddFromPreceding(info);
+  RegExpNode* sibling = GetSibling(&full_info);
+  if (sibling != NULL) return sibling;
+  EnsureSiblings();
+  ChoiceNode* choice = new ChoiceNode(*this);
+  choice->info()->AddFromPreceding(&full_info);
+  AddSibling(choice);
+  ZoneList<GuardedAlternative>* old_alternatives = alternatives();
+  int count = old_alternatives->length();
+  choice->alternatives_ = new ZoneList<GuardedAlternative>(count);
+  for (int i = 0; i < count; i++) {
+    GuardedAlternative alternative = old_alternatives->at(i);
+    alternative.set_node(alternative.node()->PropagateForward(info));
+    choice->alternatives()->Add(alternative);
+  }
+  if (!choice->on_failure_->IsBacktrack()) {
+    choice->on_failure_ = choice->on_failure_->PropagateForward(info);
+  }
+  return choice;
+}
+
+
+RegExpNode* EndNode::PropagateForward(NodeInfo* info) {
+  return PropagateToEndpoint(this, info);
+}
+
+
+RegExpNode* BackReferenceNode::PropagateForward(NodeInfo* info) {
+  NodeInfo full_info(*this->info());
+  full_info.AddFromPreceding(info);
+  RegExpNode* sibling = GetSibling(&full_info);
+  if (sibling != NULL) return sibling;
+  EnsureSiblings();
+  BackReferenceNode* back_ref = new BackReferenceNode(*this);
+  back_ref->info()->AddFromPreceding(&full_info);
+  AddSibling(back_ref);
+  // TODO(erikcorry): A back reference has to have two successors (by default
+  // the same node).  The first is used if the back reference matches a non-
+  // empty back reference, the second if it matches an empty one.  This doesn't
+  // matter for at_end, which is the only one implemented right now, but it will
+  // matter for other pieces of info.
+  back_ref->set_on_success(back_ref->on_success()->PropagateForward(info));
+  return back_ref;
+}
+
+
+RegExpNode* TextNode::PropagateForward(NodeInfo* info) {
+  return PropagateToEndpoint(this, info);
+}
+
+
+// -------------------------------------------------------------------
+// Splay tree
+
+
+OutSet* OutSet::Extend(unsigned value) {
+  if (Get(value))
+    return this;
+  if (successors() != NULL) {
+    for (int i = 0; i < successors()->length(); i++) {
+      OutSet* successor = successors()->at(i);
+      if (successor->Get(value))
+        return successor;
+    }
+  } else {
+    successors_ = new ZoneList<OutSet*>(2);
+  }
+  OutSet* result = new OutSet(first_, remaining_);
+  result->Set(value);
+  successors()->Add(result);
+  return result;
+}
+
+
+void OutSet::Set(unsigned value) {
+  if (value < kFirstLimit) {
+    first_ |= (1 << value);
+  } else {
+    if (remaining_ == NULL)
+      remaining_ = new ZoneList<unsigned>(1);
+    if (remaining_->is_empty() || !remaining_->Contains(value))
+      remaining_->Add(value);
+  }
+}
+
+
+bool OutSet::Get(unsigned value) {
+  if (value < kFirstLimit) {
+    return (first_ & (1 << value)) != 0;
+  } else if (remaining_ == NULL) {
+    return false;
+  } else {
+    return remaining_->Contains(value);
+  }
+}
+
+
+const uc16 DispatchTable::Config::kNoKey = unibrow::Utf8::kBadChar;
+const DispatchTable::Entry DispatchTable::Config::kNoValue;
+
+
+void DispatchTable::AddRange(CharacterRange full_range, int value) {
+  CharacterRange current = full_range;
+  if (tree()->is_empty()) {
+    // If this is the first range we just insert into the table.
+    ZoneSplayTree<Config>::Locator loc;
+    ASSERT_RESULT(tree()->Insert(current.from(), &loc));
+    loc.set_value(Entry(current.from(), current.to(), empty()->Extend(value)));
+    return;
+  }
+  // First see if there is a range to the left of this one that
+  // overlaps.
+  ZoneSplayTree<Config>::Locator loc;
+  if (tree()->FindGreatestLessThan(current.from(), &loc)) {
+    Entry* entry = &loc.value();
+    // If we've found a range that overlaps with this one, and it
+    // starts strictly to the left of this one, we have to fix it
+    // because the following code only handles ranges that start on
+    // or after the start point of the range we're adding.
+    if (entry->from() < current.from() && entry->to() >= current.from()) {
+      // Snap the overlapping range in half around the start point of
+      // the range we're adding.
+      CharacterRange left(entry->from(), current.from() - 1);
+      CharacterRange right(current.from(), entry->to());
+      // The left part of the overlapping range doesn't overlap.
+      // Truncate the whole entry to be just the left part.
+      entry->set_to(left.to());
+      // The right part is the one that overlaps.  We add this part
+      // to the map and let the next step deal with merging it with
+      // the range we're adding.
+      ZoneSplayTree<Config>::Locator loc;
+      ASSERT_RESULT(tree()->Insert(right.from(), &loc));
+      loc.set_value(Entry(right.from(),
+                          right.to(),
+                          entry->out_set()));
+    }
+  }
+  while (current.is_valid()) {
+    if (tree()->FindLeastGreaterThan(current.from(), &loc) &&
+        (loc.value().from() <= current.to()) &&
+        (loc.value().to() >= current.from())) {
+      Entry* entry = &loc.value();
+      // We have overlap.  If there is space between the start point of
+      // the range we're adding and where the overlapping range starts
+      // then we have to add a range covering just that space.
+      if (current.from() < entry->from()) {
+        ZoneSplayTree<Config>::Locator ins;
+        ASSERT_RESULT(tree()->Insert(current.from(), &ins));
+        ins.set_value(Entry(current.from(),
+                            entry->from() - 1,
+                            empty()->Extend(value)));
+        current.set_from(entry->from());
+      }
+      ASSERT_EQ(current.from(), entry->from());
+      // If the overlapping range extends beyond the one we want to add
+      // we have to snap the right part off and add it separately.
+      if (entry->to() > current.to()) {
+        ZoneSplayTree<Config>::Locator ins;
+        ASSERT_RESULT(tree()->Insert(current.to() + 1, &ins));
+        ins.set_value(Entry(current.to() + 1,
+                            entry->to(),
+                            entry->out_set()));
+        entry->set_to(current.to());
+      }
+      ASSERT(entry->to() <= current.to());
+      // The overlapping range is now completely contained by the range
+      // we're adding so we can just update it and move the start point
+      // of the range we're adding just past it.
+      entry->AddValue(value);
+      // Bail out if the last interval ended at 0xFFFF since otherwise
+      // adding 1 will wrap around to 0.
+      if (entry->to() == 0xFFFF)
+        break;
+      ASSERT(entry->to() + 1 > current.from());
+      current.set_from(entry->to() + 1);
+    } else {
+      // There is no overlap so we can just add the range
+      ZoneSplayTree<Config>::Locator ins;
+      ASSERT_RESULT(tree()->Insert(current.from(), &ins));
+      ins.set_value(Entry(current.from(),
+                          current.to(),
+                          empty()->Extend(value)));
+      break;
+    }
+  }
+}
+
+
+OutSet* DispatchTable::Get(uc16 value) {
+  ZoneSplayTree<Config>::Locator loc;
+  if (!tree()->FindGreatestLessThan(value, &loc))
+    return empty();
+  Entry* entry = &loc.value();
+  if (value <= entry->to())
+    return entry->out_set();
+  else
+    return empty();
+}
+
+
+// -------------------------------------------------------------------
+// Analysis
+
+
+void Analysis::EnsureAnalyzed(RegExpNode* that) {
+  if (that->info()->been_analyzed || that->info()->being_analyzed)
+    return;
+  that->info()->being_analyzed = true;
+  that->Accept(this);
+  that->info()->being_analyzed = false;
+  that->info()->been_analyzed = true;
+}
+
+
+void Analysis::VisitEnd(EndNode* that) {
+  // nothing to do
+}
+
+
+void Analysis::VisitText(TextNode* that) {
+  if (ignore_case_) {
+    that->MakeCaseIndependent();
+  }
+  EnsureAnalyzed(that->on_success());
+  EnsureAnalyzed(that->on_failure());
+  NodeInfo* info = that->info();
+  NodeInfo* next_info = that->on_success()->info();
+  // If the following node is interested in what it follows then this
+  // node must determine it.
+  info->determine_newline = next_info->follows_newline_interest;
+  info->determine_word = next_info->follows_word_interest;
+  info->determine_start = next_info->follows_start_interest;
+}
+
+
+void Analysis::VisitAction(ActionNode* that) {
+  EnsureAnalyzed(that->on_success());
+  // If the next node is interested in what it follows then this node
+  // has to be interested too so it can pass the information on.
+  that->info()->AddFromFollowing(that->on_success()->info());
+}
+
+
+void Analysis::VisitChoice(ChoiceNode* that) {
+  NodeInfo* info = that->info();
+  for (int i = 0; i < that->alternatives()->length(); i++) {
+    RegExpNode* node = that->alternatives()->at(i).node();
+    EnsureAnalyzed(node);
+    // Anything the following nodes need to know has to be known by
+    // this node also, so it can pass it on.
+    info->AddFromFollowing(node->info());
+  }
+  if (!that->table_calculated()) {
+    DispatchTableConstructor cons(that->table());
+    cons.BuildTable(that);
+  }
+  EnsureAnalyzed(that->on_failure());
+}
+
+
+void Analysis::VisitBackReference(BackReferenceNode* that) {
+  EnsureAnalyzed(that->on_success());
+  EnsureAnalyzed(that->on_failure());
+}
+
+
+// -------------------------------------------------------------------
+// Dispatch table construction
+
+
+void DispatchTableConstructor::VisitEnd(EndNode* that) {
+  AddRange(CharacterRange::Everything());
+}
+
+
+void DispatchTableConstructor::BuildTable(ChoiceNode* node) {
+  ASSERT(!node->table_calculated());
+  node->set_being_calculated(true);
+  ZoneList<GuardedAlternative>* alternatives = node->alternatives();
+  for (int i = 0; i < alternatives->length(); i++) {
+    set_choice_index(i);
+    alternatives->at(i).node()->Accept(this);
+  }
+  node->set_being_calculated(false);
+  node->set_table_calculated(true);
+}
+
+
+class AddDispatchRange {
+ public:
+  explicit AddDispatchRange(DispatchTableConstructor* constructor)
+    : constructor_(constructor) { }
+  void Call(uc32 from, DispatchTable::Entry entry);
+ private:
+  DispatchTableConstructor* constructor_;
+};
+
+
+void AddDispatchRange::Call(uc32 from, DispatchTable::Entry entry) {
+  CharacterRange range(from, entry.to());
+  constructor_->AddRange(range);
+}
+
+
+void DispatchTableConstructor::VisitChoice(ChoiceNode* node) {
+  if (node->being_calculated())
+    return;
+  if (!node->table_calculated()) {
+    DispatchTableConstructor constructor(node->table());
+    constructor.BuildTable(node);
+  }
+  ASSERT(node->table_calculated());
+  AddDispatchRange adder(this);
+  node->table()->ForEach(&adder);
+}
+
+
+void DispatchTableConstructor::VisitBackReference(BackReferenceNode* that) {
+  // TODO(160): Find the node that we refer back to and propagate its start
+  // set back to here.  For now we just accept anything.
+  AddRange(CharacterRange::Everything());
+}
+
+
+
+static int CompareRangeByFrom(const CharacterRange* a,
+                              const CharacterRange* b) {
+  return Compare<uc16>(a->from(), b->from());
+}
+
+
+void DispatchTableConstructor::AddInverse(ZoneList<CharacterRange>* ranges) {
+  ranges->Sort(CompareRangeByFrom);
+  uc16 last = 0;
+  for (int i = 0; i < ranges->length(); i++) {
+    CharacterRange range = ranges->at(i);
+    if (last < range.from())
+      AddRange(CharacterRange(last, range.from() - 1));
+    if (range.to() >= last) {
+      if (range.to() == 0xFFFF) {
+        return;
+      } else {
+        last = range.to() + 1;
+      }
+    }
+  }
+  AddRange(CharacterRange(last, 0xFFFF));
+}
+
+
+void DispatchTableConstructor::VisitText(TextNode* that) {
+  TextElement elm = that->elements()->at(0);
+  switch (elm.type) {
+    case TextElement::ATOM: {
+      uc16 c = elm.data.u_atom->data()[0];
+      AddRange(CharacterRange(c, c));
+      break;
+    }
+    case TextElement::CHAR_CLASS: {
+      RegExpCharacterClass* tree = elm.data.u_char_class;
+      ZoneList<CharacterRange>* ranges = tree->ranges();
+      if (tree->is_negated()) {
+        AddInverse(ranges);
+      } else {
+        for (int i = 0; i < ranges->length(); i++)
+          AddRange(ranges->at(i));
+      }
+      break;
+    }
+    default: {
+      UNIMPLEMENTED();
+    }
+  }
+}
+
+
+void DispatchTableConstructor::VisitAction(ActionNode* that) {
+  that->on_success()->Accept(this);
+}
+
+
+Handle<FixedArray> RegExpEngine::Compile(RegExpParseResult* input,
+                                         RegExpNode** node_return,
+                                         bool ignore_case,
+                                         bool is_multiline) {
+  RegExpCompiler compiler(input->capture_count, ignore_case);
+  // Wrap the body of the regexp in capture #0.
+  RegExpNode* captured_body = RegExpCapture::ToNode(input->tree,
+                                                    0,
+                                                    &compiler,
+                                                    compiler.accept(),
+                                                    compiler.backtrack());
+  // Add a .*? at the beginning, outside the body capture.
+  // Note: We could choose to not add this if the regexp is anchored at
+  //   the start of the input but I'm not sure how best to do that and
+  //   since we don't even handle ^ yet I'm saving that optimization for
+  //   later.
+  RegExpNode* node = RegExpQuantifier::ToNode(0,
+                                              RegExpQuantifier::kInfinity,
+                                              false,
+                                              new RegExpCharacterClass('*'),
+                                              &compiler,
+                                              captured_body,
+                                              compiler.backtrack());
+  if (node_return != NULL) *node_return = node;
+  Analysis analysis(ignore_case);
+  analysis.EnsureAnalyzed(node);
+
+  if (!FLAG_irregexp) {
+    return Handle<FixedArray>::null();
+  }
+
+  if (is_multiline && !FLAG_attempt_multiline_irregexp) {
+    return Handle<FixedArray>::null();
+  }
+
+  if (FLAG_irregexp_native) {
+#ifdef ARM
+    UNIMPLEMENTED();
+#else  // IA32
+    RegExpMacroAssemblerIA32 macro_assembler(RegExpMacroAssemblerIA32::UC16,
+                                             (input->capture_count + 1) * 2);
+    return compiler.Assemble(&macro_assembler,
+                             node,
+                             input->capture_count);
+#endif
+  }
+  EmbeddedVector<byte, 1024> codes;
+  RegExpMacroAssemblerIrregexp macro_assembler(codes);
+  return compiler.Assemble(&macro_assembler,
+                           node,
+                           input->capture_count);
+}
+
 
 }}  // namespace v8::internal