Improve C++ code for string splittig (Dromaeo benchmark).

runtime/vm/object.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
@@ skipping 10718 matching lines @@
   const String& result = String::Handle(OneByteString::New(len, space));
   for (intptr_t i = 0; i < len; ++i) {
     int32_t ch = mapping(str.CharAt(i));
     ASSERT(Utf::IsLatin1(ch));
     *CharAddr(result, i) = ch;
   }
   return OneByteString::raw(result);
 }
 
 
+RawOneByteString* OneByteString::SubStringUnchecked(const String& str,
+                                                    intptr_t begin_index,
+                                                    intptr_t length,
+                                                    Heap::Space space) {
+  ASSERT(!str.IsNull() && str.IsOneByteString());
+  ASSERT(begin_index >= 0);
+  ASSERT(length >= 0);
+  if (begin_index <= str.Length() && length == 0) {
+    return OneByteString::raw(String::Handle(Symbols::Empty()));
+  }
+  ASSERT(begin_index < str.Length());
+  RawOneByteString* result = OneByteString::New(length, space);
+  NoGCScope no_gc;
+  if (length > 0) {
+    uint8_t* dest = &result->ptr()->data_[0];
+    uint8_t* src =  &raw_ptr(str)->data_[begin_index];
+    memmove(dest, src, length);
+  }
+  return result;
+}
+
+
 RawTwoByteString* TwoByteString::EscapeSpecialCharacters(const String& str,
                                                          bool raw_str) {
   intptr_t len = str.Length();
   if (len > 0) {
     intptr_t num_escapes = 0;
     intptr_t index = 0;
     for (intptr_t i = 0; i < len; i++) {
       if (IsSpecialCharacter(*CharAddr(str, i)) ||
           (!raw_str && (*CharAddr(str, i) == '\\'))) {
         num_escapes += 1;
@@ skipping 386 matching lines @@
   return reinterpret_cast<RawImmutableArray*>(Array::New(kClassId, len, space));
 }
 
 
 const char* ImmutableArray::ToCString() const {
   return "ImmutableArray";
 }
 
 
 void GrowableObjectArray::Add(const Object& value, Heap::Space space) const {
+  Add(Isolate::Current(), value, space);
+}
+
+
+void GrowableObjectArray::Add(Isolate* isolate,
+                              const Object& value,
+                              Heap::Space space) const {
   ASSERT(!IsNull());
-  Array& contents = Array::Handle(data());
+  Array& contents = Array::Handle(isolate, data());
   if (Length() == Capacity()) {
     // TODO(Issue 2500): Need a better growth strategy.
     intptr_t new_capacity = (Capacity() == 0) ? 4 : Capacity() * 2;
     if (new_capacity <= Capacity()) {
       // Use the preallocated out of memory exception to avoid calling
       // into dart code or allocating any code.
       const Instance& exception =
-          Instance::Handle(Isolate::Current()->object_store()->out_of_memory());
+          Instance::Handle(isolate->object_store()->out_of_memory());
       Exceptions::Throw(exception);
       UNREACHABLE();
     }
     Grow(new_capacity, space);
     contents = data();
   }
   ASSERT(Length() < Capacity());
   intptr_t index = Length();
   SetLength(index + 1);
   contents.SetAt(index, value);
@@ skipping 918 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "_WeakProperty";
 }
 
 }  // namespace dart