[Isolates] Merge from bleeding_edge, revisions 5934-6100.

src/runtime.cc

 // Copyright 2010 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
@@ skipping 626 matching lines @@
   new_proto_map->set_is_hidden_prototype();
 
   // Set the object's prototype to proto.
   new_map->set_prototype(proto);
   jsobject->set_map(new_map);
 
   return isolate->heap()->undefined_value();
 }
 
 
-// Sets the magic number that identifies a function as one of the special
-// math functions that can be inlined.
-static MaybeObject* Runtime_SetMathFunctionId(RUNTIME_CALLING_CONVENTION) {
-  RUNTIME_GET_ISOLATE;
-  NoHandleAllocation ha;
-  ASSERT(args.length() == 2);
-  CONVERT_CHECKED(JSFunction, function, args[0]);
-  CONVERT_CHECKED(Smi, id, args[1]);
-  RUNTIME_ASSERT(id->value() >= 0);
-  RUNTIME_ASSERT(id->value() < SharedFunctionInfo::max_math_id_number());
-
-  function->shared()->set_math_function_id(id->value());
-
-  return isolate->heap()->undefined_value();
-}
-
-
 static MaybeObject* Runtime_IsConstructCall(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   NoHandleAllocation ha;
   ASSERT(args.length() == 0);
   JavaScriptFrameIterator it;
   return isolate->heap()->ToBoolean(it.frame()->IsConstructor());
 }
 
 
 // Recursively traverses hidden prototypes if property is not found
@@ skipping 2994 matching lines @@
 
 
 static MaybeObject* Runtime_DefineOrRedefineAccessorProperty(
     RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   ASSERT(args.length() == 5);
   HandleScope scope(isolate);
   CONVERT_ARG_CHECKED(JSObject, obj, 0);
   CONVERT_CHECKED(String, name, args[1]);
   CONVERT_CHECKED(Smi, flag_setter, args[2]);
-  CONVERT_CHECKED(JSFunction, fun, args[3]);
+  Object* fun = args[3];
+  RUNTIME_ASSERT(fun->IsJSFunction() || fun->IsUndefined());
   CONVERT_CHECKED(Smi, flag_attr, args[4]);
   int unchecked = flag_attr->value();
   RUNTIME_ASSERT((unchecked & ~(READ_ONLY | DONT_ENUM | DONT_DELETE)) == 0);
   RUNTIME_ASSERT(!obj->IsNull());
   LookupResult result;
   obj->LocalLookupRealNamedProperty(name, &result);
 
   PropertyAttributes attr = static_cast<PropertyAttributes>(unchecked);
   // If an existing property is either FIELD, NORMAL or CONSTANT_FUNCTION
   // delete it to avoid running into trouble in DefineAccessor, which
@@ skipping 37 matching lines @@
     // Normalize the elements to enable attributes on the property.
     NormalizeElements(js_object);
     Handle<NumberDictionary> dictionary(js_object->element_dictionary());
     // Make sure that we never go back to fast case.
     dictionary->set_requires_slow_elements();
     PropertyDetails details = PropertyDetails(attr, NORMAL);
     NumberDictionarySet(dictionary, index, obj_value, details);
   }
 
   LookupResult result;
-  js_object->LocalLookupRealNamedProperty(*name, &result);
+  js_object->LookupRealNamedProperty(*name, &result);
 
   // Take special care when attributes are different and there is already
   // a property. For simplicity we normalize the property which enables us
   // to not worry about changing the instance_descriptor and creating a new
   // map. The current version of SetObjectProperty does not handle attributes
   // correctly in the case where a property is a field and is reset with
   // new attributes.
-  if (result.IsProperty() && attr != result.GetAttributes()) {
+  if (result.IsProperty() &&
+      (attr != result.GetAttributes() || result.type() == CALLBACKS)) {
     // New attributes - normalize to avoid writing to instance descriptor
     NormalizeProperties(js_object, CLEAR_INOBJECT_PROPERTIES, 0);
     // Use IgnoreAttributes version since a readonly property may be
     // overridden and SetProperty does not allow this.
     return js_object->IgnoreAttributesAndSetLocalProperty(*name,
                                                           *obj_value,
                                                           attr);
   }
 
   return Runtime::SetObjectProperty(isolate, js_object, name, obj_value, attr);
@@ skipping 990 matching lines @@
     int step;
     destination->Set(dest_position, Unescape(source, i, length, &step));
     i += step;
   }
   return destination;
 }
 
 
 static const unsigned int kQuoteTableLength = 128u;
 
-static const char* const JsonQuotes[kQuoteTableLength] = {
-    "\\u0000", "\\u0001", "\\u0002", "\\u0003",
-    "\\u0004", "\\u0005", "\\u0006", "\\u0007",
-    "\\b", "\\t", "\\n", "\\u000b",
-    "\\f", "\\r", "\\u000e", "\\u000f",
-    "\\u0010", "\\u0011", "\\u0012", "\\u0013",
-    "\\u0014", "\\u0015", "\\u0016", "\\u0017",
-    "\\u0018", "\\u0019", "\\u001a", "\\u001b",
-    "\\u001c", "\\u001d", "\\u001e", "\\u001f",
-    NULL, NULL, "\\\"", NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    "\\\\", NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-    NULL, NULL, NULL, NULL,
-};
+static const int kJsonQuotesCharactersPerEntry = 8;
+static const char* const JsonQuotes =
+    "\\u0000  \\u0001  \\u0002  \\u0003  "
+    "\\u0004  \\u0005  \\u0006  \\u0007  "
+    "\\b      \\t      \\n      \\u000b  "
+    "\\f      \\r      \\u000e  \\u000f  "
+    "\\u0010  \\u0011  \\u0012  \\u0013  "
+    "\\u0014  \\u0015  \\u0016  \\u0017  "
+    "\\u0018  \\u0019  \\u001a  \\u001b  "
+    "\\u001c  \\u001d  \\u001e  \\u001f  "
+    "        !       \\\"      #       "
+    "$       %       &       '       "
+    "(       )       *       +       "
+    ",       -       .       /       "
+    "0       1       2       3       "
+    "4       5       6       7       "
+    "8       9       :       ;       "
+    "<       =       >       ?       "
+    "@       A       B       C       "
+    "D       E       F       G       "
+    "H       I       J       K       "
+    "L       M       N       O       "
+    "P       Q       R       S       "
+    "T       U       V       W       "
+    "X       Y       Z       [       "
+    "\\\\      ]       ^       _       "
+    "`       a       b       c       "
+    "d       e       f       g       "
+    "h       i       j       k       "
+    "l       m       n       o       "
+    "p       q       r       s       "
+    "t       u       v       w       "
+    "x       y       z       {       "
+    "|       }       ~       \177       ";
 
 
+// For a string that is less than 32k characters it should always be
+// possible to allocate it in new space.
+static const int kMaxGuaranteedNewSpaceString = 32 * 1024;
+
+
+// Doing JSON quoting cannot make the string more than this many times larger.
+static const int kJsonQuoteWorstCaseBlowup = 6;
+
+
+// Covers the entire ASCII range (all other characters are unchanged by JSON
+// quoting).
 static const byte JsonQuoteLengths[kQuoteTableLength] = {
     6, 6, 6, 6, 6, 6, 6, 6,
     2, 2, 2, 6, 2, 2, 6, 6,
     6, 6, 6, 6, 6, 6, 6, 6,
     6, 6, 6, 6, 6, 6, 6, 6,
     1, 1, 2, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 2, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1,
 };
 
 
-template <typename Char>
-Char* WriteString(Char* dst, const char* src_string) {
-  char c;
-  for (c = *src_string; c; c = *src_string) {
-    *dst = c;
-    dst++;
-    src_string++;
-  }
-  return dst;
-}
-
-
 template <typename StringType>
 MaybeObject* AllocateRawString(int length);
 
 
 template <>
 MaybeObject* AllocateRawString<SeqTwoByteString>(int length) {
   return HEAP->AllocateRawTwoByteString(length);
 }
 
 
 template <>
 MaybeObject* AllocateRawString<SeqAsciiString>(int length) {
   return HEAP->AllocateRawAsciiString(length);
 }
 
 
 template <typename Char, typename StringType>
+static MaybeObject* SlowQuoteJsonString(Vector<const Char> characters) {
+  int length = characters.length();
+  const Char* read_cursor = characters.start();
+  const Char* end = read_cursor + length;
+  const int kSpaceForQuotes = 2;
+  int quoted_length = kSpaceForQuotes;
+  while (read_cursor < end) {
+    Char c = *(read_cursor++);
+    if (sizeof(Char) > 1u && static_cast<unsigned>(c) >= kQuoteTableLength) {
+      quoted_length++;
+    } else {
+      quoted_length += JsonQuoteLengths[static_cast<unsigned>(c)];
+    }
+  }
+  MaybeObject* new_alloc = AllocateRawString<StringType>(quoted_length);
+  Object* new_object;
+  if (!new_alloc->ToObject(&new_object)) {
+    return new_alloc;
+  }
+  StringType* new_string = StringType::cast(new_object);
+
+  Char* write_cursor = reinterpret_cast<Char*>(
+      new_string->address() + SeqAsciiString::kHeaderSize);
+  *(write_cursor++) = '"';
+
+  read_cursor = characters.start();
+  while (read_cursor < end) {
+    Char c = *(read_cursor++);
+    if (sizeof(Char) > 1u && static_cast<unsigned>(c) >= kQuoteTableLength) {
+      *(write_cursor++) = c;
+    } else {
+      int len = JsonQuoteLengths[static_cast<unsigned>(c)];
+      const char* replacement = JsonQuotes +
+          static_cast<unsigned>(c) * kJsonQuotesCharactersPerEntry;
+      for (int i = 0; i < len; i++) {
+        *write_cursor++ = *replacement++;
+      }
+    }
+  }
+  *(write_cursor++) = '"';
+  return new_string;
+}
+
+
+template <typename Char, typename StringType>
 static MaybeObject* QuoteJsonString(Vector<const Char> characters) {
   int length = characters.length();
-  int quoted_length = 0;
-  for (int i = 0; i < length; i++) {
-    unsigned int c = characters[i];
-    if (sizeof(Char) > 1u) {
-      quoted_length += (c >= kQuoteTableLength) ? 1 : JsonQuoteLengths[c];
-    } else {
-      quoted_length += JsonQuoteLengths[c];
-    }
+  COUNTERS->quote_json_char_count()->Increment(length);
+  const int kSpaceForQuotes = 2;
+  int worst_case_length = length * kJsonQuoteWorstCaseBlowup + kSpaceForQuotes;
+  if (worst_case_length > kMaxGuaranteedNewSpaceString) {
+    return SlowQuoteJsonString<Char, StringType>(characters);
   }
-  COUNTERS->quote_json_char_count()->Increment(length);
 
-  // Add space for quotes.
-  quoted_length += 2;
-
-  MaybeObject* new_alloc = AllocateRawString<StringType>(quoted_length);
+  MaybeObject* new_alloc = AllocateRawString<StringType>(worst_case_length);
   Object* new_object;
   if (!new_alloc->ToObject(&new_object)) {
-    COUNTERS->quote_json_char_recount()->Increment(length);
     return new_alloc;
   }
+  if (!HEAP->new_space()->Contains(new_object)) {
+    // Even if our string is small enough to fit in new space we still have to
+    // handle it being allocated in old space as may happen in the third
+    // attempt.  See CALL_AND_RETRY in heap-inl.h and similar code in
+    // CEntryStub::GenerateCore.
+    return SlowQuoteJsonString<Char, StringType>(characters);
+  }
   StringType* new_string = StringType::cast(new_object);
-
+  ASSERT(HEAP->new_space()->Contains(new_string));
 
   STATIC_ASSERT(SeqTwoByteString::kHeaderSize == SeqAsciiString::kHeaderSize);
   Char* write_cursor = reinterpret_cast<Char*>(
       new_string->address() + SeqAsciiString::kHeaderSize);
   *(write_cursor++) = '"';
+
   const Char* read_cursor = characters.start();
-  if (quoted_length == length + 2) {
-    CopyChars(write_cursor, read_cursor, length);
-    write_cursor += length;
-  } else {
-    const Char* end = read_cursor + length;
-    while (read_cursor < end) {
-      Char c = *(read_cursor++);
-      if (sizeof(Char) > 1u && static_cast<unsigned>(c) >= kQuoteTableLength) {
-        *(write_cursor++) = c;
-      } else {
-        const char* replacement = JsonQuotes[static_cast<unsigned>(c)];
-        if (!replacement) {
-          *(write_cursor++) = c;
-        } else {
-          write_cursor = WriteString(write_cursor, replacement);
+  const Char* end = read_cursor + length;
+  while (read_cursor < end) {
+    Char c = *(read_cursor++);
+    if (sizeof(Char) > 1u && static_cast<unsigned>(c) >= kQuoteTableLength) {
+      *(write_cursor++) = c;
+    } else {
+      int len = JsonQuoteLengths[static_cast<unsigned>(c)];
+      const char* replacement = JsonQuotes +
+          static_cast<unsigned>(c) * kJsonQuotesCharactersPerEntry;
+      write_cursor[0] = replacement[0];
+      if (len > 1) {
+        write_cursor[1] = replacement[1];
+        if (len > 2) {
+          ASSERT(len == 6);
+          write_cursor[2] = replacement[2];
+          write_cursor[3] = replacement[3];
+          write_cursor[4] = replacement[4];
+          write_cursor[5] = replacement[5];
         }
       }
+      write_cursor += len;
     }
   }
   *(write_cursor++) = '"';
-  ASSERT_EQ(
-      static_cast<int64_t>(
-          SeqAsciiString::kHeaderSize + quoted_length * sizeof(Char)),
-      static_cast<int64_t>(
-          reinterpret_cast<Address>(write_cursor) - new_string->address()));
+
+  int final_length = static_cast<int>(
+      write_cursor - reinterpret_cast<Char*>(
+          new_string->address() + SeqAsciiString::kHeaderSize));
+  HEAP->new_space()->ShrinkStringAtAllocationBoundary<StringType>(new_string,
+                                                                  final_length);
   return new_string;
 }
 
 
 static MaybeObject* Runtime_QuoteJSONString(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   NoHandleAllocation ha;
   CONVERT_CHECKED(String, str, args[0]);
   if (!str->IsFlat()) {
     MaybeObject* try_flatten = str->TryFlatten();
@@ skipping 1344 matching lines @@
   RUNTIME_GET_ISOLATE;
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
   isolate->counters()->math_log()->Increment();
 
   CONVERT_DOUBLE_CHECKED(x, args[0]);
   return isolate->transcendental_cache()->Get(TranscendentalCache::LOG, x);
 }
 
 
-// Helper function to compute x^y, where y is known to be an
-// integer. Uses binary decomposition to limit the number of
-// multiplications; see the discussion in "Hacker's Delight" by Henry
-// S. Warren, Jr., figure 11-6, page 213.
-static double powi(double x, int y) {
-  ASSERT(y != kMinInt);
-  unsigned n = (y < 0) ? -y : y;
-  double m = x;
-  double p = 1;
-  while (true) {
-    if ((n & 1) != 0) p *= m;
-    n >>= 1;
-    if (n == 0) {
-      if (y < 0) {
-        // Unfortunately, we have to be careful when p has reached
-        // infinity in the computation, because sometimes the higher
-        // internal precision in the pow() implementation would have
-        // given us a finite p. This happens very rarely.
-        double result = 1.0 / p;
-        return (result == 0 && isinf(p))
-            ? pow(x, static_cast<double>(y))  // Avoid pow(double, int).
-            : result;
-      } else {
-        return p;
-      }
-    }
-    m *= m;
-  }
-}
-
-
 static MaybeObject* Runtime_Math_pow(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
   isolate->counters()->math_pow()->Increment();
 
   CONVERT_DOUBLE_CHECKED(x, args[0]);
 
   // If the second argument is a smi, it is much faster to call the
   // custom powi() function than the generic pow().
   if (args[1]->IsSmi()) {
     int y = Smi::cast(args[1])->value();
-    return isolate->heap()->NumberFromDouble(powi(x, y));
+    return isolate->heap()->NumberFromDouble(power_double_int(x, y));
   }
 
   CONVERT_DOUBLE_CHECKED(y, args[1]);
-
-  if (!isinf(x)) {
-    if (y == 0.5) {
-      // It's not uncommon to use Math.pow(x, 0.5) to compute the
-      // square root of a number. To speed up such computations, we
-      // explictly check for this case and use the sqrt() function
-      // which is faster than pow().
-      return isolate->heap()->AllocateHeapNumber(sqrt(x));
-    } else if (y == -0.5) {
-      // Optimized using Math.pow(x, -0.5) == 1 / Math.pow(x, 0.5).
-      return isolate->heap()->AllocateHeapNumber(1.0 / sqrt(x));
-    }
-  }
-
-  if (y == 0) {
-    return Smi::FromInt(1);
-  } else if (isnan(y) || ((x == 1 || x == -1) && isinf(y))) {
-    return isolate->heap()->nan_value();
-  } else {
-    return isolate->heap()->AllocateHeapNumber(pow(x, y));
-  }
+  return isolate->heap()->AllocateHeapNumber(power_double_double(x, y));
 }
 
 // Fast version of Math.pow if we know that y is not an integer and
 // y is not -0.5 or 0.5. Used as slowcase from codegen.
 static MaybeObject* Runtime_Math_pow_cfunction(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   NoHandleAllocation ha;
   ASSERT(args.length() == 2);
   CONVERT_DOUBLE_CHECKED(x, args[0]);
   CONVERT_DOUBLE_CHECKED(y, args[1]);
   if (y == 0) {
-      return Smi::FromInt(1);
+    return Smi::FromInt(1);
   } else if (isnan(y) || ((x == 1 || x == -1) && isinf(y))) {
-      return isolate->heap()->nan_value();
+    return isolate->heap()->nan_value();
   } else {
-      return isolate->heap()->AllocateHeapNumber(pow(x, y));
+    return isolate->heap()->AllocateHeapNumber(pow(x, y));
   }
 }
 
 
 static MaybeObject* Runtime_RoundNumber(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   NoHandleAllocation ha;
   ASSERT(args.length() == 1);
   isolate->counters()->math_round()->Increment();
 
@@ skipping 834 matching lines @@
       function->PrintName();
       PrintF("]\n");
     }
 
     // Try to compile the optimized code.  A true return value from
     // CompileOptimized means that compilation succeeded, not necessarily
     // that optimization succeeded.
     if (CompileOptimized(function, ast_id) && function->IsOptimized()) {
       DeoptimizationInputData* data = DeoptimizationInputData::cast(
           function->code()->deoptimization_data());
-      if (FLAG_trace_osr) {
-        PrintF("[on-stack replacement offset %d in optimized code]\n",
+      if (data->OsrPcOffset()->value() >= 0) {
+        if (FLAG_trace_osr) {
+          PrintF("[on-stack replacement offset %d in optimized code]\n",
                data->OsrPcOffset()->value());
+        }
+        ASSERT(data->OsrAstId()->value() == ast_id);
+      } else {
+        // We may never generate the desired OSR entry if we emit an
+        // early deoptimize.
+        succeeded = false;
       }
-      ASSERT(data->OsrAstId()->value() == ast_id);
-      ASSERT(data->OsrPcOffset()->value() >= 0);
     } else {
       succeeded = false;
     }
   }
 
   // Revert to the original stack checks in the original unoptimized code.
   if (FLAG_trace_osr) {
     PrintF("[restoring original stack checks in ");
     function->PrintName();
     PrintF("]\n");
@@ skipping 313 matching lines @@
     // The property was not found. It needs to be stored in the global context.
     ASSERT(attributes == ABSENT);
     attributes = NONE;
     context_ext = Handle<JSObject>(isolate->context()->global());
   }
 
   // Set the property, but ignore if read_only variable on the context
   // extension object itself.
   if ((attributes & READ_ONLY) == 0 ||
       (context_ext->GetLocalPropertyAttribute(*name) == ABSENT)) {
-    Handle<Object> set = SetProperty(context_ext, name, value, attributes);
+    Handle<Object> set = SetProperty(context_ext, name, value, NONE);
     if (set.is_null()) {
       // Failure::Exception is converted to a null handle in the
       // handle-based methods such as SetProperty.  We therefore need
       // to convert null handles back to exceptions.
       ASSERT(isolate->has_pending_exception());
       return Failure::Exception();
     }
   }
   return *value;
 }
@@ skipping 467 matching lines @@
   Object* allocation;
   { MaybeObject* maybe_allocation = heap->new_space()->AllocateRaw(size);
     if (maybe_allocation->ToObject(&allocation)) {
       heap->CreateFillerObjectAt(HeapObject::cast(allocation)->address(), size);
     }
     return maybe_allocation;
   }
 }
 
 
-// Push an array unto an array of arrays if it is not already in the
+// Push an object unto an array of objects if it is not already in the
 // array.  Returns true if the element was pushed on the stack and
 // false otherwise.
 static MaybeObject* Runtime_PushIfAbsent(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   ASSERT(args.length() == 2);
   CONVERT_CHECKED(JSArray, array, args[0]);
-  CONVERT_CHECKED(JSArray, element, args[1]);
+  CONVERT_CHECKED(JSObject, element, args[1]);
   RUNTIME_ASSERT(array->HasFastElements());
   int length = Smi::cast(array->length())->value();
   FixedArray* elements = FixedArray::cast(array->elements());
   for (int i = 0; i < length; i++) {
     if (elements->get(i) == element) return isolate->heap()->false_value();
   }
   Object* obj;
   { MaybeObject* maybe_obj = array->SetFastElement(length, element);
     if (!maybe_obj->ToObject(&obj)) return maybe_obj;
   }
@@ skipping 2075 matching lines @@
 // This function and the context acts as replacements for the function on the
 // stack frame presenting the same view of the values of parameters and
 // local variables as if the piece of JavaScript was evaluated at the point
 // where the function on the stack frame is currently stopped.
 static MaybeObject* Runtime_DebugEvaluate(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   HandleScope scope(isolate);
 
   // Check the execution state and decode arguments frame and source to be
   // evaluated.
-  ASSERT(args.length() == 4);
+  ASSERT(args.length() == 5);
   Object* check_result;
   { MaybeObject* maybe_check_result = Runtime_CheckExecutionState(args,
                                                                   isolate);
     if (!maybe_check_result->ToObject(&check_result)) {
       return maybe_check_result;
     }
   }
   CONVERT_CHECKED(Smi, wrapped_id, args[1]);
   CONVERT_ARG_CHECKED(String, source, 2);
   CONVERT_BOOLEAN_CHECKED(disable_break, args[3]);
+  Handle<Object> additional_context(args[4]);
 
   // Handle the processing of break.
   DisableBreak disable_break_save(disable_break);
 
   // Get the frame where the debugging is performed.
   StackFrame::Id id = UnwrapFrameId(wrapped_id);
   JavaScriptFrameIterator it(id);
   JavaScriptFrame* frame = it.frame();
   Handle<JSFunction> function(JSFunction::cast(frame->function()));
   Handle<SerializedScopeInfo> scope_info(function->shared()->scope_info());
@@ skipping 32 matching lines @@
   // object build.
   Handle<Context> context =
       isolate->factory()->NewFunctionContext(Context::MIN_CONTEXT_SLOTS,
                                              go_between);
   context->set_extension(*local_scope);
   // Copy any with contexts present and chain them in front of this context.
   Handle<Context> frame_context(Context::cast(frame->context()));
   Handle<Context> function_context(frame_context->fcontext());
   context = CopyWithContextChain(frame_context, context);
 
+  if (additional_context->IsJSObject()) {
+    context = isolate->factory()->NewWithContext(context,
+        Handle<JSObject>::cast(additional_context), false);
+  }
+
   // Wrap the evaluation statement in a new function compiled in the newly
   // created context. The function has one parameter which has to be called
   // 'arguments'. This it to have access to what would have been 'arguments' in
   // the function being debugged.
   // function(arguments,__source__) {return eval(__source__);}
 
   Handle<String> function_source =
       isolate->factory()->NewStringFromAscii(
           Vector<const char>(kSourceStr, sizeof(kSourceStr) - 1));
   Handle<SharedFunctionInfo> shared =
@@ skipping 34 matching lines @@
   return *result;
 }
 
 
 static MaybeObject* Runtime_DebugEvaluateGlobal(RUNTIME_CALLING_CONVENTION) {
   RUNTIME_GET_ISOLATE;
   HandleScope scope(isolate);
 
   // Check the execution state and decode arguments frame and source to be
   // evaluated.
-  ASSERT(args.length() == 3);
+  ASSERT(args.length() == 4);
   Object* check_result;
   { MaybeObject* maybe_check_result = Runtime_CheckExecutionState(args,
                                                                   isolate);
     if (!maybe_check_result->ToObject(&check_result)) {
       return maybe_check_result;
     }
   }
   CONVERT_ARG_CHECKED(String, source, 1);
   CONVERT_BOOLEAN_CHECKED(disable_break, args[2]);
+  Handle<Object> additional_context(args[3]);
 
   // Handle the processing of break.
   DisableBreak disable_break_save(disable_break);
 
   // Enter the top context from before the debugger was invoked.
   SaveContext save(isolate);
   SaveContext* top = &save;
   while (top != NULL && *top->context() == *isolate->debug()->debug_context()) {
     top = top->prev();
   }
   if (top != NULL) {
     isolate->set_context(*top->context());
   }
 
   // Get the global context now set to the top context from before the
   // debugger was invoked.
   Handle<Context> context = isolate->global_context();
 
+  bool is_global = true;
+
+  if (additional_context->IsJSObject()) {
+    // Create a function context first, than put 'with' context on top of it.
+    Handle<JSFunction> go_between = isolate->factory()->NewFunction(
+        isolate->factory()->empty_string(),
+        isolate->factory()->undefined_value());
+    go_between->set_context(*context);
+    context =
+        isolate->factory()->NewFunctionContext(
+            Context::MIN_CONTEXT_SLOTS, go_between);
+    context->set_extension(JSObject::cast(*additional_context));
+    is_global = false;
+  }
+
   // Compile the source to be evaluated.
   Handle<SharedFunctionInfo> shared =
       Compiler::CompileEval(source,
                             context,
-                            true);
+                            is_global);
   if (shared.is_null()) return Failure::Exception();
   Handle<JSFunction> compiled_function =
       Handle<JSFunction>(
           isolate->factory()->NewFunctionFromSharedFunctionInfo(shared,
                                                                 context));
 
   // Invoke the result of the compilation to get the evaluation function.
   bool has_pending_exception;
   Handle<Object> receiver = isolate->global();
   Handle<Object> result =
@@ skipping 984 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     COUNTERS->gc_last_resort_from_js()->Increment();
     HEAP->CollectAllGarbage(false);
   }
 }
 
 
 } }  // namespace v8::internal