diff --git a/src/extensions/statistics-extension.cc b/src/extensions/statistics-extension.cc
index 32bc07de8b..651d99d452 100644
--- a/src/extensions/statistics-extension.cc
+++ b/src/extensions/statistics-extension.cc
@@ -60,7 +60,7 @@ static void AddNumber(v8::Local<v8::Object> object,
 
 void StatisticsExtension::GetCounters(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = reinterpret_cast<Isolate*>(args.GetIsolate());
   Heap* heap = isolate->heap();
 
   if (args.Length() > 0) {  // GC if first argument evaluates to true.
diff --git a/src/factory.cc b/src/factory.cc
index 3d949210d4..c7f7806fc1 100644
--- a/src/factory.cc
+++ b/src/factory.cc
@@ -130,7 +130,8 @@ Handle<DescriptorArray> Factory::NewDescriptorArray(int number_of_descriptors,
                                                     int slack) {
   ASSERT(0 <= number_of_descriptors);
   CALL_HEAP_FUNCTION(isolate(),
-                     DescriptorArray::Allocate(number_of_descriptors, slack),
+                     DescriptorArray::Allocate(
+                         isolate(), number_of_descriptors, slack),
                      DescriptorArray);
 }
 
diff --git a/src/heap.cc b/src/heap.cc
index bd341e3fbb..722705f6b7 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -1027,7 +1027,7 @@ bool Heap::PerformGarbageCollection(GarbageCollector collector,
   isolate_->eternal_handles()->PostGarbageCollectionProcessing(this);
 
   // Update relocatables.
-  Relocatable::PostGarbageCollectionProcessing();
+  Relocatable::PostGarbageCollectionProcessing(isolate_);
 
   if (collector == MARK_COMPACTOR) {
     // Register the amount of external allocated memory.
@@ -2938,7 +2938,7 @@ MaybeObject* Heap::CreateOddball(const char* to_string,
   { MaybeObject* maybe_result = Allocate(oddball_map(), OLD_POINTER_SPACE);
     if (!maybe_result->ToObject(&result)) return maybe_result;
   }
-  return Oddball::cast(result)->Initialize(to_string, to_number, kind);
+  return Oddball::cast(result)->Initialize(this, to_string, to_number, kind);
 }
 
 
@@ -3042,15 +3042,16 @@ bool Heap::CreateInitialObjects() {
 
   // Finish initializing oddballs after creating the string table.
   { MaybeObject* maybe_obj =
-        undefined_value()->Initialize("undefined",
+        undefined_value()->Initialize(this,
+                                      "undefined",
                                       nan_value(),
                                       Oddball::kUndefined);
     if (!maybe_obj->ToObject(&obj)) return false;
   }
 
   // Initialize the null_value.
-  { MaybeObject* maybe_obj =
-        null_value()->Initialize("null", Smi::FromInt(0), Oddball::kNull);
+  { MaybeObject* maybe_obj = null_value()->Initialize(
+      this, "null", Smi::FromInt(0), Oddball::kNull);
     if (!maybe_obj->ToObject(&obj)) return false;
   }
 
@@ -6574,7 +6575,7 @@ void Heap::IterateStrongRoots(ObjectVisitor* v, VisitMode mode) {
   v->Synchronize(VisitorSynchronization::kBootstrapper);
   isolate_->Iterate(v);
   v->Synchronize(VisitorSynchronization::kTop);
-  Relocatable::Iterate(v);
+  Relocatable::Iterate(isolate_, v);
   v->Synchronize(VisitorSynchronization::kRelocatable);
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
diff --git a/src/jsregexp.cc b/src/jsregexp.cc
index 0ce10b8c3d..5c79477eb1 100644
--- a/src/jsregexp.cc
+++ b/src/jsregexp.cc
@@ -1869,7 +1869,7 @@ static void EmitUseLookupTable(
   for (int i = j; i < kSize; i++) {
     templ[i] = bit;
   }
-  Factory* factory = Isolate::Current()->factory();
+  Factory* factory = masm->zone()->isolate()->factory();
   // TODO(erikcorry): Cache these.
   Handle<ByteArray> ba = factory->NewByteArray(kSize, TENURED);
   for (int i = 0; i < kSize; i++) {
@@ -2548,7 +2548,7 @@ void TextNode::GetQuickCheckDetails(QuickCheckDetails* details,
                                     RegExpCompiler* compiler,
                                     int characters_filled_in,
                                     bool not_at_start) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = compiler->macro_assembler()->zone()->isolate();
   ASSERT(characters_filled_in < details->characters());
   int characters = details->characters();
   int char_mask;
@@ -3246,8 +3246,8 @@ void TextNode::TextEmitPass(RegExpCompiler* compiler,
                             Trace* trace,
                             bool first_element_checked,
                             int* checked_up_to) {
-  Isolate* isolate = Isolate::Current();
   RegExpMacroAssembler* assembler = compiler->macro_assembler();
+  Isolate* isolate = assembler->zone()->isolate();
   bool ascii = compiler->ascii();
   Label* backtrack = trace->backtrack();
   QuickCheckDetails* quick_check = trace->quick_check_performed();
@@ -3820,7 +3820,7 @@ bool BoyerMooreLookahead::EmitSkipInstructions(RegExpMacroAssembler* masm) {
     return true;
   }
 
-  Factory* factory = Isolate::Current()->factory();
+  Factory* factory = masm->zone()->isolate()->factory();
   Handle<ByteArray> boolean_skip_table = factory->NewByteArray(kSize, TENURED);
   int skip_distance = GetSkipTable(
       min_lookahead, max_lookahead, boolean_skip_table);
@@ -5292,7 +5292,7 @@ void CharacterRange::Split(ZoneList<CharacterRange>* base,
 void CharacterRange::AddCaseEquivalents(ZoneList<CharacterRange>* ranges,
                                         bool is_ascii,
                                         Zone* zone) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = zone->isolate();
   uc16 bottom = from();
   uc16 top = to();
   if (is_ascii && !RangeContainsLatin1Equivalents(*this)) {
@@ -5680,7 +5680,7 @@ OutSet* DispatchTable::Get(uc16 value) {
 
 
 void Analysis::EnsureAnalyzed(RegExpNode* that) {
-  StackLimitCheck check(Isolate::Current());
+  StackLimitCheck check(that->zone()->isolate());
   if (check.HasOverflowed()) {
     fail("Stack overflow");
     return;
diff --git a/src/liveedit.cc b/src/liveedit.cc
index b6ac0461c4..c3ccdf0bec 100644
--- a/src/liveedit.cc
+++ b/src/liveedit.cc
@@ -631,8 +631,8 @@ static Handle<Object> UnwrapJSValue(Handle<JSValue> jsValue) {
 
 // Wraps any object into a OpaqueReference, that will hide the object
 // from JavaScript.
-static Handle<JSValue> WrapInJSValue(Handle<Object> object) {
-  Isolate* isolate = Isolate::Current();
+static Handle<JSValue> WrapInJSValue(Handle<HeapObject> object) {
+  Isolate* isolate = object->GetIsolate();
   Handle<JSFunction> constructor = isolate->opaque_reference_function();
   Handle<JSValue> result =
       Handle<JSValue>::cast(isolate->factory()->NewJSObject(constructor));
@@ -662,8 +662,8 @@ static int GetArrayLength(Handle<JSArray> array) {
 template<typename S>
 class JSArrayBasedStruct {
  public:
-  static S Create() {
-    Factory* factory = Isolate::Current()->factory();
+  static S Create(Isolate* isolate) {
+    Factory* factory = isolate->factory();
     Handle<JSArray> array = factory->NewJSArray(S::kSize_);
     return S(array);
   }
@@ -724,7 +724,7 @@ class FunctionInfoWrapper : public JSArrayBasedStruct<FunctionInfoWrapper> {
     this->SetSmiValueField(kParentIndexOffset_, parent_index);
   }
   void SetFunctionCode(Handle<Code> function_code,
-      Handle<Object> code_scope_info) {
+      Handle<HeapObject> code_scope_info) {
     Handle<JSValue> code_wrapper = WrapInJSValue(function_code);
     this->SetField(kCodeOffset_, code_wrapper);
 
@@ -833,7 +833,7 @@ class FunctionInfoListener {
 
   void FunctionStarted(FunctionLiteral* fun) {
     HandleScope scope(isolate());
-    FunctionInfoWrapper info = FunctionInfoWrapper::Create();
+    FunctionInfoWrapper info = FunctionInfoWrapper::Create(isolate());
     info.SetInitialProperties(fun->name(), fun->start_position(),
                               fun->end_position(), fun->parameter_count(),
                               fun->materialized_literal_count(),
@@ -860,8 +860,7 @@ class FunctionInfoListener {
             result_->GetElementNoExceptionThrown(
                 isolate(), current_parent_index_));
     info.SetFunctionCode(function_code,
-                         Handle<Object>(isolate()->heap()->null_value(),
-                                        isolate()));
+                         Handle<HeapObject>(isolate()->heap()->null_value()));
   }
 
   // Saves full information about a function: its code, its scope info
@@ -876,7 +875,7 @@ class FunctionInfoListener {
             result_->GetElementNoExceptionThrown(
                 isolate(), current_parent_index_));
     info.SetFunctionCode(Handle<Code>(shared->code()),
-                         Handle<Object>(shared->scope_info(), isolate()));
+                         Handle<HeapObject>(shared->scope_info()));
     info.SetSharedFunctionInfo(shared);
 
     Handle<Object> scope_info_list(SerializeFunctionScope(scope, zone),
@@ -939,7 +938,7 @@ class FunctionInfoListener {
 
 JSArray* LiveEdit::GatherCompileInfo(Handle<Script> script,
                                      Handle<String> source) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = script->GetIsolate();
 
   FunctionInfoListener listener(isolate);
   Handle<Object> original_source =
@@ -1011,8 +1010,8 @@ void LiveEdit::WrapSharedFunctionInfos(Handle<JSArray> array) {
   for (int i = 0; i < len; i++) {
     Handle<SharedFunctionInfo> info(
         SharedFunctionInfo::cast(
-            array->GetElementNoExceptionThrown(array->GetIsolate(), i)));
-    SharedInfoWrapper info_wrapper = SharedInfoWrapper::Create();
+            array->GetElementNoExceptionThrown(isolate, i)));
+    SharedInfoWrapper info_wrapper = SharedInfoWrapper::Create(isolate);
     Handle<String> name_handle(String::cast(info->name()));
     info_wrapper.SetProperties(name_handle, info->start_position(),
                                info->end_position(), info);
@@ -1275,7 +1274,7 @@ static void DeoptimizeDependentFunctions(SharedFunctionInfo* function_info) {
 MaybeObject* LiveEdit::ReplaceFunctionCode(
     Handle<JSArray> new_compile_info_array,
     Handle<JSArray> shared_info_array) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = new_compile_info_array->GetIsolate();
   HandleScope scope(isolate);
 
   if (!SharedInfoWrapper::IsInstance(shared_info_array)) {
@@ -1349,7 +1348,7 @@ void LiveEdit::SetFunctionScript(Handle<JSValue> function_wrapper,
   CHECK(script_handle->IsScript() || script_handle->IsUndefined());
   shared_info->set_script(*script_handle);
 
-  Isolate::Current()->compilation_cache()->Remove(shared_info);
+  function_wrapper->GetIsolate()->compilation_cache()->Remove(shared_info);
 }
 
 
@@ -1518,7 +1517,7 @@ static Handle<Code> PatchPositionsInCode(
 MaybeObject* LiveEdit::PatchFunctionPositions(
     Handle<JSArray> shared_info_array, Handle<JSArray> position_change_array) {
   if (!SharedInfoWrapper::IsInstance(shared_info_array)) {
-    return Isolate::Current()->ThrowIllegalOperation();
+    return shared_info_array->GetIsolate()->ThrowIllegalOperation();
   }
 
   SharedInfoWrapper shared_info_wrapper(shared_info_array);
@@ -1662,7 +1661,7 @@ static bool CheckActivation(Handle<JSArray> shared_info_array,
 static bool FixTryCatchHandler(StackFrame* top_frame,
                                StackFrame* bottom_frame) {
   Address* pointer_address =
-      &Memory::Address_at(Isolate::Current()->get_address_from_id(
+      &Memory::Address_at(top_frame->isolate()->get_address_from_id(
           Isolate::kHandlerAddress));
 
   while (*pointer_address < top_frame->sp()) {
@@ -1698,7 +1697,7 @@ static const char* DropFrames(Vector<StackFrame*> frames,
   ASSERT(bottom_js_frame->is_java_script());
 
   // Check the nature of the top frame.
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = bottom_js_frame->isolate();
   Code* pre_top_frame_code = pre_top_frame->LookupCode();
   bool frame_has_padding;
   if (pre_top_frame_code->is_inline_cache_stub() &&
@@ -1801,7 +1800,7 @@ static const char* DropFrames(Vector<StackFrame*> frames,
   // Make sure FixTryCatchHandler is idempotent.
   ASSERT(!FixTryCatchHandler(pre_top_frame, bottom_js_frame));
 
-  Handle<Code> code = Isolate::Current()->builtins()->FrameDropper_LiveEdit();
+  Handle<Code> code = isolate->builtins()->FrameDropper_LiveEdit();
   *top_frame_pc_address = code->entry();
   pre_top_frame->SetCallerFp(bottom_js_frame->fp());
 
@@ -1849,8 +1848,7 @@ class MultipleFunctionTarget {
 // Drops all call frame matched by target and all frames above them.
 template<typename TARGET>
 static const char* DropActivationsInActiveThreadImpl(
-    TARGET& target, bool do_drop) {
-  Isolate* isolate = Isolate::Current();
+    Isolate* isolate, TARGET& target, bool do_drop) {
   Debug* debug = isolate->debug();
   Zone zone(isolate);
   Vector<StackFrame*> frames = CreateStackMap(isolate, &zone);
@@ -1949,8 +1947,8 @@ static const char* DropActivationsInActiveThread(
     Handle<JSArray> shared_info_array, Handle<JSArray> result, bool do_drop) {
   MultipleFunctionTarget target(shared_info_array, result);
 
-  const char* message =
-      DropActivationsInActiveThreadImpl(target, do_drop);
+  const char* message = DropActivationsInActiveThreadImpl(
+      shared_info_array->GetIsolate(), target, do_drop);
   if (message) {
     return message;
   }
@@ -2015,7 +2013,7 @@ Handle<JSArray> LiveEdit::CheckAndDropActivations(
   // First check inactive threads. Fail if some functions are blocked there.
   InactiveThreadActivationsChecker inactive_threads_checker(shared_info_array,
                                                             result);
-  Isolate::Current()->thread_manager()->IterateArchivedThreads(
+  isolate->thread_manager()->IterateArchivedThreads(
       &inactive_threads_checker);
   if (inactive_threads_checker.HasBlockedFunctions()) {
     return result;
@@ -2067,7 +2065,8 @@ class SingleFrameTarget {
 const char* LiveEdit::RestartFrame(JavaScriptFrame* frame) {
   SingleFrameTarget target(frame);
 
-  const char* result = DropActivationsInActiveThreadImpl(target, true);
+  const char* result = DropActivationsInActiveThreadImpl(
+      frame->isolate(), target, true);
   if (result != NULL) {
     return result;
   }
diff --git a/src/log.cc b/src/log.cc
index 74541df6d9..1b3301e672 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -1764,21 +1764,21 @@ void Logger::LogAccessorCallbacks() {
 }
 
 
-static void AddIsolateIdIfNeeded(StringStream* stream) {
-  Isolate* isolate = Isolate::Current();
+static void AddIsolateIdIfNeeded(Isolate* isolate, StringStream* stream) {
   if (isolate->IsDefaultIsolate()) return;
   stream->Add("isolate-%p-", isolate);
 }
 
 
-static SmartArrayPointer<const char> PrepareLogFileName(const char* file_name) {
+static SmartArrayPointer<const char> PrepareLogFileName(
+    Isolate* isolate, const char* file_name) {
   if (strchr(file_name, '%') != NULL ||
-      !Isolate::Current()->IsDefaultIsolate()) {
+      !isolate->IsDefaultIsolate()) {
     // If there's a '%' in the log file name we have to expand
     // placeholders.
     HeapStringAllocator allocator;
     StringStream stream(&allocator);
-    AddIsolateIdIfNeeded(&stream);
+    AddIsolateIdIfNeeded(isolate, &stream);
     for (const char* p = file_name; *p; p++) {
       if (*p == '%') {
         p++;
@@ -1832,7 +1832,7 @@ bool Logger::SetUp(Isolate* isolate) {
   }
 
   SmartArrayPointer<const char> log_file_name =
-      PrepareLogFileName(FLAG_logfile);
+      PrepareLogFileName(isolate, FLAG_logfile);
   log_->Initialize(*log_file_name);
 
   if (FLAG_ll_prof) {
diff --git a/src/objects.cc b/src/objects.cc
index bed3834246..56f267a676 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -6584,7 +6584,7 @@ MaybeObject* Map::ShareDescriptor(DescriptorArray* descriptors,
   } else {
     // Descriptor arrays grow by 50%.
     MaybeObject* maybe_descriptors = DescriptorArray::Allocate(
-        old_size, old_size < 4 ? 1 : old_size / 2);
+        GetIsolate(), old_size, old_size < 4 ? 1 : old_size / 2);
     if (!maybe_descriptors->To(&new_descriptors)) return maybe_descriptors;
 
     DescriptorArray::WhitenessWitness witness(new_descriptors);
@@ -6834,7 +6834,8 @@ MaybeObject* Map::CopyAddDescriptor(Descriptor* descriptor,
   }
 
   DescriptorArray* new_descriptors;
-  MaybeObject* maybe_descriptors = DescriptorArray::Allocate(old_size, 1);
+  MaybeObject* maybe_descriptors =
+      DescriptorArray::Allocate(GetIsolate(), old_size, 1);
   if (!maybe_descriptors->To(&new_descriptors)) return maybe_descriptors;
 
   DescriptorArray::WhitenessWitness witness(new_descriptors);
@@ -6881,7 +6882,7 @@ MaybeObject* DescriptorArray::CopyUpToAddAttributes(
   int size = enumeration_index;
 
   DescriptorArray* descriptors;
-  MaybeObject* maybe_descriptors = Allocate(size);
+  MaybeObject* maybe_descriptors = Allocate(GetIsolate(), size);
   if (!maybe_descriptors->To(&descriptors)) return maybe_descriptors;
   DescriptorArray::WhitenessWitness witness(descriptors);
 
@@ -6928,7 +6929,8 @@ MaybeObject* Map::CopyReplaceDescriptor(DescriptorArray* descriptors,
   ASSERT_LT(insertion_index, new_size);
 
   DescriptorArray* new_descriptors;
-  MaybeObject* maybe_descriptors = DescriptorArray::Allocate(new_size);
+  MaybeObject* maybe_descriptors =
+      DescriptorArray::Allocate(GetIsolate(), new_size);
   if (!maybe_descriptors->To(&new_descriptors)) return maybe_descriptors;
   DescriptorArray::WhitenessWitness witness(new_descriptors);
 
@@ -7718,8 +7720,10 @@ bool FixedArray::IsEqualTo(FixedArray* other) {
 #endif
 
 
-MaybeObject* DescriptorArray::Allocate(int number_of_descriptors, int slack) {
-  Heap* heap = Isolate::Current()->heap();
+MaybeObject* DescriptorArray::Allocate(Isolate* isolate,
+                                       int number_of_descriptors,
+                                       int slack) {
+  Heap* heap = isolate->heap();
   // Do not use DescriptorArray::cast on incomplete object.
   int size = number_of_descriptors + slack;
   if (size == 0) return heap->empty_descriptor_array();
@@ -7787,7 +7791,8 @@ MaybeObject* DescriptorArray::Merge(int verbatim,
   // Allocate a new descriptor array large enough to hold the required
   // descriptors, with minimally the exact same size as this descriptor array.
   MaybeObject* maybe_descriptors = DescriptorArray::Allocate(
-      new_size, Max(new_size, other->number_of_descriptors()) - new_size);
+      GetIsolate(), new_size,
+      Max(new_size, other->number_of_descriptors()) - new_size);
   if (!maybe_descriptors->To(&result)) return maybe_descriptors;
   ASSERT(result->length() > length() ||
          result->NumberOfSlackDescriptors() > 0 ||
@@ -8003,7 +8008,7 @@ bool Name::IsCacheable(Isolate* isolate) {
 
 
 bool String::LooksValid() {
-  if (!Isolate::Current()->heap()->Contains(this)) return false;
+  if (!GetIsolate()->heap()->Contains(this)) return false;
   return true;
 }
 
@@ -8163,8 +8168,7 @@ const uc16* SeqTwoByteString::SeqTwoByteStringGetData(unsigned start) {
 }
 
 
-void Relocatable::PostGarbageCollectionProcessing() {
-  Isolate* isolate = Isolate::Current();
+void Relocatable::PostGarbageCollectionProcessing(Isolate* isolate) {
   Relocatable* current = isolate->relocatable_top();
   while (current != NULL) {
     current->PostGarbageCollection();
@@ -8174,8 +8178,8 @@ void Relocatable::PostGarbageCollectionProcessing() {
 
 
 // Reserve space for statics needing saving and restoring.
-int Relocatable::ArchiveSpacePerThread() {
-  return sizeof(Isolate::Current()->relocatable_top());
+int Relocatable::ArchiveSpacePerThread(Isolate* isolate) {
+  return sizeof(isolate->relocatable_top());
 }
 
 
@@ -8183,26 +8187,26 @@ int Relocatable::ArchiveSpacePerThread() {
 char* Relocatable::ArchiveState(Isolate* isolate, char* to) {
   *reinterpret_cast<Relocatable**>(to) = isolate->relocatable_top();
   isolate->set_relocatable_top(NULL);
-  return to + ArchiveSpacePerThread();
+  return to + ArchiveSpacePerThread(isolate);
 }
 
 
 // Restore statics that are thread local.
 char* Relocatable::RestoreState(Isolate* isolate, char* from) {
   isolate->set_relocatable_top(*reinterpret_cast<Relocatable**>(from));
-  return from + ArchiveSpacePerThread();
+  return from + ArchiveSpacePerThread(isolate);
 }
 
 
-char* Relocatable::Iterate(ObjectVisitor* v, char* thread_storage) {
+char* Relocatable::Iterate(
+    Isolate* isolate, ObjectVisitor* v, char* thread_storage) {
   Relocatable* top = *reinterpret_cast<Relocatable**>(thread_storage);
   Iterate(v, top);
-  return thread_storage + ArchiveSpacePerThread();
+  return thread_storage + ArchiveSpacePerThread(isolate);
 }
 
 
-void Relocatable::Iterate(ObjectVisitor* v) {
-  Isolate* isolate = Isolate::Current();
+void Relocatable::Iterate(Isolate* isolate, ObjectVisitor* v) {
   Iterate(v, isolate->relocatable_top());
 }
 
@@ -9316,7 +9320,7 @@ static bool CompileLazyHelper(CompilationInfo* info,
   ASSERT(info->IsOptimizing() || !info->shared_info()->is_compiled());
   ASSERT(!info->isolate()->has_pending_exception());
   bool result = Compiler::CompileLazy(info);
-  ASSERT(result != Isolate::Current()->has_pending_exception());
+  ASSERT(result != info->isolate()->has_pending_exception());
   if (!result && flag == CLEAR_EXCEPTION) {
     info->isolate()->clear_pending_exception();
   }
@@ -9706,12 +9710,13 @@ bool JSFunction::PassesFilter(const char* raw_filter) {
 }
 
 
-MaybeObject* Oddball::Initialize(const char* to_string,
+MaybeObject* Oddball::Initialize(Heap* heap,
+                                 const char* to_string,
                                  Object* to_number,
                                  byte kind) {
   String* internalized_to_string;
   { MaybeObject* maybe_string =
-      Isolate::Current()->heap()->InternalizeUtf8String(
+      heap->InternalizeUtf8String(
           CStrVector(to_string));
     if (!maybe_string->To(&internalized_to_string)) return maybe_string;
   }
@@ -10432,7 +10437,7 @@ int Code::GetAge() {
 
 void Code::GetCodeAgeAndParity(Code* code, Age* age,
                                MarkingParity* parity) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = code->GetIsolate();
   Builtins* builtins = isolate->builtins();
   Code* stub = NULL;
 #define HANDLE_CODE_AGE(AGE)                                            \
@@ -15263,7 +15268,7 @@ MaybeObject* NameDictionary::TransformPropertiesToFastFor(
   // Allocate the instance descriptor.
   DescriptorArray* descriptors;
   MaybeObject* maybe_descriptors =
-      DescriptorArray::Allocate(instance_descriptor_length);
+      DescriptorArray::Allocate(GetIsolate(), instance_descriptor_length);
   if (!maybe_descriptors->To(&descriptors)) {
     return maybe_descriptors;
   }
@@ -15556,7 +15561,7 @@ void DebugInfo::ClearBreakPoint(Handle<DebugInfo> debug_info,
                                 int code_position,
                                 Handle<Object> break_point_object) {
   Handle<Object> break_point_info(debug_info->GetBreakPointInfo(code_position),
-                                  Isolate::Current());
+                                  debug_info->GetIsolate());
   if (break_point_info->IsUndefined()) return;
   BreakPointInfo::ClearBreakPoint(
       Handle<BreakPointInfo>::cast(break_point_info),
@@ -15569,7 +15574,7 @@ void DebugInfo::SetBreakPoint(Handle<DebugInfo> debug_info,
                               int source_position,
                               int statement_position,
                               Handle<Object> break_point_object) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = debug_info->GetIsolate();
   Handle<Object> break_point_info(debug_info->GetBreakPointInfo(code_position),
                                   isolate);
   if (!break_point_info->IsUndefined()) {
@@ -15683,7 +15688,7 @@ int DebugInfo::GetBreakPointInfoIndex(int code_position) {
 // Remove the specified break point object.
 void BreakPointInfo::ClearBreakPoint(Handle<BreakPointInfo> break_point_info,
                                      Handle<Object> break_point_object) {
-  Isolate* isolate = Isolate::Current();
+  Isolate* isolate = break_point_info->GetIsolate();
   // If there are no break points just ignore.
   if (break_point_info->break_point_objects()->IsUndefined()) return;
   // If there is a single break point clear it if it is the same.
diff --git a/src/objects.h b/src/objects.h
index d7339d627c..0a486dcff4 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -3186,7 +3186,8 @@ class DescriptorArray: public FixedArray {
 
   // Allocates a DescriptorArray, but returns the singleton
   // empty descriptor array object if number_of_descriptors is 0.
-  MUST_USE_RESULT static MaybeObject* Allocate(int number_of_descriptors,
+  MUST_USE_RESULT static MaybeObject* Allocate(Isolate* isolate,
+                                               int number_of_descriptors,
                                                int slack = 0);
 
   // Casting.
@@ -8724,13 +8725,14 @@ class Relocatable BASE_EMBEDDED {
   virtual void IterateInstance(ObjectVisitor* v) { }
   virtual void PostGarbageCollection() { }
 
-  static void PostGarbageCollectionProcessing();
-  static int ArchiveSpacePerThread();
+  static void PostGarbageCollectionProcessing(Isolate* isolate);
+  static int ArchiveSpacePerThread(Isolate* isolate);
   static char* ArchiveState(Isolate* isolate, char* to);
   static char* RestoreState(Isolate* isolate, char* from);
-  static void Iterate(ObjectVisitor* v);
+  static void Iterate(Isolate* isolate, ObjectVisitor* v);
   static void Iterate(ObjectVisitor* v, Relocatable* top);
-  static char* Iterate(ObjectVisitor* v, char* t);
+  static char* Iterate(Isolate* isolate, ObjectVisitor* v, char* t);
+
  private:
   Isolate* isolate_;
   Relocatable* prev_;
@@ -8866,7 +8868,8 @@ class Oddball: public HeapObject {
   DECLARE_VERIFIER(Oddball)
 
   // Initialize the fields.
-  MUST_USE_RESULT MaybeObject* Initialize(const char* to_string,
+  MUST_USE_RESULT MaybeObject* Initialize(Heap* heap,
+                                          const char* to_string,
                                           Object* to_number,
                                           byte kind);
 
diff --git a/src/v8threads.cc b/src/v8threads.cc
index 33b620d8ea..17277a9c50 100644
--- a/src/v8threads.cc
+++ b/src/v8threads.cc
@@ -227,7 +227,7 @@ void ThreadManager::Unlock() {
 }
 
 
-static int ArchiveSpacePerThread() {
+static int ArchiveSpacePerThread(Isolate* isolate) {
   return HandleScopeImplementer::ArchiveSpacePerThread() +
                         Isolate::ArchiveSpacePerThread() +
 #ifdef ENABLE_DEBUGGER_SUPPORT
@@ -236,7 +236,7 @@ static int ArchiveSpacePerThread() {
                      StackGuard::ArchiveSpacePerThread() +
                     RegExpStack::ArchiveSpacePerThread() +
                    Bootstrapper::ArchiveSpacePerThread() +
-                    Relocatable::ArchiveSpacePerThread();
+                    Relocatable::ArchiveSpacePerThread(isolate);
 }
 
 
@@ -256,7 +256,7 @@ ThreadState::~ThreadState() {
 
 
 void ThreadState::AllocateSpace() {
-  data_ = NewArray<char>(ArchiveSpacePerThread());
+  data_ = NewArray<char>(ArchiveSpacePerThread(Isolate::Current()));
 }
 
 
@@ -396,7 +396,7 @@ void ThreadManager::Iterate(ObjectVisitor* v) {
     char* data = state->data();
     data = HandleScopeImplementer::Iterate(v, data);
     data = isolate_->Iterate(v, data);
-    data = Relocatable::Iterate(v, data);
+    data = Relocatable::Iterate(Isolate::Current(), v, data);
   }
 }