Fix for 3303 MultithreadedParallelIsolates has a race condition.

src/arm64/assembler-arm64-inl.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ARM64_ASSEMBLER_ARM64_INL_H_
 #define V8_ARM64_ASSEMBLER_ARM64_INL_H_
 
 #include "arm64/assembler-arm64.h"
 #include "cpu.h"
 #include "debug.h"
@@ skipping 697 matching lines @@
   ASSERT(rmode_ == RelocInfo::CELL);
   return Cell::FromValueAddress(Memory::Address_at(pc_));
 }
 
 
 void RelocInfo::set_target_cell(Cell* cell, WriteBarrierMode mode) {
   UNIMPLEMENTED();
 }
 
 
-static const int kCodeAgeSequenceSize = 5 * kInstructionSize;
+static const int kNoCodeAgeSequenceLength = 5 * kInstructionSize;
 static const int kCodeAgeStubEntryOffset = 3 * kInstructionSize;
 
 
 Handle<Object> RelocInfo::code_age_stub_handle(Assembler* origin) {
   UNREACHABLE();  // This should never be reached on ARM64.
   return Handle<Object>();
 }
 
 
 Code* RelocInfo::code_age_stub() {
   ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
-  ASSERT(!Code::IsYoungSequence(pc_));
   // Read the stub entry point from the code age sequence.
   Address stub_entry_address = pc_ + kCodeAgeStubEntryOffset;
   return Code::GetCodeFromTargetAddress(Memory::Address_at(stub_entry_address));
 }
 
 
 void RelocInfo::set_code_age_stub(Code* stub) {
   ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
-  ASSERT(!Code::IsYoungSequence(pc_));
+  ASSERT(!Code::IsYoungSequence(stub->GetIsolate(), pc_));
   // Overwrite the stub entry point in the code age sequence. This is loaded as
   // a literal so there is no need to call FlushICache here.
   Address stub_entry_address = pc_ + kCodeAgeStubEntryOffset;
   Memory::Address_at(stub_entry_address) = stub->instruction_start();
 }
 
 
 Address RelocInfo::call_address() {
   ASSERT((IsJSReturn(rmode()) && IsPatchedReturnSequence()) ||
          (IsDebugBreakSlot(rmode()) && IsPatchedDebugBreakSlotSequence()));
@@ skipping 448 matching lines @@
 
 
 void Assembler::ClearRecordedAstId() {
   recorded_ast_id_ = TypeFeedbackId::None();
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_ASSEMBLER_ARM64_INL_H_