Split Thread/Isolate instances, but still maintain 1:1 relationship.

runtime/vm/isolate.h

 // Copyright (c) 2013, 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.
 
 #ifndef VM_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/base_isolate.h"
 #include "vm/class_table.h"
 #include "vm/counters.h"
 #include "vm/handles.h"
 #include "vm/megamorphic_cache_table.h"
 #include "vm/metrics.h"
 #include "vm/random.h"
 #include "vm/store_buffer.h"
 #include "vm/tags.h"
+#include "vm/thread.h"
 #include "vm/os_thread.h"
 #include "vm/trace_buffer.h"
 #include "vm/timer.h"
 
 namespace dart {
 
 DECLARE_FLAG(bool, enable_type_checks);
 DECLARE_FLAG(bool, enable_asserts);
 DECLARE_FLAG(bool, error_on_bad_type);
 DECLARE_FLAG(bool, error_on_bad_override);
@@ skipping 82 matching lines @@
   V(PcDescriptors)                                                             \
   V(String)                                                                    \
   V(TypeArguments)                                                             \
   V(TypeParameter)                                                             \
 
 class Isolate : public BaseIsolate {
  public:
   ~Isolate();
 
   static inline Isolate* Current() {
-    return reinterpret_cast<Isolate*>(OSThread::GetThreadLocal(isolate_key));
+    Thread* thread = Thread::Current();
+    return thread == NULL ? NULL : thread->isolate();
   }
-
   static void SetCurrent(Isolate* isolate);
 
   static void InitOnce();
   static Isolate* Init(const char* name_prefix, bool is_vm_isolate = false);
   void Shutdown();
 
   Isolate* ShallowCopy();
 
   // Register a newly introduced class.
   void RegisterClass(const Class& cls);
@@ skipping 24 matching lines @@
     return &megamorphic_cache_table_;
   }
 
   Dart_MessageNotifyCallback message_notify_callback() const {
     return message_notify_callback_;
   }
   void set_message_notify_callback(Dart_MessageNotifyCallback value) {
     message_notify_callback_ = value;
   }
 
+  // A thread that operates on this isolate and may execute Dart code.
+  // No other threads operating on this isolate may execute Dart code.
+  // TODO(koda): Remove after caching current thread in generated code.
+  Thread* main_thread() {

[siva, 2015/03/25 21:26:34]

The name 'main_thread' is confusing because we already implicitly refer to the
first thread in the process as main thread.

How about renaming it as the dart_execution_thread / mutator_thread

[koda, 2015/03/25 21:49:47]

Renamed to mutator_thread.

+    DEBUG_ASSERT(IsIsolateOf(main_thread_));
+    return main_thread_;
+  }
+#if defined(DEBUG)
+  bool IsIsolateOf(Thread* thread);
+#endif  // DEBUG
+
   const char* name() const { return name_; }
+  // TODO(koda): Move to Thread.
   class Log* Log() const;
 
   int64_t start_time() const { return start_time_; }
 
   Dart_Port main_port() const { return main_port_; }
   void set_main_port(Dart_Port port) {
     ASSERT(main_port_ == 0);  // Only set main port once.
     main_port_ = port;
   }
   Dart_Port origin_id() const { return origin_id_; }
@@ skipping 481 matching lines @@
 
   void BuildName(const char* name_prefix);
   void PrintInvokedFunctions();
 
   void ProfileIdle();
 
   void set_user_tag(uword tag) {
     user_tag_ = tag;
   }
 
-  CHA* cha() const { return cha_; }
-  void set_cha(CHA* value) { cha_ = value; }
-
   template<class T> T* AllocateReusableHandle();
 
-  static ThreadLocalKey isolate_key;
-
+  Thread* main_thread_;
   uword vm_tag_;
   StoreBuffer store_buffer_;
   ClassTable class_table_;
   MegamorphicCacheTable megamorphic_cache_table_;
   Dart_MessageNotifyCallback message_notify_callback_;
   char* name_;
   int64_t start_time_;
   Dart_Port main_port_;
   Dart_Port origin_id_;  // Isolates created by spawnFunc have some origin id.
   uint64_t pause_capability_;
@@ skipping 37 matching lines @@
   class Log* log_;
 
   // Status support.
   char* stacktrace_;
   intptr_t stack_frame_index_;
 
   // Timestamps of last operation via service.
   int64_t last_allocationprofile_accumulator_reset_timestamp_;
   int64_t last_allocationprofile_gc_timestamp_;
 
-  CHA* cha_;
-
   // Ring buffer of objects assigned an id.
   ObjectIdRing* object_id_ring_;
 
   // Trace buffer support.
   TraceBuffer* trace_buffer_;
 
   IsolateProfilerData* profiler_data_;
   Mutex profiler_data_mutex_;
   InterruptableThreadState* thread_state_;
 
@@ skipping 176 matching lines @@
   uint8_t* serialized_args_;
   intptr_t serialized_args_len_;
   uint8_t* serialized_message_;
   intptr_t serialized_message_len_;
   bool paused_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_