Completely remove InterruptableThreadState and Fix ThreadRegistry leak

runtime/vm/thread.h

 // Copyright (c) 2015, 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_THREAD_H_
 #define VM_THREAD_H_
 
 #include "vm/globals.h"
 #include "vm/os_thread.h"
 #include "vm/store_buffer.h"
@@ skipping 21 matching lines @@
   V(RawBool*, bool_false_, Object::bool_false().raw(), NULL)                   \
 
 #define CACHED_ADDRESSES_LIST(V)                                               \
   V(uword, update_store_buffer_entry_point_,                                   \
     StubCode::UpdateStoreBuffer_entry()->EntryPoint(), 0)
 
 #define CACHED_CONSTANTS_LIST(V)                                               \
   CACHED_VM_OBJECTS_LIST(V)                                                    \
   CACHED_ADDRESSES_LIST(V)
 
+struct InterruptedThreadState {
+  ThreadId tid;
+  uintptr_t pc;
+  uintptr_t csp;
+  uintptr_t dsp;
+  uintptr_t fp;
+  uintptr_t lr;
+};
+
+// When a thread is interrupted the thread specific interrupt callback will be
+// invoked. Each callback is given an InterruptedThreadState and the user data
+// pointer. When inside a thread interrupt callback doing any of the following
+// is forbidden:
+//   * Accessing TLS.

[Ivan Posva, 2015/08/20 18:00:10]

Can you please explain in the comments why these things are "verboten"?

[Cutch, 2015/08/20 20:40:19]

Done.

+//   * Allocating memory.

[koda, 2015/08/20 15:45:14]

To catch violations of this in DEBUG mode, consider adding a NoSafepointScope
around the callback invocation.

[Cutch, 2015/08/20 20:40:19]

This comment was about native C allocations.

+//   * Taking a lock.
+typedef void (*ThreadInterruptCallback)(const InterruptedThreadState& state,
+                                        void* data);
 
 // A VM thread; may be executing Dart code or performing helper tasks like
 // garbage collection or compilation. The Thread structure associated with
 // a thread is allocated by EnsureInit before entering an isolate, and destroyed
 // automatically when the underlying OS thread exits. NOTE: On Windows, CleanUp
 // must currently be called manually (issue 23474).
 class Thread {
  public:
   // The currently executing thread, or NULL if not yet initialized.
   static Thread* Current() {
@@ skipping 174 matching lines @@
 
   void set_timeline_block(TimelineEventBlock* block) {
     state_.timeline_block = block;
   }
 
   LongJumpScope* long_jump_base() const { return state_.long_jump_base; }
   void set_long_jump_base(LongJumpScope* value) {
     state_.long_jump_base = value;
   }
 
+  ThreadId id() const {
+    return id_;
+  }
+
+  ThreadInterruptCallback thread_interrupt_callback() const {
+    return thread_interrupt_callback_;
+  }
+
+  void* thread_interrupt_data() const {
+    return thread_interrupt_data_;
+  }
+
+  void SetThreadInterrupter(ThreadInterruptCallback callback, void* data);
+
+  bool ShouldInterrupt() const;
+
  private:
   static ThreadLocalKey thread_key_;
 
+  const ThreadId id_;
+  ThreadInterruptCallback thread_interrupt_callback_;
+  void* thread_interrupt_data_;
   Isolate* isolate_;
   Heap* heap_;
   State state_;
   StoreBufferBlock* store_buffer_block_;
 #define DECLARE_MEMBERS(type_name, member_name, expr, default_init_value)      \
   type_name member_name;
 CACHED_CONSTANTS_LIST(DECLARE_MEMBERS)
 #undef DECLARE_MEMBERS
 
   explicit Thread(bool init_vm_constants = true);
@@ skipping 23 matching lines @@
   friend class ApiZone;
   friend class Isolate;
   friend class StackZone;
   friend class ThreadRegistry;
   DISALLOW_COPY_AND_ASSIGN(Thread);
 };
 
 }  // namespace dart
 
 #endif  // VM_THREAD_H_