Completely remove InterruptableThreadState and Fix ThreadRegistry leak

runtime/vm/thread.h

Index: runtime/vm/thread.h
diff --git a/runtime/vm/thread.h b/runtime/vm/thread.h
index 44b804013e7b6ec3c85ff4c0d8ef290d7ac88ca5..c9e35175eb55460d06db53d5b43e9a44d4332def 100644
--- a/runtime/vm/thread.h
+++ b/runtime/vm/thread.h
@@ -39,6 +39,24 @@ class Zone;
   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
@@ -233,9 +251,28 @@ CACHED_CONSTANTS_LIST(DEFINE_OFFSET_METHOD)
     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_;