Moves the top_ and end_ words of the Scavenger into mutator thread.

runtime/vm/thread.h

Index: runtime/vm/thread.h
diff --git a/runtime/vm/thread.h b/runtime/vm/thread.h
index 3a226e4ee583bb912841e21e1ba6d3006e33a63c..327794de87adc27f8d11526ed55b654bf2144949 100644
--- a/runtime/vm/thread.h
+++ b/runtime/vm/thread.h
@@ -366,6 +366,21 @@ class Thread : public BaseThread {
   Heap* heap() const { return heap_; }
   static intptr_t heap_offset() { return OFFSET_OF(Thread, heap_); }

[rmacnak, 2017/07/05 17:39:53]

It should be possible to remove this now, right?

[danunez, 2017/07/05 18:12:56]

Looks like it, according to a grep. Consider it gone.

 
+  void set_top_offset(uword value) {

[rmacnak, 2017/07/05 17:39:53]

set_top

[danunez, 2017/07/05 18:12:56]

Done.

+    ASSERT(heap_ != NULL);
+    top_ = value;
+  }
+  void set_end_offset(uword value) {

[rmacnak, 2017/07/05 17:39:53]

set_end

[danunez, 2017/07/05 18:12:56]

Done.

+    ASSERT(heap_ != NULL);
+    end_ = value;
+  }
+
+  uword top() { return top_; }
+  uword end() { return end_; }
+
+  static intptr_t top_offset() { return OFFSET_OF(Thread, top_); }
+  static intptr_t end_offset() { return OFFSET_OF(Thread, end_); }
+
   int32_t no_handle_scope_depth() const {
 #if defined(DEBUG)
     return no_handle_scope_depth_;
@@ -752,6 +767,9 @@ class Thread : public BaseThread {
 
   CompilerStats* compiler_stats_;
 
+  uword top_;

[rmacnak, 2017/07/05 17:39:53]

These should move up to where heap_ is. See comment about fields accessed from
generated code.

[danunez, 2017/07/05 18:12:56]

I placed these down here after I encountered an error during testing about bad
offsets. I will try again and see if I encounter it.

+  uword end_;
+
 // Reusable handles support.
 #define REUSABLE_HANDLE_FIELDS(object) object* object##_handle_;
   REUSABLE_HANDLE_LIST(REUSABLE_HANDLE_FIELDS)