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

runtime/vm/scavenger.h

Index: runtime/vm/scavenger.h
diff --git a/runtime/vm/scavenger.h b/runtime/vm/scavenger.h
index 7fa3950f701eb2847e9356e43f952552e8f01699..9bddadaec4053fca62ce78feda384fcacfc8f67d 100644
--- a/runtime/vm/scavenger.h
+++ b/runtime/vm/scavenger.h
@@ -124,11 +124,17 @@ class Scavenger {
   uword TryAllocate(intptr_t size) {
     ASSERT(Utils::IsAligned(size, kObjectAlignment));
     ASSERT(heap_ != Dart::vm_isolate()->heap());
+
 #if defined(DEBUG)
     if (FLAG_gc_at_alloc && !scavenging_) {
       Scavenge();
+      ASSERT(Isolate::Current()->mutator_thread()->top() == top_);

[rmacnak, 2017/06/22 22:31:51]

Thread::Current() should be the mutator

[danunez, 2017/06/30 20:35:57]

Done.

     }
 #endif
+
+    top_ = Isolate::Current()->mutator_thread()->top();
+    ASSERT(Isolate::Current()->mutator_thread()->end() == end_);
+
     uword result = top_;
     intptr_t remaining = end_ - top_;
     if (remaining < size) {
@@ -139,6 +145,7 @@ class Scavenger {
 
     top_ += size;
     ASSERT(to_->Contains(top_) || (top_ == to_->end()));
+    Isolate::Current()->mutator_thread()->set_top_offset(top_);
     return result;
   }
 
@@ -234,6 +241,7 @@ class Scavenger {
   void PushToPromotedStack(uword addr) {
     ASSERT(scavenging_);
     end_ -= sizeof(addr);
+    Isolate::Current()->mutator_thread()->set_end_offset(end_);
     ASSERT(end_ > top_);
     *reinterpret_cast<uword*>(end_) = addr;
   }
@@ -241,6 +249,7 @@ class Scavenger {
     ASSERT(scavenging_);
     uword result = *reinterpret_cast<uword*>(end_);
     end_ += sizeof(result);
+    Isolate::Current()->mutator_thread()->set_end_offset(end_);
     ASSERT(end_ <= to_->end());
     return result;
   }
@@ -295,6 +304,8 @@ class Scavenger {
   // The total size of external data associated with objects in this scavenger.
   intptr_t external_size_;
 
+  Mutex* space_lock_;
+
   friend class ScavengerVisitor;
   friend class ScavengerWeakVisitor;