- Make sure to prepare all threads for GC.

runtime/vm/thread.cc

Index: runtime/vm/thread.cc
diff --git a/runtime/vm/thread.cc b/runtime/vm/thread.cc
index db6f42e20438db6f2820330a6119baddf98e748a..305d0569eb03a64115ff3c8a8745b7e8c7213c33 100644
--- a/runtime/vm/thread.cc
+++ b/runtime/vm/thread.cc
@@ -236,16 +236,13 @@ void Thread::ExitIsolateAsHelper(bool bypass_safepoint) {
 }
 
 
-// TODO(koda): Make non-static and invoke in SafepointThreads.
 void Thread::PrepareForGC() {

[siva, 2015/12/18 01:05:02]

ASSERT(isolate()->thread_registry()->AtSafepoint());

[Ivan Posva, 2015/12/18 03:59:50]

Done.

-  Thread* thread = Thread::Current();
-  // Prevent scheduling another GC.
-  thread->StoreBufferRelease(StoreBuffer::kIgnoreThreshold);
+  // Prevent scheduling another GC by ignoring the threshold.
+  StoreBufferRelease(StoreBuffer::kIgnoreThreshold);
   // Make sure to get an *empty* block; the isolate needs all entries
   // at GC time.
   // TODO(koda): Replace with an epilogue (PrepareAfterGC) that acquires.
-  thread->store_buffer_block_ =
-      thread->isolate()->store_buffer()->PopEmptyBlock();
+  store_buffer_block_ = isolate()->store_buffer()->PopEmptyBlock();
 }
 
 
@@ -274,7 +271,7 @@ void Thread::StoreBufferAddObjectGC(RawObject* obj) {
 void Thread::StoreBufferRelease(StoreBuffer::ThresholdPolicy policy) {
   StoreBufferBlock* block = store_buffer_block_;
   store_buffer_block_ = NULL;
-  isolate_->store_buffer()->PushBlock(block, policy);
+  isolate()->store_buffer()->PushBlock(block, policy);
 }