- Make sure to prepare all threads for GC.

runtime/vm/thread.cc

 // 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.
 
 #include "vm/thread.h"
 
 #include "vm/dart_api_state.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
@@ skipping 218 matching lines @@
   ASSERT(!thread->IsMutatorThread());
   thread->StoreBufferRelease();
   Isolate* isolate = thread->isolate();
   ASSERT(isolate != NULL);
   const bool kIsNotMutatorThread = false;
   ThreadRegistry* tr = isolate->thread_registry();
   tr->Unschedule(thread, kIsNotMutatorThread, 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();
 }
 
 
 void Thread::StoreBufferBlockProcess(StoreBuffer::ThresholdPolicy policy) {
   StoreBufferRelease(policy);
   StoreBufferAcquire();
 }
 
 
 void Thread::StoreBufferAddObject(RawObject* obj) {
   store_buffer_block_->Push(obj);
   if (store_buffer_block_->IsFull()) {
     StoreBufferBlockProcess(StoreBuffer::kCheckThreshold);
   }
 }
 
 
 void Thread::StoreBufferAddObjectGC(RawObject* obj) {
   store_buffer_block_->Push(obj);
   if (store_buffer_block_->IsFull()) {
     StoreBufferBlockProcess(StoreBuffer::kIgnoreThreshold);
   }
 }
 
 
 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);
 }
 
 
 void Thread::StoreBufferAcquire() {
   store_buffer_block_ = isolate()->store_buffer()->PopNonFullBlock();
 }
 
 
 bool Thread::IsMutatorThread() const {
   return ((isolate_ != NULL) && (isolate_->mutator_thread() == this));
@@ skipping 161 matching lines @@
 
 DisableThreadInterruptsScope::~DisableThreadInterruptsScope() {
   if (thread() != NULL) {
     OSThread* os_thread = thread()->os_thread();
     ASSERT(os_thread != NULL);
     os_thread->EnableThreadInterrupts();
   }
 }
 
 }  // namespace dart