Safepointing in 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/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
 #include "vm/object.h"
@@ skipping 57 matching lines @@
   if (current != NULL) {
     delete current;
   }
   SetCurrent(NULL);
 }
 #endif
 
 
 Thread::Thread(bool init_vm_constants)
     : isolate_(NULL),
-      store_buffer_block_(NULL) {
+      store_buffer_block_(NULL),
+      pass_safepoint_(kNoSafepointId) {
   ClearState();
 #define DEFAULT_INIT(type_name, member_name, init_expr, default_init_value)    \
   member_name = default_init_value;
 CACHED_CONSTANTS_LIST(DEFAULT_INIT)
 #undef DEFAULT_INIT
   if (init_vm_constants) {
     InitVMConstants();
   }
 }
 
@@ skipping 72 matching lines @@
   } else {
     isolate->set_vm_tag(VMTag::kLoadWaitTagId);
   }
   isolate->ClearMutatorThread();
   thread->isolate_ = NULL;
   ASSERT(Isolate::Current() == NULL);
   thread->heap_ = NULL;
 }
 
 
-void Thread::EnterIsolateAsHelper(Isolate* isolate) {
+void Thread::EnterIsolateAsHelper(Isolate* isolate,
+                                  SafepointId pass_safepoint) {
   Thread* thread = Thread::Current();
   ASSERT(thread != NULL);
   ASSERT(thread->isolate() == NULL);
   thread->isolate_ = isolate;
+  thread->pass_safepoint_ = pass_safepoint;
   ASSERT(isolate->heap() != NULL);
   thread->heap_ = isolate->heap();
   ASSERT(thread->thread_state() == NULL);
   // Do not update isolate->mutator_thread, but perform sanity check:
   // this thread should not be both the main mutator and helper.
   ASSERT(!isolate->MutatorThreadIsCurrentThread());
   thread->Schedule(isolate);
 }
 
 
 void Thread::ExitIsolateAsHelper() {
   Thread* thread = Thread::Current();
   // If the helper thread chose to use the store buffer, check that it has
   // already been flushed manually.
   ASSERT(thread->store_buffer_block_ == NULL);
   Isolate* isolate = thread->isolate();
   ASSERT(isolate != NULL);
   thread->Unschedule();
   thread->set_thread_state(NULL);
+  thread->pass_safepoint_ = kNoSafepointId;
   thread->isolate_ = NULL;
   thread->heap_ = NULL;
   ASSERT(!isolate->MutatorThreadIsCurrentThread());
 }
 
 
 void Thread::PrepareForGC() {
   Thread* thread = Thread::Current();
   StoreBuffer* sb = thread->isolate()->store_buffer();
   StoreBufferBlock* block = thread->store_buffer_block_;
@@ skipping 54 matching lines @@
 #define COMPUTE_OFFSET(type_name, member_name, expr, default_init_value)       \
   ASSERT((expr)->IsVMHeapObject());                                            \
   if (object.raw() == expr) return Thread::member_name##offset();
 CACHED_VM_OBJECTS_LIST(COMPUTE_OFFSET)
 #undef COMPUTE_OFFSET
   UNREACHABLE();
   return -1;
 }
 
 }  // namespace dart