Add test of full GC on helper thread

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 109 matching lines @@
 
 void Thread::EnterIsolate(Isolate* isolate) {
   Thread* thread = Thread::Current();
   ASSERT(thread != NULL);
   ASSERT(thread->isolate() == NULL);
   ASSERT(!isolate->HasMutatorThread());
   thread->isolate_ = isolate;
   isolate->MakeCurrentThreadMutator(thread);
   isolate->set_vm_tag(VMTag::kVMTagId);
   ASSERT(thread->store_buffer_block_ == NULL);
-  thread->store_buffer_block_ = isolate->store_buffer()->PopNonFullBlock();
+  thread->StoreBufferAcquire();
   ASSERT(isolate->heap() != NULL);
   thread->heap_ = isolate->heap();
   thread->Schedule(isolate);
   ASSERT(thread->thread_state() == NULL);
   InterruptableThreadState* thread_state =
       ThreadInterrupter::GetCurrentThreadState();
 #if defined(DEBUG)
   thread->set_thread_state(NULL);  // Exclude thread itself from the dupe check.
   Isolate::CheckForDuplicateThreadState(thread_state);
   thread->set_thread_state(thread_state);
 #endif
   ASSERT(thread_state != NULL);
   // TODO(koda): Migrate profiler interface to use Thread.
   Profiler::BeginExecution(isolate);
 }
 
 
 void Thread::ExitIsolate() {
   Thread* thread = Thread::Current();
   // TODO(koda): Audit callers; they should know whether they're in an isolate.
   if (thread == NULL || thread->isolate() == NULL) return;
   Isolate* isolate = thread->isolate();
   Profiler::EndExecution(isolate);
   thread->set_thread_state(NULL);
   thread->Unschedule();
-  StoreBufferBlock* block = thread->store_buffer_block_;
-  thread->store_buffer_block_ = NULL;
-  isolate->store_buffer()->PushBlock(block);
+  // TODO(koda): Move store_buffer_block_ into State.
+  thread->StoreBufferRelease();
   if (isolate->is_runnable()) {
     isolate->set_vm_tag(VMTag::kIdleTagId);
   } else {
     isolate->set_vm_tag(VMTag::kLoadWaitTagId);
   }
   isolate->ClearMutatorThread();
   thread->isolate_ = NULL;
   ASSERT(Isolate::Current() == NULL);
   thread->heap_ = NULL;
 }
 
 
 void Thread::EnterIsolateAsHelper(Isolate* isolate) {
   Thread* thread = Thread::Current();
   ASSERT(thread != NULL);
   ASSERT(thread->isolate() == NULL);
   thread->isolate_ = isolate;
+  ASSERT(thread->store_buffer_block_ == NULL);
+  thread->StoreBufferAcquire();
   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();
+  // TODO(koda): Move store_buffer_block_ into State.
+  thread->StoreBufferRelease();
   thread->set_thread_state(NULL);
   thread->isolate_ = NULL;
   thread->heap_ = NULL;
   ASSERT(!isolate->MutatorThreadIsCurrentThread());
 }
 
 
+// TODO(koda): Make non-static and invoke in SafepointThreads.
 void Thread::PrepareForGC() {
   Thread* thread = Thread::Current();
-  StoreBuffer* sb = thread->isolate()->store_buffer();
-  StoreBufferBlock* block = thread->store_buffer_block_;
-  thread->store_buffer_block_ = NULL;
-  const bool kCheckThreshold = false;  // Prevent scheduling another GC.
-  sb->PushBlock(block, kCheckThreshold);
-  thread->store_buffer_block_ = sb->PopEmptyBlock();
+  const bool kDoNotCheckThreshold = false;  // Prevent scheduling another GC.
+  thread->StoreBufferRelease(kDoNotCheckThreshold);
+  // 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();
 }
 
 
 void Thread::StoreBufferBlockProcess(bool check_threshold) {
-  StoreBuffer* sb = isolate()->store_buffer();
-  StoreBufferBlock* block = store_buffer_block_;
-  store_buffer_block_ = NULL;
-  sb->PushBlock(block, check_threshold);
-  store_buffer_block_ = sb->PopNonFullBlock();
+  StoreBufferRelease(check_threshold);
+  StoreBufferAcquire();
 }
 
 
 void Thread::StoreBufferAddObject(RawObject* obj) {
   store_buffer_block_->Push(obj);
   if (store_buffer_block_->IsFull()) {
     StoreBufferBlockProcess(true);
   }
 }
 
 
 void Thread::StoreBufferAddObjectGC(RawObject* obj) {
   store_buffer_block_->Push(obj);
   if (store_buffer_block_->IsFull()) {
     StoreBufferBlockProcess(false);
   }
 }
 
 
+void Thread::StoreBufferRelease(bool check_threshold) {
+  StoreBufferBlock* block = store_buffer_block_;
+  store_buffer_block_ = NULL;
+  isolate_->store_buffer()->PushBlock(block, check_threshold);
+}
+
+
+void Thread::StoreBufferAcquire() {
+  store_buffer_block_ = isolate()->store_buffer()->PopNonFullBlock();
+}
+
+
 CHA* Thread::cha() const {
   ASSERT(isolate_ != NULL);
   return isolate_->cha_;
 }
 
 
 void Thread::set_cha(CHA* value) {
   ASSERT(isolate_ != NULL);
   isolate_->cha_ = value;
 }
@@ skipping 12 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