ObjectGraph: Establish a HeapIterationScope *before* making the heap writable, least the sweeper in…

runtime/vm/object_graph.cc

 // Copyright (c) 2014, 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/object_graph.h"
 
 #include "vm/dart.h"
 #include "vm/growable_array.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
@@ skipping 131 matching lines @@
   Unmarker() {}
 
   void VisitObject(RawObject* obj) {
     if (obj->IsMarked()) {
       obj->ClearMarkBit();
     }
   }
 
   static void UnmarkAll(Isolate* isolate) {
     Unmarker unmarker;
-    isolate->heap()->IterateObjects(&unmarker);
+    isolate->heap()->VisitObjects(&unmarker);
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(Unmarker);
 };
 
 
 ObjectGraph::ObjectGraph(Thread* thread) : StackResource(thread) {
   // The VM isolate has all its objects pre-marked, so iterating over it
   // would be a no-op.
   ASSERT(thread->isolate() != Dart::vm_isolate());
-  thread->isolate()->heap()->WriteProtectCode(false);
 }
 
 
-ObjectGraph::~ObjectGraph() {
-  isolate()->heap()->WriteProtectCode(true);
-}
+ObjectGraph::~ObjectGraph() {}
 
 
 void ObjectGraph::IterateObjects(ObjectGraph::Visitor* visitor) {
   NoSafepointScope no_safepoint_scope_;
   Stack stack(isolate());
-  isolate()->IterateObjectPointers(&stack, false);
+  isolate()->VisitObjectPointers(&stack, false);
   stack.TraverseGraph(visitor);
   Unmarker::UnmarkAll(isolate());
 }
 
 
 void ObjectGraph::IterateObjectsFrom(const Object& root,
                                      ObjectGraph::Visitor* visitor) {
   NoSafepointScope no_safepoint_scope_;
   Stack stack(isolate());
   RawObject* root_raw = root.raw();
@@ skipping 22 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(InstanceAccumulator);
 };
 
 
 void ObjectGraph::IterateObjectsFrom(intptr_t class_id,
                                      ObjectGraph::Visitor* visitor) {
   NoSafepointScope no_safepoint_scope_;
   Stack stack(isolate());
 
   InstanceAccumulator accumulator(&stack, class_id);
-  isolate()->heap()->IterateObjects(&accumulator);
+  isolate()->heap()->VisitObjects(&accumulator);
 
   stack.TraverseGraph(visitor);
   Unmarker::UnmarkAll(isolate());
 }
 
 
 class SizeVisitor : public ObjectGraph::Visitor {
  public:
   SizeVisitor() : size_(0) {}
   intptr_t size() const { return size_; }
@@ skipping 28 matching lines @@
   virtual bool ShouldSkip(RawObject* obj) const {
     return obj->GetClassId() == skip_;
   }
 
  private:
   const intptr_t skip_;
 };
 
 
 intptr_t ObjectGraph::SizeRetainedByInstance(const Object& obj) {
+  HeapIterationScope iteration_scope(true);
   SizeVisitor total;
   IterateObjects(&total);
   intptr_t size_total = total.size();
   SizeExcludingObjectVisitor excluding_obj(obj);
   IterateObjects(&excluding_obj);
   intptr_t size_excluding_obj = excluding_obj.size();
   return size_total - size_excluding_obj;
 }
 
 
 intptr_t ObjectGraph::SizeReachableByInstance(const Object& obj) {
+  HeapIterationScope iteration_scope(true);
   SizeVisitor total;
   IterateObjectsFrom(obj, &total);
   return total.size();
 }
 
 
 intptr_t ObjectGraph::SizeRetainedByClass(intptr_t class_id) {
+  HeapIterationScope iteration_scope(true);
   SizeVisitor total;
   IterateObjects(&total);
   intptr_t size_total = total.size();
   SizeExcludingClassVisitor excluding_class(class_id);
   IterateObjects(&excluding_class);
   intptr_t size_excluding_class = excluding_class.size();
   return size_total - size_excluding_class;
 }
 
 
 intptr_t ObjectGraph::SizeReachableByClass(intptr_t class_id) {
+  HeapIterationScope iteration_scope(true);
   SizeVisitor total;
   IterateObjectsFrom(class_id, &total);
   return total.size();
 }
 
 
 class RetainingPathVisitor : public ObjectGraph::Visitor {
  public:
   // We cannot use a GrowableObjectArray, since we must not trigger GC.
   RetainingPathVisitor(RawObject* obj, const Array& path)
@@ skipping 76 matching lines @@
   Thread* thread_;
   RawObject* obj_;
   const Array& path_;
   intptr_t length_;
   bool was_last_array_;
 };
 
 
 intptr_t ObjectGraph::RetainingPath(Object* obj, const Array& path) {
   NoSafepointScope no_safepoint_scope_;
+  HeapIterationScope iteration_scope(true);
   // To break the trivial path, the handle 'obj' is temporarily cleared during
   // the search, but restored before returning.
   RawObject* raw = obj->raw();
   *obj = Object::null();
   RetainingPathVisitor visitor(raw, path);
   IterateObjects(&visitor);
   *obj = raw;
   return visitor.length();
 }
 
@@ skipping 57 matching lines @@
   RawObject* source_;
   RawObject* target_;
   const Array& references_;
   Object* scratch_;
   intptr_t length_;
 };
 
 
 intptr_t ObjectGraph::InboundReferences(Object* obj, const Array& references) {
   Object& scratch = Object::Handle();
-  NoSafepointScope no_safepoint_scope_;
+  NoSafepointScope no_safepoint_scope;
   InboundReferencesVisitor visitor(isolate(), obj->raw(), references, &scratch);
   isolate()->heap()->IterateObjects(&visitor);
   return visitor.length();
 }
 
 
 static void WritePtr(RawObject* raw, WriteStream* stream) {
   ASSERT(raw->IsHeapObject());
   ASSERT(raw->IsOldObject());
   uword addr = RawObject::ToAddr(raw);
@@ skipping 123 matching lines @@
 
 
 intptr_t ObjectGraph::Serialize(WriteStream* stream,
                                 SnapshotRoots roots,
                                 bool collect_garbage) {
   if (collect_garbage) {
     isolate()->heap()->CollectAllGarbage();
   }
   // Current encoding assumes objects do not move, so promote everything to old.
   isolate()->heap()->new_space()->Evacuate();
+  HeapIterationScope iteration_scope(true);
 
   RawObject* kRootAddress = reinterpret_cast<RawObject*>(kHeapObjectTag);
   const intptr_t kRootCid = kIllegalCid;
   RawObject* kStackAddress =
       reinterpret_cast<RawObject*>(kObjectAlignment + kHeapObjectTag);
 
   stream->WriteUnsigned(kObjectAlignment);
   stream->WriteUnsigned(kStackCid);
 
   if (roots == kVM) {
     // Write root "object".
     WriteHeader(kRootAddress, 0, kRootCid, stream);
     WritePointerVisitor ptr_writer(isolate(), stream, false);
-    isolate()->IterateObjectPointers(&ptr_writer, false);
+    isolate()->VisitObjectPointers(&ptr_writer, false);
     stream->WriteUnsigned(0);
   } else {
     {
       // Write root "object".
       WriteHeader(kRootAddress, 0, kRootCid, stream);
       WritePointerVisitor ptr_writer(isolate(), stream, false);
       IterateUserFields(&ptr_writer);
       WritePtr(kStackAddress, stream);
       stream->WriteUnsigned(0);
     }
 
     {
       // Write stack "object".
       WriteHeader(kStackAddress, 0, kStackCid, stream);
       WritePointerVisitor ptr_writer(isolate(), stream, true);
-      isolate()->IterateStackPointers(&ptr_writer, false);
+      isolate()->VisitStackPointers(&ptr_writer, false);
       stream->WriteUnsigned(0);
     }
   }
 
   WriteGraphVisitor visitor(isolate(), stream, roots);
   IterateObjects(&visitor);
 
   intptr_t object_count = visitor.count();
   if (roots == kVM) {
     object_count += 1;  // root
   } else {
     object_count += 2;  // root and stack
   }
   return object_count;
 }
 
 }  // namespace dart