commit e4275c07e9852a6944f47efa9d0591fceb8e8e36
author Mathieu Chartier <mathieuc@google.com> Thu Aug 06 15:34:15 2015 -0700
committer Mathieu Chartier <mathieuc@google.com> Wed Aug 12 15:50:24 2015 -0700
tree 92d5e69374f88555f454d137e5d60fb1c925b4d8
parent 82b844fb449ddc5d7b4e43e71a55eb934a1b0b45

Visit class roots from ClassLoader::VisitReferences

This causes the classes of a class loader to get marked when that
class loader gets marked instead of during class root visiting.

Bug: 22720414

Change-Id: If53f042aff1d9f7bf94ecbe6886601edda029b7d

runtime/hprof/hprof.cc

diff --git a/runtime/hprof/hprof.cc b/runtime/hprof/hprof.cc
index e67ea3f..713797f 100644
--- a/runtime/hprof/hprof.cc
+++ b/runtime/hprof/hprof.cc
@@ -883,6 +883,7 @@
                      gc::EqAllocRecordTypesPtr<gc::AllocRecordStackTraceElement>> frames_;
   std::unordered_map<const mirror::Object*, const gc::AllocRecordStackTrace*> allocation_records_;
 
+  friend class GcRootVisitor;
   DISALLOW_COPY_AND_ASSIGN(Hprof);
 };
 
@@ -1023,12 +1024,47 @@
   ++objects_in_segment_;
 }
 
+// Use for visiting the GcRoots held live by ArtFields, ArtMethods, and ClassLoaders.
+class GcRootVisitor {
+ public:
+  explicit GcRootVisitor(Hprof* hprof) : hprof_(hprof) {}
+
+  void operator()(mirror::Object* obj ATTRIBUTE_UNUSED,
+                  MemberOffset offset ATTRIBUTE_UNUSED,
+                  bool is_static ATTRIBUTE_UNUSED) const {}
+
+  // Note that these don't have read barriers. Its OK however since the GC is guaranteed to not be
+  // running during the hprof dumping process.
+  void VisitRootIfNonNull(mirror::CompressedReference<mirror::Object>* root) const
+      SHARED_REQUIRES(Locks::mutator_lock_) {
+    if (!root->IsNull()) {
+      VisitRoot(root);
+    }
+  }
+
+  void VisitRoot(mirror::CompressedReference<mirror::Object>* root) const
+      SHARED_REQUIRES(Locks::mutator_lock_) {
+    mirror::Object* obj = root->AsMirrorPtr();
+    // The two cases are either classes or dex cache arrays. If it is a dex cache array, then use
+    // VM internal. Otherwise the object is a declaring class of an ArtField or ArtMethod or a
+    // class from a ClassLoader.
+    hprof_->VisitRoot(obj, RootInfo(obj->IsClass() ? kRootStickyClass : kRootVMInternal));
+  }
+
+
+ private:
+  Hprof* const hprof_;
+};
+
 void Hprof::DumpHeapObject(mirror::Object* obj) {
   // Ignore classes that are retired.
   if (obj->IsClass() && obj->AsClass()->IsRetired()) {
     return;
   }
 
+  GcRootVisitor visitor(this);
+  obj->VisitReferences<true>(visitor, VoidFunctor());
+
   gc::Heap* const heap = Runtime::Current()->GetHeap();
   const gc::space::ContinuousSpace* const space = heap->FindContinuousSpaceFromObject(obj, true);
   HprofHeapId heap_type = HPROF_HEAP_APP;