Update native gc-roots separately in compaction pause

The concurrent compaction algorithm requires all GC roots to be updated
to post-compact addresses before resuming mutators for concurrent
compaction. Therefore, unlike CC, we cannot update native roots in
classes/dex-caches/class-loaders while visiting references
(VisitReferences) on heap objects.

This CL separates the two and updates all the gc-roots in the compaction
pause.

Bug: 160737021
Test: art/test/testrunner/testrunner.py
Change-Id: I8a57472ba49b9dc30bc0f41a7db3f5efa7eafd9a

1 files changed, 16 insertions, 0 deletions

diff --git a/runtime/class_linker.h b/runtime/class_linker.h
index 895d820c7b..1ac47562b2 100644
--- a/runtime/class_linker.h
+++ b/runtime/class_linker.h
@@ -128,6 +128,13 @@ class ClassLoaderVisitor {
       REQUIRES_SHARED(Locks::classlinker_classes_lock_, Locks::mutator_lock_) = 0;
 };
 
+class DexCacheVisitor {
+ public:
+  virtual ~DexCacheVisitor() {}
+  virtual void Visit(ObjPtr<mirror::DexCache> dex_cache)
+      REQUIRES_SHARED(Locks::dex_lock_, Locks::mutator_lock_) = 0;
+};
+
 template <typename Func>
 class ClassLoaderFuncVisitor final : public ClassLoaderVisitor {
  public:
@@ -479,6 +486,11 @@ class ClassLinker {
       REQUIRES(!Locks::classlinker_classes_lock_)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
+  // Visits only the classes in the boot class path.
+  template <typename Visitor>
+  inline void VisitBootClasses(Visitor* visitor)
+      REQUIRES_SHARED(Locks::classlinker_classes_lock_)
+      REQUIRES_SHARED(Locks::mutator_lock_);
   // Less efficient variant of VisitClasses that copies the class_table_ into secondary storage
   // so that it can visit individual classes without holding the doesn't hold the
   // Locks::classlinker_classes_lock_. As the Locks::classlinker_classes_lock_ isn't held this code
@@ -780,6 +792,10 @@ class ClassLinker {
   void VisitClassLoaders(ClassLoaderVisitor* visitor) const
       REQUIRES_SHARED(Locks::classlinker_classes_lock_, Locks::mutator_lock_);
 
+  // Visit all of the dex caches in the class linker.
+  void VisitDexCaches(DexCacheVisitor* visitor) const
+      REQUIRES_SHARED(Locks::dex_lock_, Locks::mutator_lock_);
+
   // Checks that a class and its superclass from another class loader have the same virtual methods.
   bool ValidateSuperClassDescriptors(Handle<mirror::Class> klass)
       REQUIRES_SHARED(Locks::mutator_lock_);