Compacting collector.

The compacting collector is currently similar to semispace. It works by
copying objects back and forth between two bump pointer spaces. There
are types of objects which are "non-movable" due to current runtime
limitations. These are Classes, Methods, and Fields.

Bump pointer spaces are a new type of continuous alloc space which have
no lock in the allocation code path. When you allocate from these it uses
atomic operations to increase an index. Traversing the objects in the bump
pointer space relies on Object::SizeOf matching the allocated size exactly.

Runtime changes:
JNI::GetArrayElements returns copies objects if you attempt to get the
backing data of a movable array. For GetArrayElementsCritical, we return
direct backing storage for any types of arrays, but temporarily disable
the GC until the critical region is completed.

Added a new runtime call called VisitObjects, this is used in place of
the old pattern which was flushing the allocation stack and walking
the bitmaps.

Changed image writer to be compaction safe and use object monitor word
for forwarding addresses.

Added a bunch of added SIRTs to ClassLinker, MethodLinker, etc..

TODO: Enable switching allocators, compacting on background, etc..

Bug: 8981901

Change-Id: I3c886fd322a6eef2b99388d19a765042ec26ab99

1 files changed, 6 insertions, 4 deletions

diff --git a/runtime/dex_file.h b/runtime/dex_file.h
index a9c24e6..51ab8d8 100644
--- a/runtime/dex_file.h
+++ b/runtime/dex_file.h
@@ -43,6 +43,8 @@ namespace mirror {
 }  // namespace mirror
 class ClassLinker;
 class Signature;
+template <typename T>
+class SirtRef;
 class StringPiece;
 class ZipArchive;
 
@@ -1152,8 +1154,8 @@ class ClassDataItemIterator {
 
 class EncodedStaticFieldValueIterator {
  public:
-  EncodedStaticFieldValueIterator(const DexFile& dex_file, mirror::DexCache* dex_cache,
-                                  mirror::ClassLoader* class_loader,
+  EncodedStaticFieldValueIterator(const DexFile& dex_file, SirtRef<mirror::DexCache>* dex_cache,
+                                  SirtRef<mirror::ClassLoader>* class_loader,
                                   ClassLinker* linker, const DexFile::ClassDef& class_def)
       SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
@@ -1187,8 +1189,8 @@ class EncodedStaticFieldValueIterator {
   static const byte kEncodedValueArgShift = 5;
 
   const DexFile& dex_file_;
-  mirror::DexCache* dex_cache_;  // Dex cache to resolve literal objects.
-  mirror::ClassLoader* class_loader_;  // ClassLoader to resolve types.
+  SirtRef<mirror::DexCache>* const dex_cache_;  // Dex cache to resolve literal objects.
+  SirtRef<mirror::ClassLoader>* const class_loader_;  // ClassLoader to resolve types.
   ClassLinker* linker_;  // Linker to resolve literal objects.
   size_t array_size_;  // Size of array.
   size_t pos_;  // Current position.