commit 12b58b23de974232e991c650405f929f8b0dcc9f
author Hiroshi Yamauchi <yamauchi@google.com> Tue Nov 01 11:55:29 2016 -0700
committer Hiroshi Yamauchi <yamauchi@google.com> Wed Nov 02 16:31:04 2016 -0700
tree bc08011e3b9f4c132fc605dc54d1d5f50c932a29
parent b0b2080b4cea8365052d1be973e927f8ee85f609

Clean up the runtime read barrier and fix fake address dependency.

- Rename GetReadBarrierPointer to GetReadBarrierState.
- Change its return type to uint32_t.
- Fix the runtime fake address dependency for arm/arm64 using inline
  asm.
- Drop ReadBarrier::black_ptr_ and some brooks code.

Bug: 12687968
Test: test-art with CC, Ritz EAAC, libartd boot on N9.
Change-Id: I595970db825db5be2e98ee1fcbd7696d5501af55

runtime/mirror/object.h

diff --git a/runtime/mirror/object.h b/runtime/mirror/object.h
index 886637b..67b5ddb 100644
--- a/runtime/mirror/object.h
+++ b/runtime/mirror/object.h
@@ -94,19 +94,22 @@
   template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags>
   void SetClass(ObjPtr<Class> new_klass) REQUIRES_SHARED(Locks::mutator_lock_);
 
-  // TODO: Clean these up and change to return int32_t
-  Object* GetReadBarrierPointer() REQUIRES_SHARED(Locks::mutator_lock_);
-
-  // Get the read barrier pointer with release semantics, only supported for baker.
-  Object* GetReadBarrierPointerAcquire() REQUIRES_SHARED(Locks::mutator_lock_);
+  // Get the read barrier state with a fake address dependency.
+  // '*fake_address_dependency' will be set to 0.
+  ALWAYS_INLINE uint32_t GetReadBarrierState(uintptr_t* fake_address_dependency)
+      REQUIRES_SHARED(Locks::mutator_lock_);
+  // This version does not offer any special mechanism to prevent load-load reordering.
+  ALWAYS_INLINE uint32_t GetReadBarrierState() REQUIRES_SHARED(Locks::mutator_lock_);
+  // Get the read barrier state with a load-acquire.
+  ALWAYS_INLINE uint32_t GetReadBarrierStateAcquire() REQUIRES_SHARED(Locks::mutator_lock_);
 
 #ifndef USE_BAKER_OR_BROOKS_READ_BARRIER
   NO_RETURN
 #endif
-  void SetReadBarrierPointer(Object* rb_ptr) REQUIRES_SHARED(Locks::mutator_lock_);
+  ALWAYS_INLINE void SetReadBarrierState(uint32_t rb_state) REQUIRES_SHARED(Locks::mutator_lock_);
 
   template<bool kCasRelease = false>
-  ALWAYS_INLINE bool AtomicSetReadBarrierPointer(Object* expected_rb_ptr, Object* rb_ptr)
+  ALWAYS_INLINE bool AtomicSetReadBarrierState(uint32_t expected_rb_state, uint32_t rb_state)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
   ALWAYS_INLINE uint32_t GetMarkBit() REQUIRES_SHARED(Locks::mutator_lock_);
@@ -114,7 +117,8 @@
   ALWAYS_INLINE bool AtomicSetMarkBit(uint32_t expected_mark_bit, uint32_t mark_bit)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
-  void AssertReadBarrierPointer() const REQUIRES_SHARED(Locks::mutator_lock_);
+  // Assert that the read barrier state is in the default (white) state.
+  ALWAYS_INLINE void AssertReadBarrierState() const REQUIRES_SHARED(Locks::mutator_lock_);
 
   // The verifier treats all interfaces as java.lang.Object and relies on runtime checks in
   // invoke-interface to detect incompatible interface types.