Revert "JNI: Rewrite locking for synchronized methods."

This reverts commit c17656bcf477e57d59ff051037c96994fd0ac8f2.

Reason for revert: Broke tests.
At least the arm64 macro UNLOCK_OBJECT_FAST_PATH uses
an incorrect label for one branch to slow path.

Bug: 172332525
Bug: 207408813
Change-Id: I6764dcfcba3b3d780fc13a66d6e676a3e3946a0f

1 files changed, 5 insertions, 9 deletions

diff --git a/runtime/entrypoints/entrypoint_utils-inl.h b/runtime/entrypoints/entrypoint_utils-inl.h
index a160a7baf0..6e78b53ff8 100644
--- a/runtime/entrypoints/entrypoint_utils-inl.h
+++ b/runtime/entrypoints/entrypoint_utils-inl.h
@@ -805,27 +805,23 @@ inline bool NeedsClinitCheckBeforeCall(ArtMethod* method) {
   return method->IsStatic() && !method->IsConstructor();
 }
 
-inline ObjPtr<mirror::Object> GetGenericJniSynchronizationObject(Thread* self, ArtMethod* called)
+inline jobject GetGenericJniSynchronizationObject(Thread* self, ArtMethod* called)
     REQUIRES_SHARED(Locks::mutator_lock_) {
   DCHECK(!called->IsCriticalNative());
   DCHECK(!called->IsFastNative());
   DCHECK(self->GetManagedStack()->GetTopQuickFrame() != nullptr);
   DCHECK_EQ(*self->GetManagedStack()->GetTopQuickFrame(), called);
-  // We do not need read barriers here.
-  // On method entry, all reference arguments are to-space references and we mark the
-  // declaring class of a static native method if needed. When visiting thread roots at
-  // the start of a GC, we visit all these references to ensure they point to the to-space.
   if (called->IsStatic()) {
     // Static methods synchronize on the declaring class object.
-    return called->GetDeclaringClass<kWithoutReadBarrier>();
+    // The `jclass` is a pointer to the method's declaring class.
+    return reinterpret_cast<jobject>(called->GetDeclaringClassAddressWithoutBarrier());
   } else {
     // Instance methods synchronize on the `this` object.
     // The `this` reference is stored in the first out vreg in the caller's frame.
+    // The `jobject` is a pointer to the spill slot.
     uint8_t* sp = reinterpret_cast<uint8_t*>(self->GetManagedStack()->GetTopQuickFrame());
     size_t frame_size = RuntimeCalleeSaveFrame::GetFrameSize(CalleeSaveType::kSaveRefsAndArgs);
-    StackReference<mirror::Object>* this_ref = reinterpret_cast<StackReference<mirror::Object>*>(
-        sp + frame_size + static_cast<size_t>(kRuntimePointerSize));
-    return this_ref->AsMirrorPtr();
+    return reinterpret_cast<jobject>(sp + frame_size + static_cast<size_t>(kRuntimePointerSize));
   }
 }