runtime: Minor cleanup and extra comments around interpreter
Change-Id: I24c0b261de8cf737babd9d01bf679482d48c8bc9
diff --git a/runtime/interpreter/interpreter_common.cc b/runtime/interpreter/interpreter_common.cc
index 86a79ce..0f6f788 100644
--- a/runtime/interpreter/interpreter_common.cc
+++ b/runtime/interpreter/interpreter_common.cc
@@ -450,10 +450,13 @@
static inline void AssignRegister(ShadowFrame* new_shadow_frame, const ShadowFrame& shadow_frame,
size_t dest_reg, size_t src_reg)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
- // If both register locations contains the same value, the register probably holds a reference.
// Uint required, so that sign extension does not make this wrong on 64b systems
uint32_t src_value = shadow_frame.GetVReg(src_reg);
mirror::Object* o = shadow_frame.GetVRegReference<kVerifyNone>(src_reg);
+
+ // If both register locations contains the same value, the register probably holds a reference.
+ // Note: As an optimization, non-moving collectors leave a stale reference value
+ // in the references array even after the original vreg was overwritten to a non-reference.
if (src_value == reinterpret_cast<uintptr_t>(o)) {
new_shadow_frame->SetVRegReference(dest_reg, o);
} else {