Don't hardcode the location of the caller.

This is to avoid shooting ourselves in the foot when
dealing with inlined frames. Instead, use common methods
for fetching the caller and its dex pc.

Change-Id: I3467a7b50cf163022d332e80356f0aab747de252
diff --git a/runtime/entrypoints/entrypoint_utils-inl.h b/runtime/entrypoints/entrypoint_utils-inl.h
index 9292cff..625e695 100644
--- a/runtime/entrypoints/entrypoint_utils-inl.h
+++ b/runtime/entrypoints/entrypoint_utils-inl.h
@@ -38,25 +38,34 @@
 
 namespace art {
 
-inline mirror::ArtMethod* GetCalleeSaveMethodCaller(Thread* self, Runtime::CalleeSaveType type)
+inline mirror::ArtMethod* GetCalleeSaveMethodCaller(StackReference<mirror::ArtMethod>* sp,
+                                                    Runtime::CalleeSaveType type,
+                                                    bool do_caller_check = false)
     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
-  auto* refs_only_sp = self->GetManagedStack()->GetTopQuickFrame();
-  DCHECK_EQ(refs_only_sp->AsMirrorPtr(), Runtime::Current()->GetCalleeSaveMethod(type));
+  DCHECK_EQ(sp->AsMirrorPtr(), Runtime::Current()->GetCalleeSaveMethod(type));
 
   const size_t callee_frame_size = GetCalleeSaveFrameSize(kRuntimeISA, type);
   auto* caller_sp = reinterpret_cast<StackReference<mirror::ArtMethod>*>(
-          reinterpret_cast<uintptr_t>(refs_only_sp) + callee_frame_size);
+          reinterpret_cast<uintptr_t>(sp) + callee_frame_size);
   auto* caller = caller_sp->AsMirrorPtr();
 
-  if (kIsDebugBuild) {
-    NthCallerVisitor visitor(self, 1, true);
+  if (kIsDebugBuild && do_caller_check) {
+    // Note that do_caller_check is optional, as this method can be called by
+    // stubs, and tests without a proper call stack.
+    NthCallerVisitor visitor(Thread::Current(), 1, true);
     visitor.WalkStack();
-    CHECK(caller == visitor.caller);
+    CHECK_EQ(caller, visitor.caller);
   }
 
   return caller;
 }
 
+inline mirror::ArtMethod* GetCalleeSaveMethodCaller(Thread* self, Runtime::CalleeSaveType type)
+    SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+  return GetCalleeSaveMethodCaller(
+      self->GetManagedStack()->GetTopQuickFrame(), type, true /* do_caller_check */);
+}
+
 template <const bool kAccessCheck>
 ALWAYS_INLINE
 inline mirror::Class* CheckObjectAlloc(uint32_t type_idx,