Add missing references.

This mainly avoids implicit copies when extracting an object from a container.

Change-Id: If4d0e6153e8c2b48345fde5bb546b4c65649fcf3

2 files changed, 3 insertions, 3 deletions

diff --git a/runtime/stack.cc b/runtime/stack.cc
index 1715664..5d3a9a5 100644
--- a/runtime/stack.cc
+++ b/runtime/stack.cc
@@ -253,7 +253,7 @@ std::string StackVisitor::DescribeLocation() const {
   return result;
 }
 
-instrumentation::InstrumentationStackFrame StackVisitor::GetInstrumentationStackFrame(uint32_t depth) const {
+instrumentation::InstrumentationStackFrame& StackVisitor::GetInstrumentationStackFrame(uint32_t depth) const {
   return thread_->GetInstrumentationStack()->at(depth);
 }
 
@@ -309,7 +309,7 @@ void StackVisitor::WalkStack(bool include_transitions) {
           // While profiling, the return pc is restored from the side stack, except when walking
           // the stack for an exception where the side stack will be unwound in VisitFrame.
           if (GetQuickInstrumentationExitPc() == return_pc) {
-            instrumentation::InstrumentationStackFrame instrumentation_frame =
+            const instrumentation::InstrumentationStackFrame& instrumentation_frame =
                 GetInstrumentationStackFrame(instrumentation_stack_depth);
             instrumentation_stack_depth++;
             if (GetMethod() == Runtime::Current()->GetCalleeSaveMethod(Runtime::kSaveAll)) {
diff --git a/runtime/stack.h b/runtime/stack.h
index 700b7f1..a4b93bc 100644
--- a/runtime/stack.h
+++ b/runtime/stack.h
@@ -567,7 +567,7 @@ class StackVisitor {
   static void DescribeStack(Thread* thread) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
  private:
-  instrumentation::InstrumentationStackFrame GetInstrumentationStackFrame(uint32_t depth) const;
+  instrumentation::InstrumentationStackFrame& GetInstrumentationStackFrame(uint32_t depth) const;
 
   void SanityCheckFrame() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);