diff --git a/runtime/interpreter/shadow_frame.h b/runtime/interpreter/shadow_frame.h
index 91371d1..88eb413 100644
--- a/runtime/interpreter/shadow_frame.h
+++ b/runtime/interpreter/shadow_frame.h
@@ -179,12 +179,8 @@
   mirror::Object* GetVRegReference(size_t i) const REQUIRES_SHARED(Locks::mutator_lock_) {
     DCHECK_LT(i, NumberOfVRegs());
     mirror::Object* ref;
-    if (HasReferenceArray()) {
-      ref = References()[i].AsMirrorPtr();
-    } else {
-      const uint32_t* vreg_ptr = &vregs_[i];
-      ref = reinterpret_cast<const StackReference<mirror::Object>*>(vreg_ptr)->AsMirrorPtr();
-    }
+    DCHECK(HasReferenceArray());
+    ref = References()[i].AsMirrorPtr();
     ReadBarrier::MaybeAssertToSpaceInvariant(ref);
     if (kVerifyFlags & kVerifyReads) {
       VerifyObject(ref);
diff --git a/runtime/stack.cc b/runtime/stack.cc
index eb9c661..25939d2 100644
--- a/runtime/stack.cc
+++ b/runtime/stack.cc
@@ -139,9 +139,9 @@
     } else {
       uint16_t reg = accessor.RegistersSize() - accessor.InsSize();
       uint32_t value = 0;
-      bool success = GetVReg(m, reg, kReferenceVReg, &value);
-      // We currently always guarantee the `this` object is live throughout the method.
-      CHECK(success) << "Failed to read the this object in " << ArtMethod::PrettyMethod(m);
+      if (!GetVReg(m, reg, kReferenceVReg, &value)) {
+        return nullptr;
+      }
       return reinterpret_cast<mirror::Object*>(value);
     }
   }
@@ -223,20 +223,39 @@
   switch (location_kind) {
     case DexRegisterLocation::Kind::kInStack: {
       const int32_t offset = dex_register_map[vreg].GetStackOffsetInBytes();
+      BitMemoryRegion stack_mask = code_info.GetStackMaskOf(stack_map);
+      if (kind == kReferenceVReg && !stack_mask.LoadBit(offset / kFrameSlotSize)) {
+        return false;
+      }
       const uint8_t* addr = reinterpret_cast<const uint8_t*>(cur_quick_frame_) + offset;
       *val = *reinterpret_cast<const uint32_t*>(addr);
       return true;
     }
-    case DexRegisterLocation::Kind::kInRegister:
+    case DexRegisterLocation::Kind::kInRegister: {
+      uint32_t register_mask = code_info.GetRegisterMaskOf(stack_map);
+      uint32_t reg = dex_register_map[vreg].GetMachineRegister();
+      if (kind == kReferenceVReg && !(register_mask & (1 << reg))) {
+        return false;
+      }
+      return GetRegisterIfAccessible(reg, kind, val);
+    }
     case DexRegisterLocation::Kind::kInRegisterHigh:
     case DexRegisterLocation::Kind::kInFpuRegister:
     case DexRegisterLocation::Kind::kInFpuRegisterHigh: {
+      if (kind == kReferenceVReg) {
+        return false;
+      }
       uint32_t reg = dex_register_map[vreg].GetMachineRegister();
       return GetRegisterIfAccessible(reg, kind, val);
     }
-    case DexRegisterLocation::Kind::kConstant:
-      *val = dex_register_map[vreg].GetConstant();
+    case DexRegisterLocation::Kind::kConstant: {
+      uint32_t result = dex_register_map[vreg].GetConstant();
+      if (kind == kReferenceVReg && result != 0) {
+        return false;
+      }
+      *val = result;
       return true;
+    }
     case DexRegisterLocation::Kind::kNone:
       return false;
     default:
diff --git a/test/686-get-this/expected.txt b/test/686-get-this/expected.txt
new file mode 100644
index 0000000..6a5618e
--- /dev/null
+++ b/test/686-get-this/expected.txt
@@ -0,0 +1 @@
+JNI_OnLoad called
diff --git a/test/686-get-this/info.txt b/test/686-get-this/info.txt
new file mode 100644
index 0000000..7227bad
--- /dev/null
+++ b/test/686-get-this/info.txt
@@ -0,0 +1,2 @@
+Test that we can successfully call StackVisitor.GetThis() even when
+'this' gets overwritten.
diff --git a/test/686-get-this/smali/Test.smali b/test/686-get-this/smali/Test.smali
new file mode 100644
index 0000000..533f607
--- /dev/null
+++ b/test/686-get-this/smali/Test.smali
@@ -0,0 +1,45 @@
+# Copyright (C) 2018 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+.class public LTest;
+.super Ljava/lang/Object;
+
+.method public constructor <init>()V
+    .registers 2
+    invoke-direct {p0}, Ljava/lang/Object;-><init>()V
+    const/4 v0, 0x1
+    sput v0, LTest;->field:I
+    return-void
+.end method
+
+
+.method public testEmpty()V
+  .registers 2
+  const/4 p0, 0x1
+  invoke-static {}, LMain;->getThisOfCaller()Ljava/lang/Object;
+  move-result-object v0
+  sput-object v0, LMain;->field:Ljava/lang/Object;
+  return-void
+.end method
+
+.method public testPrimitive()I
+  .registers 2
+  sget p0, LTest;->field:I
+  invoke-static {}, LMain;->getThisOfCaller()Ljava/lang/Object;
+  move-result-object v0
+  sput-object v0, LMain;->field:Ljava/lang/Object;
+  return p0
+.end method
+
+.field static public field:I
diff --git a/test/686-get-this/src/Main.java b/test/686-get-this/src/Main.java
new file mode 100644
index 0000000..4ea5301
--- /dev/null
+++ b/test/686-get-this/src/Main.java
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Method;
+
+public class Main {
+  public static void main(String[] args) throws Exception {
+    System.loadLibrary(args[0]);
+
+    Class<?> c = Class.forName("Test");
+    ensureJitCompiled(c, "testEmpty");
+    ensureJitCompiled(c, "testPrimitive");
+
+    Method m = c.getMethod("testEmpty");
+    m.invoke(c.newInstance());
+    if (field != null) {
+      throw new Error("Expected null");
+    }
+
+    m = c.getMethod("testPrimitive");
+    int a = (Integer)m.invoke(c.newInstance());
+    if (a != 1) {
+      throw new Error("Expected 1, got " + a);
+    }
+    if (field != null) {
+      throw new Error("Expected null");
+    }
+  }
+
+  public static Object field;
+
+  private static native void ensureJitCompiled(Class<?> itf, String method_name);
+  public static native Object getThisOfCaller();
+}
diff --git a/test/common/stack_inspect.cc b/test/common/stack_inspect.cc
index d74d2ef..581aa74 100644
--- a/test/common/stack_inspect.cc
+++ b/test/common/stack_inspect.cc
@@ -196,4 +196,24 @@
   }
 }
 
+struct GetCallingFrameVisitor : public StackVisitor {
+  GetCallingFrameVisitor(Thread* thread, Context* context)
+      REQUIRES_SHARED(Locks::mutator_lock_)
+      : StackVisitor(thread, context, StackVisitor::StackWalkKind::kIncludeInlinedFrames) {}
+
+  bool VisitFrame() override NO_THREAD_SAFETY_ANALYSIS {
+    // Discard stubs and Main.getThisOfCaller.
+    return GetMethod() == nullptr || GetMethod()->IsNative();
+  }
+};
+
+extern "C" JNIEXPORT jobject JNICALL Java_Main_getThisOfCaller(
+    JNIEnv* env, jclass cls ATTRIBUTE_UNUSED) {
+  ScopedObjectAccess soa(env);
+  std::unique_ptr<art::Context> context(art::Context::Create());
+  GetCallingFrameVisitor visitor(soa.Self(), context.get());
+  visitor.WalkStack();
+  return soa.AddLocalReference<jobject>(visitor.GetThisObject());
+}
+
 }  // namespace art
diff --git a/test/knownfailures.json b/test/knownfailures.json
index e27a4d6..db06c4e 100644
--- a/test/knownfailures.json
+++ b/test/knownfailures.json
@@ -947,6 +947,7 @@
           "676-resolve-field-type",
           "685-deoptimizeable",
           "685-shifts",
+          "686-get-this",
           "706-checker-scheduler",
           "707-checker-invalid-profile",
           "714-invoke-custom-lambda-metafactory",