diff --git a/runtime/compiler_callbacks.h b/runtime/compiler_callbacks.h
index 3fabe3e..b296e39 100644
--- a/runtime/compiler_callbacks.h
+++ b/runtime/compiler_callbacks.h
@@ -29,27 +29,32 @@
 }  // namespace verifier
 
 class CompilerCallbacks {
-  public:
-    virtual ~CompilerCallbacks() { }
+ public:
+  enum class CallbackMode {  // private
+    kCompileBootImage,
+    kCompileApp
+  };
 
-    virtual bool MethodVerified(verifier::MethodVerifier* verifier)
-        SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
-    virtual void ClassRejected(ClassReference ref) = 0;
+  virtual ~CompilerCallbacks() { }
 
-    // Return true if we should attempt to relocate to a random base address if we have not already
-    // done so. Return false if relocating in this way would be problematic.
-    virtual bool IsRelocationPossible() = 0;
+  virtual bool MethodVerified(verifier::MethodVerifier* verifier)
+  SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
+  virtual void ClassRejected(ClassReference ref) = 0;
 
-    bool IsBootImage() {
-      return boot_image_;
-    }
+  // Return true if we should attempt to relocate to a random base address if we have not already
+  // done so. Return false if relocating in this way would be problematic.
+  virtual bool IsRelocationPossible() = 0;
 
-  protected:
-    explicit CompilerCallbacks(bool boot_image) : boot_image_(boot_image) { }
+  bool IsBootImage() {
+    return mode_ == CallbackMode::kCompileBootImage;
+  }
 
-  private:
-    // Whether the compiler is creating a boot image.
-    const bool boot_image_;
+ protected:
+  explicit CompilerCallbacks(CallbackMode mode) : mode_(mode) { }
+
+ private:
+  // Whether the compiler is creating a boot image.
+  const CallbackMode mode_;
 };
 
 }  // namespace art