diff --git a/tools/llvm-mca/FetchStage.cpp b/tools/llvm-mca/FetchStage.cpp
index b9e5e0d5ee4..b582b4ed263 100644
--- a/tools/llvm-mca/FetchStage.cpp
+++ b/tools/llvm-mca/FetchStage.cpp
@@ -18,7 +18,7 @@
 
 using namespace mca;
 
-bool FetchStage::isReady() { return SM.hasNext(); }
+bool FetchStage::isReady() const { return SM.hasNext(); }
 
 bool FetchStage::execute(InstRef &IR) {
   if (!SM.hasNext())
diff --git a/tools/llvm-mca/FetchStage.h b/tools/llvm-mca/FetchStage.h
index 823dc37b132..93de961a820 100644
--- a/tools/llvm-mca/FetchStage.h
+++ b/tools/llvm-mca/FetchStage.h
@@ -37,7 +37,7 @@ public:
   FetchStage(const FetchStage &Other) = delete;
   FetchStage &operator=(const FetchStage &Other) = delete;
 
-  bool isReady() override final;
+  bool isReady() const override final;
   bool execute(InstRef &IR) override final;
   void postExecute(const InstRef &IR) override final;
 };
diff --git a/tools/llvm-mca/Stage.cpp b/tools/llvm-mca/Stage.cpp
index 5d6ae56b5df..f4eb8db1881 100644
--- a/tools/llvm-mca/Stage.cpp
+++ b/tools/llvm-mca/Stage.cpp
@@ -22,7 +22,7 @@ namespace mca {
 Stage::Stage() {}
 
 void Stage::addListener(HWEventListener *Listener) {
-  llvm::llvm_unreachable_internal("Stage-based eventing is not implemented.");
+  llvm_unreachable("Stage-based eventing is not implemented.");
 }
 
 } // namespace mca
diff --git a/tools/llvm-mca/Stage.h b/tools/llvm-mca/Stage.h
index 829803d107d..ffaf371921a 100644
--- a/tools/llvm-mca/Stage.h
+++ b/tools/llvm-mca/Stage.h
@@ -16,14 +16,13 @@
 #ifndef LLVM_TOOLS_LLVM_MCA_STAGE_H
 #define LLVM_TOOLS_LLVM_MCA_STAGE_H
 
-#include "HWEventListener.h"
-#include "Instruction.h"
-#include "SourceMgr.h"
-#include <memory>
-#include <string>
+#include <set>
 
 namespace mca {
 
+class HWEventListener;
+class InstRef;
+
 class Stage {
   std::set<HWEventListener *> Listeners;
   Stage(const Stage &Other) = delete;
@@ -36,7 +35,7 @@ public:
   /// Called prior to preExecute to ensure that the stage can operate.
   /// TODO: Remove this logic once backend::run and backend::runCycle become
   /// one routine.
-  virtual bool isReady() { return true; }
+  virtual bool isReady() const { return true; }
 
   /// Called as a setup phase to prepare for the main stage execution.
   virtual void preExecute(const InstRef &IR) {}