[opt] Error if -debug-pass is specified alongside the new PM

Reviewed By: ychen

Differential Revision: https://reviews.llvm.org/D97810

GitOrigin-RevId: 99f1e86cbb34b4a09fa422fe95e8f88f86360eab
diff --git a/lib/IR/LegacyPassManager.cpp b/lib/IR/LegacyPassManager.cpp
index 94be208..32840fd 100644
--- a/lib/IR/LegacyPassManager.cpp
+++ b/lib/IR/LegacyPassManager.cpp
@@ -242,6 +242,8 @@
 
 namespace llvm {
 namespace legacy {
+bool debugPassSpecified() { return PassDebugging != Disabled; }
+
 //===----------------------------------------------------------------------===//
 // FunctionPassManagerImpl
 //