Index: include/llvm/Support/Error.h
===================================================================
--- include/llvm/Support/Error.h
+++ include/llvm/Support/Error.h
@@ -48,6 +48,14 @@
 /// the ErrorInfo template subclass instead.
 class ErrorInfoBase {
 public:
+  ErrorInfoBase() {
+#if !defined(NDEBUG)
+    if (BreakOnError) {
+      LLVM_BUILTIN_DEBUGTRAP;
+    }
+#endif
+  }
+
   virtual ~ErrorInfoBase() = default;
 
   /// Print an error message to an output stream.
@@ -88,6 +96,11 @@
   virtual void anchor();
 
   static char ID;
+
+#if !defined(NDEBUG)
+  // Set to true in debug sessions to immediately break when an error occcurs.
+  static bool BreakOnError;
+#endif
 };
 
 /// Lightweight error class with error context and mandatory checking.
Index: lib/Support/Error.cpp
===================================================================
--- lib/Support/Error.cpp
+++ lib/Support/Error.cpp
@@ -54,6 +54,10 @@
 char ECError::ID = 0;
 char StringError::ID = 0;
 
+#if !defined(NDEBUG)
+bool ErrorInfoBase::BreakOnError = false;
+#endif
+
 void logAllUnhandledErrors(Error E, raw_ostream &OS, Twine ErrorBanner) {
   if (!E)
     return;