diff --git a/lldb/source/Breakpoint/Breakpoint.cpp b/lldb/source/Breakpoint/Breakpoint.cpp
--- a/lldb/source/Breakpoint/Breakpoint.cpp
+++ b/lldb/source/Breakpoint/Breakpoint.cpp
@@ -1026,6 +1026,7 @@
     case eBreakpointEventTypeThreadChanged: return "thread changed";
     case eBreakpointEventTypeAutoContinueChanged: return "autocontinue changed";
   };
+  llvm_unreachable("Fully covered switch above!");
 }
 
 Log *Breakpoint::BreakpointEventData::GetLogChannel() {
diff --git a/lldb/source/Core/DebuggerEvents.cpp b/lldb/source/Core/DebuggerEvents.cpp
--- a/lldb/source/Core/DebuggerEvents.cpp
+++ b/lldb/source/Core/DebuggerEvents.cpp
@@ -52,6 +52,7 @@
   case Type::Error:
     return "error";
   }
+  llvm_unreachable("Fully covered switch above!");
 }
 
 void DiagnosticEventData::Dump(Stream *s) const {
diff --git a/lldb/source/Plugins/Process/Linux/IntelPTCollector.cpp b/lldb/source/Plugins/Process/Linux/IntelPTCollector.cpp
--- a/lldb/source/Plugins/Process/Linux/IntelPTCollector.cpp
+++ b/lldb/source/Plugins/Process/Linux/IntelPTCollector.cpp
@@ -102,6 +102,7 @@
     case BitOffset:
       return 10;
     }
+    llvm_unreachable("Fully covered switch above!");
   };
 
   auto createError = [&](const char *expected_value_message) {