Index: lldb/trunk/tools/debugserver/source/CMakeLists.txt
===================================================================
--- lldb/trunk/tools/debugserver/source/CMakeLists.txt
+++ lldb/trunk/tools/debugserver/source/CMakeLists.txt
@@ -142,6 +142,21 @@
   message(STATUS "lldb debugserver will not be available.")
 endif()
 
+# On MacOS, debugserver needs to be codesigned when built. Check if we have
+# a certificate instead of failing in the middle of the build.
+if(build_and_sign_debugserver)
+  execute_process(
+    COMMAND security find-certificate -Z -p -c ${LLDB_CODESIGN_IDENTITY_USED} /Library/Keychains/System.keychain
+    RESULT_VARIABLE cert_return
+    OUTPUT_QUIET
+    ERROR_QUIET)
+
+  if (cert_return)
+    message(FATAL_ERROR "Certificate for debugserver not found. Run scripts/macos-setup-codesign.sh or "
+                        "use the system debugserver passing -DLLDB_USE_SYSTEM_DEBUGSERVER=ON to CMake")
+  endif()
+endif()
+
 if(APPLE)
   if(IOS)
     find_library(BACKBOARD_LIBRARY BackBoardServices