[lldb] add support to filter lang/swift tests through an environment variable

Author: charles-zablit

lldb/test/CMakeLists.txt

@@ -274,8 +274,19 @@ configure_lit_site_cfg(
   MAIN_CONFIG
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.cfg.py)
 
+# BEGIN SWIFT MOD
+if(DEFINED ENV{ONLY_SWIFT_LLDB_TESTS} AND $ENV{ONLY_SWIFT_LLDB_TESTS})
+  set(CHECK_LLDB_ARGS "--filter=[sS]wift")
+else()
+  set(CHECK_LLDB_ARGS "")
+endif()
+# END SWIFT MOD
+
 add_lit_testsuite(check-lldb "Running lldb lit test suite"
   ${CMAKE_CURRENT_BINARY_DIR}
+  # BEGIN SWIFT MOD
+  ARGS ${CHECK_LLDB_ARGS}
+  # END SWIFT MOD
   DEPENDS
     lldb-api-test-deps
     lldb-shell-test-deps