[CMake] Ignore hidden/metadata files when adding lit check-* testsuites

[eladcohen]

Summary

When we have hidden/metadata files (for example .svn dirs) under the test dirs, cmake creates a bloated Makefile with tons of fake check-.* targets which increases build time.

[mgorny]

cmake/modules/AddLLVM.cmake

1216

Any reason not to just use literal ${lit_suite} MATCHES "^[.]" in if?

The Inputs/Output check could be made nicer too, I guess; but only if you want to play with them. I'm pretty sure the current version would match Inputs somewhere in path or filename.

[eladcohen]

cmake/modules/AddLLVM.cmake

1216

Makes sense, I'll change it to an if(var MATCHES regex) - thanks!

About the Inputs/Output - I rather not change this, I'm really no CMake expert. Maybe @bogner knows if the intention was to actually match Inputs anywhere in path or filename?

[eladcohen]

Fixed Michał's comment

[mgorny]

cmake/modules/AddLLVM.cmake

1219

Why the second slash? If you're trying to escape the ., then it shouldn't be necessary since it's in []. With the first one, I think you use \\ for the literal backwards slash but please test how CMake handles it.

cmake/modules/AddLLVM.cmake

add_lit_target(${target} ${comment}
     )
 endfunction()
 
 function(add_lit_testsuites project directory)
   if (NOT CMAKE_CONFIGURATION_TYPES)
     cmake_parse_arguments(ARG "" "" "PARAMS;DEPENDS;ARGS" ${ARGN})
 
     # Search recursively for test directories by assuming anything not
-    # in a directory called Inputs contains tests.
+    # in a directory called Inputs/Output/.* contains tests.
     file(GLOB_RECURSE to_process LIST_DIRECTORIES true ${directory}/*)
     foreach(lit_suite ${to_process})
       if(NOT IS_DIRECTORY ${lit_suite})
         continue()
       endif()
       string(FIND ${lit_suite} Inputs is_inputs)
       string(FIND ${lit_suite} Output is_output)
       if (NOT (is_inputs EQUAL -1 AND is_output EQUAL -1))
         continue()
       endif()
+      if(${lit_suite} MATCHES ".*[\/][\.].*")
+        continue()
+      endif()
 
       # Create a check- target for the directory.
       string(REPLACE ${directory} "" name_slash ${lit_suite})
       if (name_slash)
         string(REPLACE "/" "-" name_slash ${name_slash})
         string(REPLACE "\\" "-" name_dashes ${name_slash})
         string(TOLOWER "${project}${name_dashes}" name_var)
         add_lit_target("check-${name_var}" "Running lit suite ${lit_suite}"