[Polly][CMake] Skip unit-tests in lit if gtest is not available

[philip.pfaffe]

Summary

There is a bug in the current lit configurations for the unittests. If gtest is not available, the site-config for the unit tests won't be generated. Because lit recurses through the test directory, the lit configuration for the unit tests will be discovered nevertheless, leading to a fatal error in lit.

This patch semi-gracefully skips the unittests if gtest is not available. As a result, running lit now prints this: warning: test suite 'Polly-Unit' contained no test.

If people think that this is too annoying, the alternative would be to pick apart the test directory, so that the lit testsuite discovery will always only find one configuration. In fact, both of these things could be combined. While it's certainly nice that running a single lit command runs all the tests, I suppose people use the check-polly make target over lit most of the time, so the difference might not be noticed.

[grosser]

I am fine with this "solution". Let's see what Michael says.

[philip.pfaffe]

@Meinersbur Ping?

[grosser]

@Meinersbur : Do you happen to have any final comments on this or can this be committed?

[grosser]

Michael is still on vacation. I think we should just commit it as is. Michael can do a post-commit review or update if he feels like. Thanks Philip for working on this!

CMakeLists.txt

if (NOT DEFINED LLVM_MAIN_SRC_DIR)
   else()
     execute_process(COMMAND "${LLVM_TOOLS_BINARY_DIR}/llvm-config" --src-root
       OUTPUT_VARIABLE MAIN_SRC_DIR
       OUTPUT_STRIP_TRAILING_WHITESPACE)
     set(LLVM_SOURCE_ROOT ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
   endif()
 
   # Enable unit tests if available.
+  set(POLLY_GTEST_AVAIL 0)
   set(UNITTEST_DIR ${LLVM_SOURCE_ROOT}/utils/unittest)
   if(EXISTS ${UNITTEST_DIR}/googletest/include/gtest/gtest.h)
     # The build tree already exports the gtest target, which we can reuse
     if (TARGET gtest)
       # LLVM Doesn't export gtest's include directorys, so do that here
       set_target_properties(gtest
         PROPERTIES INTERFACE_INCLUDE_DIRECTORIES
         "${UNITTEST_DIR}/googletest/include;${UNITTEST_DIR}/googlemock/include"

test/CMakeLists.txt

add_lit_testsuite(check-polly-tests "Running polly regression tests"
   ${CMAKE_CURRENT_BINARY_DIR}
   PARAMS polly_site_config=${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg
   polly_unit_site_config=${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg
   DEPENDS ${POLLY_TEST_DEPS}
   )
 set_target_properties(check-polly-tests PROPERTIES FOLDER "Polly")
 add_dependencies(check-polly check-polly-tests)
 
-if (POLLY_GTEST_AVAIL)
-  configure_lit_site_cfg(
-    ${CMAKE_CURRENT_SOURCE_DIR}/Unit/lit.site.cfg.in
-    ${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg
-    )
 
+if (POLLY_GTEST_AVAIL)
   # Run only unit tests
   add_lit_testsuite(check-polly-unittests "Running polly unit tests only"
     ${CMAKE_CURRENT_BINARY_DIR}/Unit
     PARAMS polly_site_config=${CMAKE_CURRENT_BINARY_DIR}/Unit/lit.site.cfg
     DEPENDS PollyUnitTests
     )
   set_target_properties(check-polly-unittests PROPERTIES FOLDER "Polly")
 endif ()

test/Unit/lit.cfg

 # -*- Python -*-
 
 # Configuration file for the 'lit' test runner.
 
 import os
 import platform
 
 import lit.formats
 import lit.util
 
 # name: The name of this test suite.
 config.name = 'Polly-Unit'
 
+if not config.has_unittests:
+    raise SystemExit
+
 # suffixes: A list of file extensions to treat as test files.
 config.suffixes = []
 
 # test_source_root: The root path where tests are located.
 # test_exec_root: The root path where tests should be run.
 polly_obj_root = getattr(config, 'polly_obj_root', None)
 if polly_obj_root is not None:
     config.test_exec_root = os.path.join(polly_obj_root, 'unittests')

test/Unit/lit.site.cfg.in

 @LIT_SITE_CFG_IN_HEADER@
 
 import sys
 
 config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
 config.llvm_build_mode = "@LLVM_BUILD_MODE@"
 config.polly_obj_root = "@POLLY_BINARY_DIR@"
 config.polly_lib_dir = "@POLLY_LIB_DIR@"
 config.enable_shared = @ENABLE_SHARED@
 config.shlibdir = "@SHLIBDIR@"
 config.target_triple = "@TARGET_TRIPLE@"
 config.enable_gpgpu_codegen = "@GPU_CODEGEN@"
 config.link_polly_into_tools = "@LINK_POLLY_INTO_TOOLS@"
+config.has_unittests = @POLLY_GTEST_AVAIL@
 
 # Support substitution of the tools_dir, libs_dirs, and build_mode with user
 # parameters. This is used when we can't determine the tool dir at
 # configuration time.
 try:
     config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
     config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
     config.llvm_build_mode = config.llvm_build_mode % lit_config.params
 except KeyError:
     e = sys.exc_info()[1]
     key, = e.args
     lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
 
 # Let the main config do the real work.
 lit_config.load_config(config, "@POLLY_SOURCE_DIR@/test/Unit/lit.cfg")