[debuginfo-tests] Remove explicit checks for Python 3

[jhenderson]

Summary

LLVM has a minimum requirement of python 3.6 now, so these are no longer needed.

[aprantl]

So CMake for LLVM will fail without Python3?
If that's the case then this LGTM.

[jhenderson]

In D96499#2560198, @aprantl wrote:

So CMake for LLVM will fail without Python3?
If that's the case then this LGTM.

Yes, the LLVM core CMakeLists.txt located at llvm/CMakeLists.txt already has the check that has been removed from the debuginfo-tests. As debuginfo-tests cannot be configured by a direct CMake execution, this seems reasonable to me (even if CMake did somehow successfully generate targets for check-debuginfo-tests or similar, it would quickly fail if the user wasn't using python 3).

debuginfo-tests/CMakeLists.txt

if("lldb" IN_LIST LLVM_ENABLE_PROJECTS)
   list(APPEND DEBUGINFO_TEST_DEPS lldb lldb-server)
 endif()
 
 # The Windows builder scripts pass -fuse-ld=lld.
 if (WIN32)
   set(DEBUGINFO_TEST_DEPS ${DEBUGINFO_TEST_DEPS} lld)
 endif()
 
-if (NOT DEFINED Python3_EXECUTABLE)
-  message(FATAL_ERROR "Cannot run debuginfo-tests without python 3")
-endif()
-
 configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
   ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg.py
   MAIN_CONFIG
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.cfg.py
   )
 
 add_lit_testsuite(check-debuginfo "Running debug info integration tests"

debuginfo-tests/lit.cfg.py

 
 if lldb_path is not None:
     config.available_features.add('lldb')
 
 # Produce dexter path, lldb path, and combine into the %dexter substitution
 # for running a test.
 dexter_path = os.path.join(config.debuginfo_tests_src_root,
                            'dexter', 'dexter.py')
-dexter_test_cmd = '"{}" "{}" test'.format(config.python3_executable, dexter_path)
+dexter_test_cmd = '"{}" "{}" test'.format(sys.executable, dexter_path)
 if lldb_path is not None:
   dexter_test_cmd += ' --lldb-executable "{}"'.format(lldb_path)
 tools.append(ToolSubst('%dexter', dexter_test_cmd))
 
 # For testing other bits of dexter that aren't under the "test" subcommand,
 # have a %dexter_base substitution.
-dexter_base_cmd = '"{}" "{}"'.format(config.python3_executable, dexter_path)
+dexter_base_cmd = '"{}" "{}"'.format(sys.executable, dexter_path)
 tools.append(ToolSubst('%dexter_base', dexter_base_cmd))
 
 # Set up commands for DexTer regression tests.
 # Builder, debugger, optimisation level and several other flags differ
 # depending on whether we're running a unix like or windows os.
 if platform.system() == 'Windows': 
   dexter_regression_test_builder = '--builder clang-cl_vs2015'
   dexter_regression_test_debugger = '--debugger dbgeng'
   dexter_regression_test_cflags = '--cflags "/Zi /Od"'
   dexter_regression_test_ldflags = '--ldflags "/Zi"'
 else:
   dexter_regression_test_builder = '--builder clang'
   dexter_regression_test_debugger = "--debugger lldb"
   dexter_regression_test_cflags = '--cflags "-O0 -glldb"'
   dexter_regression_test_ldflags = ''
 
 # Typical command would take the form:
 # ./path_to_py/python.exe ./path_to_dex/dexter.py test --fail-lt 1.0 -w --builder clang --debugger lldb --cflags '-O0 -g'
 dexter_regression_test_command = ' '.join(
-  # "python3", "dexter.py", test, fail_mode, builder, debugger, cflags, ldflags
-  ['"{}"'.format(config.python3_executable),
+  # "python", "dexter.py", test, fail_mode, builder, debugger, cflags, ldflags
+  ['"{}"'.format(sys.executable),
   '"{}"'.format(dexter_path),
   'test',
   '--fail-lt 1.0 -w',
   dexter_regression_test_builder,
   dexter_regression_test_debugger,
   dexter_regression_test_cflags,
   dexter_regression_test_ldflags])
 

debuginfo-tests/lit.site.cfg.py.in

 config.target_triple = "@TARGET_TRIPLE@"
 config.host_arch = "@HOST_ARCH@"
 config.is_msvc = lit.util.pythonize_bool("@MSVC@")
 
 config.mlir_src_root = "@MLIR_SOURCE_DIR@"
 
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
 
-config.python3_executable = "@Python3_EXECUTABLE@"
-
 # Support substitution of the tools_dir 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_shlib_dir = config.llvm_shlib_dir % 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))
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
 
 # Let the main config do the real work.
 lit_config.load_config(config, "@DEBUGINFO_TESTS_SOURCE_DIR@/lit.cfg.py")