[compiler-rt][lit] initialize LIT LLVMConfig instance

[ychen]

Summary

to handle lit tools searching. Otherwise
compiler-rt depends on system environment variable PATH for lit tools
which diverge from the other LLVM projects. This reverts D83486 which
really should be implemented in LIT itself when the PATH is constructed.

compiler-rt/test/lit.common.cfg.py

if compiler_libdir != compiler_rt_libdir_real:
     lit_config.note(f'Testing using libraries in "{config.compiler_rt_libdir}"')
 
 # If needed, add cflag for shadow scale.
 if config.asan_shadow_scale != '':
   config.target_cflags += " -mllvm -asan-mapping-scale=" + config.asan_shadow_scale
 if config.memprof_shadow_scale != '':
   config.target_cflags += " -mllvm -memprof-mapping-scale=" + config.memprof_shadow_scale
 
-config.environment = dict(os.environ)
-
 # Clear some environment variables that might affect Clang.
 possibly_dangerous_env_vars = ['ASAN_OPTIONS', 'DFSAN_OPTIONS', 'HWASAN_OPTIONS',
                                'LSAN_OPTIONS', 'MSAN_OPTIONS', 'UBSAN_OPTIONS',
                                'COMPILER_PATH', 'RC_DEBUG_OPTIONS',
                                'CINDEXTEST_PREAMBLE_FILE', 'LIBRARY_PATH',
                                'CPATH', 'C_INCLUDE_PATH', 'CPLUS_INCLUDE_PATH',
                                'OBJC_INCLUDE_PATH', 'OBJCPLUS_INCLUDE_PATH',
                                'LIBCLANG_TIMING', 'LIBCLANG_OBJTRACKING',

compiler-rt/test/lit.common.configured.in

 set_default("host_os", "@HOST_OS@")
 set_default("llvm_build_mode", "@LLVM_BUILD_MODE@")
 set_default("llvm_src_root", "@LLVM_MAIN_SRC_DIR@")
 set_default("llvm_obj_root", "@LLVM_BINARY_DIR@")
 set_default("compiler_rt_src_root", "@COMPILER_RT_SOURCE_DIR@")
 set_default("compiler_rt_obj_root", "@COMPILER_RT_BINARY_DIR@")
 set_default("enable_per_target_runtime_dir", @LLVM_ENABLE_PER_TARGET_RUNTIME_DIR_PYBOOL@)
 set_default("llvm_tools_dir", "@LLVM_TOOLS_DIR@")
+set_default("lit_tools_dir", "@LLVM_LIT_TOOLS_DIR@")
 set_default("llvm_shlib_dir", "@LLVM_LIBRARY_OUTPUT_INTDIR@")
 set_default("gnu_ld_executable", "@GNU_LD_EXECUTABLE@")
 set_default("gold_executable", "@GOLD_EXECUTABLE@")
 set_default("clang", "@COMPILER_RT_RESOLVED_TEST_COMPILER@")
 set_default("compiler_id", "@COMPILER_RT_TEST_COMPILER_ID@")
 set_default("python_executable", "@Python3_EXECUTABLE@")
 set_default("compiler_rt_debug", @COMPILER_RT_DEBUG_PYBOOL@)
 set_default("compiler_rt_intercept_libdispatch", @COMPILER_RT_INTERCEPT_LIBDISPATCH_PYBOOL@)

 # apply substitution.
 config.llvm_tools_dir = lit_config.substitute(config.llvm_tools_dir)
 config.clang = lit_config.substitute(config.clang)
 config.compiler_rt_libdir = lit_config.substitute(config.compiler_rt_libdir)
 
 if not os.path.exists(config.clang):
   lit_config.fatal("Can't find compiler on path %r" % config.clang)
 
+import lit.llvm
+lit.llvm.initialize(lit_config, config)
+
 # Setup attributes common for all compiler-rt projects.
 lit_config.load_config(config, "@COMPILER_RT_SOURCE_DIR@/test/lit.common.cfg.py")