diff --git a/bolt/test/lit.cfg.py b/bolt/test/lit.cfg.py
--- a/bolt/test/lit.cfg.py
+++ b/bolt/test/lit.cfg.py
@@ -55,8 +55,10 @@
 
 llvm_config.use_default_substitutions()
 
-llvm_config.use_clang(additional_tool_dirs=[os.path.dirname(config.bolt_clang)])
-llvm_config.use_lld(additional_tool_dirs=[os.path.dirname(config.bolt_lld)])
+llvm_config.config.environment['BOLT_CLANG_EXE'] = config.bolt_clang
+llvm_config.config.environment['BOLT_LLD_EXE'] = config.bolt_lld
+llvm_config.use_clang(search_env='BOLT_CLANG_EXE')
+llvm_config.use_llvm_tool('lld', required=True, search_env='BOLT_LLD_EXE')
 
 config.substitutions.append(('%cflags', '-no-pie'))
 config.substitutions.append(('%cxxflags', '-no-pie'))