diff --git a/test/lit.cfg b/test/lit.cfg
index 5d67e1403481b..1570fac4143f2 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -2,7 +2,7 @@
 #
 # This source file is part of the Swift.org open source project
 #
-# Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+# Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
 # Licensed under Apache License v2.0 with Runtime Library Exception
 #
 # See https://swift.org/LICENSE.txt for license information
@@ -297,6 +297,8 @@ config.swift_refactor = inferSwiftBinary('swift-refactor')
 config.swift_demangle_yamldump = inferSwiftBinary('swift-demangle-yamldump')
 config.benchmark_o = inferSwiftBinary('Benchmark_O')
 config.benchmark_driver = inferSwiftBinary('Benchmark_Driver')
+config.wasmer = inferSwiftBinary('wasmer')
+config.wasm_ld = inferSwiftBinary('wasm-ld')
 
 config.swift_utils = make_path(config.swift_src_root, 'utils')
 config.line_directive = make_path(config.swift_utils, 'line-directive')
@@ -1340,6 +1342,73 @@ elif run_os == 'linux-androideabi' or run_os == 'linux-android':
         '-L%s' % make_path(test_resource_dir, config.target_sdk_name)])
     # The Swift interpreter is not available when targeting Android.
     config.available_features.discard('swift_interpreter')
+elif run_os == 'wasi':
+    lit_config.note("Testing WebAssembly/WASI " + config.variant_triple)
+
+    config.target_object_format = "wasm"
+    config.target_shared_library_prefix = 'lib'
+    config.target_shared_library_suffix = ".a"
+    config.target_sdk_name = "wasi"
+    config.target_runtime = "native"
+
+    config.target_swift_autolink_extract = inferSwiftBinary("swift-autolink-extract")
+
+    config.target_build_swift = ' '.join([
+        config.swiftc,
+        '-target', config.variant_triple,
+        '-Xcc', '--sysroot=%s' % config.variant_sdk,
+        '-Xclang-linker', '--sysroot=%s' % config.variant_sdk,
+        '-toolchain-stdlib-rpath', resource_dir_opt, 
+        mcp_opt, config.swift_test_options,
+        config.swift_driver_test_options, swift_execution_tests_extra_flags])
+    config.target_codesign = "echo"
+    config.target_build_swift_dylib = (
+        "%s -parse-as-library -emit-library -o '\\1'"
+        % (config.target_build_swift))
+    config.target_add_rpath = ''
+    config.target_swift_frontend = ' '.join([
+        config.swift,
+        '-frontend',
+        '-target', config.variant_triple,
+        '-Xcc', '--sysroot=%s' % config.variant_sdk,
+        resource_dir_opt, mcp_opt,
+        config.swift_test_options, config.swift_frontend_test_options])
+    subst_target_swift_frontend_mock_sdk = config.target_swift_frontend
+    subst_target_swift_frontend_mock_sdk_after = ""
+    config.target_run = '%s run --backend cranelift --' % config.wasmer
+    if 'interpret' in lit_config.params:
+        use_interpreter_for_simple_runs()
+    config.target_sil_opt = (
+        '%s -target %s %s %s %s' %
+        (config.sil_opt, config.variant_triple, resource_dir_opt, mcp_opt, config.sil_test_options))
+    config.target_swift_symbolgraph_extract = ' '.join([
+        config.swift_symbolgraph_extract,
+        '-target', config.variant_triple,
+        mcp_opt])
+    config.target_swift_ide_test = (
+        '%s -target %s %s %s %s' %
+        (config.swift_ide_test, config.variant_triple, resource_dir_opt,
+         mcp_opt, ccp_opt))
+    subst_target_swift_ide_test_mock_sdk = config.target_swift_ide_test
+    subst_target_swift_ide_test_mock_sdk_after = ""
+    config.target_swiftc_driver = (
+        "%s -target %s -toolchain-stdlib-rpath %s %s" %
+        (config.swiftc, config.variant_triple, resource_dir_opt, mcp_opt))
+    config.target_swift_modulewrap = (
+        '%s -modulewrap -target %s' %
+        (config.swiftc, config.variant_triple))
+    config.target_swift_emit_pcm = (
+        '%s -emit-pcm -target %s' %
+        (config.swiftc, config.variant_triple))
+    config.target_clang = (
+        "%s -target %s %s -fobjc-runtime=ios-5.0" %
+        (config.clang, config.variant_triple, clang_mcp_opt))
+    config.target_ld = (
+        "%s -L%r" % 
+        (config.wasm_ld, make_path(test_resource_dir, config.target_sdk_name)))
+
+    # The Swift interpreter is not available when targeting WebAssembly/WASI.
+    config.available_features.discard('swift_interpreter')
 
 else:
     lit_config.fatal("Don't know how to define target_run and "