Index: clang/test/lit.site.cfg.py.in
===================================================================
--- clang/test/lit.site.cfg.py.in
+++ clang/test/lit.site.cfg.py.in
@@ -9,6 +9,7 @@
 config.llvm_shlib_dir = path(r"@SHLIBDIR@")
 config.llvm_plugin_ext = "@LLVM_PLUGIN_EXT@"
 config.lit_tools_dir = path(r"@LLVM_LIT_TOOLS_DIR@")
+config.errc_messages = "@LLVM_LIT_ERRC_MESSAGES@"
 config.clang_obj_root = path(r"@CLANG_BINARY_DIR@")
 config.clang_src_dir = path(r"@CLANG_SOURCE_DIR@")
 config.clang_tools_dir = path(r"@CLANG_TOOLS_DIR@")
Index: lld/test/lit.site.cfg.py.in
===================================================================
--- lld/test/lit.site.cfg.py.in
+++ lld/test/lit.site.cfg.py.in
@@ -8,6 +8,7 @@
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
+config.errc_messages = "@LLVM_LIT_ERRC_MESSAGES@"
 config.lld_obj_root = "@LLD_BINARY_DIR@"
 config.lld_libs_dir = "@LLD_LIBS_DIR@"
 config.lld_tools_dir = "@LLD_TOOLS_DIR@"
Index: llvm/cmake/config-ix.cmake
===================================================================
--- llvm/cmake/config-ix.cmake
+++ llvm/cmake/config-ix.cmake
@@ -490,6 +490,9 @@
   endif ()
 endif ()
 
+include(GetErrcMessages)
+get_errc_messages(LLVM_LIT_ERRC_MESSAGES)
+
 if( MSVC )
   set(SHLIBEXT ".lib")
   set(stricmp "_stricmp")
Index: llvm/cmake/modules/GetErrcMessages.cmake
===================================================================
--- /dev/null
+++ llvm/cmake/modules/GetErrcMessages.cmake
@@ -0,0 +1,39 @@
+
+# This function returns the messages of various POSIX error codes as they are returned by std::error_code.
+# The purpose of this function is to supply those error messages to llvm-lit using the errc_messages config
+# Currently supplied and needed error codes: ENOENT, EISDIR, EINVAL and EACCES
+# Messages are semi colon separated
+# Keep amount, order and tested error codes in sync with llvm/utils/lit/lit/llvm/config.py
+function(get_errc_messages outvar)
+
+    set(errc_test_code ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeTmp/getErrc.cpp)
+
+    file(WRITE ${errc_test_code} "
+        #include <cerrno>
+        #include <iostream>
+        #include <string>
+        #include <system_error>
+
+        std::string getMessageFor(int err) {
+            return std::make_error_code(static_cast<std::errc>(err)).message();
+        }
+
+        int main() {
+            std::cout << getMessageFor(ENOENT) << ';' << getMessageFor(EISDIR);
+            std::cout << ';' << getMessageFor(EINVAL) << ';' << getMessageFor(EACCES);
+        }
+    ")
+
+    try_run(errc_exit_code
+            errc_compiled
+            ${CMAKE_BINARY_DIR}
+            ${errc_test_code}
+            RUN_OUTPUT_VARIABLE errc_result
+            COMPILE_OUTPUT_VARIABLE errc_compile_errors)
+    if (errc_compiled)
+        set(${outvar} ${errc_result} PARENT_SCOPE)
+    else()
+        set(${outvar} "" PARENT_SCOPE)
+        message(STATUS "Failed to get errc messages")
+    endif ()
+endfunction()
Index: llvm/test/lit.site.cfg.py.in
===================================================================
--- llvm/test/lit.site.cfg.py.in
+++ llvm/test/lit.site.cfg.py.in
@@ -12,6 +12,7 @@
 config.llvm_shlib_ext = "@SHLIBEXT@"
 config.llvm_exe_ext = "@EXEEXT@"
 config.lit_tools_dir = path(r"@LLVM_LIT_TOOLS_DIR@")
+config.errc_messages = "@LLVM_LIT_ERRC_MESSAGES@"
 config.python_executable = "@Python3_EXECUTABLE@"
 config.gold_executable = "@GOLD_EXECUTABLE@"
 config.ld64_executable = "@LD64_EXECUTABLE@"
Index: llvm/utils/lit/lit/llvm/config.py
===================================================================
--- llvm/utils/lit/lit/llvm/config.py
+++ llvm/utils/lit/lit/llvm/config.py
@@ -347,14 +347,17 @@
         return True
 
     def add_err_msg_substitutions(self):
-        host_cxx = getattr(self.config, 'host_cxx', '')
-        # On Windows, python's os.strerror() does not emit the same spelling as the C++ std::error_code.
-        # As a workaround, hardcode the Windows error message.
-        if (sys.platform == 'win32' and 'MSYS' not in host_cxx):
-            self.config.substitutions.append(('%errc_ENOENT', '\'no such file or directory\''))
-            self.config.substitutions.append(('%errc_EISDIR', '\'is a directory\''))
-            self.config.substitutions.append(('%errc_EINVAL', '\'invalid argument\''))
-            self.config.substitutions.append(('%errc_EACCES', '\'permission denied\''))
+        # Python's strerror may not supply the same message as C++ std::error_code. One example of such a platform
+        # is Visual Studio. errc_messages may be supplied which contains the error messages for
+        # ENOENT, EISDIR, EINVAL and EACCES as a semi colon separated string.
+        # LLVM testsuites can use get_errc_messages cmake to automatically get the messages and pass them into lit.
+        errc_messages = getattr(self.config, 'errc_messages', '')
+        if len(errc_messages) != 0:
+            (errc_enoent, errc_eisdir, errc_einval, errc_eacces) = errc_messages.split(';')
+            self.config.substitutions.append(('%errc_ENOENT', '\'' + errc_enoent + '\''))
+            self.config.substitutions.append(('%errc_EISDIR', '\'' + errc_eisdir + '\''))
+            self.config.substitutions.append(('%errc_EINVAL', '\'' + errc_einval + '\''))
+            self.config.substitutions.append(('%errc_EACCES', '\'' + errc_eacces + '\''))
         else:
             self.config.substitutions.append(('%errc_ENOENT', '\'' + os.strerror(errno.ENOENT) + '\''))
             self.config.substitutions.append(('%errc_EISDIR', '\'' + os.strerror(errno.EISDIR) + '\''))