diff --git a/system/lib/libcxxabi/src/format_exception.cpp b/system/lib/libcxxabi/src/cxa_exception_emscripten.cpp
similarity index 73%
rename from system/lib/libcxxabi/src/format_exception.cpp
rename to system/lib/libcxxabi/src/cxa_exception_emscripten.cpp
index 815e8b9918f59..e740d0fec97a0 100644
--- a/system/lib/libcxxabi/src/format_exception.cpp
+++ b/system/lib/libcxxabi/src/cxa_exception_emscripten.cpp
@@ -1,3 +1,13 @@
+//===------------------- cxa_exception_emscripten.cpp ---------------------===//
+//
+// This code contains Emscripten specific code for exception handling.
+// Emscripten has two modes of exception handling: Emscripten EH, which uses JS
+// glue code, and Wasm EH, which uses the new Wasm exception handling proposal
+// and meant to be faster. Code for different modes is demarcated with
+// '__USING_EMSCRIPTEN_EXCEPTIONS__' and '__USING_WASM_EXCEPTIONS__'.
+//
+//===----------------------------------------------------------------------===//
+
 #include "cxa_exception.h"
 #include "private_typeinfo.h"
 #include <stdio.h>
diff --git a/tools/system_libs.py b/tools/system_libs.py
index 5c2c003cf1497..2f1d72b19879a 100644
--- a/tools/system_libs.py
+++ b/tools/system_libs.py
@@ -1203,7 +1203,7 @@ def get_files(self):
       'stdlib_stdexcept.cpp',
       'stdlib_typeinfo.cpp',
       'private_typeinfo.cpp',
-      'format_exception.cpp',
+      'cxa_exception_emscripten.cpp',
     ]
     if self.eh_mode == Exceptions.NONE:
       filenames += ['cxa_noexception.cpp']