diff --git a/emcc.py b/emcc.py
index fd26a57743c8b..7c15ad599ef64 100755
--- a/emcc.py
+++ b/emcc.py
@@ -23,6 +23,8 @@
 from tools.toolchain_profiler import ToolchainProfiler
 
 import base64
+import glob
+import hashlib
 import json
 import logging
 import os
@@ -500,8 +502,7 @@ def ensure_archive_index(archive_file):
     run_process([shared.LLVM_RANLIB, archive_file])
 
 
-@ToolchainProfiler.profile_block('JS symbol generation')
-def get_all_js_syms():
+def generate_js_symbols():
   # Runs the js compiler to generate a list of all symbols available in the JS
   # libraries.  This must be done separately for each linker invokation since the
   # list of symbols depends on what settings are used.
@@ -516,6 +517,58 @@ def get_all_js_syms():
     if shared.is_c_symbol(name):
       name = shared.demangle_c_symbol_name(name)
       library_syms.add(name)
+  return library_syms
+
+
+@ToolchainProfiler.profile_block('JS symbol generation')
+def get_all_js_syms():
+  # Avoiding using the cache when generating struct info since
+  # this step is performed while the cache is locked.
+  if settings.BOOTSTRAPPING_STRUCT_INFO or config.FROZEN_CACHE:
+    return generate_js_symbols()
+
+  # To avoid the cost of calling generate_js_symbols each time an executable is
+  # linked we cache symbol lists for the N most recently used configs.
+  # We define a cache hit as when the settings and `--js-library` contents are
+  # identical.
+  input_files = {}
+  input_files['settings.json'] = json.dumps(settings.dict(), sort_keys=True, indent=2)
+  for jslib in sorted(glob.glob(utils.path_from_root('src') + '/library*.js')):
+    input_files[jslib] = read_file(jslib)
+  for jslib in settings.JS_LIBRARIES:
+    if os.path.abspath(jslib):
+      jslib = utils.path_from_root('src', jslib)
+    input_files[jslib] = read_file(jslib)
+  input_data = []
+  for name, content in input_files.items():
+    content_hash = hashlib.sha1(content.encode('utf-8')).hexdigest()
+    input_data.append(f'{name}: {content_hash}')
+
+  input_data = '\n'.join(input_data) + '\n'
+  cache_filename = None
+  num_cache_entries = 20
+
+  with cache.lock('js_symbol_lists'):
+    oldest_timestamp = 0
+    for i in range(num_cache_entries):
+      input_file = cache.get_path(f'js_symbol_list_{i}.inputs')
+      list_file = cache.get_path(f'js_symbol_list_{i}.txt')
+      if not os.path.exists(input_file) or not os.path.exists(list_file):
+        cache_filename = list_file
+        break
+      timestamp = os.path.getmtime(input_file)
+      if timestamp < oldest_timestamp or not oldest_timestamp:
+        oldest_timestamp = timestamp
+        cache_filename = list_file
+      if read_file(input_file) == input_data:
+        # Cache hit, read the symbol list from the list_file
+        return read_file(list_file).splitlines()
+
+    # Cache miss. Generate a new symbol list and write to the the cache
+    library_syms = generate_js_symbols()
+
+    write_file(cache_filename, '\n'.join(library_syms) + '\n')
+    write_file(shared.replace_suffix(cache_filename, '.inputs'), input_data)
 
   return library_syms