Increase node stack size of 8Mb when running js_optimizer

On windows the default stack size is still limited to 1MB in older
versions of node.  See nodejs/node#43632 which
made it into v19.0.0.

Fixes: emscripten-core#17897

site/source/docs/getting_started/FAQ.rst

@@ -654,10 +654,10 @@ Why do I get a stack size error when optimizing: ``RangeError: Maximum call stac
 
 You may need to increase the stack size for :term:`node.js`.
 
-On Linux and Mac macOS, you can just do ``NODE_JS = ['node',
-'--stack_size=8192']`` in the :ref:`compiler-configuration-file`. On Windows,
-you will also need ``--max-stack-size=8192``, and also run ``editbin
-/stack:33554432 node.exe``.
+On Linux and Mac macOS, you can just do ``NODE_JS = ['/path/to/node',
+'--stack_size=8192']`` in the :ref:`compiler-configuration-file`. On Windows
+(for node versions older than v19), you will also need
+``--max-stack-size=8192``, and also run ``editbin /stack:33554432 node.exe``.
 
 
 How do I pass int64_t and uint64_t values from js into Wasm functions?

tools/building.py

@@ -342,7 +342,7 @@ def opt_level_to_str(opt_level, shrink_level=0):
 def js_optimizer(filename, passes):
   from . import js_optimizer
   try:
-    return js_optimizer.run_on_js(filename, passes)
+    return js_optimizer.run_on_file(filename, passes)
   except subprocess.CalledProcessError as e:
     exit_with_error("'%s' failed (%d)", ' '.join(e.cmd), e.returncode)
 

tools/js_optimizer.py

@@ -37,6 +37,15 @@
 import_sig = re.compile(r'(var|const) ([_\w$]+ *=[^;]+);')
 
 
+def get_acorn_cmd():
+  node = config.NODE_JS
+  if not any('--stack-size' in arg for arg in node):
+    # Use an 8Mb stack (rather than the ~1Mb default) when running the
+    # js optimizer since larger inputs can cause terser to use a lot of stack.
+    node.append('--stack-size=8192')
+  return node + [ACORN_OPTIMIZER]
+
+
 def split_funcs(js):
   # split properly even if there are no newlines,
   # which is important for deterministic builds (as which functions
@@ -88,7 +97,7 @@ def minify_shell(self, shell, minify_whitespace):
         f.write('\n')
         f.write('// EXTRA_INFO:' + json.dumps(self.serialize()))
 
-      cmd = config.NODE_JS + [ACORN_OPTIMIZER, temp_file, 'minifyGlobals']
+      cmd = get_acorn_cmd() + [temp_file, 'minifyGlobals']
       if minify_whitespace:
         cmd.append('minifyWhitespace')
       output = shared.run_process(cmd, stdout=subprocess.PIPE).stdout
@@ -139,8 +148,8 @@ def chunkify(funcs, chunk_size):
   return [''.join(func[1] for func in chunk) for chunk in chunks] # remove function names
 
 
-@ToolchainProfiler.profile_block('js_optimizer.run_on_js')
-def run_on_js(filename, passes, extra_info=None):
+@ToolchainProfiler.profile_block('js_optimizer.run_on_file')
+def run_on_file(filename, passes, extra_info=None):
   with ToolchainProfiler.profile_block('js_optimizer.split_markers'):
     if not isinstance(passes, list):
       passes = [passes]
@@ -261,7 +270,7 @@ def write_chunk(chunk, i):
       filenames = [write_chunk(chunk, i) for i, chunk in enumerate(chunks)]
 
   with ToolchainProfiler.profile_block('run_optimizer'):
-    commands = [config.NODE_JS + [ACORN_OPTIMIZER, f] + passes for f in filenames]
+    commands = [get_acorn_cmd() + [f] + passes for f in filenames]
     filenames = shared.run_multiple_processes(commands, route_stdout_to_temp_files_suffix='js_opt.jo.js')
 
   with ToolchainProfiler.profile_block('split_closure_cleanup'):
@@ -348,7 +357,7 @@ def main():
     sys.argv = sys.argv[:-1]
   else:
     extra_info = None
-  out = run_on_js(sys.argv[1], sys.argv[2:], extra_info=extra_info)
+  out = run_on_file(sys.argv[1], sys.argv[2:], extra_info=extra_info)
   shutil.copyfile(out, sys.argv[1] + '.jsopt.js')
   return 0