How to add frozen modules to webassembly port?

[cwalther]

I am trying unsuccessfully to freeze a Python module in the webassembly port (current git master, emsdk 3.1.17). The module appears and is importable, but something seems to be jumbled up with the qstrs in it: functions appear under wrong or empty names, and strings used within them come out empty. In build/frozen_content.c, all the strings seem to be there. Does anyone have a quick idea what might be wrong here? I can probably figure it out on my own with sufficient debugging effort, but maybe someone can tell sooner whether I’m doing anything wrong or whether this is a bug in MicroPython.

I had to #define MICROPY_MODULE_FROZEN_MPY (1) in mpconfigport.h to avoid a compiler error, do any other additional features need to be enabled?

Minimal reproducing example:

diff --git a/ports/webassembly/helloworld.py b/ports/webassembly/helloworld.py
new file mode 100644
index 0000000..a8d8ea5
--- /dev/null
+++ b/ports/webassembly/helloworld.py
@@ -0,0 +1,5 @@
+def hello():
+	print(42, 'Hello World!', 56)
+
+def goodbye():
+	print(87, 'Goodbye World!', 90)
diff --git a/ports/webassembly/manifest.py b/ports/webassembly/manifest.py
new file mode 100644
index 0000000..cc85d6b
--- /dev/null
+++ b/ports/webassembly/manifest.py
@@ -0,0 +1 @@
+module("helloworld.py")
diff --git a/ports/webassembly/mpconfigport.h b/ports/webassembly/mpconfigport.h
index 4fbd922..004d1ba 100644
--- a/ports/webassembly/mpconfigport.h
+++ b/ports/webassembly/mpconfigport.h
@@ -125,6 +125,8 @@
 #define MICROPY_ENABLE_SCHEDULER    (1)
 #define MICROPY_SCHEDULER_DEPTH     (1)
 
+#define MICROPY_MODULE_FROZEN_MPY   (1)
+
 #define MP_SSIZE_MAX (0x7fffffff)
 
 // #define MICROPY_EVENT_POLL_HOOK {ets_event_poll();}

Actual result:

$ make FROZEN_MANIFEST=manifest.py
(success)
$ node build/micropython.js 

MicroPython b8982ec-dirty on 2022-10-09; JS with Emscripten
Type "help()" for more information.
>>> import helloworld
>>> help(helloworld)
object <module 'helloworld' from 'helloworld.py'> is of type module
  helloworld.py -- <function helloworld.py at 0x50d670>
   -- <function  at 0x50d660>
  __name__ -- helloworld
  __file__ -- helloworld.py
>>> getattr(helloworld, 'helloworld.py')()
42  56
>>> 

Expected result:

>>> import helloworld
>>> help(helloworld)
object <module 'helloworld' from 'helloworld.py'> is of type module
  hello -- <function hello at 0x50d670>
  goodbye -- <function goodbye at 0x50d660>
  __name__ -- helloworld
  __file__ -- helloworld.py
>>> helloworld.hello()
42 Hello World! 56
>>> 

[dpgeorge]

You'll need to add this line to mpconfigport.h as well:

#define MICROPY_QSTR_EXTRA_POOL             mp_qstr_frozen_const_pool

[cwalther]

Thanks, that did the trick!