Narrow down `atomvm.packbeam` warning

Questions / Help
1

Hi,

I’m trying to build an atomvm image with atomvm.packbeam which gives me the following warnings:

Warning: following modules or functions are not available on AtomVM:
* Elixir.Macro:escape/1
* elixir_module:compile/6

I’m using an external library and I would like to track down where those calls are coming from, to understand what they are used for and whether I might run into problems down the row.

A search for those calls didn’t reveal anything. The library does use some macros, but those should (if my understanding is correct) be resolved at compile time. Of course the issue might come from some transient dependencies.

Is there a good way to figure out where those function calls are coming from?

Thanks for any ideas and help

2

well they are definitely from a dep, but that is obvious..

can you try using MIX_ENV=prod in front of the mix call as to consolidate all protocols? (my hunch is we have to enforce MIX_ENV=prod in exatomvm for this very reason..)

3

stupid me, should have thought about that one. Let me try that and report back.

Thanks

4

Unfortunately that’s not the reason, still the same result. :frowning:

5

I could track them both down with a lot of trial and error. Problem solved :slight_smile:

The issues were (in one of the deps):

  • Wrong use of Macro.escape instead of unquote
  • One module was using some Code.loaded?, Code.ensure_loaded?, :code.purge, and :code.delete. Removing that part removed the second warning too.

Regarding the first one:
The code looked like the following:

defmacro __using__(opts) do
  ...
  other = calc_something()
  ast = create_ast()
  quote bind_quoted: [other: other, ast: ast] do
    Macro.escape(ast)
    func(other)
    ...
  end
end

The tricky part is that removing the ast: ast from the bind_quoted and doing an explicit unquote(ast) didn’t work. Only by removing the whole bind_quoted did the trick, i.e. the following worked:

defmacro __using__(opts) do
  ...
  other = calc_something()
  ast = create_ast()
  quote do
    unquote(ast)
    func(unquote(other))
    ...
  end
end
1 Like
6

Glad you solved it, is that dep public?

Either way opened Improve not available warning with path · Issue #67 · atomvm/exatomvm · GitHub as to hopefully be able to improve the warnings..

Did MIX_ENV=prod make any difference?

7

no MIX_ENV=prod did not make any difference. I can share the repo, but will take me a couple of days

8

ok, don’t think I need it..

If possible can you try Code warning: show module and function name by petermm · Pull Request #68 · atomvm/exatomvm · GitHub with (the offending code and):
{:exatomvm, github: "petermm/ExAtomVM", branch: "add-modules-to-warning", runtime: false},

Should give you output similar to:

Warning: following modules or functions are not available on AtomVM:

Elixir.GenServer:cast/2
in: lib/scanner.ex (stop/0)

Elixir.GenServer:start_link/3
in: lib/scanner.ex (start_link/1)

Let me know..

9

I’ll comment on your PR. That’s probably easier

1 Like