AssertionError when declaring bytearray inside of kernel

[MorganTL]

Bug Report

One-Line Summary

AssertionError when declaring bytearray(len) inside of kernel, see example below

Issue Details

Steps to Reproduce

example with error

from artiq.language.core import kernel
from artiq.experiment import *

class Test(EnvExperiment):
    def build(self):
        self.setattr_device("core")

    @kernel
    def run(self):
        buf = bytearray(1)

example that runs fine

from artiq.language.core import kernel
from artiq.experiment import *

class Test(EnvExperiment):
    def build(self):
        self.setattr_device("core")

    @kernel
    def run(self):
        buf = bytearray([0x00])

Expected Behavior

No AssertionError when using bytearray(len)

Actual (undesired) Behavior

❯ artiq_run error_kernel.py
Traceback (most recent call last):
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/bin/.artiq_run-wrapped", line 9, in <module>
    sys.exit(main())
             ^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/frontend/artiq_run.py", line 269, in main
    return run(with_file=True)
           ^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/frontend/artiq_run.py", line 253, in run
    raise exn
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/frontend/artiq_run.py", line 245, in run
    exp_inst.run()
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/language/core.py", line 54, in run_on_core
    return getattr(self, arg).run(run_on_core, ((self,) + k_args), k_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/coredevice/core.py", line 175, in run
    self.compile(function, args, kwargs, set_result)
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/coredevice/core.py", line 144, in compile
    module = Module(stitcher,
             ^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/module.py", line 78, in __init__
    self.artiq_ir = artiq_ir_generator.visit(src.typedtree)
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 181, in visit
    return self._visit_one(obj)
           ^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/lfsad748z7m0xxmwxagx3drv2qjl9d6c-python3.12-pythonparser-1.4/lib/python3.12/site-packages/pythonparser/algorithm.py", line 32, in _visit_one
    return getattr(self, visit_attr)(node)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 209, in visit_ModuleT
    self.generic_visit(node)
  File "/nix/store/lfsad748z7m0xxmwxagx3drv2qjl9d6c-python3.12-pythonparser-1.4/lib/python3.12/site-packages/pythonparser/algorithm.py", line 27, in generic_visit
    self.visit(getattr(node, field_name))
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 177, in visit
    self.visit(elt)
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 181, in visit
    return self._visit_one(obj)
           ^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/lfsad748z7m0xxmwxagx3drv2qjl9d6c-python3.12-pythonparser-1.4/lib/python3.12/site-packages/pythonparser/algorithm.py", line 32, in _visit_one
    return getattr(self, visit_attr)(node)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 362, in visit_QuotedFunctionDefT
    self.visit_function(node, is_internal=True, is_quoted=True, flags=node.flags)
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 322, in visit_function
    result = self.visit(node.body)
             ^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 177, in visit
    self.visit(elt)
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 181, in visit
    return self._visit_one(obj)
           ^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/lfsad748z7m0xxmwxagx3drv2qjl9d6c-python3.12-pythonparser-1.4/lib/python3.12/site-packages/pythonparser/algorithm.py", line 32, in _visit_one
    return getattr(self, visit_attr)(node)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 392, in visit_Assign
    self.current_assign = self.visit(node.value)
                          ^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 181, in visit
    return self._visit_one(obj)
           ^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/lfsad748z7m0xxmwxagx3drv2qjl9d6c-python3.12-pythonparser-1.4/lib/python3.12/site-packages/pythonparser/algorithm.py", line 32, in _visit_one
    return getattr(self, visit_attr)(node)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 2731, in visit_CallT
    insn = self.visit_builtin_call(node)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 2279, in visit_builtin_call
    length = self.iterable_len(arg)
             ^^^^^^^^^^^^^^^^^^^^^^
  File "/nix/store/jcxld3n9l2xhccck94sy8qk961ly509h-python3.12-artiq-9.0+unknown.beta/lib/python3.12/site-packages/artiq/compiler/transforms/artiq_ir_generator.py", line 529, in iterable_len
    assert False
           ^^^^^
AssertionError
                                                                                                                                                                                                                  

Your System (omit irrelevant parts)

• Operating System: Nixos
• ARTIQ version: artiq master (994f60e)

[SimonRenblad]

artiq/artiq/compiler/transforms/artiq_ir_generator.py

Lines 2277 to 2290 in 994f60e

	elif len(node.args) == 1 and len(node.keywords) == 0:
	arg = self.visit(node.args[0])
	length = self.iterable_len(arg)
	result = self.append(ir.Alloc([length], node.type))
	def body_gen(index):
	elt = self.iterable_get(arg, index)
	elt = self.append(ir.Coerce(elt, builtins.get_iterable_elt(node.type)))
	self.append(ir.SetElem(result, index, elt))
	return self.append(ir.Arith(ast.Add(loc=None), index,
	ir.Constant(1, length.type)))
	self._make_loop(ir.Constant(0, length.type),
	lambda index: self.append(ir.Compare(ast.Lt(loc=None), index, length)),
	body_gen)

The compiler reuses the same logic as for lists here and assumes the argument is an iterable. The same issue should exist for bytes(len) I would imagine.

[sbourdeauducq]

What's the use case for bytes in kernels?
In nac3 we just don't support them entirely, seems everything is covered with integer lists and numpy arrays.

[MorganTL]

I was implementing downloading the camera xml files via cxp syscall. And bytearray was used to store the result before outputting to the PC.