Cannot build example usercmodule in nrf port

[microbit-carlos]

Checks

• I agree to follow the MicroPython Code of Conduct to ensure a safe and respectful space for everyone.
• I've searched for existing issues matching this bug, and didn't find any.

Port, board and/or hardware

nrf port, tested with default PCA10040 board and MICROBIT board

MicroPython version

8762fe8

Reproduction

git clone https://github.com/micropython/micropython.git
cd micropython/mpy-cross/
make
cd ../ports/nrf
make submodules
make USER_C_MODULES=../../examples/usercmodule

Expected behaviour

No build errors

Observed behaviour

The modules are correctly found:

Including User C Module from ../../examples/usercmodule/cexample
Including User C Module from ../../examples/usercmodule/cppexample
Including User C Module from ../../examples/usercmodule/subpackage

But it produces a build error on the cppexample/example.cpp file as it cannot find py/runtime.h:

In file included from ../../examples/usercmodule/cppexample/example.cpp:2:
../../examples/usercmodule/cppexample/examplemodule.h:2:10: fatal error: py/runtime.h: No such file or directory
    2 | #include "py/runtime.h"
      |          ^~~~~~~~~~~~~~
compilation terminated.
Command '['arm-none-eabi-gcc', '-E', '-I../../examples/usercmodule/cppexample', '-std=c++11', '-DNO_QSTR', '../../examples/usercmodule/cppexample/example.cpp']' returned non-zero exit status 1.
make: *** [build-PCA10040/genhdr/qstr.i.last] Error 1
make: *** Deleting file `build-PCA10040/genhdr/qstr.i.last'

Looking at the limited amount of flags used to compile the file something in the nrf port could be resetting CXXFLAGS? Or maybe they are not being set at all?

Full build output

❯ git clone https://github.com/micropython/micropython.git
Cloning into 'micropython'...
remote: Enumerating objects: 120730, done.
remote: Counting objects: 100% (64/64), done.
remote: Compressing objects: 100% (33/33), done.
remote: Total 120730 (delta 31), reused 51 (delta 30), pack-reused 120666
Receiving objects: 100% (120730/120730), 61.44 MiB | 30.37 MiB/s, done.
Resolving deltas: 100% (90584/90584), done.


❯ cd micropython/mpy-cross/


❯ make
Use make V=1 or set BUILD_VERBOSE in your environment to increase build verbosity.
mkdir -p build/genhdr
GEN build/genhdr/mpversion.h
GEN build/genhdr/qstr.i.last
GEN build/genhdr/qstr.split
GEN build/genhdr/qstrdefs.collected.h
QSTR updated
GEN build/genhdr/qstrdefs.generated.h
GEN build/genhdr/moduledefs.split
GEN build/genhdr/moduledefs.collected
Module registrations updated
GEN build/genhdr/moduledefs.h
GEN build/genhdr/root_pointers.split
GEN build/genhdr/root_pointers.collected
Root pointer registrations updated
GEN build/genhdr/root_pointers.h
mkdir -p build/py
mkdir -p build/shared/runtime
CC ../py/mpstate.c
CC ../py/nlr.c
CC ../py/nlrx86.c
CC ../py/nlrx64.c
CC ../py/nlrthumb.c
CC ../py/nlraarch64.c
CC ../py/nlrmips.c
CC ../py/nlrpowerpc.c
CC ../py/nlrxtensa.c
CC ../py/nlrsetjmp.c
CC ../py/malloc.c
CC ../py/gc.c
CC ../py/pystack.c
CC ../py/qstr.c
CC ../py/vstr.c
CC ../py/mpprint.c
CC ../py/unicode.c
CC ../py/mpz.c
CC ../py/reader.c
CC ../py/lexer.c
CC ../py/parse.c
CC ../py/scope.c
CC ../py/compile.c
CC ../py/emitcommon.c
CC ../py/emitbc.c
CC ../py/asmbase.c
CC ../py/asmx64.c
CC ../py/emitnx64.c
CC ../py/asmx86.c
CC ../py/emitnx86.c
CC ../py/asmthumb.c
CC ../py/emitnthumb.c
CC ../py/emitinlinethumb.c
CC ../py/asmarm.c
CC ../py/emitnarm.c
CC ../py/asmxtensa.c
CC ../py/emitnxtensa.c
CC ../py/emitinlinextensa.c
CC ../py/emitnxtensawin.c
CC ../py/formatfloat.c
CC ../py/parsenumbase.c
CC ../py/parsenum.c
CC ../py/emitglue.c
CC ../py/persistentcode.c
CC ../py/runtime.c
CC ../py/runtime_utils.c
CC ../py/scheduler.c
CC ../py/nativeglue.c
CC ../py/pairheap.c
CC ../py/ringbuf.c
CC ../py/stackctrl.c
CC ../py/argcheck.c
CC ../py/warning.c
CC ../py/profile.c
CC ../py/map.c
CC ../py/obj.c
CC ../py/objarray.c
CC ../py/objattrtuple.c
CC ../py/objbool.c
CC ../py/objboundmeth.c
CC ../py/objcell.c
CC ../py/objclosure.c
CC ../py/objcomplex.c
CC ../py/objdeque.c
CC ../py/objdict.c
CC ../py/objenumerate.c
CC ../py/objexcept.c
CC ../py/objfilter.c
CC ../py/objfloat.c
CC ../py/objfun.c
CC ../py/objgenerator.c
CC ../py/objgetitemiter.c
CC ../py/objint.c
CC ../py/objint_longlong.c
CC ../py/objint_mpz.c
CC ../py/objlist.c
CC ../py/objmap.c
CC ../py/objmodule.c
CC ../py/objobject.c
CC ../py/objpolyiter.c
CC ../py/objproperty.c
CC ../py/objnone.c
CC ../py/objnamedtuple.c
CC ../py/objrange.c
CC ../py/objreversed.c
CC ../py/objset.c
CC ../py/objsingleton.c
CC ../py/objslice.c
CC ../py/objstr.c
CC ../py/objstrunicode.c
CC ../py/objstringio.c
CC ../py/objtuple.c
CC ../py/objtype.c
CC ../py/objzip.c
CC ../py/opmethods.c
CC ../py/sequence.c
CC ../py/stream.c
CC ../py/binary.c
CC ../py/builtinimport.c
CC ../py/builtinevex.c
CC ../py/builtinhelp.c
CC ../py/modarray.c
CC ../py/modbuiltins.c
CC ../py/modcollections.c
CC ../py/modgc.c
CC ../py/modio.c
CC ../py/modmath.c
CC ../py/modcmath.c
CC ../py/modmicropython.c
CC ../py/modstruct.c
CC ../py/modsys.c
CC ../py/moderrno.c
CC ../py/modthread.c
CC ../py/vm.c
CC ../py/bc.c
CC ../py/showbc.c
CC ../py/repl.c
CC ../py/smallint.c
CC ../py/frozenmod.c
CC main.c
CC gccollect.c
CC ../shared/runtime/gchelper_generic.c
LINK build/mpy-cross
__TEXT	__DATA	__OBJC	others	dec	hex
327680	16384	0	4295000928	4295344992	10005c360


❯ cd ../ports/nrf


❯ make submodules
Use make V=1 or set BUILD_VERBOSE in your environment to increase build verbosity.
Updating submodules: lib/nrfx lib/tinyusb lib/micropython-lib
Submodule 'lib/micropython-lib' (https://github.com/micropython/micropython-lib.git) registered for path '../../lib/micropython-lib'
Submodule 'lib/nrfx' (https://github.com/NordicSemiconductor/nrfx.git) registered for path '../../lib/nrfx'
Submodule 'lib/tinyusb' (https://github.com/hathach/tinyusb) registered for path '../../lib/tinyusb'
Cloning into '/Users/microbit-carlos/workspace/mbef/micropython/rm/micropython/lib/micropython-lib'...
Cloning into '/Users/microbit-carlos/workspace/mbef/micropython/rm/micropython/lib/nrfx'...
Cloning into '/Users/microbit-carlos/workspace/mbef/micropython/rm/micropython/lib/tinyusb'...
Submodule path '../../lib/micropython-lib': checked out 'ddb1a279578bfff8c1b18aff3baa668620684f64'
Submodule path '../../lib/nrfx': checked out '7a4c9d946cf1801771fc180acdbf7b878f270093'
Submodule path '../../lib/tinyusb': checked out '1fdf29075d4e613eacfa881166015263797db0f6'


❯ make USER_C_MODULES=../../examples/usercmodule
Use make V=1 or set BUILD_VERBOSE in your environment to increase build verbosity.
Including User C Module from ../../examples/usercmodule/cexample
Including User C Module from ../../examples/usercmodule/cppexample
Including User C Module from ../../examples/usercmodule/subpackage
mkdir -p build-PCA10040/genhdr
Create build-PCA10040/genhdr/pins.h
GEN build-PCA10040/genhdr/mpversion.h
GEN build-PCA10040/genhdr/qstr.i.last
In file included from ../../examples/usercmodule/cppexample/example.cpp:2:
../../examples/usercmodule/cppexample/examplemodule.h:2:10: fatal error: py/runtime.h: No such file or directory
    2 | #include "py/runtime.h"
      |          ^~~~~~~~~~~~~~
compilation terminated.
Command '['arm-none-eabi-gcc', '-E', '-I../../examples/usercmodule/cppexample', '-std=c++11', '-DNO_QSTR', '../../examples/usercmodule/cppexample/example.cpp']' returned non-zero exit status 1.
make: *** [build-PCA10040/genhdr/qstr.i.last] Error 1
make: *** Deleting file `build-PCA10040/genhdr/qstr.i.last'

Additional Information

Also tested the MICROBIT board and produces the same error.

Building the c module examples in the Unix port or the PYBV11 board does build correctly.

[microbit-carlos]

I guess the nordic port (and possibly others as well) is missing setting the flags like these:

micropython/ports/unix/Makefile

Line 236 in 8762fe8

CXXFLAGS += $(filter-out -Wmissing-prototypes -Wold-style-definition -std=gnu99,$(CFLAGS) $(CXXFLAGS_MOD))

micropython/ports/stm32/Makefile

Line 164 in 8762fe8

CXXFLAGS += $(filter-out -Wmissing-prototypes -Wold-style-definition -std=gnu99,$(CFLAGS))

micropython/ports/samd/Makefile

Line 90 in 8762fe8

CXXFLAGS += $(filter-out -std=c99,$(CFLAGS))

I don't have a specific need for this in the nrf port, I was just trying it. Would this be something that would ideally go into all the ports? Or could that have adverse effects in some case?

[andrewleech]

Good find, yes the nordic port hasn't had as much use as some of the other ports and there are a number of little things like this missing I find.
You could start with just CXXFLAGS += $(filter-out -std=c99,$(CFLAGS)) in the Makefile and see if that's enough. If the c++ compiler complains about other things it doesn't support simply filter them out too.