zephyr: picolibc is incompatible with xcc / xcc-clang toolchains

Describe the bug

Compilation of picolibc module for picolibc tests fails with XCC on ADSP platforms. Followup to https://github.com/zephyrproject-rtos/zephyr/issues/54224.

A few of the flags used by GCC to build the picolibc module are not compatible with XCC. Different flags are observed to be not working for different versions of XCC toolchain.

RI-2021.7-linux (xcc-clang) + MTL:

clang-10: error: unknown argument: '-fno-printf-return-value'
clang-10: warning: optimization flag '-fsignaling-nans' is not supported [-Wignored-optimization-argument]

RG-2017.8-linux (xcc) + CAVS15, 18, CAVS25:

xt-xcc ERROR parsing -frounding-math:  unknown flag
xt-xcc ERROR parsing -fsignaling-nans:  unknown flag
xt-xcc ERROR parsing -fno-stack-protector:  unknown flag
xt-xcc ERROR parsing -Warray-bounds:  unknown flag
xt-xcc ERROR parsing -ftls-model=local-exec:  unknown flag
xt-xcc ERROR parsing -fno-printf-return-value:  unknown flag

To Reproduce

export ZEPHYR_TOOLCHAIN_VARIANT=xcc
west build -p -b intel_adsp_cavs15 -T tests/kernel/common/kernel.common.picolibc

Expected behavior Compilation

Impact Annoyance

Logs and console output See above.

Environment

OS: Ubuntu 20.04
Toolchain: XCC / XCC-clang (see above)
Recent main

About this issue

Original URL
State: closed
Created a year ago
Comments: 27 (13 by maintainers)

Commits related to this issue

ci: add picolibc to xcc twister quarantine Adds picolibc to XCC Twister quarantine file as compilation of picolibc module fails with XCC on ADSP platforms. Bug #54336 filed upstream. Signed-off-by: ... — committed to ghu0510/zephyr by laurenmurphyx64 a year ago

Most upvoted comments

Given that we are in feaure freeze I suggest to apply this for now while we work on adding clang support:

It’s a bit more subtle than that – we’re not ‘adding’ clang support anywhere, just fixing some wiring between the existing clang support in picolibc and the clang support in Zephyr. I’d suggest waiting a couple of days and see how the proposed fixes work out and then decide if clang+picolibc should be removed from the release.

keith-packard on Feb 2, 2023