toolchain/toolchain-buildroot: introduce BR2_TOOLCHAIN_BUILDROOT_NONE

In the internal toolchain backend, we have a choice..endchoice block
to allow the user to select the C library, between glibc, uClibc and
musl.

However, there are situations were no C library at all is
supported. In this case, the choice does not appear, and does not
allow to see the Config.in comments that are within the
choice..endchoice block and that may explain why no C library is
available.

For example, on RISC-V 32-bit, the only C library supported is glibc,
and the minimum kernel header version required by glibc on this
architecture is 5.4.0. In a future commit, we are going to add this
dependency on glibc (to fix build issues on configurations that have
headers < 5.4.0). But since glibc is the only supported C library on
RISC-V 32-bit, it means that the choice..endchoice for the C library
contains no entry, preventing from seeing the Config.in comment.

To address this issue, this commit adds a "dummy"
BR2_TOOLCHAIN_BUILDROOT_NONE option that shows up in the
choice..endchoice only when no C library is available. Thanks to this,
the choice..endchoice is never empty, and the Config.in comments can
be seen.

If the user keeps BR2_TOOLCHAIN_BUILDROOT_NONE selected, then the
build will anyway abort early because package/Makefile.in has a check
to verify that a C library is selected, and aborts the build if not.

Some could say that the problem should be resolved by instead
preventing the selection of headers < 5.4.0 on RISC-V 32-bit, but that
is difficult to do as the user can choose a custom header version, or
simply specific that (s)he wants to use the headers of the kernel
being built. In those situations, it's difficult to prevent selecting
headers < 5.4.0.

Prevent random configurations from triggering a build failure in our
autobuilders, by excluding that symbol from accepted configuration.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
[yann.morin.1998@free.fr: update genrandconfig]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
This commit is contained in:
Thomas Petazzoni 2022-10-26 20:34:26 +02:00 committed by Yann E. MORIN
parent 69d311687a
commit e1550ef755
2 changed files with 16 additions and 0 deletions

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@ -80,6 +80,18 @@ config BR2_TOOLCHAIN_BUILDROOT_MUSL
https://www.musl-libc.org/
config BR2_TOOLCHAIN_BUILDROOT_NONE
bool "none"
depends on !BR2_PACKAGE_UCLIBC_SUPPORTS && \
!BR2_PACKAGE_GLIBC_SUPPORTS && \
!BR2_PACKAGE_MUSL_SUPPORTS
help
This option is visible if no C library is available for the
currently selected configuration. If you select this option,
the build will refuse to start as Buildroot needs a C
library to build a toolchain. Change your configuration
settings to make sure one of the C libraries is selected.
endchoice
config BR2_TOOLCHAIN_BUILDROOT_LIBC

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@ -301,6 +301,10 @@ def fixup_config(sysinfo, configfile):
if 'BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_NIOSII=y\n' in configlines and \
'BR2_PACKAGE_FLANN=y\n' in configlines:
return False
# No C library for internal toolchain
if 'BR2_TOOLCHAIN_BUILDROOT_NONE=y' in configlines:
return False
if 'BR2_PACKAGE_AUFS_UTIL=y\n' in configlines and \
'BR2_PACKAGE_AUFS_UTIL_VERSION=""\n' in configlines:
return False