[Buildroot] [PATCH v2] toolchain: add a harmless link when sysroot detection is not accurate

[Romain Naour <romain.naour@gmail.com>]

Hi Vicente,

Le 02/02/2016 16:14, Vicente Olivert Riera a ?crit :
> Hello Romain,
> 
> On 02/02/16 15:21, Romain Naour wrote:
>> Hi Vicente,
>>
>> Le 02/02/2016 11:57, Vicente Olivert Riera a ?crit :
>>> ping
>>>
>>> Currently Codescape MIPS toolchains are broken for big-endian. This patch fixes
>>> the problem.
>>>
>>> On 22/01/16 16:05, Vicente Olivert Riera wrote:
>>>> Sometimes is not possible to detect if the sysroots are nested or side
>>>> by side. For instance this happens for MIPS big endian, where the
>>>> sysroot and the arch-sysroot directories are the same. Examples:
>>
>> By sometime, you mean toolchains generated by Crosstool-ng and Buildroot which
>> doesn't support multi-lib.
> 
> Only toolchains generated by Crosstool-ng and Buildroot? Are you sure about
> that? I think the Codescape toolchains are not generated by Crosstool-ng and
> they do support multi-lib.

Well, I checked with two of the autobuilder toolchains:

http://autobuild.buildroot.org/toolchains/tarballs/br-arm-cortex-a9-musl-2015.11-rc1-71-g90d1299.tar.bz2

http://autobuild.buildroot.org/toolchains/tarballs/i686-ctng-linux-gnu.tar.xz

And I get this:

SYSROOT_DIR_CANON:
/home/naourr/git/buildroot/test/musl/host/opt/ext-toolchain/arm-buildroot-linux-musleabihf/sysroot
ARCH_SYSROOT_DIR_CANON:
/home/naourr/git/buildroot/test/musl/host/opt/ext-toolchain/arm-buildroot-linux-musleabihf/sysroot

Unable to detect if sysroots are nested or side by side.
Creating a harmless symlink necessary for certain toolchains.
Symlinking
/home/naourr/git/buildroot/test/musl/host/usr/arm-buildroot-linux-musleabihf/sysroot/sysroot
-> ./


> 
>>>>
>>>> === Mentor Sourcery CodeBench toolchain
>>>>
>>>> $ readlink -f $(LANG=C mips-linux-gnu-gcc -print-file-name=libc.a) | sed
>>>> -r -e 's:(usr/)?lib(32|64)?([^/]*)?/([^/]*/)?libc\.a::'
>>>> /toolchains/mips-2015.11/mips-linux-gnu/libc/
>>>>
>>>> $ readlink -f $(LANG=C mips-linux-gnu-gcc -EB -print-file-name=libc.a) |
>>>> sed -r -e 's:(usr/)?lib(32|64)?([^/]*)?/([^/]*/)?libc\.a::'
>>>> /toolchains/mips-2015.11/mips-linux-gnu/libc/
>>>>
>>>> === Codescape toolchain
>>>>
>>>> $ readlink -f $(LANG=C mips-img-linux-gnu-gcc -print-file-name=libc.a) |
>>>> sed -r -e 's:(usr/)?lib(32|64)?([^/]*)?/([^/]*/)?libc\.a::'
>>>> /toolchains/mips-img-linux-gnu/2015.06-05/sysroot/mips-r6-hard/
>>>>
>>>> $ readlink -f $(LANG=C mips-img-linux-gnu-gcc -EB
>>>> -print-file-name=libc.a) | sed -r -e
>>>> 's:(usr/)?lib(32|64)?([^/]*)?/([^/]*/)?libc\.a::'
>>>> /toolchains/mips-img-linux-gnu/2015.06-05/sysroot/mips-r6-hard/
>>>>
>>>> For those cases where the sysroot detection is not accurate we add a
>>>> harmless symlink necessary for certain toolchains such as Codescape for
>>>> MIPS. The other toolchains in this situation (unknown sysroot layout)
>>>> don't need this symlink to work, but as stated before, this symlink is
>>>> harmless.
>>
>> Since Codescape are supported in Buildroot as external toolchain and the issue
>> appear only with it for BE, you can probability use a
>> TOOLCHAIN_EXTERNAL_POST_INSTALL_STAGING_HOOKS like for some Linaro toolchains
>> instead ?
>>
>> Thoughts ?
> 
> Well, the whole point for this patch [1] was to get rid of that hook (which was
> the first approach when I sent the patches to add the Codescape toolchains) and
> add that functionality in the toolchain infra just in case more toolchains with
> this problem were added in the future.

I understand, let see what maintainers says.

Best regards,
Romain

> 
> 1:
> https://git.busybox.net/buildroot/commit/?id=9a1e9efe2618ebbf12ed2567bcd6e8cca5619547
> 
> 
> Maintainers, thoughts?
> 
>>>>
>>>> Signed-off-by: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
>>>> ---
>>>> Changes v1 -> v2:
>>>>    - Update the comment above the copy_toolchain_sysroot function.
>>>>    - Explain in the commit log which toolchains are affected and provide
>>>>      some outputs of -print-file-name to explain the problem.
>>>>      (Both changes requested by Thomas Petazzoni)
>>>>
>>>>    toolchain/helpers.mk | 16 ++++++++++++++++
>>>>    1 file changed, 16 insertions(+)
>>>>
>>>> diff --git a/toolchain/helpers.mk b/toolchain/helpers.mk
>>>> index 70695ee..c8245f7 100644
>>>> --- a/toolchain/helpers.mk
>>>> +++ b/toolchain/helpers.mk
>>>> @@ -130,6 +130,12 @@ copy_toolchain_lib_root = \
>>>>    #
>>>>    # * Create a symbolic link
>>>>    #
>>>> +# If we are in the situation where we don't know if the sysroot layout
>>>> +# is nested of side by side, we:
>>>> +#
>>>> +# * Create a symbolic link because it's harmless and is necessary for
>>>> +#   certain toolchains like Codescape for MIPS.
>>>> +#
>>>>    # Finally, some toolchains (i.e Linaro binary toolchains) store
>>>>    # support libraries (libstdc++, libgcc_s) outside of the sysroot, so
>>>>    # we simply copy all the libraries from the "support lib directory"
>>>> @@ -160,9 +166,12 @@ copy_toolchain_sysroot = \
>>>>        done ; \
>>>>        SYSROOT_DIR_CANON=`readlink -f $${SYSROOT_DIR}` ; \
>>>>        ARCH_SYSROOT_DIR_CANON=`readlink -f $${ARCH_SYSROOT_DIR}` ; \
>>>> +    echo "SYSROOT_DIR_CANON: $${ARCH_SYSROOT_DIR_CANON}" ; \
>>
>> should be SYSROOT_DIR_CANON
> 
> Yes, that's right.
> 
> Regards,
> 
> Vincent.
> 
>> Best regards,
>> Romain
>>
>>>> +    echo "ARCH_SYSROOT_DIR_CANON: $${ARCH_SYSROOT_DIR_CANON}" ; \
>>>>        if [ $${SYSROOT_DIR_CANON} != $${ARCH_SYSROOT_DIR_CANON} ] ; then \
>>>>            relpath="./" ; \
>>>>            if [ $${ARCH_SYSROOT_DIR_CANON:0:$${\#SYSROOT_DIR_CANON}} ==
>>>> $${SYSROOT_DIR_CANON} ] ; then \
>>>> +            echo "Nested sysroots detected." ; \
>>>>                if [ ! -d $${ARCH_SYSROOT_DIR}/usr/include ] ; then \
>>>>                    cp -a $${SYSROOT_DIR}/usr/include $(STAGING_DIR)/usr ; \
>>>>                fi ; \
>>>> @@ -174,9 +183,16 @@ copy_toolchain_sysroot = \
>>>>                ln -s $${relpath} $(STAGING_DIR)/$${ARCH_SUBDIR} ; \
>>>>                echo "Symlinking $(STAGING_DIR)/$${ARCH_SUBDIR} ->
>>>> $${relpath}" ; \
>>>>            elif [ `dirname $${ARCH_SYSROOT_DIR_CANON}` == `dirname
>>>> $${SYSROOT_DIR_CANON}` ] ; then \
>>>> +            echo "Side by side sysroots detected." ; \
>>>>                ln -snf $${relpath} $(STAGING_DIR)/`basename
>>>> $${ARCH_SYSROOT_DIR_CANON}` ; \
>>>>                echo "Symlinking $(STAGING_DIR)/`basename
>>>> $${ARCH_SYSROOT_DIR_CANON}` -> $${relpath}" ; \
>>>>            fi ; \
>>>> +    else \
>>>> +        relpath="./" ; \
>>>> +        echo "Unable to detect if sysroots are nested or side by side." ; \
>>>> +        echo "Creating a harmless symlink necessary for certain
>>>> toolchains." ; \
>>>> +        ln -snf $${relpath} $(STAGING_DIR)/`basename
>>>> $${ARCH_SYSROOT_DIR_CANON}` ; \
>>>> +        echo "Symlinking $(STAGING_DIR)/`basename $${ARCH_SYSROOT_DIR_CANON}`
>>>> -> $${relpath}" ; \
>>>>        fi ; \
>>>>        if test -n "$${SUPPORT_LIB_DIR}" ; then \
>>>>            cp -a $${SUPPORT_LIB_DIR}/* $(STAGING_DIR)/lib/ ; \
>>>>
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