Re: [OE-core] [scarthgap] recipe's sysroot misconfiguration in multilib

[Joao Marcos Costa <joaomarcos.costa@bootlin.com>]

Hello, Richard

Thanks for your reply

On 3/26/25 19:55, Richard Purdie via lists.openembedded.org wrote:
> On Wed, 2025-03-26 at 19:47 +0100, Joao Marcos Costa wrote:
>> I have been trying to set up a multilib environment to generate
>> libraries built with Control Flow Integrity support. The gcc toolchain
>> is already patched to support this custom multilib ABI, and it is indeed
>> capable of generating binaries with the CFI flags.
>>
>> I am, however, facing this strange issue where a header is not found in
>> the multilib recipe-sysroot (i.e., libcfi-recipe-sysroot) of a given
>> package (e.g., zstd), and do_compile task fails:
>>
(...)
>>
>> Besides my TUNE_*, DEFAULTTUNE, BASE_LIB values set up, I also added
>> 'GCCMULTILIB = "--enable-multilib"' to gcc-cross.inc, to enable multilib
>> for the cross toolchain. Could I be missing something, maybe with
>> recipes-devtools/gcc/gcc-multilib-config.inc?
> 
> I'm finding it odd that you have to add --enable-multilib since in
> general with gcc-cross, we use separate cross toolchains for each
> multilib. This kind of implies you're configuring the setup differently
> to how the system would expect.

If I don't, my cross toolchain is configured with "--disable-multilib". 
To confirm this, I ran gcc with "-v" from within the recipe's native 
sysroot, and the output is:

Target: riscv64-freedomusdkmllibcfi-linux
Configured with: 
../../../../../../work-shared/gcc-internal-13.2.0-r0/git/configure 
--build=x86_64-linux --host=x86_64-linux 
--target=riscv64-freedomusdkmllibcfi-linux --prefix=//host/usr 
--exec_prefix=//host/usr 
--bindir=//host/usr/bin/riscv64-freedomusdkmllibcfi-linux 
--sbindir=//host/usr/bin/riscv64-freedomusdkmllibcfi-linux 
--libexecdir=//host/usr/libexec/riscv64-freedomusdkmllibcfi-linux 
--datadir=//host/usr/share --sysconfdir=//host/etc 
--sharedstatedir=//host/com --localstatedir=//host/var 
--libdir=//host/usr/lib/riscv64-freedomusdkmllibcfi-linux 
--includedir=//host/usr/include --oldincludedir=//host/usr/include 
--infodir=//host/usr/share/info --mandir=//host/usr/share/man 
--disable-silent-rules --disable-dependency-tracking 
--with-libtool-sysroot=//host --enable-clocale=generic --with-gnu-ld 
--enable-shared --enable-languages=c,c++,fortran --enable-threads=posix 
--disable-multilib --enable-default-pie --enable-c99 --enable-long-long 
--enable-(...)

As a consequence, the build fails even before it gets to libcfi-zstd:

...libcfi-glibc-internal/2.37/recipe-sysroot-native/usr/bin/riscv64-freedomusdkmllibcfi-linux/../../libexec/riscv64-freedomusdkmllibcfi-linux/gcc/riscv64-freedomusdkmllibcfi-linux/13.2.0/ld.bfd: 
cannot find -lgcc: No such file or directory
| collect2: error: ld returned 1 exit status
| make[2]: *** [Makefile:1293: 
...libcfi-glibc-internal/2.37/build-riscv64-freedomusdkmllibcfi-linux/elf/librtld.map] 
Error 1


> 
> The recipe-sysroot-native/installeddeps/ directory will show you what
> is installed in each and might help narrow down the size difference.
> 

Oddly enough, both installeddeps seem to contain (at least) the same 
number of items:

$ ls -l zstd/1.5.5/recipe-sysroot-native/installeddeps/ | wc -l
74
$ ls 
../riscv64cfi-freedomusdkmllibcfi-linux/libcfi-zstd/1.5.5/recipe-sysroot-native/installeddeps/ 
-l | wc -l
75

But, to be honest, my comparison didn't go any further than comparing 
this line count.

> Cheers,
> 
> Richard

Thanks!

-- 
Best regards,
João Marcos Costa