Created attachment 875869 [details] Successfull emerge of broken gcc:11 After a successfull emerge of sys-devel/gcc:11[cet,d] on musl you get a D compiler with a broken shandard library. This is because the library references functions like swapcontext, makecontext, getcontext which do not exist on musl. The root cause of this problem is https://github.com/gcc-mirror/gcc/blob/7eaf95689bf495ab07473951ededa835eb618123/libphobos/libdruntime/core/thread/fiber.d#L76-L80. In which cet support disables the assembly implementations of some of the functions in that module, falling back to the ucontext implementations. Since musl doesn't implement makecontext, swapcontext or getcontext, even though it provided prototypes in ucontext.h linker errors appear. An example of the errors when trying to compile a hello_world program: ------ /usr/lib/gcc/x86_64-gentoo-linux-musl/11/../../../../x86_64-gentoo-linux-musl/bin/ld: /usr/lib/gcc/x86_64-gentoo-linux-musl/11/libgphobos.a(fiber.o): in function `fiber_switchContext': (.text.fiber_switchContext+0x3b): undefined reference to `swapcontext' /usr/lib/gcc/x86_64-gentoo-linux-musl/11/../../../../x86_64-gentoo-linux-musl/bin/ld: /usr/lib/gcc/x86_64-gentoo-linux-musl/11/libgphobos.a(fiber.o): in function `_D4core6thread5fiber5Fiber9initStackMFNbNiZv': (.text._D4core6thread5fiber5Fiber9initStackMFNbNiZv+0x2e): undefined reference to `getcontext' /usr/lib/gcc/x86_64-gentoo-linux-musl/11/../../../../x86_64-gentoo-linux-musl/bin/ld: (.text._D4core6thread5fiber5Fiber9initStackMFNbNiZv+0x5f): undefined reference to `makecontext' /usr/lib/gcc/x86_64-gentoo-linux-musl/11/../../../../x86_64-gentoo-linux-musl/bin/ld: /usr/lib/gcc/x86_64-gentoo-linux-musl/11/libgphobos.a(fiber.o): in function `_D4core6thread5fiber5Fiber12_staticCtor1FZv': (.text._D4core6thread5fiber5Fiber12_staticCtor1FZv+0x1c): undefined reference to `getcontext' collect2: error: ld returned 1 exit status ------ The same errors appear, during emerge this time, for sys-devel/gcc:13 and it should happen to the other slots as well though I have not tested them specifically. A snippet: ------ /usr/x86_64-gentoo-linux-musl/bin/ld: /var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/build/prev-x86_64-gentoo-linux-musl/libphobos/src/.libs/libgphobos.a(fiber.o): in function `fiber_switchContext': /var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/gcc-13-20231014/libphobos/libdruntime/core/thread/fiber.d:430: undefined reference to `swapcontext' /usr/x86_64-gentoo-linux-musl/bin/ld: /var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/build/prev-x86_64-gentoo-linux-musl/libphobos/src/.libs/libgphobos.a(fiber.o): in function `_D4core6thread5fiber5Fiber9initStackMFNbNiZv': /var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/gcc-13-20231014/libphobos/libdruntime/core/thread/fiber.d:1537: undefined reference to `getcontext' /usr/x86_64-gentoo-linux-musl/bin/ld: /var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/gcc-13-20231014/libphobos/libdruntime/core/thread/fiber.d:1540: undefined reference to `makecontext' /usr/x86_64-gentoo-linux-musl/bin/ld: /var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/build/prev-x86_64-gentoo-linux-musl/libphobos/src/.libs/libgphobos.a(fiber.o): in function `_D4core6thread5fiber5Fiber19_staticCtor_L921_C9FZv': /var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/gcc-13-20231014/libphobos/libdruntime/core/thread/fiber.d:925: undefined reference to `getcontext' collect2: error: ld returned 1 exit status make[3]: *** [/var/tmp/portage/sys-devel/gcc-13.2.1_p20231014/work/gcc-13-20231014/gcc/d/Make-lang.in:236: d21] Error 1 ------ A fix upstream would be to also check if cet support is enabled when deciding if needing a ucontext implementation for the D runtime in the autoconf macro: https://github.com/gcc-mirror/gcc/blob/7eaf95689bf495ab07473951ededa835eb618123/libphobos/m4/druntime/libraries.m4#L213
Created attachment 875870 [details] build.log of gcc:13
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=c52997d9b125de280d75b169b8bc6f3964d5d051 commit c52997d9b125de280d75b169b8bc6f3964d5d051 Author: Andrei Horodniceanu <a.horodniceanu@proton.me> AuthorDate: 2024-09-30 16:32:52 +0000 Commit: Sam James <sam@gentoo.org> CommitDate: 2024-10-01 06:59:28 +0000 toolchain.eclass: Try harder to disable cet automagic On arches that support USE=cet (those being amd64, arm64, and, x86) always pass --enable-cet or --disable-cet (or aarch64 standard-branch-protection equivalent) to prevent any configure automagic from happening. Preserve the same CTARGET logic so only pass --enable-cet if the target environment supports it and if `use cet`. Also fix the regex `i[[34567]]86` as that matches an i, followed by any of the digits from 3 to 7 or the [ character, followed by ], followed by 8, followed by 6. The regex originated in config/cet.m4 which uses [] for quotes. The automatic specifically breaks gcc[d] on musl because it prevents the code from using an internal assembly implementation for a function and deferring to using an implementation that would be provided by sys-libs/libucontext which results in undefined symbol errors: ``` /usr/lib/gcc/x86_64-pc-linux-musl/11/../../../../x86_64-pc-linux-musl/bin/ld: /usr/lib/gcc/x86_64-pc-linux-musl/11/libgphobos.a(fiber.o): in function `_D4core6thread5fiber5Fiber9initStackMFNbNiZv': (.text._D4core6thread5fiber5Fiber9initStackMFNbNiZv+0x2e): undefined reference to `getcontext' /usr/lib/gcc/x86_64-pc-linux-musl/11/../../../../x86_64-pc-linux-musl/bin/ld: (.text._D4core6thread5fiber5Fiber9initStackMFNbNiZv+0x5f): undefined reference to `makecontext' /usr/lib/gcc/x86_64-pc-linux-musl/11/../../../../x86_64-pc-linux-musl/bin/ld: /usr/lib/gcc/x86_64-pc-linux-musl/11/libgphobos.a(fiber.o): in function `_D4core6thread5fiber5Fiber12_staticCtor1FZv': (.text._D4core6thread5fiber5Fiber12_staticCtor1FZv+0x1c): undefined reference to `getcontext' ``` Bug: https://bugs.gentoo.org/939874 Closes: https://bugs.gentoo.org/918692 Signed-off-by: Andrei Horodniceanu <a.horodniceanu@proton.me> Closes: https://github.com/gentoo/gentoo/pull/38830 Signed-off-by: Sam James <sam@gentoo.org> eclass/toolchain.eclass | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
