On 28/01/2020 05:00, Mathias Lang wrote:
> Hi,
>
> This patch fixes GDC on s390x-linux-musl targets. It was specifically
> tested under Alpine Linux (see
> https://gitlab.alpinelinux.org/alpine/aports/commit/c123e0f14ab73976a36c651d47d134f249413f29
> ).
> The patch fixes two issues: First, Musl always provide
> `__tls_get_addr`, so we can always use it to get the TLS range instead
> of the internal function (which is glibc-specific).
> Second, druntime provide an ASM implementation for
> `fiber_switchContext` for most platform under
> libphobos/libdruntime/config/$ARCH/switchcontext.S, and default to
> `swapcontext` when not available, which is the case on s390x.
> However, the configure script did not depend on `swapcontext` being
> present, as it's part of glibc, but not Musl (there is a libucontext
> available on Alpine for this), which is added here.
>
> @Iain: Any chance those could be backported to v9 ?
>
Thanks, I see no reason not to backport.
> ---
> Mathias Lang
> ---
> libphobos/ChangeLog:
>
> * libdruntime/gcc/sections/elf_shared.d Always use
> __tls_get_addr on Musl.
> * configure.ac: Search librairies for swapcontext when
> LIBDRUNTIME_NEEDS_UCONTEXT is yes.
> * configure.tgt: Set LIBDRUNTIME_NEEDS_UCONTEXT on s390*-linux*.
> * configure: Regenerate.
> ---
> diff -Nurp a/libphobos/libdruntime/gcc/sections/elf_shared.d
> b/libphobos/libdruntime/gcc/sections/elf_shared.d
> --- a/libphobos/libdruntime/gcc/sections/elf_shared.d
> +++ b/libphobos/libdruntime/gcc/sections/elf_shared.d
> @@ -1084,7 +1084,9 @@ void[] getTLSRange(size_t mod, size_t sz) nothrow @nogc
>
> // base offset
> auto ti = tls_index(mod, 0);
> - version (IBMZ_Any)
> + version (CRuntime_Musl)
> + return (__tls_get_addr(&ti)-TLS_DTV_OFFSET)[0 .. sz];
> + else version (IBMZ_Any)
> {
> auto idx = cast(void *)__tls_get_addr_internal(&ti)
> + cast(ulong)__builtin_thread_pointer();
This is fine.
> diff -Nurp a/libphobos/configure.ac b/libphobos/configure.ac
> --- a/libphobos/configure.ac
> +++ b/libphobos/configure.ac
> @@ -140,6 +140,14 @@ case ${host} in
> esac
> AC_MSG_RESULT($LIBPHOBOS_SUPPORTED)
>
> +AC_MSG_CHECKING([if target needs to link in swapcontext])
> +AC_MSG_RESULT($LIBDRUNTIME_NEEDS_UCONTEXT)
> +AS_IF([test "x$LIBDRUNTIME_NEEDS_UCONTEXT" = xyes], [
> + AC_SEARCH_LIBS([swapcontext], [c ucontext], [], [
> + AC_MSG_ERROR([[can't find library providing swapcontext]])
> + ])
> +])
> +
Rather than adding LIBDRUNTIME_NEEDS_UCONTEXT, couldn't you just add a
one-liner AC_SEARCH_LIBS to the WITH_LOCAL_DRUNTIME list?
Testing as I suggest locally, there is no problems on x86 and x86_64.
Iain.
