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linux: fix musl linking and warn on dynamic glibc cross-compilation #3278

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Merged
lerno merged 1 commit into from
May 29, 2026
Merged

linux: fix musl linking and warn on dynamic glibc cross-compilation #3278

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4 changes: 2 additions & 2 deletions scripts/tools/test_distros.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -34,10 +34,10 @@ declare -A DISTRO_IMAGES=(
[debian]="debian:bookworm-slim|apt-get update -qq && apt-get install -y -qq gcc bash"
[fedora]="fedora:latest|dnf install -y -q gcc bash"
[alpine]="alpine:3.23|apk add --no-cache gcc musl-dev bash"
[arch]="archlinux:latest|pacman -Sy --noconfirm gcc bash"
[arch]="archlinux:latest|pacman -Sy --noconfirm gcc bash libx11 libxrandr libxinerama libxi libxxf86vm libxcursor"
[opensuse]="opensuse/tumbleweed:latest|zypper install -y gcc glibc-devel bash"
[rocky]="rockylinux:9|dnf install -y -q gcc bash"
[void]="ghcr.io/void-linux/void-linux:latest-full-x86_64|xbps-install -Suy xbps && xbps-install -Sy gcc bash"
[void]="ghcr.io/void-linux/void-linux:latest-full-x86_64|xbps-install -Suy xbps && xbps-install -Sy gcc bash libX11-devel libXrandr-devel libXinerama-devel libXi-devel libXxf86vm-devel libXcursor-devel"
)

# Resolve which distros to test
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31 changes: 31 additions & 0 deletions src/build/builder.c
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Expand Up @@ -629,6 +629,37 @@ static void update_build_target_from_options(BuildTarget *target, BuildOptions *
}
#endif
if (target->linuxpaths.libc == LINUX_LIBC_NOT_SET) target->linuxpaths.libc = default_libc;

bool is_static = false;
for (size_t i = 0; i < options->linker_arg_count; i++)
{
const char *arg = options->linker_args[i];
if (strcmp(arg, "-static") == 0 || strcmp(arg, "--static") == 0 || strcmp(arg, "static") == 0)
{
is_static = true;
break;
}
}

if (target->linuxpaths.libc == LINUX_LIBC_MUSL && default_libc == LINUX_LIBC_GNU)
{
if (is_static)
{
if (target->linker_type != LINKER_TYPE_BUILTIN)
{
WARNING("Static linking against musl on a glibc system should use the built-in linker to avoid linking host libraries. Consider adding `--linker=builtin`.");
}
}
else
{
WARNING("Dynamically linking against musl on a glibc system produces non-portable binaries. Consider using `-z -static --linker=builtin`.");
}
}
else if (target->linuxpaths.libc == LINUX_LIBC_GNU && is_static)
{
WARNING("Statically linking against glibc produces binaries that still require glibc shared libraries at runtime for NSS/dns lookups. Consider targeting musl instead using `-linux-libc=musl --linker=builtin`.");
}

target->benchmarking = options->benchmarking;
target->testing = options->testing;
target->docgen = options->command == COMMAND_DOCGEN;
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22 changes: 13 additions & 9 deletions src/compiler/linker.c
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Expand Up @@ -586,11 +586,12 @@ static void linker_setup_linux(const char ***args_ref, Linker linker_type, bool
}
add_plain_arg("--eh-frame-hdr");
if (!link_libc()) return;
const char *crt_begin_dir = find_linux_crt_begin();
bool is_musl = compiler.build.linuxpaths.libc == LINUX_LIBC_MUSL;
const char *crt_begin_dir = is_musl ? NULL : find_linux_crt_begin();
const char *crt_dir = find_linux_crt();

if (is_exe && strip_unused()) add_plain_arg("--gc-sections");
if (!crt_begin_dir || !crt_dir)
if (!crt_dir || (!is_musl && !crt_begin_dir))
{
error_exit("Failed to find the C runtime at link time.");
}
Expand All @@ -607,19 +608,19 @@ static void linker_setup_linux(const char ***args_ref, Linker linker_type, bool
{
add_concat_file_arg(crt_dir, "crti.o");
if (!is_dylib) add_concat_file_arg(crt_dir, "Scrt1.o");
add_concat_file_arg(crt_begin_dir, "crtbeginS.o");
add_concat_file_arg(crt_begin_dir, "crtendS.o");
if (!is_musl) add_concat_file_arg(crt_begin_dir, "crtbeginS.o");
if (!is_musl) add_concat_file_arg(crt_begin_dir, "crtendS.o");
}
else
{
add_concat_file_arg(crt_dir, "crti.o");
if (!is_dylib) add_concat_file_arg(crt_dir, "crt1.o");
add_concat_file_arg(crt_begin_dir, "crtbegin.o");
add_concat_file_arg(crt_begin_dir, "crtend.o");
if (!is_musl) add_concat_file_arg(crt_begin_dir, "crtbegin.o");
if (!is_musl) add_concat_file_arg(crt_begin_dir, "crtend.o");
}
add_concat_file_arg(crt_dir, "crtn.o");
add_concat_quote_arg("-L", crt_dir);
add_concat_quote_arg("-L", crt_begin_dir);
if (!is_musl) add_concat_quote_arg("-L", crt_begin_dir);

if (compiler.platform.arch == ARCH_TYPE_RISCV64 || compiler.platform.arch == ARCH_TYPE_RISCV32)
{
Expand All @@ -637,8 +638,11 @@ static void linker_setup_linux(const char ***args_ref, Linker linker_type, bool

if (compiler.linking.link_math) linking_add_link(&compiler.linking, "m");
linking_add_link(&compiler.linking, "pthread");
linking_add_link(&compiler.linking, "gcc");
linking_add_link(&compiler.linking, "gcc_s");
if (!is_musl)
{
linking_add_link(&compiler.linking, "gcc");
linking_add_link(&compiler.linking, "gcc_s");
}
linking_add_link(&compiler.linking, "c");
add_plain_arg("-L/usr/lib/");
add_plain_arg("-L/lib/");
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