Yangyu Chen <c...@cyyself.name> writes:
> We forgot to apply DECL_EXTERNAL to __init_cpu_features_resolver decl. When
> building with LTO, the linker cannot find the
> __init_cpu_features_resolver.lto_priv* symbol, causing the link error.
>
> This patch get this fixed by adding DECL_EXTERNAL to the decl. To avoid used
> but
> never defined warning for this symbol, we also mark TREE_PUBLIC to the decl.
>
> Minimal steps to reproduce the bug:
>
> echo '__attribute__((target_clones("default", "aes"))) void func1() { }' > 1.c
> echo '__attribute__((target_clones("default", "aes"))) void func2() { }' > 2.c
> echo 'void func1();void func2();int main(){func1();func2();return 0;}' >
> main.c
> gcc -flto -c 1.c 2.c
> gcc -flto main.c 1.o 2.o
>
> Fixes: 0cfde688e213 ("[aarch64] Add function multiversioning support")
>
> gcc/ChangeLog:
>
> * config/aarch64/aarch64.cc (dispatch_function_versions): Adding
> DECL_EXTERNAL and TREE_PUBLIC to __init_cpu_features_resolver decl.
Thanks for doing this. I suppose at the same time, we should also
mark __aarch64_cpu_features as TREE_PUBLIC. We could also mark both
of them as having hidden visibility, via:
DECL_VISIBILITY (...) = VISIBILITY_HIDDEN;
DECL_VISIBILITY_SPECIFIED (...) = 1;
Richard
> ---
> gcc/config/aarch64/aarch64.cc | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
> index 5770491b30c..37123befeaf 100644
> --- a/gcc/config/aarch64/aarch64.cc
> +++ b/gcc/config/aarch64/aarch64.cc
> @@ -20437,6 +20437,8 @@ dispatch_function_versions (tree dispatch_decl,
> tree init_fn_id = get_identifier ("__init_cpu_features_resolver");
> tree init_fn_decl = build_decl (UNKNOWN_LOCATION, FUNCTION_DECL,
> init_fn_id, init_fn_type);
> + DECL_EXTERNAL (init_fn_decl) = 1;
> + TREE_PUBLIC (init_fn_decl) = 1;
> tree arg1 = DECL_ARGUMENTS (dispatch_decl);
> tree arg2 = TREE_CHAIN (arg1);
> ifunc_cpu_init_stmt = gimple_build_call (init_fn_decl, 2, arg1, arg2);
