> [changes from v1: simplify the new conditional logic as suggested.]
>
> The old method for computing a member index for a CO-RE relocation
> relied on a name comparison, which could SEGV if the member in question
> is itself part of an anonymous inner struct or union.
>
> This patch changes the index computation to not rely on a name, while
> maintaining the ability to account for other sibling fields which may
> not have a representation in BTF.
>
> Tested in bpf-unknown-none, no known regressions.
> OK?
OK, thank you.
> Thanks.
>
> gcc/ChangeLog:
>
> PR target/106745
> * config/bpf/coreout.cc (bpf_core_get_sou_member_index): Fix
> computation of index for anonymous members.
>
> gcc/testsuite/ChangeLog:
>
> PR target/106745
> * gcc.target/bpf/core-pr106745.c: New test.
> ---
> gcc/config/bpf/coreout.cc | 16 +++++++----
> gcc/testsuite/gcc.target/bpf/core-pr106745.c | 30 ++++++++++++++++++++
> 2 files changed, 40 insertions(+), 6 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/bpf/core-pr106745.c
>
> diff --git a/gcc/config/bpf/coreout.cc b/gcc/config/bpf/coreout.cc
> index cceaaa969cc..8897a045ea1 100644
> --- a/gcc/config/bpf/coreout.cc
> +++ b/gcc/config/bpf/coreout.cc
> @@ -207,7 +207,6 @@ bpf_core_get_sou_member_index (ctf_container_ref ctfc,
> const tree node)
> if (TREE_CODE (node) == FIELD_DECL)
> {
> const tree container = DECL_CONTEXT (node);
> - const char * name = IDENTIFIER_POINTER (DECL_NAME (node));
>
> /* Lookup the CTF type info for the containing type. */
> dw_die_ref die = lookup_type_die (container);
> @@ -222,16 +221,21 @@ bpf_core_get_sou_member_index (ctf_container_ref ctfc,
> const tree node)
> if (kind != CTF_K_STRUCT && kind != CTF_K_UNION)
> return -1;
>
> + tree field = TYPE_FIELDS (container);
> int i = 0;
> ctf_dmdef_t * dmd;
> for (dmd = dtd->dtd_u.dtu_members;
> dmd != NULL; dmd = (ctf_dmdef_t *) ctf_dmd_list_next (dmd))
> {
> - if (get_btf_id (dmd->dmd_type) > BTF_MAX_TYPE)
> - continue;
> - if (strcmp (dmd->dmd_name, name) == 0)
> - return i;
> - i++;
> + bool field_has_btf = get_btf_id (dmd->dmd_type) <= BTF_MAX_TYPE;
> +
> + if (field == node)
> + return field_has_btf ? i : -1;
> +
> + if (field_has_btf)
> + i++;
> +
> + field = DECL_CHAIN (field);
> }
> }
> return -1;
> diff --git a/gcc/testsuite/gcc.target/bpf/core-pr106745.c
> b/gcc/testsuite/gcc.target/bpf/core-pr106745.c
> new file mode 100644
> index 00000000000..9d347006a69
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/bpf/core-pr106745.c
> @@ -0,0 +1,30 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O0 -gbtf -dA -mco-re" } */
> +
> +struct weird
> +{
> + struct
> + {
> + int b;
> + };
> +
> + char x;
> +
> + union
> + {
> + int a;
> + int c;
> + };
> +};
> +
> +
> +int test (struct weird *arg) {
> + int *x = __builtin_preserve_access_index (&arg->b);
> + int *y = __builtin_preserve_access_index (&arg->c);
> +
> + return *x + *y;
> +}
> +
> +
> +/* { dg-final { scan-assembler-times "ascii \"0:0:0.0\"\[\t
> \]+\[^\n\]*btf_aux_string" 1 } } */
> +/* { dg-final { scan-assembler-times "ascii \"0:2:1.0\"\[\t
> \]+\[^\n\]*btf_aux_string" 1 } } */
