On 3/26/24 07:28, Cupertino Miranda wrote:
> Hi everyone,
>
> This patch is an expected fix for the issue reported by systemd in:
> https://github.com/systemd/systemd/issues/31888
> Also, Jose Marchesi opened the following bugzilla to report it:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114431
>
> Please notice that the function created was inspired by existing code
> in the function btf_asm_type_ref.
>
> Looking forward to your comments.
OK, LGTM.
Thanks for the fix!
>
> Cupertino
>
>
> GCC was defining bts_offset entry to always contain 0.
> When comparing with clang, the same entry is instead a label to the
> respective variable or function. The assembler emits relocations for
> those labels.
>
> gcc/ChangeLog:
> PR target/114431
> * btfout.cc (get_name_for_datasec_entry): Add function.
> (btf_asm_datasec_entry): Print label when possible.
>
> gcc/testsuite/ChangeLog:
> gcc.dg/debug/btf/btf-datasec-1.c: Correct for new
> implementation.
> gcc.dg/debug/btf/btf-datasec-2.c: Likewise
> gcc.dg/debug/btf/btf-pr106773.c: Likewise
> ---
> gcc/btfout.cc | 30 ++++++++++++++++++-
> .../gcc.dg/debug/btf/btf-datasec-1.c | 6 ++--
> .../gcc.dg/debug/btf/btf-datasec-2.c | 7 +++--
> gcc/testsuite/gcc.dg/debug/btf/btf-pr106773.c | 2 +-
> 4 files changed, 39 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/btfout.cc b/gcc/btfout.cc
> index e63289bc554..5f708630e04 100644
> --- a/gcc/btfout.cc
> +++ b/gcc/btfout.cc
> @@ -1014,13 +1014,41 @@ btf_asm_func_type (ctf_container_ref ctfc,
> ctf_dtdef_ref dtd, ctf_id_t id)
> btf_asm_type_ref ("btt_type", ctfc, get_btf_id (ref_id));
> }
>
> +/* Collect the name for the DATASEC reference required to be output as a
> + symbol. */
> +
> +static const char *
> +get_name_for_datasec_entry (ctf_container_ref ctfc, ctf_id_t ref_id)
> +{
> + if (ref_id >= num_types_added + 1
> + && ref_id < num_types_added + num_vars_added + 1)
> + {
> + /* Ref to a variable. Should only appear in DATASEC entries. */
> + ctf_id_t var_id = btf_relative_var_id (ref_id);
> + ctf_dvdef_ref dvd = ctfc->ctfc_vars_list[var_id];
> + return dvd->dvd_name;
> + }
> + else if (ref_id >= num_types_added + num_vars_added + 1)
> + {
> + /* Ref to a FUNC record. */
> + size_t func_id = btf_relative_func_id (ref_id);
> + ctf_dtdef_ref ref_type = (*funcs)[func_id];
> + return get_btf_type_name (ref_type);
> + }
> + return NULL;
> +}
> +
> /* Asm'out a variable entry following a BTF_KIND_DATASEC. */
>
> static void
> btf_asm_datasec_entry (ctf_container_ref ctfc, struct btf_var_secinfo info)
> {
> + const char *symbol_name = get_name_for_datasec_entry (ctfc, info.type);
> btf_asm_type_ref ("bts_type", ctfc, info.type);
> - dw2_asm_output_data (4, info.offset, "bts_offset");
> + if (symbol_name == NULL)
> + dw2_asm_output_data (4, info.offset, "bts_offset");
> + else
> + dw2_asm_output_offset (4, symbol_name, NULL, "bts_offset");
> dw2_asm_output_data (4, info.size, "bts_size");
> }
>
> diff --git a/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-1.c
> b/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-1.c
> index 77df88648c5..8557c38c20d 100644
> --- a/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-1.c
> +++ b/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-1.c
> @@ -19,8 +19,10 @@
> /* { dg-final { scan-assembler-times "0xf000003\[\t \]+\[^\n\]*btt_info" 2 }
> } */
> /* { dg-final { scan-assembler-times "0xf000001\[\t \]+\[^\n\]*btt_info" 1 }
> } */
>
> -/* The offset entry for each variable in a DATSEC should be 0 at compile
> time. */
> -/* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bts_offset" 7 } } */
> +/* The offset entry for each variable in a DATSEC should contain a label. */
> +/* { dg-final { scan-assembler-times ".4byte\[\t \]\[a-e\]\[\t
> \]+\[^\n\]*bts_offset" 5 } } */
> +/* { dg-final { scan-assembler-times "my_cstruct\[\t \]+\[^\n\]*bts_offset"
> 1 } } */
> +/* { dg-final { scan-assembler-times "bigarr\[\t \]+\[^\n\]*bts_offset" 1 }
> } */
>
> /* Check that strings for each DATASEC have been added to the BTF string
> table. */
> /* { dg-final { scan-assembler-times "ascii \".data.0\"\[\t
> \]+\[^\n\]*btf_aux_string" 1 } } */
> diff --git a/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-2.c
> b/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-2.c
> index d6f3358d6fb..857d830e446 100644
> --- a/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-2.c
> +++ b/gcc/testsuite/gcc.dg/debug/btf/btf-datasec-2.c
> @@ -9,8 +9,11 @@
> /* { dg-final { scan-assembler-times " BTF_KIND_DATASEC
> '.foo_sec'\[\\r\\n\]+\[^\\r\\n\]*0xf000001\[\t \]+\[^\n\]*btt_info" 1 } } */
> /* { dg-final { scan-assembler-times " BTF_KIND_DATASEC
> '.bar_sec'\[\\r\\n\]+\[^\\r\\n\]*0xf000002\[\t \]+\[^\n\]*btt_info" 1 } } */
>
> -/* Function entries should have offset and size of 0 at compile time. */
> -/* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bts_offset" 3 } } */
> +/* Function entries should have offset with a label and size of 0 at compile
> time. */
> +/* { dg-final { scan-assembler-times "chacha\[\t \]+\[^\n\]*bts_offset" 1 }
> } */
> +/* { dg-final { scan-assembler-times "bar\[\t \]+\[^\n\]*bts_offset" 1 } } */
> +/* { dg-final { scan-assembler-times "foo\[\t \]+\[^\n\]*bts_offset" 1 } } */
> +
> /* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bts_size" 3 } } */
>
> extern int foo (int a) __attribute__((section(".foo_sec")));
> diff --git a/gcc/testsuite/gcc.dg/debug/btf/btf-pr106773.c
> b/gcc/testsuite/gcc.dg/debug/btf/btf-pr106773.c
> index 940f129408d..c06220eb520 100644
> --- a/gcc/testsuite/gcc.dg/debug/btf/btf-pr106773.c
> +++ b/gcc/testsuite/gcc.dg/debug/btf/btf-pr106773.c
> @@ -11,7 +11,7 @@
>
> /* { dg-final { scan-assembler-times "ascii \"foo.0\"\[\t
> \]+\[^\n\]*btf_string" 1 } } */
>
> -/* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bts_offset" 1 } } */
> +/* { dg-final { scan-assembler-times "foo\[\t \]+\[^\n\]*bts_offset" 1 } } */
> /* { dg-final { scan-assembler-times "1\[\t \]+\[^\n\]*bts_size" 1 } } */
>
> extern const void foo __attribute__((weak)) __attribute__((section
> (".ksyms")));
