David Faust writes:
> On 3/13/24 07:24, Cupertino Miranda wrote:
>> Although part of all CO-RE relocation data, type based relocations do
>> not require an access string.
>> Initial implementation defined it as an empty string.
>> On the other hand, libbpf when parsing the CO-RE relocations verifies
>> that those strings would contain "0", otherwise reports an error.
>> This patch makes GCC compliant with libbpf expectations.
>
> OK, thanks.
>
Pushed! Thanks
>>
>> gcc/Changelog:
>> * config/bpf/btfext-out.cc (cpf_core_reloc_add): Correct for new code.
>> Add assert to validate the string is set.
>> * config/bpf/core-builtins.cc (cr_final): Make string struct
>> field as const.
>> (process_enum_value): Correct for field type change.
>> (process_type): Set access string to "0".
>>
>> gcc/testsuite/ChangeLog:
>> * gcc.target/bpf/core-builtin-type-based.c: Correct.
>> * gcc.target/bpf/core-builtin-type-id.c: Correct.
>> ---
>> gcc/config/bpf/btfext-out.cc | 5 +++--
>> gcc/config/bpf/core-builtins.cc | 10 ++++++----
>> gcc/testsuite/gcc.target/bpf/core-builtin-type-based.c | 1 +
>> gcc/testsuite/gcc.target/bpf/core-builtin-type-id.c | 1 +
>> 4 files changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/gcc/config/bpf/btfext-out.cc b/gcc/config/bpf/btfext-out.cc
>> index 57c0dc323812..ff1fd0739f1e 100644
>> --- a/gcc/config/bpf/btfext-out.cc
>> +++ b/gcc/config/bpf/btfext-out.cc
>> @@ -299,8 +299,9 @@ bpf_core_reloc_add (const tree type, const char *
>> section_name,
>>
>> /* Buffer the access string in the auxiliary strtab. */
>> bpfcr->bpfcr_astr_off = 0;
>> - if (accessor != NULL)
>> - bpfcr->bpfcr_astr_off = btf_ext_add_string (accessor);
>> + gcc_assert (accessor != NULL);
>> + bpfcr->bpfcr_astr_off = btf_ext_add_string (accessor);
>> +
>> bpfcr->bpfcr_type = get_btf_id (ctf_lookup_tree_type (ctfc, type));
>> bpfcr->bpfcr_insn_label = label;
>> bpfcr->bpfcr_kind = kind;
>> diff --git a/gcc/config/bpf/core-builtins.cc
>> b/gcc/config/bpf/core-builtins.cc
>> index 4256fea15e49..70b14e48e6e5 100644
>> --- a/gcc/config/bpf/core-builtins.cc
>> +++ b/gcc/config/bpf/core-builtins.cc
>> @@ -205,7 +205,7 @@ struct cr_local
>> /* Core Relocation Final data */
>> struct cr_final
>> {
>> - char *str;
>> + const char *str;
>> tree type;
>> enum btf_core_reloc_kind kind;
>> };
>> @@ -868,8 +868,10 @@ process_enum_value (struct cr_builtins *data)
>> {
>> if (TREE_VALUE (l) == expr)
>> {
>> - ret.str = (char *) ggc_alloc_atomic ((index / 10) + 1);
>> - sprintf (ret.str, "%d", index);
>> + char *tmp = (char *) ggc_alloc_atomic ((index / 10) + 1);
>> + sprintf (tmp, "%d", index);
>> + ret.str = (const char *) tmp;
>> +
>> break;
>> }
>> index++;
>> @@ -987,7 +989,7 @@ process_type (struct cr_builtins *data)
>> || data->kind == BPF_RELO_TYPE_MATCHES);
>>
>> struct cr_final ret;
>> - ret.str = NULL;
>> + ret.str = ggc_strdup ("0");
>> ret.type = data->type;
>> ret.kind = data->kind;
>>
>> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-type-based.c
>> b/gcc/testsuite/gcc.target/bpf/core-builtin-type-based.c
>> index 74a8d5a14d9d..9d818133c084 100644
>> --- a/gcc/testsuite/gcc.target/bpf/core-builtin-type-based.c
>> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-type-based.c
>> @@ -56,3 +56,4 @@ int foo(void *data)
>> /* { dg-final { scan-assembler-times "0x8\[\t \]+\[^\n\]*bpfcr_kind" 13 } }
>> BPF_TYPE_EXISTS */
>> /* { dg-final { scan-assembler-times "0x9\[\t \]+\[^\n\]*bpfcr_kind" 11 } }
>> BPF_TYPE_SIZE */
>> /* { dg-final { scan-assembler-times "0xc\[\t \]+\[^\n\]*bpfcr_kind" 13 } }
>> BPF_TYPE_MATCHES */
>> +/* { dg-final { scan-assembler-times "bpfcr_astr_off \[(\"\]+0\[(\"\]+" 37
>> } } */
>> diff --git a/gcc/testsuite/gcc.target/bpf/core-builtin-type-id.c
>> b/gcc/testsuite/gcc.target/bpf/core-builtin-type-id.c
>> index 4b23288eac08..9576b91bc940 100644
>> --- a/gcc/testsuite/gcc.target/bpf/core-builtin-type-id.c
>> +++ b/gcc/testsuite/gcc.target/bpf/core-builtin-type-id.c
>> @@ -38,3 +38,4 @@ int foo(void *data)
>> /* { dg-final { scan-assembler-times "0\[\t \]+\[^\n\]*bpfcr_type" 0 {
>> xfail *-*-* } } } */
>> /* { dg-final { scan-assembler-times "0x6\[\t \]+\[^\n\]*bpfcr_kind" 13 } }
>> BPF_TYPE_ID_LOCAL */
>> /* { dg-final { scan-assembler-times "0x7\[\t \]+\[^\n\]*bpfcr_kind" 7 } }
>> BPF_TYPE_ID_TARGET */
>> +/* { dg-final { scan-assembler-times "bpfcr_astr_off \[(\"\]+0\[(\"\]+" 20
>> } } */
