Support for clang's __attribute__((btf_decl_tag("..."))) by
btf_dump__dump_type and btf_dump__dump_type_data functions.
Decl tag attributes are restored for:
- structs and unions
- struct and union fields
- typedefs
- global variables
- function prototype parameters
The attribute is restored using __btf_decl_tag macro that is printed
upon first call to btf_dump__dump_type function:
#if __has_attribute(btf_decl_tag)
#define __btf_decl_tag(x) __attribute__((btf_decl_tag(x)))
#else
#define __btf_decl_tag(x)
#endif
To simplify testing of the btf_dump__dump_type_data the
prog_tests/btf_dump.c:test_btf_dump_case is extended to invoke
btf_dump__dump_type_data for each DATASEC object in the test case
binary file.
Changelog:
v2 -> v3:
- rebase to fix merge issues after recent hashmap interface update;
- call to btf_dump_assign_decl_tags removed from btf_dump__new as
redundant.
v1 -> v2:
- prog_tests/btf_dump.c:test_btf_dump_case modified to print DATASECs
using btf_dump__dump_type_data;
- support for decl tags applied to global variables and function
prototype parameters;
- update to support interleaved calls to btf_dump__dump_type and
btf__add_decl_tag (incremental dump);
- fix for potential double free error in btf_dump_assign_decl_tags;
- styling fixes suggested by Andrii.
RFC -> v1:
- support for decl tags applied to struct / union fields and typedefs;
- __btf_decl_tag macro;
- btf_dump->decl_tags hash and equal functions updated to use integer
key instead of a pointer;
- realloc_decl_tags function removed;
- update for allocation logic in btf_dump_assign_decl_tags.
[v2] https://lore.kernel.org/bpf/20221108153135.491383-1-eddyz87@xxxxxxxxx/
[v1] https://lore.kernel.org/bpf/20221103134522.2764601-1-eddyz87@xxxxxxxxx/
[RFC] https://lore.kernel.org/bpf/20221025222802.2295103-4-eddyz87@xxxxxxxxx/
Eduard Zingerman (3):
libbpf: __attribute__((btf_decl_tag("..."))) for btf dump in C format
selftests/bpf: Dump data sections as part of btf_dump_test_case tests
selftests/bpf: Tests for BTF_KIND_DECL_TAG dump in C format
tools/lib/bpf/btf_dump.c | 181 +++++++++++++++-
.../selftests/bpf/prog_tests/btf_dump.c | 197 ++++++++++++++++--
.../bpf/progs/btf_dump_test_case_decl_tag.c | 65 ++++++
3 files changed, 421 insertions(+), 22 deletions(-)
create mode 100644 tools/testing/selftests/bpf/progs/btf_dump_test_case_decl_tag.c
--
2.34.1
