libbpf: Update BTF reloc support to latest Clang format

BTF offset reloc was generalized in recent Clang into field relocation,
capturing extra u32 field, specifying what aspect of captured field
needs to be relocated. This changes .BTF.ext's record size for this
relocation from 12 bytes to 16 bytes. Given these format changes
happened in Clang before official released version, it's ok to not
support outdated 12-byte record size w/o breaking ABI.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191015182849.3922287-2-andriin@fb.com

1 files changed, 12 insertions, 12 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index a02cdedc4e3f..d6c7699de405 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -2326,7 +2326,7 @@ static bool str_is_empty(const char *s)
 }
 
 /*
- * Turn bpf_offset_reloc into a low- and high-level spec representation,
+ * Turn bpf_field_reloc into a low- and high-level spec representation,
  * validating correctness along the way, as well as calculating resulting
  * field offset (in bytes), specified by accessor string. Low-level spec
  * captures every single level of nestedness, including traversing anonymous
@@ -2977,7 +2977,7 @@ static void *u32_as_hash_key(__u32 x)
  *    types should be compatible (see bpf_core_fields_are_compat for details).
  * 3. It is supported and expected that there might be multiple flavors
  *    matching the spec. As long as all the specs resolve to the same set of
- *    offsets across all candidates, there is not error. If there is any
+ *    offsets across all candidates, there is no error. If there is any
  *    ambiguity, CO-RE relocation will fail. This is necessary to accomodate
  *    imprefection of BTF deduplication, which can cause slight duplication of
  *    the same BTF type, if some directly or indirectly referenced (by
@@ -2992,12 +2992,12 @@ static void *u32_as_hash_key(__u32 x)
  *    CPU-wise compared to prebuilding a map from all local type names to
  *    a list of candidate type names. It's also sped up by caching resolved
  *    list of matching candidates per each local "root" type ID, that has at
- *    least one bpf_offset_reloc associated with it. This list is shared
+ *    least one bpf_field_reloc associated with it. This list is shared
  *    between multiple relocations for the same type ID and is updated as some
  *    of the candidates are pruned due to structural incompatibility.
  */
-static int bpf_core_reloc_offset(struct bpf_program *prog,
-				 const struct bpf_offset_reloc *relo,
+static int bpf_core_reloc_field(struct bpf_program *prog,
+				 const struct bpf_field_reloc *relo,
 				 int relo_idx,
 				 const struct btf *local_btf,
 				 const struct btf *targ_btf,
@@ -3106,10 +3106,10 @@ static int bpf_core_reloc_offset(struct bpf_program *prog,
 }
 
 static int
-bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
+bpf_core_reloc_fields(struct bpf_object *obj, const char *targ_btf_path)
 {
 	const struct btf_ext_info_sec *sec;
-	const struct bpf_offset_reloc *rec;
+	const struct bpf_field_reloc *rec;
 	const struct btf_ext_info *seg;
 	struct hashmap_entry *entry;
 	struct hashmap *cand_cache = NULL;
@@ -3134,7 +3134,7 @@ bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
 		goto out;
 	}
 
-	seg = &obj->btf_ext->offset_reloc_info;
+	seg = &obj->btf_ext->field_reloc_info;
 	for_each_btf_ext_sec(seg, sec) {
 		sec_name = btf__name_by_offset(obj->btf, sec->sec_name_off);
 		if (str_is_empty(sec_name)) {
@@ -3153,8 +3153,8 @@ bpf_core_reloc_offsets(struct bpf_object *obj, const char *targ_btf_path)
 			 sec_name, sec->num_info);
 
 		for_each_btf_ext_rec(seg, sec, i, rec) {
-			err = bpf_core_reloc_offset(prog, rec, i, obj->btf,
-						    targ_btf, cand_cache);
+			err = bpf_core_reloc_field(prog, rec, i, obj->btf,
+						   targ_btf, cand_cache);
 			if (err) {
 				pr_warning("prog '%s': relo #%d: failed to relocate: %d\n",
 					   sec_name, i, err);
@@ -3179,8 +3179,8 @@ bpf_object__relocate_core(struct bpf_object *obj, const char *targ_btf_path)
 {
 	int err = 0;
 
-	if (obj->btf_ext->offset_reloc_info.len)
-		err = bpf_core_reloc_offsets(obj, targ_btf_path);
+	if (obj->btf_ext->field_reloc_info.len)
+		err = bpf_core_reloc_fields(obj, targ_btf_path);
 
 	return err;
 }