From: Yonghong Song <yhs@fb.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
<dwarves@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>, <bpf@vger.kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>
Subject: [PATCH dwarves 2/2] btf_encoder: generate BTF_KIND_DECL_TAGs for typedef btf_decl_tag attributes
Date: Wed, 27 Oct 2021 16:08:34 -0700 [thread overview]
Message-ID: <20211027230834.2466282-1-yhs@fb.com> (raw)
In-Reply-To: <20211027230822.2465100-1-yhs@fb.com>
Emit BTF BTF_KIND_DECL_TAGs for btf_decl_tag attributes attached to
typedef declarations. The following is a simple example:
$ cat t.c
#define __tag1 __attribute__((btf_decl_tag("tag1")))
#define __tag2 __attribute__((btf_decl_tag("tag2")))
typedef struct { int a; int b; } __t __tag1 __tag2;
__t g;
$ clang -O2 -g -c t.c
$ pahole -JV t.o
btf_encoder__new: 't.o' doesn't have '.data..percpu' section
Found 0 per-CPU variables!
File t.o:
[1] TYPEDEF __t type_id=2
[2] STRUCT (anon) size=8
a type_id=3 bits_offset=0
b type_id=3 bits_offset=32
[3] INT int size=4 nr_bits=32 encoding=SIGNED
[4] DECL_TAG tag1 type_id=1 component_idx=-1
[5] DECL_TAG tag2 type_id=1 component_idx=-1
Signed-off-by: Yonghong Song <yhs@fb.com>
---
btf_encoder.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/btf_encoder.c b/btf_encoder.c
index 40f6aa3..2f1f4ae 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -1437,19 +1437,25 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu)
}
cu__for_each_type(cu, core_id, pos) {
+ const char *tag_name = "typedef";
struct namespace *ns;
- if (pos->tag != DW_TAG_structure_type && pos->tag != DW_TAG_union_type)
+ if (pos->tag != DW_TAG_structure_type && pos->tag != DW_TAG_union_type &&
+ pos->tag != DW_TAG_typedef)
continue;
+ if (pos->tag == DW_TAG_structure_type)
+ tag_name = "struct";
+ else if (pos->tag == DW_TAG_union_type)
+ tag_name = "union";
+
btf_type_id = type_id_off + core_id;
ns = tag__namespace(pos);
list_for_each_entry(annot, &ns->annots, node) {
tag_type_id = btf_encoder__add_decl_tag(encoder, annot->value, btf_type_id, annot->component_idx);
if (tag_type_id < 0) {
fprintf(stderr, "error: failed to encode tag '%s' to %s '%s' with component_idx %d\n",
- annot->value, pos->tag == DW_TAG_structure_type ? "struct" : "union",
- namespace__name(ns), annot->component_idx);
+ annot->value, tag_name, namespace__name(ns), annot->component_idx);
goto out;
}
}
--
2.30.2
next prev parent reply other threads:[~2021-10-27 23:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-27 23:08 [PATCH dwarves 0/2] btf: support typedef DW_TAG_LLVM_annotation Yonghong Song
2021-10-27 23:08 ` [PATCH dwarves 1/2] dwarf_loader: " Yonghong Song
2021-10-27 23:08 ` Yonghong Song [this message]
2021-11-02 2:58 ` [PATCH dwarves 2/2] btf_encoder: generate BTF_KIND_DECL_TAGs for typedef btf_decl_tag attributes Andrii Nakryiko
2021-11-02 23:21 ` Yonghong Song
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