From ec62499774c4bcac720706018385ced0c1f060ab Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 2 Nov 2021 16:35:10 -0700 Subject: [PATCH] btf_encoder: generate BTF_KIND_DECL_TAGs for typedef btf_decl_tag attributes 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 Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Daniel Borkmann Cc: bpf@vger.kernel.org Cc: dwarves@vger.kernel.org Cc: kernel-team@fb.com Signed-off-by: Arnaldo Carvalho de Melo --- btf_encoder.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/btf_encoder.c b/btf_encoder.c index 40f6aa3..117656e 100644 --- a/btf_encoder.c +++ b/btf_encoder.c @@ -1438,9 +1438,21 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu) cu__for_each_type(cu, core_id, pos) { struct namespace *ns; + const char *tag_name; - if (pos->tag != DW_TAG_structure_type && pos->tag != DW_TAG_union_type) + switch (pos->tag) { + case DW_TAG_structure_type: + tag_name = "struct"; + break; + case DW_TAG_union_type: + tag_name = "union"; + break; + case DW_TAG_typedef: + tag_name = "typedef"; + break; + default: continue; + } btf_type_id = type_id_off + core_id; ns = tag__namespace(pos); @@ -1448,8 +1460,7 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu) 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; } }