Add encoding of DWARF's DW_TAG_subprogram_type into BTF's BTF_KIND_FUNC
(plus corresponding BTF_KIND_FUNC_PROTO). Only exported functions are
converted for now. This allows to capture all the exported kernel functions,
same subset that's exposed through /proc/kallsyms.
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Tested-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
---
btf_encoder.c | 16 ++++++++++++++++
dwarf_loader.c | 1 +
dwarves.h | 1 +
3 files changed, 18 insertions(+)
diff --git a/btf_encoder.c b/btf_encoder.c
index f85b978a3981..df16ba0ae98e 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -173,6 +173,7 @@ int cu__encode_btf(struct cu *cu, int verbose)
bool add_index_type = false;
uint32_t type_id_off;
uint32_t core_id;
+ struct function *fn;
struct tag *pos;
int err = 0;
@@ -225,6 +226,21 @@ int cu__encode_btf(struct cu *cu, int verbose)
btf_elf__add_base_type(btfe, &bt);
}
+ cu__for_each_function(cu, core_id, fn) {
+ int btf_fnproto_id, btf_fn_id;
+
+ if (fn->declaration || !fn->external)
+ continue;
+
+ btf_fnproto_id = btf_elf__add_func_proto(btfe, &fn->proto, type_id_off);
+ btf_fn_id = btf_elf__add_ref_type(btfe, BTF_KIND_FUNC, btf_fnproto_id, fn->name, false);
+ if (btf_fnproto_id < 0 || btf_fn_id < 0) {
+ err = -1;
+ printf("error: failed to encode function '%s'\n", function__name(fn, cu));
+ goto out;
+ }
+ }
+
out:
if (err)
btf_elf__delete(btfe);
diff --git a/dwarf_loader.c b/dwarf_loader.c
index 4c6783b9af7e..09edcfb91bf0 100644
--- a/dwarf_loader.c
+++ b/dwarf_loader.c
@@ -920,6 +920,7 @@ static struct function *function__new(Dwarf_Die *die, struct cu *cu)
func->name = strings__add(strings, attr_string(die, DW_AT_name));
func->linkage_name = strings__add(strings, attr_string(die, DW_AT_MIPS_linkage_name));
func->inlined = attr_numeric(die, DW_AT_inline);
+ func->declaration = dwarf_hasattr(die, DW_AT_declaration);
func->external = dwarf_hasattr(die, DW_AT_external);
func->abstract_origin = dwarf_hasattr(die, DW_AT_abstract_origin);
dwarf_tag__set_spec(func->proto.tag.priv,
diff --git a/dwarves.h b/dwarves.h
index b162e751cc99..b53bdfc2bca9 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -784,6 +784,7 @@ struct function {
uint8_t external:1;
uint8_t accessibility:2; /* DW_ACCESS_{public,protected,private} */
uint8_t virtuality:2; /* DW_VIRTUALITY_{none,virtual,pure_virtual} */
+ uint8_t declaration:1;
int32_t vtable_entry;
struct list_head vtable_node;
/* fields used by tools */
--
2.17.1
