Dwarves Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH dwarves] btf_loader: handle union forward declaration properly
@ 2020-10-09 19:26 Andrii Nakryiko
  2020-10-21 15:35 ` Andrii Nakryiko
  2020-10-21 19:25 ` Arnaldo Carvalho de Melo
  0 siblings, 2 replies; 6+ messages in thread
From: Andrii Nakryiko @ 2020-10-09 19:26 UTC (permalink / raw)
  To: dwarves, acme; +Cc: bpf, kernel-team, ast, Andrii Nakryiko

Differentiate between struct and union forwards. For BTF_KIND_FWD this is
determined by kflag. So teach btf_loader to use that bit to decide whether
forward is for union or struct.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
N.B. This patch is based on top of tmp.libbtf_encoder branch.

Also seems like non-forward declared union has a slightly different
representation from struct (class). Not sure why it is so, but this change
doesn't seem to break anything.
---

 btf_loader.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/btf_loader.c b/btf_loader.c
index 9b5da3a4997a..0cb23967fec3 100644
--- a/btf_loader.c
+++ b/btf_loader.c
@@ -134,12 +134,13 @@ static struct type *type__new(uint16_t tag, strings_t name, size_t size)
 	return type;
 }
 
-static struct class *class__new(strings_t name, size_t size)
+static struct class *class__new(strings_t name, size_t size, bool is_union)
 {
 	struct class *class = tag__alloc(sizeof(*class));
+	uint32_t tag = is_union ? DW_TAG_union_type : DW_TAG_structure_type;
 
 	if (class != NULL) {
-		type__init(&class->type, DW_TAG_structure_type, name, size);
+		type__init(&class->type, tag, name, size);
 		INIT_LIST_HEAD(&class->vtable);
 	}
 
@@ -228,7 +229,7 @@ static int create_members(struct btf_elf *btfe, const struct btf_type *tp,
 
 static int create_new_class(struct btf_elf *btfe, const struct btf_type *tp, uint32_t id)
 {
-	struct class *class = class__new(tp->name_off, tp->size);
+	struct class *class = class__new(tp->name_off, tp->size, false);
 	int member_size = create_members(btfe, tp, &class->type);
 
 	if (member_size < 0)
@@ -313,7 +314,7 @@ static int create_new_subroutine_type(struct btf_elf *btfe, const struct btf_typ
 
 static int create_new_forward_decl(struct btf_elf *btfe, const struct btf_type *tp, uint32_t id)
 {
-	struct class *fwd = class__new(tp->name_off, 0);
+	struct class *fwd = class__new(tp->name_off, 0, btf_kind(tp));
 
 	if (fwd == NULL)
 		return -ENOMEM;
-- 
2.24.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, back to index

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-10-09 19:26 [PATCH dwarves] btf_loader: handle union forward declaration properly Andrii Nakryiko
2020-10-21 15:35 ` Andrii Nakryiko
2020-10-21 16:38   ` Arnaldo Carvalho de Melo
2020-10-21 19:25 ` Arnaldo Carvalho de Melo
2020-10-21 19:47   ` Andrii Nakryiko
2020-10-21 20:15     ` Arnaldo Carvalho de Melo

Dwarves Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/dwarves/0 dwarves/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dwarves dwarves/ https://lore.kernel.org/dwarves \
		dwarves@vger.kernel.org
	public-inbox-index dwarves

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.dwarves


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git