static void btf_dump_emit_type()

in third/libbpf/src/btf_dump.c [680:825]

• 111 lines of code
• 34 McCabe index (conditional complexity)

static void btf_dump_emit_type(struct btf_dump *d, __u32 id, __u32 cont_id)
{
	struct btf_dump_type_aux_state *tstate = &d->type_states[id];
	bool top_level_def = cont_id == 0;
	const struct btf_type *t;
	__u16 kind;

	if (tstate->emit_state == EMITTED)
		return;

	t = btf__type_by_id(d->btf, id);
	kind = btf_kind(t);

	if (tstate->emit_state == EMITTING) {
		if (tstate->fwd_emitted)
			return;

		switch (kind) {
		case BTF_KIND_STRUCT:
		case BTF_KIND_UNION:
			/*
			 * if we are referencing a struct/union that we are
			 * part of - then no need for fwd declaration
			 */
			if (id == cont_id)
				return;
			if (t->name_off == 0) {
				pr_warn("anonymous struct/union loop, id:[%u]\n",
					id);
				return;
			}
			btf_dump_emit_struct_fwd(d, id, t);
			btf_dump_printf(d, ";\n\n");
			tstate->fwd_emitted = 1;
			break;
		case BTF_KIND_TYPEDEF:
			/*
			 * for typedef fwd_emitted means typedef definition
			 * was emitted, but it can be used only for "weak"
			 * references through pointer only, not for embedding
			 */
			if (!btf_dump_is_blacklisted(d, id)) {
				btf_dump_emit_typedef_def(d, id, t, 0);
				btf_dump_printf(d, ";\n\n");
			}
			tstate->fwd_emitted = 1;
			break;
		default:
			break;
		}

		return;
	}

	switch (kind) {
	case BTF_KIND_INT:
		/* Emit type alias definitions if necessary */
		btf_dump_emit_missing_aliases(d, id, t);

		tstate->emit_state = EMITTED;
		break;
	case BTF_KIND_ENUM:
		if (top_level_def) {
			btf_dump_emit_enum_def(d, id, t, 0);
			btf_dump_printf(d, ";\n\n");
		}
		tstate->emit_state = EMITTED;
		break;
	case BTF_KIND_PTR:
	case BTF_KIND_VOLATILE:
	case BTF_KIND_CONST:
	case BTF_KIND_RESTRICT:
	case BTF_KIND_TYPE_TAG:
		btf_dump_emit_type(d, t->type, cont_id);
		break;
	case BTF_KIND_ARRAY:
		btf_dump_emit_type(d, btf_array(t)->type, cont_id);
		break;
	case BTF_KIND_FWD:
		btf_dump_emit_fwd_def(d, id, t);
		btf_dump_printf(d, ";\n\n");
		tstate->emit_state = EMITTED;
		break;
	case BTF_KIND_TYPEDEF:
		tstate->emit_state = EMITTING;
		btf_dump_emit_type(d, t->type, id);
		/*
		 * typedef can server as both definition and forward
		 * declaration; at this stage someone depends on
		 * typedef as a forward declaration (refers to it
		 * through pointer), so unless we already did it,
		 * emit typedef as a forward declaration
		 */
		if (!tstate->fwd_emitted && !btf_dump_is_blacklisted(d, id)) {
			btf_dump_emit_typedef_def(d, id, t, 0);
			btf_dump_printf(d, ";\n\n");
		}
		tstate->emit_state = EMITTED;
		break;
	case BTF_KIND_STRUCT:
	case BTF_KIND_UNION:
		tstate->emit_state = EMITTING;
		/* if it's a top-level struct/union definition or struct/union
		 * is anonymous, then in C we'll be emitting all fields and
		 * their types (as opposed to just `struct X`), so we need to
		 * make sure that all types, referenced from struct/union
		 * members have necessary forward-declarations, where
		 * applicable
		 */
		if (top_level_def || t->name_off == 0) {
			const struct btf_member *m = btf_members(t);
			__u16 vlen = btf_vlen(t);
			int i, new_cont_id;

			new_cont_id = t->name_off == 0 ? cont_id : id;
			for (i = 0; i < vlen; i++, m++)
				btf_dump_emit_type(d, m->type, new_cont_id);
		} else if (!tstate->fwd_emitted && id != cont_id) {
			btf_dump_emit_struct_fwd(d, id, t);
			btf_dump_printf(d, ";\n\n");
			tstate->fwd_emitted = 1;
		}

		if (top_level_def) {
			btf_dump_emit_struct_def(d, id, t, 0);
			btf_dump_printf(d, ";\n\n");
			tstate->emit_state = EMITTED;
		} else {
			tstate->emit_state = NOT_EMITTED;
		}
		break;
	case BTF_KIND_FUNC_PROTO: {
		const struct btf_param *p = btf_params(t);
		__u16 n = btf_vlen(t);
		int i;

		btf_dump_emit_type(d, t->type, cont_id);
		for (i = 0; i < n; i++, p++)
			btf_dump_emit_type(d, p->type, cont_id);

		break;
	}
	default:
		break;
	}
}