On Thu, Nov 28, 2024 at 01:23:49AM +0000, Ihor Solodrai wrote:
> From: Alan Maguire <alan.maguire@xxxxxxxxxx>
>
> Currently we have two modes of function encoding; one adds functions
> based upon the first instance found and ignores inconsistent
> representations. The second saves function representations and later
> finds inconsistencies. The mode chosen is determined by
> conf_load->skip_encoding_btf_inconsistent_proto.
>
> The knock-on effect is that we need to support two modes in
> btf_encoder__add_func(); one for each case. Simplify by using
> the "save function" approach for both cases; only difference is
> that we allow inconsistent representations if
> skip_encoding_btf_inconsistent_proto is not set (it is set by default
> for upstream kernels and has been for a while).
>
> Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
jirka
> ---
> btf_encoder.c | 79 +++++++++++++++++----------------------------------
> 1 file changed, 26 insertions(+), 53 deletions(-)
>
> diff --git a/btf_encoder.c b/btf_encoder.c
> index e1adddf..98e4d7d 100644
> --- a/btf_encoder.c
> +++ b/btf_encoder.c
> @@ -88,7 +88,6 @@ struct btf_encoder_func_state {
> struct elf_function {
> const char *name;
> char *alias;
> - bool generated;
> size_t prefixlen;
> struct btf_encoder_func_state state;
> };
> @@ -120,6 +119,7 @@ struct btf_encoder {
> force,
> gen_floats,
> skip_encoding_decl_tag,
> + skip_encoding_inconsistent_proto,
> tag_kfuncs,
> gen_distilled_base;
> uint32_t array_index_id;
> @@ -1165,18 +1165,18 @@ out:
> return err;
> }
>
> -static int32_t btf_encoder__add_func(struct btf_encoder *encoder, struct function *fn,
> +static int32_t btf_encoder__add_func(struct btf_encoder *encoder,
> struct elf_function *func)
> {
> + struct btf_encoder_func_state *state = &func->state;
> int btf_fnproto_id, btf_fn_id, tag_type_id = 0;
> int16_t component_idx = -1;
> const char *name;
> const char *value;
> char tmp_value[KSYM_NAME_LEN];
> + uint16_t idx;
>
> - assert(fn != NULL || func != NULL);
> -
> - btf_fnproto_id = btf_encoder__add_func_proto(encoder, fn ? &fn->proto : NULL, func);
> + btf_fnproto_id = btf_encoder__add_func_proto(encoder, NULL, func);
> name = func->alias ?: func->name;
> if (btf_fnproto_id >= 0)
> btf_fn_id = btf_encoder__add_ref_type(encoder, BTF_KIND_FUNC, btf_fnproto_id,
> @@ -1186,40 +1186,23 @@ static int32_t btf_encoder__add_func(struct btf_encoder *encoder, struct functio
> name, btf_fnproto_id < 0 ? "proto" : "func");
> return -1;
> }
> - if (!fn) {
> - struct btf_encoder_func_state *state = &func->state;
> - uint16_t idx;
> -
> - if (state->nr_annots == 0)
> - return 0;
> + if (state->nr_annots == 0)
> + return 0;
>
> - for (idx = 0; idx < state->nr_annots; idx++) {
> - struct btf_encoder_func_annot *a = &state->annots[idx];
> + for (idx = 0; idx < state->nr_annots; idx++) {
> + struct btf_encoder_func_annot *a = &state->annots[idx];
>
> - value = btf__str_by_offset(encoder->btf, a->value);
> - /* adding BTF data may result in a mode of the
> - * value string memory, so make a temporary copy.
> - */
> - strncpy(tmp_value, value, sizeof(tmp_value) - 1);
> - component_idx = a->component_idx;
> -
> - tag_type_id = btf_encoder__add_decl_tag(encoder, tmp_value,
> - btf_fn_id, component_idx);
> - if (tag_type_id < 0)
> - break;
> - }
> - } else {
> - struct llvm_annotation *annot;
> -
> - list_for_each_entry(annot, &fn->annots, node) {
> - value = annot->value;
> - component_idx = annot->component_idx;
> + value = btf__str_by_offset(encoder->btf, a->value);
> + /* adding BTF data may result in a mode of the
> + * value string memory, so make a temporary copy.
> + */
> + strncpy(tmp_value, value, sizeof(tmp_value) - 1);
> + component_idx = a->component_idx;
>
> - tag_type_id = btf_encoder__add_decl_tag(encoder, value, btf_fn_id,
> - component_idx);
> - if (tag_type_id < 0)
> - break;
> - }
> + tag_type_id = btf_encoder__add_decl_tag(encoder, tmp_value,
> + btf_fn_id, component_idx);
> + if (tag_type_id < 0)
> + break;
> }
> if (tag_type_id < 0) {
> fprintf(stderr,
> @@ -1277,8 +1260,9 @@ static int btf_encoder__add_saved_funcs(struct btf_encoder *encoder)
> * just do not _use_ them. Only exclude functions with
> * unexpected register use or multiple inconsistent prototypes.
> */
> - if (!state->unexpected_reg && !state->inconsistent_proto) {
> - if (btf_encoder__add_func(encoder, NULL, func))
> + if (!encoder->skip_encoding_inconsistent_proto ||
> + (!state->unexpected_reg && !state->inconsistent_proto)) {
> + if (btf_encoder__add_func(encoder, func))
> return -1;
> }
> state->processed = 1;
> @@ -2339,6 +2323,7 @@ struct btf_encoder *btf_encoder__new(struct cu *cu, const char *detached_filenam
> encoder->force = conf_load->btf_encode_force;
> encoder->gen_floats = conf_load->btf_gen_floats;
> encoder->skip_encoding_decl_tag = conf_load->skip_encoding_btf_decl_tag;
> + encoder->skip_encoding_inconsistent_proto = conf_load->skip_encoding_btf_inconsistent_proto;
> encoder->tag_kfuncs = conf_load->btf_decl_tag_kfuncs;
> encoder->gen_distilled_base = conf_load->btf_gen_distilled_base;
> encoder->verbose = verbose;
> @@ -2544,7 +2529,6 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
>
> cu__for_each_function(cu, core_id, fn) {
> struct elf_function *func = NULL;
> - bool save = false;
>
> /*
> * Skip functions that:
> @@ -2566,15 +2550,8 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
>
> /* prefer exact function name match... */
> func = btf_encoder__find_function(encoder, name, 0);
> - if (func) {
> - if (func->generated)
> - continue;
> - if (conf_load->skip_encoding_btf_inconsistent_proto)
> - save = true;
> - else
> - func->generated = true;
> - } else if (encoder->functions.suffix_cnt &&
> - conf_load->btf_gen_optimized) {
> + if (!func && encoder->functions.suffix_cnt &&
> + conf_load->btf_gen_optimized) {
> /* falling back to name.isra.0 match if no exact
> * match is found; only bother if we found any
> * .suffix function names. The function
> @@ -2585,7 +2562,6 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
> func = btf_encoder__find_function(encoder, name,
> strlen(name));
> if (func) {
> - save = true;
> if (encoder->verbose)
> printf("matched function '%s' with '%s'%s\n",
> name, func->name,
> @@ -2603,10 +2579,7 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
> if (!func)
> continue;
>
> - if (save)
> - err = btf_encoder__save_func(encoder, fn, func);
> - else
> - err = btf_encoder__add_func(encoder, fn, func);
> + err = btf_encoder__save_func(encoder, fn, func);
> if (err)
> goto out;
> }
> --
> 2.47.0
>
>
