On Tue, Jan 24, 2023 at 01:45:31PM +0000, Alan Maguire wrote:
SNIP
> static int32_t btf_encoder__save_func(struct btf_encoder *encoder, struct function *fn)
> {
> @@ -819,13 +837,51 @@ static int32_t btf_encoder__save_func(struct btf_encoder *encoder, struct functi
> }
> /* If we find an existing entry, we want to merge observations
> * across both functions, checking that the "seen optimized-out
> - * parameters" status is reflected in our tree entry.
> + * parameters"/inconsistent proto status is reflected in tree entry.
> * If the entry is new, record encoder state required
> * to add the local function later (encoder + type_id_off)
> - * such that we can add the function later.
> + * such that we can add the function later. Parameter names are
> + * also stored in state to speed up multiple static function
> + * comparisons.
> */
> if (*nodep != fn) {
> - (*nodep)->proto.optimized_parms |= fn->proto.optimized_parms;
> + struct function *ofn = *nodep;
> +
> + ofn->proto.optimized_parms |= fn->proto.optimized_parms;
> + /* compare parameters to see if signatures match */
> +
> + if (ofn->proto.inconsistent_proto)
> + goto out;
> +
> + if (ofn->proto.nr_parms != fn->proto.nr_parms) {
> + ofn->proto.inconsistent_proto = 1;
> + goto out;
> + }
> + if (ofn->proto.nr_parms > 0) {
> + struct btf_encoder_state *state = ofn->priv;
> + const char *parameter_names[BTF_ENCODER_MAX_PARAMETERS];
> + int i;
> +
> + if (!state->got_parameter_names) {
> + parameter_names__get(&ofn->proto, BTF_ENCODER_MAX_PARAMETERS,
> + state->parameter_names);
> + state->got_parameter_names = true;
> + }
> + parameter_names__get(&fn->proto, BTF_ENCODER_MAX_PARAMETERS,
> + parameter_names);
> + for (i = 0; i < ofn->proto.nr_parms; i++) {
> + if (!state->parameter_names[i]) {
> + if (!parameter_names[i])
> + continue;
> + } else if (parameter_names[i]) {
> + if (strcmp(state->parameter_names[i],
> + parameter_names[i]) == 0)
> + continue;
I guess we can't check type easily? tag has type field,
but I'm not sure if we can get reasonable type info from that
jirka
> + }
> + ofn->proto.inconsistent_proto = 1;
> + goto out;
> + }
> + }
> } else {
> struct btf_encoder_state *state = zalloc(sizeof(*state));
>
> @@ -898,10 +954,12 @@ static void btf_encoder__add_saved_func(const void *nodep, const VISIT which,
> /* we can safely free encoder state since we visit each node once */
> free(fn->priv);
> fn->priv = NULL;
> - if (fn->proto.optimized_parms) {
> + if (fn->proto.optimized_parms || fn->proto.inconsistent_proto) {
> if (encoder->verbose)
> - printf("skipping addition of '%s' due to optimized-out parameters\n",
> - function__name(fn));
> + printf("skipping addition of '%s' due to %s\n",
> + function__name(fn),
> + fn->proto.optimized_parms ? "optimized-out parameters" :
> + "multiple inconsistent function prototypes");
> } else {
> btf_encoder__add_func(encoder, fn);
> }
> @@ -1775,6 +1833,8 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
> */
> if (fn->declaration)
> continue;
> + if (!fn->external)
> + save = true;
> if (!ftype__has_arg_names(&fn->proto))
> continue;
> if (encoder->functions.cnt) {
> @@ -1790,7 +1850,8 @@ int btf_encoder__encode_cu(struct btf_encoder *encoder, struct cu *cu, struct co
> if (func) {
> if (func->generated)
> continue;
> - func->generated = true;
> + if (!save)
> + func->generated = true;
> } else if (encoder->functions.suffix_cnt) {
> /* falling back to name.isra.0 match if no exact
> * match is found; only bother if we found any
> diff --git a/dwarves.h b/dwarves.h
> index 1ad1b3b..9b80262 100644
> --- a/dwarves.h
> +++ b/dwarves.h
> @@ -830,6 +830,7 @@ struct ftype {
> uint16_t nr_parms;
> uint8_t unspec_parms:1; /* just one bit is needed */
> uint8_t optimized_parms:1;
> + uint8_t inconsistent_proto:1;
> };
>
> static inline struct ftype *tag__ftype(const struct tag *tag)
> --
> 1.8.3.1
>
