On Wed, Oct 11, 2023 at 10:17:31AM +0100, Alan Maguire wrote:
SNIP
> +#define BTF_FEATURE(name, alias, skip) \
> + { #name, #alias, offsetof(struct conf_load, alias), skip }
> +
> +struct btf_feature {
> + const char *name;
> + const char *option_alias;
> + size_t conf_load_offset;
> + bool skip;
> +} btf_features[] = {
> + BTF_FEATURE(encode_force, btf_encode_force, false),
> + BTF_FEATURE(var, skip_encoding_btf_vars, true),
> + BTF_FEATURE(float, btf_gen_floats, false),
> + BTF_FEATURE(decl_tag, skip_encoding_btf_decl_tag, true),
> + BTF_FEATURE(type_tag, skip_encoding_btf_type_tag, true),
> + BTF_FEATURE(enum64, skip_encoding_btf_enum64, true),
> + BTF_FEATURE(optimized, btf_gen_optimized, false),
> + /* the "skip" in skip_encoding_btf_inconsistent_proto is misleading
> + * here; this is a positive feature to ensure consistency of
> + * representation rather than a negative option which we want
> + * to invert. So as a result, "skip" is false here.
> + */
> + BTF_FEATURE(consistent, skip_encoding_btf_inconsistent_proto, false),
> +};
> +
> +#define BTF_MAX_FEATURES 32
> +#define BTF_MAX_FEATURE_STR 256
> +
> +/* Translate --btf_features=feature1[,feature2] into conf_load values.
> + * Explicitly ignores unrecognized features to allow future specification
> + * of new opt-in features.
> + */
> +static void parse_btf_features(const char *features, struct conf_load *conf_load)
> +{
> + char *feature_list[BTF_MAX_FEATURES] = {};
> + char f[BTF_MAX_FEATURE_STR];
> + bool encode_all = false;
> + int i, j, n = 0;
> +
> + strncpy(f, features, sizeof(f));
> +
> + if (strcmp(features, "all") == 0) {
> + encode_all = true;
> + } else {
> + char *saveptr = NULL, *s = f, *t;
> +
> + while ((t = strtok_r(s, ",", &saveptr)) != NULL) {
> + s = NULL;
> + feature_list[n++] = t;
> + }
> + }
> +
> + for (i = 0; i < ARRAY_SIZE(btf_features); i++) {
> + bool *bval = (bool *)(((void *)conf_load) + btf_features[i].conf_load_offset);
nit, would it be easier to have btf_features defined inside the function
and pass specific bool pointers directly to BTF_FEATURE macro?
jirka
> + bool match = encode_all;
> +
> + if (!match) {
> + for (j = 0; j < n; j++) {
> + if (strcmp(feature_list[j], btf_features[i].name) == 0) {
> + match = true;
> + break;
> + }
> + }
> + }
> + if (match)
> + *bval = btf_features[i].skip ? false : true;
> + }
> +}
>
> static const struct argp_option pahole__options[] = {
> {
> @@ -1651,6 +1728,12 @@ static const struct argp_option pahole__options[] = {
> .key = ARGP_skip_encoding_btf_inconsistent_proto,
> .doc = "Skip functions that have multiple inconsistent function prototypes sharing the same name, or that use unexpected registers for parameter values."
> },
> + {
> + .name = "btf_features",
> + .key = ARGP_btf_features,
> + .arg = "FEATURE_LIST",
> + .doc = "Specify supported BTF features in FEATURE_LIST or 'all' for all supported features. See the pahole manual page for the list of supported features."
> + },
> {
> .name = NULL,
> }
> @@ -1796,7 +1879,7 @@ static error_t pahole__options_parser(int key, char *arg,
> case ARGP_btf_gen_floats:
> conf_load.btf_gen_floats = true; break;
> case ARGP_btf_gen_all:
> - conf_load.btf_gen_floats = true; break;
> + parse_btf_features("all", &conf_load); break;
> case ARGP_with_flexible_array:
> show_with_flexible_array = true; break;
> case ARGP_prettify_input_filename:
> @@ -1826,6 +1909,8 @@ static error_t pahole__options_parser(int key, char *arg,
> conf_load.btf_gen_optimized = true; break;
> case ARGP_skip_encoding_btf_inconsistent_proto:
> conf_load.skip_encoding_btf_inconsistent_proto = true; break;
> + case ARGP_btf_features:
> + parse_btf_features(arg, &conf_load); break;
> default:
> return ARGP_ERR_UNKNOWN;
> }
> --
> 2.31.1
>
