Re: [PATCH v3 dwarves 5/8] btf_encoder: Represent "."-suffixed functions (".isra.0") in BTF

[Jiri Olsa <olsajiri@gmail.com>]

On Tue, Feb 07, 2023 at 05:14:59PM +0000, Alan Maguire wrote:

SNIP

> +
>  /*
>   * This corresponds to the same macro defined in
>   * include/linux/kallsyms.h
> @@ -818,6 +901,11 @@ static int functions_cmp(const void *_a, const void *_b)
>  	const struct elf_function *a = _a;
>  	const struct elf_function *b = _b;
>  
> +	/* if search key allows prefix match, verify target has matching
> +	 * prefix len and prefix matches.
> +	 */
> +	if (a->prefixlen && a->prefixlen == b->prefixlen)
> +		return strncmp(a->name, b->name, b->prefixlen);
>  	return strcmp(a->name, b->name);
>  }
>  
> @@ -850,14 +938,22 @@ static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *
>  	}
>  
>  	encoder->functions.entries[encoder->functions.cnt].name = name;
> +	if (strchr(name, '.')) {
> +		const char *suffix = strchr(name, '.');
> +
> +		encoder->functions.suffix_cnt++;
> +		encoder->functions.entries[encoder->functions.cnt].prefixlen = suffix - name;
> +	}
>  	encoder->functions.entries[encoder->functions.cnt].generated = false;
> +	encoder->functions.entries[encoder->functions.cnt].function = NULL;

should we zero functions.state in here? next patch adds other stuff
like got_parameter_names and parameter_names in it, so looks like it
could actually matter

jirka

>  	encoder->functions.cnt++;
>  	return 0;
>  }
>  
> -static struct elf_function *btf_encoder__find_function(const struct btf_encoder *encoder, const char *name)
> +static struct elf_function *btf_encoder__find_function(const struct btf_encoder *encoder,
> +						       const char *name, size_t prefixlen)
>  {
> -	struct elf_function key = { .name = name };
> +	struct elf_function key = { .name = name, .prefixlen = prefixlen };
>  

SNIP